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Chapter 28 Reproductive System (RS)

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Chapter 28 Reproductive System (RS) Chapter 28 Reproductive System (RS) AP2 Chapter 28 1 Chapter 28 Outline I. Anatomy of the Male RS II. Physiology of the male RS III. Anatomy of the female RS IV. Physiology of the female RS V. FX of aging on the RS AP2 Chapter 28 2 The Reproductive System • Controls the development of the structural & fxnal diff between ♀ and ♂ • Not only are reproductive structures different but integumentary, muscular & skeletal system diff’s also exist • Reproduction: essential to all living organisms (Thus fxnal RS are required to successfully reproduce) • The ♂ RS is designed to prod sperm & deliver it to the ♀ oocyte • The ♀ RS is designed to prod oocytes & receive sperm from the ♂ RS. It is also intimately involved with nurturing the development of the new individual until and well after birth. AP2 Chapter 28 3 I. Anatomy of the ♂ RS AP2 Chapter 28 4 I. Anatomy of the ♂ RS Pathway • Consists of: • Temp sensitive sperm cells 1. Testes develop outside the body 2. Ducts cavity in the testes & ED Epididymides (ED) Ductus Differentia (DD) • DD lead from the testes into Urethra the pelvis & join with the SV 3. Accessory glands to form the ampullae Seminal Vesicles (SV) Prostate Gland (PG) • Extensions called Bulbourethral Gland (BG) ejaculatory ducts pass thru 4. Supporting Structures the PG & empty into the Scrotum urethra w/in the PG Penis • Urethra exits the pelvis & passes thru the penis to the outside of the body 5 I. Anatomy of the ♂ RS: Scrotum • Holds testes in compartments separated by an incomplete CT septum • Raphe: external irregular midline ridge on the scrotum that continues to the anus (posteriorly) and Base of the penis (anteriorly) • Outer layers of scrotum: – Skin Raphe – Superficial Fascia (LCT) – Dartos Muscle • 2 muscles control the scrotum’s hold on the testes: – Dartos muscle & cremaster muscle – Hot they both relax & testes move away from the body – Cold and they contract bringing testes toward the warmth of the body – Normal sperm formation is temperature sensitive 6 I. Anatomy of the ♂ RS: Perineum • A diamond shaped area between the thighs, consists of the urogenital triangle (contains base of the penis & scrotum) & the anal triangle (contains the anal Fig 28.2 pg 1034 opening) AP2 Chapter 28 7 I. Anatomy of the ♂ RS: Testes: Testicular Histology • Testes: Fig 28.3 pg 1035 – Small ovoid organs w/in the scrotum that are endocrine (testosterone) and exocrine (sperm cells) glands • Tunica Albuginea (TA): – Outer thick white capsule made of mostly fibrous CT – Septa formed by CT of TA • Lobules: – cone shaped divisions formed Fig 28.3 pg 1035 by internal septa • Sts empty into the tubuli recti • Seminiferous tubules (Sts): (short straight tubes) which in – Tubes that fill the lobules turn empty into the rete testis – Location of sperm development (tubular network) these empty – Stroma (Supporting tissue) into 15-20 tubules called the contains Interstitial/Leydig efferent ductules (pseudo Cells that secrete testosterone strat. Epi that help sperm exit the testis) 8 I. Anatomy of the ♂ RS: Testes: Descent of the Testes AP2 Chapter 28 Fig 28.4pg1036 9 I. Anatomy of the ♂ RS: Sperm Cell Development • B4 puberty the testes remain relatively simple and unΔ’d • Interstitial cells aren’t prominent and a lumen has yet to develop in the seminiferous tubules • @ 12-14 yrs of age the interstitial cells increase in number & size, a lumen develops in each Fig 28.1 pg 1033 seminiferous tubule, & sperm cell prod’n begins – 74 days for a sperm cell to be prod’d and 50 are spent in the seminiferous tubule AP2 Chapter 28 10 I. Anatomy of the ♂ RS: Sperm Cell Development Fig 28.3 pg 1035 • Spermatogenesis: – Sperm cell development – Occurs in the seminiferous tubules Outside of the Seminiferous tubules are leydig cells (endocrine cells) – Process in wh/germ cells divide & differentiate to form sperm cells – Sustentacular/Sertoli Cells – large cells that extend from the sides to the lumen. Fxn: nourish germ cells and probably w/leydig cells prod a # of hormones such as androgens, estrogens, and inhibin • Blood-testes Barrier: tight jxns between sertoli cells req’d b/c sperm cells create surface antigens that can stimulate an immune response 11 I. Anatomy of the ♂ RS: Sperm Cell Development Fig 28.3 pg 1035 • Leydig cells prod testosterone – This passes into sertoli cells and binds to receptors • Fxn #1: Binding is required for normal sertoli cell fxn • Fxn #2: Testosterone (T) is converted into 2 other steroids: – Dihydrotestosterone (DHT) & estrogen (E) • Sertoli cells also secrete androgen-binding hormone (ABH) into the seminiferous tubules • T & DHT bind to ABH and are carried w/other secretions to the epididymis • Estradiol & DHT may be the active hormones to promote sperm cell formation 12 Fig 28.5 pg 1040 AP2 Chapter 28 13 I. Anatomy of the ♂ RS: Ducts Sperm Seminiferous tubules Tubuli recti Rete testis Efferent ductules Epididymis Ductus epididymis Ductus deferens Ejaculatory duct Urethra Exterior of the body AP2 Chapter 28 Figure 28.6 pg 1041 14 I. Anatomy of the ♂ RS: Figure 28.6 pg 1041 Ducts: Epididymis • Made from convoluted efferent ductules that empty into the duct of the epididymis (DoE). – DoE: pseudo strt col epi w/stereocilia (microvilli) surface area for fluid absorption • Final maturation of sperm occurs here & takes 10-12 days to travel it’s length – Δ’s to sperm include: loss of more cytoplasm, maturation of acrosome, ability to bind zona pellucida of the 2o oocyte • 3 regions: – Head • Sperm from this region are still non- motile – Body – Tail Fig 28.3 pg 1035 • Sperm from this region are motile AP2 Chapter 28 15 I. Anatomy of the ♂ RS: Ducts: Ductus deferens (DD) • DD: emerges from the tail of the epididymis and becomes the Spermatic Cord (SC) – DD, testicular artery, venous plexus, lymphatic vessels, nerves, • DD Coverings: – External spermatic fascia, cremaster muscle, internal spermatic fascia • Path – Goes up and around the ureter enlarges at the end to form the ampulla and lined with psedo str col epi and smooth muscle to allow for peristaltic contractions to aid in sperm propulsion Figure 28.6 pg 1041 I. Anatomy of the ♂ RS: Ducts: Ejaculatory Duct (ED) • Adjacent to the DD ampulla is the seminal vesicle (SV) (sac-shaped gland) • A short duct formed by the joining of the ampulla & SV is called the Figure 28.6 pg 1041 Ejaculatory Duct – Project into the prostate and end by opening into the urethra AP2 Chapter 28 17 I. Anatomy of the ♂ RS: Ducts: Urethra • 20 cm long extends from the bladder to the exterior • Males: passageway for – Urine & Reproductive Fluids • Most of urethra str col epi w/ mucus glands throughout • 3 major regions 1. Prostatic Urethra Transitional epi; Bladder thru prostate 15-30 prostate ducts & 2 ED’s 2. Membranous Urethra Shortest from prostate to muscular floor of the pelvis Figure 28.7 pg 1043 3. Spongy Urethra Longest extends from 2. thru length of the penis; tip strat squ epi AP2 Chapter 28 18 I. Anatomy of the ♂ RS: Penis • Male organ of copulation thru wh/sperm is transferred from male to female • Erectile tissue engorgement causes the penis to enlarge and become firm in a process called erection • 3 columns of erectile tissue: – 2 corpora cavernosa • Lateral & Dorsal • Expands at the base to form the crus of the penis (Attach the penis to the coxae) – 1 corpus spongiosum • Ventral expands over the tip to form the glans penis and expands at the base to form the bulb of the penis at the root – Root of the penis: Crus & bulb 19 I. Anatomy of the ♂ RS: Penis • Skin of the penis is loosely attached to CT that surrounds erectile columns • Thinner skin covers the glans penis • Well supplies with sensory receptors (esp glans penis) • Foreskin/prepuse covers the glans penis • Primary nerves, arteries, & veins pass along the dorsal surface. – 1 midline vein surrounded by 1st an artery then a nerve. – Additional deep arteries are in the corpus cavernosa 20 I. Anatomy of the ♂ RS: Accessory Glands • Seminal Vesicles – Sac-shaped glands located near the ampulla of the DD tapers into a short excretory duct that joins the ampulla of the DD to form the ejaculatory duct – Have a capsule w/fibrous CT & smooth muscle cells • Prostate Gland • Bulbourethral Gland – Glandular & muscular tissue, – Pair of small glands near surrounds prostatic urethra & membranous urethra the 2 ejaculatory ducts – Young males size of a pea – Fibrous CT capsule w/distinct but decreases w/age. Sm muscle cells & numerous Compound mucus gland at fibrous partitions w/sm muscle the base of the penis with that radiate toward the urethra. a single duct entering the – 15-30 prostaic ducts carry spongy urethra secretions to the urethra 21 I. Anatomy of the ♂ RS: Accessory Glands: Semen • Semen: a composite of sperm cells from the testes (5%) & secretions from the seminal vesicles (60%), prostate (30%), & bulbourethral glands (5%) • Emission: discharge of secretions from all of the above into the urethra to form semen • Ejaculation: forceful expulsion of semen from the urethra caused by the contraction of: – Urethra – Skeletal muscles at the floor of the pelvis – Muscles at the base of the penis AP2 Chapter 28 22 I. Anatomy of the ♂ RS: Accessory Glands: Semen Bulbourethral gland (bug), seminal vesicle (sv), Prostate (pst), & testicular secretions (ts) • B4 ejaculation: • Pre-ejaculate – DD starts peristaltic – bug + urethral muscus contractions to propel its glands secretions toward the – Fxn: ampullae • Lubricates the urethra – Contractions of the • Small amount of ampullae, SV, & lubrication for intercourse ejaculatory duct cause • Neutralization of both the sperm cells & all male urethra & female secretions to move to vagina the prostatic urethra along with pst secretion AP2 Chapter 28 23 I.
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