UNIT 2 ANATOMY AND PHYSIOLOGY OF REPRODUCTIVE SYSTEM AND DEVELOPMENT OF FOETUS Structure

2.0 Objectives 2.1 Introduction 2.2 Anatomy and Physiology of Reproductive System 2.2.1 The Female Reproductive System 2.3 Menstrual Cycle 2.4 Structure and Functions of Breasts or Mammary Glands 2.4.1 External Structure 2.4.2 Internal Structures 2.5 Female Pelvis 2.5.1 The Bony Pelvis 2.5.2 Part of the Bony Pelvis 2.5.3 Diameters of the Brim 2.5.4 The Pelvic Cavity 2.6 Pelvic Floor 2.6.1 Functions of Pelvic Floor 2.6.2 Injury to Pelvic Floor During Labour 2.7 Foetal Skull 2.8 Anatomy and Physiology of Male Reproductive System 2.8.1 Structure and Functions of Male Reproductive Organs 2.8.2 Spermatogenesis 2.9 Conception 2.9.1 Definition and the Process of Fertilization 2.10 Development of Embryo 2.10.1 Development of the Fertilized Ovum 2.10.2 The Placenta 2.10.3 The Foetal Membranes 2.10.4 Liquor Amnii (Amniotic Fluid) 2.10.5 Umbilical Cord (Funis) 2.11 The Foetus, Foetal Growth and Foetal Circulation 2.12 Let us Sum Up 2.13 Answers to Check your Progress 2.14 Further Readings 2.0 OBJECTIVES

After completing this unit, you will be able to: l describe the Anatomy and Physiology of both Female and Male Reproductive systems; l discuss the structure and functions of breasts; l explain the female pelvis, pelvic floor and fetal skull and identify their significance for child birth; l describe the development of fertilized ovum; and l explain the foetal circulations and identify the normal changes at birth. 2.1 INTRODUCTION

Over the past decade the role of nurse in the care of woman and neonate has changed dramatically because of socio-economic changes, consumer’s education, scientific and 19 technological advancement. Strengthening the knowledge of reproductive health orients Maternal Health and Nursing you in anticipating problems, mastering procedures, identifying complications, responding Intervention to emergencies, reviewing laboratory investigations, planning nursing intervention for client and her family based on nursing process. Reproductive health care explores the basic health concerns that bring women into contact with health care professionals. To provide the knowledge base, it is essential to have a thorough understanding of reproductive anatomy and physiology of both female and male, conception and foetal development. 2.2 ANATOMY AND PHYSIOLOGY OF REPRODUCTIVE SYSTEM You have already learnt in General Nursing the anatomy and physiology of Reproductive System of both female and male. Let us now review the structure and functions, so that you will have deeper understanding about Reproductive Health. Within this Unit you will review your knowledge about the female organs of regeneration such as , , and . You will also learn about the menstrual cycle, the breasts. Further, you will learn about the male genito urinary organs including spermatogenesis. Let us discuss first the Female Reproductive organs. 2.2.1 The Female Reproductive System The female reproductive system consists of internal organs, located in the pelvic cavity and supported by the pelvic floor and external genitals located in the perineum. The female’s internal and external reproductive structures develop and mature in response to oestrogens and progesterone, starting in foetal life and continuing throughout puberty and the child bearing years. External Reproductive Organs The external female genitals are located in the perineum. The external structures are presented in the following orders (from anterior to posterior) l (mon veneris) l majora and (sing. Labia majus) l l Vestibule l Fourchette l Perineum External genitals are illustrated in Fig. 2.1.

Mons veneris

Labium majus

Clitoris

Vestibule Labium minus Urethral meatus Vaginal orifice Fourchette

Central part of perineum

Anus

Fig. 2.1: External female genitals 20 Mons Pubis Anatomy and Physiology of Reproductive System and The mons pubis or mons veneris is the rounded pad of subcutaneous fatty tissue and loose Development of Foetus connective tissue over the symphysis pubis. It contains many sebaceous glands and develops course dark, curly hair at puberty, about 1-2 years before the onset of menses. Menarche occurs on an average at 13 years of age. The functions of the mons are to play a role in sensuality and to protect the symphysis pubis during coitus. The labia majora are two rounded lengthwise folds of skin-covered fat and connective tissues that merge with the mons. They extend from the mons downwards round the labia minora ending in the perineum in the midline. The labia majora functions as a protection for the labia minora., urinary meatus and vaginal introitus. In the women who has never experienced vaginal childbirth, the labia majora come together in the midline, obscuring the vaginal introitus. Some labial separation and even gaping of the vaginal introitus follow childbirth and perineal or vaginal injury. The medial surface of the labia majora are smooth, thick and without hair. Labia Minora The labia minora, located between the labia majora, is narrow lengthwise folds of hairless skin extending downward from beneath the clitoris and merging with the fourchette. Whereas the lateral and anterior aspects of the labia are usually pigmented, their medial surfaces are similar to vaginal mucosa: pink and moist. Their rich vascularity gives them a reddish colour and permits marked turgescence of the labia minora. With emotional or physical stimulation the glands in the labia minora also lubricate the . A rich nerve supply make them sensitive, enhancing their erotic function. Clitoris The clitoris is a short, cylindrical, erectile organ fixed just beneath the arch of the pubis. The tip of the clitoral body is called the glans and is more sensitive than its shaft. When sexually aroused, the glans and shaft increase in size. The clitoris contains many nerve endings and is the homologue of the penis of the male. Its main function is to stimulate and elevate levels of sexual tension. Vestibule Vestibule is a triangular area between the labia minora laterally, from clitoris at the apex to fourchette anteroposterioraly. There are four openings into the vestibule: i) External urethral opening This is a midline anteroposterior slit with two lateral lips lying behind clitoris and just in front of vaginal orifice. Paraurethral ducts (Skene’s ducts) open on either side of external urethral meatus or on its posterior wall inside the orifice. ii) Vaginal orifice (introitus) It is a median slit behind urethral opening. It is completely guarded by a septum of mucous membrane called hymen. In a virgin, hymen has a small accentric opening not usually admitting the finger tip. On coitus it gets ruptured. Following child-birth per vagina hymeneal tags (crunculae myrtiformes) are visible. Hymen is composed of double layer of stratified squamous epithelium with intervening vascular connective tissues. Vaginal introitus gets dilated on coitus and childbirth. iii) Two opening of Bartholin glands ducts Bartholin glands are pea sized mucous secreting oval glands. Each gland is situated posterior to vestibule. The duct is about 2 cm long and opens in the groove between hymes and labia minora. The gland and duct are lined by single layer of columnar epithelia, except for the duct opening which is lined with stratified squamous epithelium. On sexual excitement bartholin glands secrete alkaline mucus that lubricate the vaginal introitus to facilitate coitus. The gland can become infected and lead to bartholinitis or bartholin abscess. Fourchette The fourchette is a thin, flat, transverse fold of tissue formed where the tapering labia majora and minora merge in the midline below the vaginal orifice. A small depression, the fossa naviculoris, lies between the fourchette and the hymen.

21 Maternal Health and Nursing Perineum Intervention The perineum is the skin covered muscular area between the vaginal introitus and the anus.The perineum forms the base of the perineal body. Internal Reproductive Organs Internal structure consists of: l Vagina l Uterus l Fallopian tubes l Ovaries

Fundus

Uterine tube

Ovary Fimbria of

Isthmus

Endometrium

Internal os

Vagina

Cervical canal External os

Fig. 2.2: Female internal genital organs

Vagina

The vagina is a fibromuscular distensible tube joining vestibule of vulva with Uterus. It forms the lowest vestibule of vulva with uterus. It forms the lowest part of internal genital tract to provide canal for menstrual blood outflow from the uterus, coital canal and birth canal. The vaginal canal is directed upward and backward towards sacrum making an angle of 45 degrees with horizon in erect posture of a woman.

Cervix projects into the upper end of the vagina is called a vault. The anterior wall of vagina is 7.5 cm long, posterior wall 9 cm. Four fornices are formed due to projection of uterine into the vagina–one anterior, two laterals and one posterior. Normal uterus can be palpated through fornices.

Anterior upper half of vaigna is related to base of urinary bladder and lower half with . Posteriorly lower third of vagina is related to perineum, middle third to rectovaginal septum and anterior rectal wall and upper third to Pouch of Douglas. The vagina consists of four layers: l Mucous membrane the innermost layer of stratified squamous epithelium. It has numerous rugae. l Submucous layer with vascular loose areolar tissue. l Muscular layer – inner circular – outer longitudinal 22 l Fibrous layer with rich blood supply. Vagina has rich blood supply from cervicovaginal branch of the uterine artery, vaginal Anatomy and Physiology of branches of Internal iliac artery and Internal podendal artery of internal iliac artery. Vein Reproductive System and Development of Foetus and lymphatics follow the arteries.

Pouch of douglas

Isthmus

Uterus

Rectum

Utero-vesical pouch

Urinary bladder

Vagina

Fig. 2.3: Sagittal section through internal pelvic organs

Functions – Excretory duct for menstrual blood. – Coitas canal – Helps in capacitation of sperm by supplying sperm. – Protective function – acidic vaginal secretion prevents infection. – Absorbtive function – Seminal prostaglandin are absorbed to cause contraction of myometrium and fallopian tube. – Immunological function – sperm antibody, antimicrobial antibodies. – Birth canal for delivery of baby. Uterus and its Appendages The uterus is a hollow muscular organ located centrally in the pelvic cavity. It is situated between the urinary bladder in front and rectum behind. It is anteverted inclining forward over the bladder at about right angle to the vagina and anteflexed bending slightly forward on itself at the internal os between the corpus and cervix. Size Length 7.5 cm Width 5.0 cm at the fundus Thick 2.5 cm Weight 50 gm each wall is 1.25 cm thick.

Size Nulliparous Woman Parous Woman Length 7.5 cm 8.2 cm Width at the fundus 2.5 cm 6.2 cm Each wall is thick 1.25 cm - Weight 50 gm 70-80 gm

23 Maternal Health and Nursing Intervention Fundus

5 cm

Corpus

Isthmus Internal os

Supravaginal 2.5 cm Cervix

Portio vaginalis

External os

Fig. 2.4: Parts of uterus

Parts of uterus are:

– Body of corpus – Cervix

Body of Corpus

This is broader upper 5 cm. portion of uterus. Domeshaped corpus lying above the line of attachment of fallopian tubes is:

i) Fundus: Fundus is solid and not hollowed. At upper and lateral angles of fundus called cornua. Fallopian tubes are attached one on either sides. Cavity of corpus is triangular with base at fundus communicating with the lumens of the fallopian tubes on either side and below through internal Os. ii) Isthmus: Isthmus is the lower 0.5 cm portion of corpus lying above internal Os of cervix. Isthmus forms the lower uterine segment after first trimester. Cervix (neck) Cervix is cylindrical lower 2.5 cm portion of uterus. Vagina is attached obliquely to middle of cervix thus dividing it into two halves—lower half vaginal portion and upper half supravaginal portion. Cervical canal dilates during labour to permit foetus to be delivered through vaginal canal for birth. The body of uterus has three layers: i) : Outer peritoneal coat. ii) Myometrium: Intermediate bundles of smooth muscle fibres with intervening connective tissues. During pregnancy three layers can be distinguished – outer longitudinal, middle oblique and inner circular layer. Uterine contractions control blood flow through the uterine wall. iii) : It consists of:

24 a) Surface epithelium b) Endometrial tubular glands Anatomy and Physiology of Reproductive System and c) Stroma or supporting tissue Development of Foetus

Supporting

There are four pairs of ligaments which give additional support and maintain the uterus in its forward inclination. These are: i) The two broad ligaments – continuous structure that is formed by a fold of peritoneum. ii) The two round ligaments, one on each side, are fibromuscular chords composed of muscles and small amount of connective tissues. iii) The two utero sacral ligaments, one on each side extending backward from the cervix, pass on each side of the rectum, and insert at the posterior wall of the pelvis. iv) The transverse cervical ligaments gives support to the uterus from below.

Blood supply i) Uterine artery ii) Ovarian artery

Veins – Venous channels corresponding to artery drain the uterus.

Lymphatic – Lymphatic drainage into external and internal iliac nodes.

Nerves – Uterus is supplied by symphathetic and parasympathetic nerves.

Functions of Uterus

Endometrial lining provides: – Cyclical menstrual bleeding from puberty to menopause. – Canal for transmission of sperm to lumen of fallopian tube for fertilization. – Embedding of fertilized egg on endometrium – Receptical for growing uterus. – Supplies oxygen and nutrition to foetus through placenta. – Expels foetus from to exterior through cervical and vaginal canal. – Enlarged uterus returns back to normal size after delivery to start menstrual cycles. Fallopian Tubes

Fallopian tubes are also called oviduct or uterine tubes. Fallopian tubes are paired hollow muscular one on either side of uterus. It lies at upper margin of broad ligament of the uterus. The fallopian tubes has two openings – uterine opening measuring less than 1 mm in diameter. Each fallopian tube is 10 cm long and 1 cm in breadth. It has four parts from medial to lateralward. i) Interstitial or intramural: It is the narrowest part lying in the uterine wall and measures 1.25 cm in length and its lumen 1-2 mm in diameter. ii) Isthmus: It is the straight to tortuous thick part measuring 2.5 cm in length and its lumen 1-2 mm in diameter. iii) Ampulla: It is the widest part of the tube of 5 cm in length and its lumen measuring 1-2 mm medially to 6 mm at outer end. iv) Infundibulum: It is funnel shaped open abdominal extremity measuring 1.25 cm. At the bottom of this part lies the abdominal ostium of 3 mm width. Fingerlike projections are called fibriae which are internally lined by mucous membrane. One big fimbria is applied to ovary called ovarian fimbria.

Fallopian tubes has three layers : i) Serous layer: It is the outermost layer. ii) Muscular layer: The middle layer. Further it has two layers – outer longitudinal and the inner circular. 25 Maternal Health and Nursing iii) Mucous membrane: It lines the muscular layer. It is lined with tall columnar ciliated Intervention secretory cells with intervening ciliated columnar cells. Mucous membrane is thrown into longitudinal folds which are complex at ampulla.

Interstitial Isthmus Ampulla

Abdominal Ostium Infundibulum

Tubal Isthmus (section) Fimbria

Tubal Ampulla (section) Fig. 2.5: Parts of fallopian tubes

Functions

– Fallopian tubes or oviducts transporting ovum from ovary to uterine cavity after it is being picked by the fimbrial end. Tubal transport of ovum is affected by tubal peristalsis and mucosal ciliary function. Ovum stays three days in the tube. – Tubal secretion provides media for ovum in its transport and nourishment. – Fertilization of ovum takes place in ampulla and fertilized ovum is transported to the uterus. The Ovary The ovaries are the female sex glands (gonads) producing ovum and sex hormones during reproductive period of a woman. The ovary is a solid flat ovoid gland measuring 3 cm in length, 2 cm in breadth and 1cm in thickness. Each ovary weighs 5-10 gm during reproductive period. It is an intra peritoneal gland without peritoneal covering. It is attached to the posterior layer of broad ligaments by mesovarian and is suspended from uterine cornua by . It consists of : – cortex – medulla – hilum Cortex Cortex is composed of highly cellular spindle shaped cells supporting ovarian follicles except at the hilum. The graafian follicles are oestrogen – progesterone and ovum producing functional units that lie scattered in the cortex. All forms of graafian follicles at different stages can be seen as: 1) Primordial follicles: Newborn ovaries contain about 2 million primordial follicles. At puberty 40,000 primordial follicles remain in ovaries and rest undergoes atresia. Around 400 follicles ovulate in 30 years of woman’s reproductive life from puberty to menopause. 2) Primary follicles: Twenty in number grow in a menstrual cycle from primordial follicles in both ovaries. In the primary follicle a coat of poly saccharide develops around primary oocyte called . Granulosa cells proliferate around zona 26 pellucida to form . Around proliferating granulosa, cell layer develops a layer of vascular stromal layer called . Anatomy and Physiology of Follicle beginning of Reproductive System and antrum formation Development of Foetus Developing Mature Follicle Germinal Primary Follicle Epithelium

Ovum

Ruptured Follicle

Corpus albicans

Theca Internal Young corpus Luteum Theca external Corpus Luteum (fully formed) Fig. 2.6: The structure of ovary 3) Secondary follicle: Develops with proliferated granulose cell mass around oocyte and formation of fluid filled spaces antrum follicali. Ovarian follicle with antrum is called graafian follicle. 4) Tertiary follicle: Single dominant follicle grows to 16.25 mm in size. The tertiary follicle contains: a) Mature secondary oocyte is called ovum. b) A mass of granulose cells grow around ovum is called discus proligerus. Granulosa cells lying close to ovum are arranged in radial fashion called corona radiata. Discus proligerus remain at one side of the antrum. c) Wall of antrum is formed by layers of granulose cells – Membrana granulose. d) Theca Interna – a vascular layer of ovarian stroma surrounding the cystic follicle and fibrous theca external layer around theca interna.

Ovum

Nucleus Zona pellucida

Corona radiata

Cumulus oophours

Membrana granulosa

Theca Interna Fig. 2.7: Structure of graafian follicle 27 Maternal Health and Nursing Granulosa cells in maturing graafian follicle develop receptors of follicle stimulating Intervention hormone (FSH) of anterior pituitary gland. FSH hormone causes proliferation of granulose cells in ovarian follicle. The dominant follicle discharges ovum (ovulation) on the ovarial surface. Ovum is picked up by tubal fimbria and it gets fertilized by sperm at tubal ampulla. Oestrogen is secreted by graafian follicle. Corpus Luteum is formed out of shell of ruptured Graafian folicle. Corpus Luteum matures on19th day, retain its maturity for 26 days. It measures 1-2 cm and secretes progesterone. Normal functional life of corpus luteum is 12-14 days. If pregnancy does not occur, corpus luteum regresses on 27th or 28th day with falling of progesterone and oestradiol levels in blood. Corpus luteum finally degenerates to form hyaline mass called in the .

The ovum gets disintegrated in fallopian tube within 24-48 hours if unfertilized. In pregnancy, corpus luteum is maintained as corpus luteum of pregnancy.

Functions of Ovary

l During reproductive period, the ovary discharges mature ovum at each menstrual cycle. l Produces sex hormones – oestrogens and progesterone to prepare uterine endometrium for embedding of fertilized ovum. 2.3 MENSTRUAL CYCLE

As you have now reviewed about the female external and internal structures of reproduction, we will now discuss about the menstrual cycle; what it is and how does it take place? Definition Menstruation is monthly uterine bleeding for 4-5 days in 28 days cycle during reproductive life of a woman from menarche to menopause. Menses are normal uterine function whereby endometrium prepares itself to receive the fertilized ovum. In the event of fertilization of the ovum on meeting a sperm, conception takes place and there is no monthly bleeding. Bleeding comes from oestrogen-progesterone primed endometrium. Woman gets 13 menses in a year and around 400 menses in her reproductive life. The menstrual cycle of 28 days starts on day of onset of menstruation and ends at day 28 on start of next menstruation. Ovarian Cycle Ovarian follicles (20 in number) are grown in a menstrual cycle in three steps. a) Ovarian Follicles are grown from primordial follicles. A single graafian follicle matures and becomes dominant by the effect of FSH while other follicles regress. b) Oestradel is secreted by maturing ovarian follicle in the circulation – stimulates hypothalamus and anterior pituitary to cause surge of LH and FSH hormones in blood on 12th day of menstrual cycle. c) Ovulation occurs on 14th day of menstrual cycle. Corpus luteum is in the mature graafian follicle following ovulation due to LH effect.

Corpus luteum remains mature from 19th to 26th day, then it degenerates on 27th or 28th day if no pregnancy occurs in menstrual cycle.

Uterine Cycle

a) Proliferative phase: Oestradiol from ovarian follicles causes proliferative changes in endometrium (7-10 day) b) Secretory phase: Progesterone from Corpus luteum causes secretary changes in endometrium to receive fertilized ovum for embedding. c) Menstural bleeding: Occurs for 4-5 days due to shedding away of endometrial bits and bleeding from endometrial bed. Menstrual phase is caused by withdrawal of oestradiol and progesterone support to endometrium.

28 Anatomy and Physiology of Reproductive System and Development of Foetus

Cerebral Cortex Aminergic neuron

Hypothalamus Peptidergic neuron

Ant. pituitary

FSH LH

Ovarian Cycle

Graafian Follicle Ovulation Corpus Luteum progesterone Oestradiol

1 Days 4 Proliferative 14 21 28 Menstruation Endometrial Cycle Fig. 2.8: Menstrual cycle, FSH (follicle stimulating hormone), LH (leutinising hormone) 2.4 STRUCTURE AND FUNCTIONS OF BREASTS OR MAMMARY GLANDS

As you have learnt about the female internal and external organs of reproduction and menstrual cycle, we will now acquaint with the structures of breasts which are very important accessory organs of reproductions.

Breasts are the accessory glands. Their functions are associated with reproduction. Breasts develop at puberty and lactation occur in response to high level of female hormones. The breasts are abundant with nerves and are sensitive to pressure.

The breast of a woman who has never given birth to a child are conic or hemispherical in form; shape and size vary among women and at different ages. The breasts of woman who has one or more babies tend to become pendulous. Certain exercises can aid in restoring the tone of breast tissue after lactation has been terminated. 2.4.1 External Structure

The soft, smooth skin surface surrounding the circumference of the gland to the areola.

Areola: Pigmentation of the areolae varies from pink to brown. The surface of each areola is roughed by small, fine lumps of papillae known as montgomery’s tubercles. Hormonal influences in pregnancy cause the areola to darken. Often this darkening is a presumptive sign of pregnancy in primigravida.

Nipple: The nipples are composed of sensitive erectile tissue. They form large, conic papilla projecting from the center of the areola. The openings of the milk ducts are the summit of each nipple. 2.4.2 Internal Structures

The breasts are composed of glandular tissue and fat. Each organ is divided into 15-20 lobes, which are separated by fibrous and fatty walls. Each lobe is subdivided into many lobules (alveolar glands) which contain numerous acini cells.

Acini cells comprise a single layer of epithelium, beneath which is a small amount of connective tissue richly supplied with capillaries. Milk secretion begins in the acini cells. 29 Maternal Health and Nursing As the lactiferous ducts leading from the alveoli approach the nipple, they dilate to form Intervention little reservoirs in which milk is stored. They narrow again as they pass into the nipple. Size of the breasts is not predictive to a women’s ability to produce adequate amounts of milk to nurse her infant successfully.

Blood supply – Internal mammary and intercostals arteries. – Mammary veins follow these arteries.

Clavic

Pectoralis minor muscles

Dust

Lactiferous dust

Alveoli (glands) Nipple Areola Pectoralis major muscles

Fat lobules Fifth rib

Intercostal muscles

Ampulla

Fig. 2.9: Structure of breast

Check Your Progress 1

1) List the internal organs of female reproductive system...... 2) Fill in the blanks. a) The Mons pubis is a rounded pad of ...... fatty tissue. b) The ...... surface of labia majora are smooth, thick and without hair. c) The triangular area from clitoris to fourchatte is termed as the ...... d) Inflammation of the gland situated posterior to vestibule is called ...... e) The broader upper 5 cm portion of uterus is ...... 3) State true or false. a) Perimetrium is outer coat of the uterus. (T/F) b) Blood supply to the uterus is only from uterine artery. (T/F) c) Funnel shaped part of the fallopian tubes is ampulla. (T/F) d) Medulla of ovary is composed of highly cellular spindle shaped cells supporting ovarian follicles. (T/F) e) Progesterone is secreted by ovary. (T/F)

30 4) Define Menstruation Anatomy and Physiology of Reproductive System and ...... Development of Foetus ...... 2.5 FEMALE PELVIS

The pelvis has been classified into four types according to the shape of the brim (Fig. 2.10).

Anthropoid

Gynaecoid Android

Platypelloid (flat)

Fig. 2.10: Characteristic inlet of the four types of pelvis l The gynaecoid or female pelvis has round brim l The android pelvis has a heart shaped brim (male pelvis) l Anthropoid pelvis has an oval brim l The platepelloid pelvis or simple flat pelvis has a kidney shaped brim narrow in the anteroposterior diameter.

We will discuss here only Gynaecoid pelvis as it is of obstetrical importance. The bony pelvis anteriorly is filled up with maternal soft tissues such as muscles ligaments and etc. During the process of delivery birth canal dilates and the foetus passes through the true pelvis. A knowledge of pelvic anatomy is needed for the conduction of labour. Progress of labour is estimated by assessing the relationship of the foetus to certain pelvic landmarks. You must be competent to recognize a normal pelvis in order to be able to detect deviations from normal and refer them to doctor. 31 Maternal Health and Nursing 2.5.1 The Bony Pelvis Intervention The pelvis is composed of four bones:

– Two Innominate or hip bones – One Sacrum – One Coccyx

a) Innominate Bone

Each innominate bone is composed of three parts. The ilium is the large flared out part. At the front of the iliac crest can be felt a bony prominence known as the anterior superior iliac spine. A short distance below it is the anterior inferior iliac spine. There are two similar points at the other end of the iliac creast, namely the posterior superior and the posterior inferior iliac spines. The concave anterior surface of the illium is the iliac fossa.

The Ischium is the thick lowest part. It has a large prominence known as the ischial tuberosity on which the body rests when sitting. In labour the station of the foetal head is estimated in relation to the ischial spines.

The Pubic bone forms the anterior part. It has a body and two rami–the superior and inferior. The two pubic bones meet at the symphysis pubis and two inferior rami form the pubic arch, merging into a similar ramus on the ischium.

On the lower border of the innominate bone are found two curves the greater sciatic notch and the lesser sciatic notch.

Crest of Ilium

Anterior superior Posterior superior iliac spine iliac spine

Posterior inferior iliac spine Greater sciatic notch

Ischial spine

Lesser sciatic notch Symphysis pubis

Ischial tuberosity Inferior ramus of pubic bone

Obturator foramen Inferior ramus of ischium

Fig. 2.11: Innominate bone showing important landmarks

b) The Sacrum

The Sacrum is a wedge shaped bone consisting of five fused vertebrae. The upper border of the first sacral vertebra projects forward and is known as the sacral promontory. The anterior surface of the sacrum is concave and is referred as the hollow of the sacrum. It has two wings or ala. Nerves from the cauda equina emerge to supply the pelvic organs. The 32 posterior surface is roughened to receive attachments of muscles. c) The Coccyx Anatomy and Physiology of Reproductive System and It consists of four fused vertebrae, forming a small triangular bone. Development of Foetus

Pelvic Joints

– The Symphysis pubis – 1 – The Sacroiliac joints – 2 – The Sacrococcygeal joints – 2

During pregnancy endocrine activity causes the ligaments to soften to provide more room for the foetal head as it passes through the pelvis.

Pelvic Ligaments

Each of the pelvic joint is held together by ligaments: These are:

– Interpubic ligament – Sacroiliac ligaments – Sacrococcygeal ligament – Sacrotuberous ligament – Sacrospinous ligament

Iliac crest

Posterior superior iliac spine

Sacrospinous ligament Ischial spine Sacrotuberous ligament

Fig. 2.12: Posterior view of the pelvis to show ligaments 2.5.2 Parts of Pelvis

The pelvis is divided in two sections: i) The False Pelvis It is shallow and basin shaped lies above the brim and varies considerably in size in different women and of no obstetrical importance. ii) The True Pelvis

It plays a significant role in childbirth and consists of brim, cavity and outlet.

The brim is round except where the sacropromontory projects into it. The important landmarks are:

– Sacral promontory – Sacral ala or wing – Sacroiliac joint – Iliopectineal line which is the edge formed at the inward aspects of the illium. – Iliopectineal eminence which is a roughened area formed where the superior ramus of the pubic bone meets the illium. 33 Maternal Health and Nursing – Superior ramus of the pubic bone Intervention – Upper inner border of the pubic bone – Upper inner border of the symphysis pubis.

Right

Oblique Post Trans Verse Oblique Left Ant

Fig. 2.13: View of pelvic inlet showing diameters 2.5.3 Diameters of the Brim

Three diameters are measured as given below:

i) Antero Posterior Diameter is the line from the sacral promontory to the upper border of the symphysis pubis. When the line is taken to the uppermost point of the symphysis pubis it is called Anatomical Conjugate and measures 12 cm; when it is taken to the posterior border of the upper surface, which is about 1.25 cm lower, it is called Obstetrical Conjugate and measures 11 cm. The reason for this is that the obstetrical conjugate represents the available space for the passage of the foetus. The term true conjugate may be used to refer to either of these measurements and the midwife should take care to establish which is meant. Diagonal Conjugate measures 12-13 cm. is measured antroposteriorly from the lower border of the symphysis to the sacral promontory. It may be estimated per vagina as part of pelvic assessment. It is measured when sacral promontory can be palpated in sub normal pelvis. The depth of introduction of fingers from under surface of symphysis pubis is measured by pelvimeter (or) caliber on withdrawal of fingers. If it is measured less than 12-13 cm, we can suspect the other anteroposterior diameter of inlet won’t be in normal measurement.

Anatomical or true conjugate

Obstetrical Conjugate Internal or Diagonal Conjugate

Obstetrical Anatomical Post of outlet

Fig. 2.14: Median section of the pelvis showing antero posterior diameter

ii) The Oblique diameter measures 12 cm. It is measured from one sacroiliac joint to opposite iliopectineal eminence. Right oblique is taken from Right sacro iliac joint to left iliopectineal eminence and vice-versa. 34 iii) The Transverse diameter measures 13 cm. It is the maximum distance between Anatomy and Physiology of farthest apart points on the ilio-pectineal eminence. This diameter lies close to sacral Reproductive System and Development of Foetus promontory (at a distance of 4 cm) than symphysis pubis. 2.5.4 The Pelvic Cavity

The cavity extends from the brim above to the outlet below. The anterior wall is formed by the pubic bones and symphysis pubis and its depth is 4 cm. The posterior wall is formed by the curve of the sacrum which is 12 cm in length. The cavity forms a curved canal. The cavity is circular in shape. All the diameters are considered 12 cm.

The Pelivic Outlet

Two outlets are described – the anatomical and the obstetrical. The anatomical outlet is formed by the lower borders of each of the bones together with the sacrotuberous ligament. The obstetrical outlet is of greater practical significance because it includes the narrow pelvic strait through which the foetus must pass. Its three diameters are as follows :

The antroposterior diameter – 13 cm The oblique diameter – 12 cm The transverse diameter – 11 cm

Antero-posterior Oblique Transverse

11 12 13 Brim

Cavity 12 12 12

Outlet 13 12 11

Fig. 2.15: The pelvic measurements

Pelvic Inclination

When a woman is standing in the upright position, her pelvis is on an incline. It would form an angle of 60 degrees with the floor, at the center of symphysis pubis 30 degrees and at the outlet 15 degrees. 2.6 PELVIC FLOOR

Soft tissues which fill the outlet of the pelvis is called pelvic floor. Through it passes the urethra, vagina and anal canal. Pelvic floor is mainly made up of muscular tissue but skin, fat, fascia and connective tissue go to form this structure which fills in the irregular-shaped pelvic outlet. 35 Maternal Health and Nursing Muscles of pelvic floor consists of: Intervention – Superficial muscles, and – Deep muscles.

Superficial Muscles

The superficial layer is composed of five muscles:

– The external anal sphineter surrounding the anus. – The Transverse perineal muscles pass from the ischial tuberosities to the center of the perineum. – The bulbo cavernous muscles pass from the perineum forward around the vagina. – Ischio cavernous muscles pass from ischial tuberosities along the pubic arch. – The membraneous sphincter of the urethra is composed of muscle fibres passing above and below the urethra and attached to the pubic bones.

Symphysis pubis Membranous sphincter of the urethra Clitoris Ischiocavenosus

Bulbocavenosus Urethral orifice Vaginal orifice Transverse perineal muscle Triangular ligament

External anal Anus Ischial tuberosity sphincter

Coccyx

Fig. 2.16: The Pelvic floor – superficial structures

Deep Muscles

These are three pairs of muscles which together are known as the levator Ani muscles. Each levator ani muscle consists of the following:

– The pubococcygeus muscle – The iliococcygeus muscle – The Ischio coccygeus muscle

The levator ani muscle, by their mode of attachment to the pelvic, act like a sting or hammock. In front they are attached to the lateral part of the os pubis, behind to the ischeal spines and coccyx and laterally to the fascia. The three levator ani muscles meet to form a gutter which slopes forward and is perforated by three canals, i.e. urethra, vagina and rectum. (Fig. 2.17) 2.6.1 Functions of Pelvic Floor

l The pelvic floor supports the weight of abdominal and pelvic organs. l Its muscles are responsible for voluntary control of micturition and defaccation. l Play an important part in sexual intercourse. l During child birth it influences the passive movements of the foetus through the birth canal and relaxes to allow its exit from the pelvis. 36 Anatomy and Physiology of Reproductive System and Clitoris Development of Foetus

Urethral orifice Ischio-cavernosus

Vaginal orifice Bulbo-cavernosus

Levator ani and Transvarso perinel coceygeus muscles

Anus

Anal sphincter Gluteus maximus

Fig. 2.17: Deep muscles of the pelvic floor 2.6.2 Injury to Pelvic Floor During Labour

Under the influence of hormones the pelvic floor softens in preparation for labour during the last weeks of pregnancy. If the woman bears down during first stage of labour the paracervical tissue and transverse cervical ligaments will be subjected to excessive strain. The uterus may then sag downwards and become retroverted. The stress to which the pelvic floor is subjected during second stage of labour may be very great and if the second stage is unduly prolonged then the fascia supporting the bladder may become overstretched which results in subsequent prolapse of anterior vaginal wall forming a sac containing the bladder known as cystoceli. When the head is on perineum too long, the excessive strain that this structure undergoes will give rise to a lax, sagging pelvic floor resulting in weak inadequate support to the pelvic organ.

The nurse midwife who is attending to the mother in labour need to have adequate knowledge and skill for conducting a delivery, so that she can prevent injury to pelvic floor.

2.7 FOETAL SKULL

The foetal skull consists of: – Vault, and – Base Bones of foetal head are compressible, thus facilitate in easy delivery while head passing through the birth passage in second stage of delivery.

Landmarks of Foetal Skull l Occiput l Sinciput – is the forehead l Parietal eminences – are eminences of parietal bones on either side l Mentum is the chin l Vertical point is the center of sagittal suture l Frontal point is the root of the nose is called glabella l Subocciput is the junction of foetal neck and occiput (nape of neck) l Submentum is the junction between neck and chin l Biparietal is the transverse distance between two parietal eminences l Bitemporal is the distance between two lower ends of coronal sature. 37 Maternal Health and Nursing Sutures and Fontanelles Intervention Sutures Sutures are junctions of edges of two or more bones. Fontanelles are membraneous space formed by unossified membrane separating edges of bones of foetal skull.

There are four important sutures on foetal skull:

– Sagittal suture – Frontal suture – Coronal suture – Lambdoidal suture

Fontanelles

l Anterior Fontanelle or Bregma: It is diamond shaped of unossified membrane. It is the junction of frontal, coronal (left and right) and sagittal sutures. It ossifies after 18 months after birth.

l Posterior Fontanelle or Lambda: It is triangular suture line at junction of sagittal and lambdoidal suture.

Occipital

Lambdoidal Suture Posterior Fontanelle

Sagittal Suture

R. Parietal L. Parietal

Anterior Fontanelle Coronal Suture

½ Frontal ½ Frontal

Frontal Suture

Fig. 2.18: Foetal head showing sutures and fontanelle

Clinical Importance of Sutures and Fontanelle

1) Palpation of sagittal suture with fontanelle in labour can identify Vertex Presentation. Position of fontanelles and sagittal suture can identify attitude and position of vertex.

2) Overlapping of cranial bones at sutures signifies moulding of foetal head.

Regions of Foetal Skull

– Vertex

– Face

– Brow 38 Diameter of Foetal Skull Anatomy and Physiology of Reproductive System and Development of Foetus Diameter Length of diameter Presentation

Suboccipito bregmatic 9.5 cm Vertex (fully flexed) Suboccipito frontal 10 cm Vertex (deflexed head) Occipito frontal 11.4 cm Vertex (extreme extension) Submentobregmatic 9.5 cm Face completely extended Submento vertical 11.5 cm Incomplete extended face in face presentation Mento vertical 13.5 cm Brow presentation Bitemporal 8.2 cm Biparietal 9.5 cm

Changes in Foetal Skull During Labour

Moulding : It is the alteration in shape in foetal head due to overlapping of cranial bones at sutures. In normal labour, moulding is physiological and harmless. It disappears within few hours after delivery.

Extreme moulding in cephalopelvic disproportion is pathological and causes intracranial stress after birth.

Caput succedaneum : It is localised area of oedema on foetal skull on vertex presentation due to pressure effect of dilating cervical ring and vaginal introitus. It usually develops after rupture of membrane. Caput also forms on face and brow but not in breech presentation. Caput succedaneum is physiological and disappears in 24 hours after birth of baby.

Check Your Progress 2

1) Encircle the correct statement.

a) Which of the following is not the characteristics of a gynaecoid pelvis? i) Brim is heart shape. ii) Ischial spines are not prominent. iii) Pubic angle is 95 degree. iv) Sacrum is well curved. b) Pelvis is composed of: i) Three bones ii) Four bones iii) Two bones iv) None of the above c) Obstetrical conjugate measures: i) 11 cm ii) 13 cm iii) 10 cm iv) 12 cm d) The largest diameter of the outlet is: i) Antroposterior ii) Transverse iii) Oblique iv) (a) & (b)

39 Maternal Health and Nursing 2) List four functions of pelvic floor. Intervention ...... 3) Fill in the blanks: a) Anterior fontanelle closes at ...... months. b) The largest diameter of foetal skull is ...... c) The engaging diameter in well flexed head is ...... and measures ...... d) Bitemporal diameter measures ...... e) Alteration in shape in foetal head due to overlapping of cranial bones at sutures is called...... 4) Define: a) Caput Succedaneum ...... b) Pelvic inclination ...... c) Sinciput ...... d) Vertex ...... e) Face ...... 2.8 ANATOMY AND PHYSIOLOGY OF MALE REPRODUCTIVE SYSTEM

You have learnt the anatomy and physiology of female reproductive system. We shall now review the anatomy and physiology of male reproductive system. 2.8.1 Structure and Functions of Male Reproductive Organs

The structure and functions of male reproductive organs are:

– Testes 40 – Epididymis – Vas deferentia (Singular – Vas deferens) Anatomy and Physiology of Reproductive System and – Seminal Vesicles Development of Foetus – Ejaculatory ducts – Prostate glands – Bulbo urethral glands (cowper’s glands) – Penis – Scrotum and spermatic cord

Bladder Seminal vesicle

Vas deference

Ejaculatory duct Urethra Prostate gland

Efferent ductule

Seminiferous tubules

Tunica albuginea Ductus epididymis Testes

Septum Lobule Fig. 2.19: Male reproductive organs

Let us discuss each of these organs. i) Testes: The testes, the sex organs or gonads, of the male are two slightly flattened, ovoid glandular bodies. The testes are formed in the peritoneal cavity during foetal development and then normally migrate through the inguinal canal into the scrotum during the eight or ninth month of pregnancy, or occasionally soon after birth. Testes descent into the scrotum by the age of puberty is essential for normal spermatogenesis, which is adversely affected by the relatively higher temperature within the body. Each testes has a mass of narrow, coiled tubules, called semiferous tubules. These tubules are from 1 to 3 feet long. The combined length of many tubules in one testes equals almost one mile. ii) Epididymis: The epididymies are bilateral narrow bodies situated along the upper posterior part of each testes. Each contain a narrow, tortuous tubule approximately 20 feet in length. This tubule serves as the area to which the spermatozoa that have been released into the semiferous tubules are conveyed, and where they may remain for about three weeks. Here they are retained until physiological maturation is complete and until they become motile. As the tubule of the epididymis leaves the body, it becomes known as vas deferens. iii) Vas deferentia: The vas deferentia are bilateral ducts, approximately 18 inches long, which continue from each epididymis and then terminate in the bilateral ejaculatory ducts, which open into the urethra. A vas deferens ascends from each testes through a 41 Maternal Health and Nursing spermatic cord, passes through the inguinal canal, crosses the pelvic cavity, and after Intervention coursing upward and medially, passes downward to the base of the bladder where it widens into an ampulla. This terminal end joins with a duct from seminal vesicle, and they become the ejaculatory duct. The vas deferens serves as a storage site for sperm. iv) Seminal Vesicles: The seminal vesicles are two membraneous pouches, situated between the lower part of the bladder and the rectum. Through a short duct each vesicle joins the terminal end of a vas deferens and with it becomes an ejaculatory duct. v) Ejaculatory Ducts: The ejaculatory ducts are paired, narrow, short tubes formed by the joining of the terminal ends of the vas deferentia and the ducts from the seminal vesicles. These two ducts descend between the lobes of the prostate gland and open into the urethra into which they discharge sperm and secretions from the seminal vesicles and epididymis. vi) Prostate Gland: The prostate gland is located just below the bladder and surrounds the upper portion of the urethra. It secretes a thin, complex fluid that is discharged into the urethra through many small tubules that open into it. vii) Bulbo Urethral Glands (Cowper’s Glands): The bulbo urethral glands are two small pea sized bodies located below the prostate gland within the pelvic floor. They secrete an alkaline, viscous fluid that is emptied into the urethra, through a small duct from each gland. viii) Penis: The penis is the male organ of copulation. Semen is ejaculated through it into the vagina of the female during intercourse, and the active spermatozoa in the semen can enter the cervix and travel through the fallopian tubes where fertilization of an ovum may take place. The penis is cylindrical organ composed of three elongated masses of erectile tissue. A slight enlargement at the end of the penis, called the glans penis, contains urethral opening and many sensitive nerve endings. The skin of the penis extends over its end, covers the glans, and become folded upon itself. This is called the prepuce or the foreskin and is the portion that is surgically removed when a circumcision is performed. ix) Urethra: The male urethra, which extends from the neck of the bladder to the orifice in the glans of the penis, serves two purposes. It conveys urine from the urinary bladder at urination and transmits semen containing spermatozoa at copulation. x) Scrotum and Spermatic Cord: The spermatic cords originate just above the inguinal canal, pass through the canal, and down to the scrotum. Scrotum, a pouch like double chambered structure, is made up of skin, fascia and muscle. The testes, epididymis, and parts of the spermatic cords are enclosed. 2.8.2 Spermatogenesis Spermatogenesis is the process by which spermatozoa are formed, during which the diploid chromosome number (46) is reduced by half (haploid, 23). At the time of puberty, the onset of secretion of follicle stimulating hormone (FSH) from the adenohypophysis, under the influence of hypothalamic releasing factor, initiates the development of the spermatozoa in the seminiferous tubules of the testes. Spermatogenesis (production and maturation of germ cells) continues throughout adult life. Germ cells called spermatogonia is formed during fetal life. Now begin to proliferate and differentiate through definite stages to form spermatozoa. As these cells divide, increase in number and move towards the center of the tubule, they become spermatocytes. Primary spermatocytes then go through reduction, division, during which the number of chromosomes of the developing cells is halved from 46, the diploid number to 23, the haploid number.

The spermatid develops into a spermatozoon. The mature spermatozoon has four sections. – Head – Neck – Body – Tail 42 Acrosome Anatomy and Physiology of Reproductive System and Development of Foetus

Head

Middle piece

Tail

End piece

Fig. 2.20: Spermatozoon

Check Your Progress 3 1) Fill in the blanks: a) Each testes has a mass of narrow coiled tubules called as ...... b) Bulbo urethral glands are called ...... glands. c) Germ cells are called ...... 2) Define spermatogenesis...... 3) List six structures of male reproductive organs......

2.9 CONCEPTION

Pregnancy is achieved by woman doing sexual intercourse with husband during 11-18th day of menstruation. Semen on intercourse gets deposited deep in the vagina at external os of cervix. Thousands of sperm swim up the uterine cavity and hundred or more reach outer third of fallopian tube within 5-10 minutes. Ovum retain fertilizable in tubal ampulla for 24 hours after ovulation while sperm retain its fertility for 24-28 hours after ejaculation in the vagina. 2.9.1 Definition and Process of Fertilization

Definition

Union of single spermatozoon with ovum at tubul ampulla occurring 24-48 hours after ejaculation in the vagina by sexual act is called conception. 43 Maternal Health and Nursing Capacitation of Spermatozoa Intervention In the Uterotubal canal sperm head undergoes biochemical changes called capacitation. The process causes release of enzyme hyalurinadase. On entry into the ovum, sperm tail dissolves, head and neck increases in size to form male pronucleus. Both female pronucleus (23 X) and male pronucleus (23 Y or 23 X) fuse to form single nucleus of zygote.

Sex of the fertilized ovum is determined by sex chromosome of fertilizing spermatozoon. If 23X chromosome carrying sperm fertilizes 23X ovum, female zygote forms. On the other hand when 23 Y chromosomes carrying sperm fertilizes ovum (23X), male zygote (46XY) results. Thus father’s sperm determines sex of the baby. 2.10 DEVELOPMENT OF EMBRYO

The sperm and the ovum are known as the male and female gametes respectively. The fertilized ovum is called zygote. The zygote undergoes various stages of development.

Morula Blastocyst 10 days

Fig. 2.21: Development and implantation of fertilized ovum

2.10.1 Development of the Fertilized Ovum

i) Ovum Stage

From single cell at fertilization the fetus grows to 6 billion cells at 38 weeks of pregnancy. When the ovum has been fertilized it continue its passage through the fallopian tube and reached the uterus 3-4 days later. During this time segmentation of cell division takes place. The fertilized ovum divides into two cells, then into four, then 8, 16 and so on until a cluster of cells is formed known as morula (mullberry). These divisions occur very slowly.

Blastocyst: Morula expands with accumulation of fluid in it, is called blastocyst. At one side of blastocyst cells proliferate to form inner cell mass which forms the embryo. The outer layer of flattened cells of blastocyst is called trophoblast which gets implanted into the endometrium and forms placenta.

44 Anatomy and Physiology of Ectoderm Amniotic sac Reproductive System and Development of Foetus Mesoderm

Chorion

Embryo

Endoderm Embryonic Area Yolk Sac

Blastocyst 13 days Blastocyst 18 days

Blastocyst

Trophoblast Inner cell mass

Placenta + Chorion

Fetus + Amnion + Umbilical cord

Fig. 2.22: The development of the blastocyst ii) Implantation

Blastocyst penetrates endometrial surface and stroma in between glands by its histolytic action. Blastocyst enters into the compact layer of endometrium without any bulging. Original point is seated by fibrin clot and later by epithelium. This is called interstitial implantation which is completed by the end of 10th day. By this time HCG is secreted by trophoblast that can be measured in maternal serum or urine.

Trophoblast: When blastocyst embeds into endometrium, outer trophoblast cells proliferate to form inner cytotrophoblast (Langhan’s cell layer) and outer layer of multinucleated synctium of plasmedio trophoblast. Synctiotrophoblast opens up spaces around, called lacunae which get filled up with maternal blood.

The trophoblastic epithelial layer becomes lined with mesenchyme runs continuously with that in inner cell mass. iii) Chorion and Chorionic Villi

Trophoblastic cells lined internally with mesenchyme is called chorion. Finger like projections of trophoblastic layer peojects out on the surface of embedded blastocyst – the Chorionic Villi.

Types of Chorionic Villi

Primary chorionic Villi: Solid trophoblastic layer by 12th day of fertilization.

Secondary Villi: Villi with mesenchymal lining by 16th day.

Tertiary Villi: Secondary villi with blood vessels.

Villi lying on the side of uterine cavity atrophy (chorion laeve) and disappear but those on the side of uterine wall show branching (chorion frondosum) to form placenta. 45 Maternal Health and Nursing Intervention Fetal vessels leading from and to umbilical vessels

Intervillous space

Cytotrophoblast

Mesoderm

Syncytiotrophoblast

Intervillous space Fetal capillary

Maternal vessel

Decidual gland

Fig. 2.23: Chorionic villi

iv) Decidua This is the 5-10 mm thickened vascular endometrium of the pregnant uterus. Structure of Decidua: It has three layers: 1) Stratum Compactum: Superficial layer containing gland duct. In this layer blastocyte implants. 2) Stratum Spongiosum: Intermediate area with dilated glands. Through this layer separation of placenta and membranes occur. 3) Stratum Basalis: Thin basal layer containing deepest portions of glands is opposed on uterine muscle. From this layer new endometrium regenerates after parturition. Changes of deciduas: After the embedding of ovum deciduas are renamed: 1) Decidua Basalis: Portion of deciduas lying between blastocyst and uterine muscle. This layer goes to form placenta. 2) Decidua Capsularis: The superficial layer of compact layer overlying blastocyst. 3) Decidua Vera or parietalis: Rest of deciduas lining pregnant uterus except at the site of implantation. Functions 1) It provides soil for implantation of blastocyst. 2) It provides nutrition to blastocyst by glycogen and fat it contains. 3) It is protective against penetration of blastocyst by ground substance containing mucopolysaccharide. Development of Embryo and Foetus Along with the changes in inner cell mass, two cavities appear on each side of the germ disc, amniotic cavity and yolk sac germ disk. Most of the tissues and organs are developed during this period. The embryo can be differentiated as human at 8th week. Major structures which are developed from the three germinal layers: a) Ectoderm: Central and peripheral nervous system, epidermis of skin, pituitary gland, salivary glands, mucous lining of the nasal cavity, paranasal sinus and roof of the mouth. 46 b) Mesoderm layer: Bones, cartilage, muscles, cardiovascular system, kidney, gonads, Anatomy and Physiology of superarenals, spleen, genital tract, mesothelial lining of pericardial, pleural and Reproductive System and Development of Foetus peritoneal cavity etc. c) Endoderm: Epithelial lining of the gastro intestinal tract, liver, gall bladder, pancreas, intestinal tract, epithelial lining of respiratory tract and most of the mucous membrane of urinary bladder and urethra.

Capsular decidua Chorionic villi Embryo Chorion Chorion and Amnion Amnion flused Capsular Parietal decidua decidua Basal decidua Basal decidua

(a) 3 Weeks (b) 4 Weeks

Amnion Chorion Placenta

Parietal decidua Basal decidua

(c) 12 Week

Fig. 2.24: The developing embryo 2.10.2 The Placenta

Placenta is developed from chorionic Frondosum and decidua. It begins at 6th week and completed by 12th week.

The Placenta at Term

The placenta at term is almost circular disc with a diameter of 15-20 cm. It is 2.5 cm thick at its centre. It weighs about 500 gm. of 1/6th of baby’s weight. It has two surfaces: a) Maternal surface: It is rough and spongy. It is red dull colour. It has 15-20 lobes, known as cotyledons, separated from each other by furrow. b) Foetal surface: The foetal surface is covered by the smooth and glistening amnion with the umbilical cord attached near to its centre. Branches of the umbilical vessels are visible beneath the amnion as they radiate from the insertion of the cord. The amnion can be peeled off from the underlying chorion except at the insertion of the cord.

Placenta separates after the birth of the baby and the line of separation is through the desidua spongiosum.

The placenta is lined internally by the amniotic membrane and chorionic plate, externally by the basal plate and in between these two lies the choriodecidual space containing the stem villi with their branches. The space being filled with maternal blood. 47 Maternal Health and Nursing Structures of Placenta from Foetal to Maternal Surface Intervention l Amniotic membrane

l Chorionic plate

l Choriodecidual plate (maternal sinus)

Placenta villi: Two types of placental villi develop as:

l Anchoring villi: A few villus get attached to deciduas basalis.

l Nutritive Villi: Majority of chorionic villi, branch freely in the choriodecidual space. Primary villi branch to secondary and tertiary villi. These floats in the maternal sinus and provide nutrition to the foetus.

Placental Circulation

It consists of two independent circulation:

a) Maternal Circulation: At term 120 spiral arteries enter maternal sinus. Venous blood is collected by venous channel.

b) Foetal Circulation: Through umbilical cord two arteries spirally around unbilical vein carry venous impure blood from foetus to chorionic plate of placenta. Branches of umbilical artery enters to each villus. Single umbilical vein emerging from placenta into umbilical cord carries oxygenated blood. Foetal and maternal blood streams flow side by side in opposite direction. Foetal blood has higher oxygen carrying capacity due to red cells carrying foetal haemoglobin.

Placental Aging

Placenta has limited life span. Near term pregnancy normal placenta shows white infarcts – degenerated villi with deposition of fibrin and calcium. These infarcts are more common at placental margin.

Functions of Placenta

1) Foetal Respiratory Function: By simple diffusion, oxygen goes to foetal circulation from maternal sinus and carbon dioxide diffuses out.

2) Foetal Alimentary Function: All nutrient such as glucose, aminoacids, lipids, vitamins, minerals, water and electrolytes pass from maternal sinus to foetal circulation.

3) Foetal Excretory Function: Placenta acts as a foetal kidney by excreting small amount of placental hormones and steroids hormones.

4) Foetal Barrier Functions: This prevents large molecular size substance to pass from mother to foetus. Currently this barrier function is considered a myth since many infective organisms, drugs easily cross over to the foetus.

5) Enzyme Function: Various enzymes are involved in hormone synthesis and metabolism are elaborated by placenta.

6) Immunological Function

Abnormalities of Placenta

1) Large placenta occur in syphilis, diabetes mellitus and in erythroblastosis.

2) Placenta succenturiata: One or more small accessory lobes lie away from the main mass containing blood vessels.

Clinical importance is that it can be retained after the main placenta is expelled producing postpartum haemorrhage.

3) Bipartite of tripartite placenta: There are two or three almost equal lobes lying close to each other. Foetal vessels extend from one lobe to other before uniting at umbilical cord. This may cause antepartum haemorrhage and retained placenta.

48 4) Battle dore Placenta: In this the cord is situated at the very edge of placenta. Anatomy and Physiology of Reproductive System and Development of Foetus

The umbilical vessels bifurcate at the point of insertion of the cord

Fig. 2.25: Placenta bipartite 2.10.3 The Foetal Membranes Foetal membranes are of two layers: a) Outer Chorion: It forms outer layer of foetal membranes formed out of chorionic leave and ends at placental margin. It is thicker than amnion but friable and shaggy on both sides. It consists of two layers of trophoblastic epithelium lined internally by mesoderm. b) Inner Amnion: It is the inner layer of foetal membranes. It is smooth, shiny and slippery that lies in contact with amniotic fluids. It is tough membrane. Functions of Foetal Membrane 1) Protective for foetus 2) Form liquor amnii 3) Prevents infection 4) Facilitates cervical dilatation 5) Shows enzymatic activities 6) Serves as a source of precursor of prostaglandin. 2.10.4 Liquor Amnii (Amniotic Fluid) The watery alkaline fluid of amniotic Sac in which embryo, foetus grow is called the amniotic fluid. i) Physical Characteristics: It is clear fluid in early pregnancy. In mid-pregnancy due to more bile pigments it becomes yellow. But in late pregnancy it is colourless as billirubin becomes negligible. It also contains vernix caseosa and desquamated epidermis. ii) Volume: Amniotic fluid is detected at 8 weeks of pregnancy and its average volume varies. At 38 weeks the amount is 1000 ml, at 40 weeks 800 ml and at 43 weeks 200 ml. iii) Composition: Water 98-99% Organic substances: Protein 0.25 gm% Uric Acid 4 mg% Creatinine 1.8 mg% Glucose 20 mg% 49 Maternal Health and Nursing Lipids, phospholipids, billirubin (a trace), hormones (Prolactin) Vitamins, Intervention prostaglandins. Inorganic substances Electrolytes – (Sodium, Potassium Chloride) same as in maternal plasma. pH is 7.2 Specific gravity 1008 iv) Sources of Amniotic Fluid l Foetal urine l Exudation of umbilical vessels l Amniotic epithelium Foetus swallow liquor after 16 weeks 450 ml daily. v) Functions During Pregnancy: l It helps in foetal growth. l It protects foetus from external injuries. l Maintains even temperature for foetus. l Allows free movements of foetus and prevents adhesions. l Serves Immunological, Biochemical and Hormonal functions. During Labour: l Helps in dilatation of os l Protects foetus and placenta from direct pressure from contracting uterus. l Fore waters washes the vagina before birth of baby preventing infection of baby and uterine cavity and the hind waters clears the birth passage after the baby is born. 2.10.5 Umbilical Cord (Funis)

Umbilical cord of Funis is a long cord like structure that connects the foetal umbilicus with foetal surface of placenta. It is developed from body stalk of mesodormal cells stretching between embryonic disc and chorion.

i) Structure of Umbilical Cord at Term

It is bluish white cord about 50 cm. long and 1.5 cm. in diameter. Three blood vessels are embedded in it. One umbilical vein and two umbilical arteries. It is twisted spirally from left to right. There are collection of Wharton’s jelly at places. These are false knots. Umbilical cord attached foetus to placenta. It is covered by amnion. Underneath Warton’s jelly supports the blood vessels.

Remanants of Vitelline duct at foetal end of cord and yellow sac as minute yellow body at the site of placental attachment and allanois at foetal end of cord.

ii) Functions

l It is the life line between placenta and foetus supplying oxygen and nutrients for foetus and disposing waste products. l Exchange of fluid and electrolyte between umbilical vessels and amniotic fluid.

iii) Abnormalities of Cord l Short cord less than 30 cm. l No cord (achordia) l Long cord 100-300 cm long. Long cord may lead to prolapse of the cord before and during labour. l True knots. 50 l False knots due to collection of Wharton’s jelly. Anatomy and Physiology of Reproductive System and l Loop around the neck, may be once, twice or three times. Development of Foetus l Single artery in umbilical cord. 2.11 THE FOETUS, FOETAL GROWTH AND FOETAL CIRCULATION

In this sub-section you will learn about foetus, foetal growth and circulation. Foetus is where the child is in utero about the eighth week after conception, until birth. i) Foetal growth is divided into three phases: 1) Ovular period – Four week of gastational age. 2) Embryo period – Fifth to tenth week of gestational age. This is the period for organ development. 3) Foetal period – 11th to 40th week of gestational age. This is the period of organ maturation and growth. Foetal length is more accurate estimate for foetal age. ii) Factors of Foetal Growth

l Genetic l Maternal biological factors: – Pregnancy weight – Pregnancy weight gain – Age – Parity – Nutritional status – Uteroplacental circulation

Embryo Foetal Growth

Gestational Crown Rump Crown Heal Weight Features age in week length length Development

Embryo Form 3 mm — — Head, Tail, Heart, Guts

5 Gestational sac can be visible in ultrasound

6 4 mm 0.4 gm Neural tube, limb buds Chorionic villi

8 3 mm 3.5 2.0 gm Limbs develop and embryo freely floats, eye, ear, nose, gonads, limbs develop

10 2.3 cm 4 cm 6 gm Eyes developing, limb digits and all organs further develop. Ultrasound Dopper can pick up heart sound

Foetus

12 8 cm 11.5 cm 14 cm Foetus looks human being. Head is disproportionately large, skin pink, sex determined 51 Maternal Health and Nursing Intervention Gestational Crown Rump Crown Heal Weight Features age in week length length Development

16 13.5 cm 19 cm 100 gm Foetus active

20 18.5 cm 22 cm 300 gm Languo Hair

24 23 cm 32 cm 600 gm Skin reddish, Vernix appears. From 500 gm onward foetus attempt to breathe on birth but usually dies

28 27 cm 36 cm 1000 gm Foetus may survive eyes open testes in at ingurnal canal

32 31 cm 41 cm 1800 gm Foetus usually survive under proper care.

36 34 cm 46 cm 2500 gm Testes in scrotum. Foetus has excellent chances of survival

40 40 cm 50 cm 3200 gm Finger nails extend beyond finger tips.

iii) Foetal Circulation

Embryo develops separate circulation from 16th week after fertilization. Foetal heart starts beating from 21st day of fertilization. Foetus in utero derives oxygen from placenta.

Course of foetal circulation: From placenta single umbilical cord carries oxygenated (80%) blood, goes to liver through foetus umbilicus and branches out into two one large and one small branch.

Large branch (ductus venosum) by pass the liver to enter inferior vena cava and then to right atrium of heart. Oxygen saturation of blood at inferior vena cava before entry of heart is 65%. A small branch unit with portal vein goes to liver wherefrom hepatic veins drain into inferior vena cava.

55% of blood from right atrium goes to left atrium through formen ovale, from left atrium to left ventricle and is pumped to coronary arteries and aorta. From aorta blood with 60% oxygen saturation is pumped to head, neck and superior extremities. Twenty five percent blood in right atrium mixes with blood from superior Vena cava draining head, neck and upper extremities into right Ventricle. Then blood is pumped to pulmonary artery. This blood goes to collapsed lungs and is drained back into left atrium by pulmonary veins. Its large part is shunted to descending aorta then to abdominal aorta with 60% oxygen saturation. The major part of blood from abdominal aorta enters two internal iliae arteries. These arteries run towards umbilicus and enters the cord as two umbilical arteries which carry Venous blood to placenta for purification.

Changes in Circulation after Birth

1) Closure of ductus venosum and becomes ligamentum Venosum. Umbilical Vein becomes ligmentum teres by one year time. 2) Closure of ductus arteriosus occurs after establishment of Pulmonary Ventilation. Ductus arteriosus becomes ligamentus arteriosum. 3) Closure of foamen ovale occurs due to rise in pressure in left atrium and close foramen ovale gives fossa ovalis. 4) Obliterated umbilical arteries form lateral umbilical ligaments. Functional closure occurs soon after birth but anatomical closure occurs in about one year time. 52 Anatomy and Physiology of Reproductive System and Ductus arteriosus Development of Foetus

Superior vena cava

Pulmonary artery Pulmonary vein

Foramen ovale

RIGHT LUNG LEFT LUNG

Ductus venosus

Inferior vena cave

Renal vein and artery Portal vein

Aorta Umbilicus

Umbilicus vein

Umbilical arteries

Hypogastric arterries

Fig. 2.26: Foetal Circulation

Check Your Progress 4

1) Define:

a) Fertilization ...... b) Capacitation ...... 53 Maternal Health and Nursing c) Zygote Intervention ...... 2) Fill in the blanks:

a) Fingerlike projections of trophoblastic layer which project out on the surface of embedded blastocyst is called ...... b) The 5-10 mm thickened vascular endometrium is called ...... c) The embryo can be differentiated as human at ...... weeks of pregnancy. d) The diameter of full term placenta is ...... e) The placenta has 15-20 lobes known as ......

3) State ‘True’ or ‘False’

a) During intrauterine life the foetus has separate circulation (T/F) b) Anchoring villi get attached to deciduas basalis (T/F) c) Degenerated villi with deposition of fibrin and calcium if found in placenta at term is dangerous. (T/F) d) Progestrone is a steroid hormone. (T/F) e) Foetus gets oxygen from mother’s blood through the process of osmosis (T/F)

4) Explain the functions of placenta......

5) a) Explain the abnormalities of placenta.

...... b) List the functions of foetal sac membranes.

...... c) Describe the functions of liquor amnii.

...... d) Explain the structure and functions of umbilical cord.

......

54 ...... 6) Draw a diagram of foetal circulation and describe what changes occur in foetal circulation Anatomy and Physiology of after birth. Reproductive System and Development of Foetus ......

2.12 LET US SUM UP

In this unit you have learnt the anatomy and physiology of both female as well as male reproductive organs in order to have deeper understanding about reproductive health of the couple. The study of anatomy of bony pelvis gives you an understanding of the process of birth of the baby through birth canal to identify deviations from normal. The process of conception is a complex phenomena. Basic knowledge of this would facilitate better understanding of reproductive health as explained in subsequent units. Foetus continue to grow in the uterus thoughout pregnancy. Placenta performs number of functions for foetus survival through maternal and foetal circulation. Maternal and foetal circulation of placenta are separate. Normally there is no mixing of blood. After child birth, certain changes occur in foetal circulation and extra structures present during intrauterine life function no more. Foetus grows in a sac of membranes, i.e. amnion and chorion. Inside the sqc there is liquor amnii and foetus floats in it. The umbilical cord containing two arteries and one vein connects the foetus to mother through placenta. 2.13 ANSWERS TO CHECK YOUR PROGRESS

Check Your Progress 1

1) a) Uterus b) Fellopian Tubes c) Ovaries d) Vagina

2) a) subcutaneous b) medial c) vestibule d) bartholinitis e) the body of corpus

3) a) T b) F c) F d) F e) T

4) a) Menstruation may be defined as the monthly uterine bleeding occurring for 4-5 days during reproductive life of an woman from menarche to menopause. Menstruation is a normal uterine function whereby uterus prepares itself to receive the ovum.

Check Your Progtess 2

1) a) i b) ii c) iii d) ii

2) Refer sub-section 2.6.1. 55 Maternal Health and Nursing 3) a) 18 months Intervention b) mentovertical c) suboccipitobregmatic, 9.5 cm d) 8.2 cm e) moulding 4) a) Refer section 2.7 b) Refer sub-section 2.5.4 c) Refer section 2.7 d) Refer section 2.7 e) Refer section 2.7

Check Your Progress 3

1) a) semiferous tubules b) couper’s glands c) spermatogonia 2) Refer sub-section 2.8.2 3) a) Testes b) Epididymis c) Vas-deferens d) Seminal vesicles e) Prostate glands f) Bulbo urithral glands

Check your Progress 4

1) a) Refer sub-section 2.9.1 b) Refer sub-section 2.9.1 c) Refer sub-section 2.9.1 2) a) Chorionic villi b) decidua c) 8 weeks d) 18-20 cm. e) cotyledos 3) a) T b) T c) F d) T e) F 4) Refer sub-section 2.10.2 5) a) Refer sub-section 2.10.2 b) Refer sub-section 2.10.3 c) Refer sub-section 2.10.4 d) Refer sub-section 2.10.5

6) Refer section 2.11 2.14 FURTHER READINGS

Bennett, V.R. and Brown, L.K. (eds.), Myles Text Book For Midwives, ELBS Churchill Livingstone.

Dawn, C.S. Text Book of Obstetrics and Neonatology, Dawnbook.

Dutta, D.C., Text Book of Obstetrics, New Central Book Agency, Calcutta. 56