EXTRA-EMBRYONIC MEMBRANES IN CHICK The history of the foetal-membranes in chick is with the of an correlated presence anormous mass of and an yolk embryonic life within a shell. the a spent Although, original blastoderm is small disc, it spreads by peripheral and covers the surface of the But growth eventually entire egg. only the most central region is directly concerned with the formation of the The is embryo proper. remaining blastoderm extra-embryonic and it is this portion that furnishes the embryonic or foetal membranes. These which arise are auxillary organs partly for protection of the embryo, and more especially to provide for nutrition, respiration and excretion until the independent existence is attained. its The fundamental set of embryonic membranes in chick and other amniotes includes the yolksac, amnion, (serosa in mammals) and allantois which have evolved in relation to the structures that were already in existence following (gut); amnion and chorion (body wall) and allantois (primitive bladder). All these extra-embryonic membranous sacs are composite structures and involve two germ The layers. amnion and chorion are composeed of extra-embryonic ectoderm and somatic layer of mesoderm (somatopleure) whiler the yolk sac and allantois are composed of extra-embryonic endoderm and splanchnic layer of mesoderm (splanchnopleure), separated by a space which is extra-embryonic coelom. These components are continuous with their counterparts in the embryonic teritory of the blastoderm.. 1. Yolk Sac Yolk sac is the first of the extra-embryonic membranes to make its appearance. The splanchnopleure of the chick, instead of forming a closed gut, grows over the yolk surface as extra-embryonic extension and eventually encloses the entire yok to form the yolk sae, The primitive gut has a cellular wall dorsally only, with the yolk acting as a temporary floor (Fig. 24). However, concomitantly with the spreading of extra-embryonic splanchnopleure about the yolk, the intra-embryonic splanchnopleure is undergoing a series of changes which result in the establishment ofa completely walled gut in the body of embryo. Part of the gut which stil remains open to the yolk is known as the midgut. But by the progress of the sub-cephalic and sub-caudal folds, the foregut and hindgut increase in extent at the expense of midgut. The midgut is finally diminished until it opens ventrally by a small aperture which flares out like an inverted funnel into the yolk sac. This opening is the yolk duct and its wall constitutes the narrow yolk stalk through which the walls of yolk sac are still continuous with the wall of the gut. As the neck of the yolk sac is constricted, the omphalomesenteric (vitelline) arteries and omphalomesenteric (vitelline) veins are brought together and trasverse the yolk stalk side by side. The vascular network in the splanchnopleure of the yolk sac encompass it. Apparently no yolk passes directly through the yolk duct into the intestine, rather endodermal cells lining the yolk sac secrete some approrpriate digestive enzymes which make the yolk soluble at the spot. This soluble material is absorbed through the lining of the vitelline blood vessels to the circulating blood by which it is to cariedinto the all parts of the growing embryo. In older embryos the epithelium of the yolk sac penetrates deep yolk and formsa series of foldings which greatly increase its surface area for absorption. development, albumen loses water, becomes more viscid and rapidly decreases in bulk. The

Duri allante an pur the allantois, extra-embryonic of structure, forces the albumen towards the distal end of the grOwthwdhksac (Fig. 33.2:33.25B) and the albumen is eventually compressed by the yolk sac. The yolk sac absorbs Ik way of the circulation ansfers by extra-embryonic to the embryo. and ofinc gnd the end of period, on the owards incubation usually 19th day the remains of yolk sac are pulled into 10vitycavity ofof the. the embryo through the naval and the remaining contents and wall of the yolk sac belly the disappear, their absorption is completed in the first six days after hatching and the body wall rapidly closes behindit.

and Chorion Amnion 2. rhe amnion and chochorion are so closely associated during their origin that they are considered The amnion Roth are derived from the The together. extra-embryonic somatopleure. first indication of appears at about 30 hours of incubation. The head of the embryo sinks slightly into theamnion yolk

form TOhethe samesamne time extra-embryonic somatopleure in front of the head forms a fold, the head fold of the d at In dorsal aspect the margin of this fold is crescentic in shape with its concavity directed towards amnion.i ae head of the embryo. As the embryo increases in length, its head grows anteriorly into the amniotic thehead. d At the same time growth in the somatopleure makes the head-fold over the head of the embryo. By fold. ontinuation of these two growth processes the head soon comes to lie in a double-walled pocket of extra-embryonicssomatopleure which covers the head like:a cap. On the third day, the tail-fold of the emnion springs up similarly from the margin of a posterior limiting fold. It grows in the opposite direction towards head. Its concavity is directed anteriorly and progression towards head. the The lateral folds of amnion develop dorso-medianlly. The head and tail folds grow to meet over are soon formed lateral folds of the amnion to hack of the embryo and joined mid-dorsally by similarly of stalk. At the enclose the embryo in two sheets of somatopleure from all sides except the region yolk a called sero-amniotic or Doint where the folds meet, they become fused in scar-like thickening raphe later and at a time sero-amniotic connection. Since, the tail-fold of amnion arises at the much stage of the of the tail fold is smaller, when the head-fold has already grown beyond the middle length embryo, The amniotic folds invovle and sero-amniotic connection is behind the middle of the embryo. essentially the doubling of somatopleure upon itself. of ectoderm and an inner lining of somatic The outer wall of the somatopleure has an outer layer The inner wall of the fold has the layers reversed, the two form the chorion. mesoderm, layers together The inner and the two together form amnion. ie, its outer layer is of somatic mesoderm and of ectoderm is a of the extra-embryonic chorion and amnion (sero-amniotic cavity) part cavity between (serosa) fold it formed in front of head of embryo (the head ), cOelom. when amniotic fold is first However, from the start consist of ectodermal layer. The lateral folds consists only of part of the extra-embryonic the mesoderm. Meseoderm also secondarily penetrates CAUTa-embryonic ectoderm and extra-embryonic of the fold becomes uniform throughout. aierior portion of the fokd, so composition over and around the embryo enclose an amniotic cavity, AS they the folds of amnion meet, slit between the embryo and the is at first a very narrow lined ectoderm. This cavity the amniotic pletely by secreted into the cavity by epithelium, soon a fluid is of the amniotic fold, but in the cavity, connected to wall lies in a pond, floating freely distends it. Thus, embryo, in a way umbilical cora. Ad-embryonic parts only by the Neural tube Notochord Ectoderm Somatic mesoderm Amniotic Gut cavity Amnion Chorion (Serosa) Allantoic Sero-amniotic vesicle cavity Yolk sac (Extraembryonic) cavity Splanchnic mesoderm

Septa in Endoderm yoik sac

Vitelline membrane Yolk

A Gut

Allantoic Chorio-allantoic vesicle membrane (Serosa and Allantois allantois) Amnion Amniotic cavity Allantoic Extra- stalk embryonic coelom Yolk sac Spianchnic mesoderm Endoderm Yolk 3

Fig. 33.25 Stages in the development of foetal membranes. the îluid to dissociation. Besides this, o The salty amniotic fluid does all that is necessary prevent from desiccation. Unstripe efficient shock absorber and protects embryo possible amniotic cavity is an rocking waves of contraction, tne the mesoderm on the fifth day and produce muscle fibres develop in from adhesion to various embryonie membranes or to itselfor frietno embryo genily, thus, preventing its against it. continues to and orionrion (serosa) grow keeps pace with the growing blastoderm and exocoel. It (serosa) sac and ChOnd the yolk envelope it. The albumen sac is also surrounded by folds of establio chorion. grows its ws afterer its establishment, develops between chorion and amnion. Thus, chorion encompasses Allantois, other extraembryonic membranes. over the Aabryo and aall It forms an additional protective umbrella

embryo. effect. It e Accordingrding to BaBalinsky (1970), formation of amniotic cavity has a slightly negative the embryo fronfrom the surface of egg and forms the source of oxygen. removesthe

3. Allantois It evolved in and birds as a temporary sac for urinary storage. This accessory organ primarily reptiles and serosa because it arises within the of the embryo. Its proximal portion ars from amnion body however, carried outside the remains intra-embry throughout development. Its distal portion, ins intra-embryonic is membranes. coelom becomes with other extra-embryonic confinesfines ofofint intra-embryonic and assoçiated of out late on the third day of incubation as a diverticulum splanchnopleure fromn Allantois grows allantois in front of the anal plate. During fourth day of development ntral wall of the hindgut just ventr coelom. Its narrow proximal portion, of the body of into the extra-embryonic shes out the embryo and the distal portion caudal to the stalk, is known as allantoic stalk enlarged is parallel and yolk of its terminal hich in allnatois distends making the appearance ac allantoic vesicle. Fluid accumulating portion balloon-like. into the from fourth to tenth day of incubation. Extending vesicle enlarges very rapidiy between the Allantoic and yolk sac becomes flattened and finally encompasses embryo cavity, it fused with somatic sero-amniotic mesoderm of allantois becomes chorion. In this process splanchnic amnion and membrane. form allanto-chorionic mesoderm of chorion to which is connected rich vascular network develops of mesoderm an extremely allantois carries In this double layer veins. this circulation allantoic arteries and Through is circulation by it of carbon dioxide. This with the embryonic of the embryo and relieving of oxygenating the blood separated from its primary function close beneath the porous shell, only occupied by allantois, made possible by the position membranes. for excreta of the it by the shell capacity as a reservoir continues to act in its primitive with the allantoic cavity involves metabolism of protein In addition, of embryo acid. bladder. The growth becomes uric rather the urinary excreted material chiefly kidney or and later base the of development (cloaca) near its by formation of urea in early stages down into the hind-gut formed are passed when ill Ihese wastes the embryo, allantois without effects. of stored in the then and albumen. Wolffian ducts, passed of egg assists in absorption combined with yolk allontois wall also and is The part of development proceeds further narrow as the time of hatching, body becomes umblical cord. At stalk or as a allantoic stalk is left behind The to form the body products outer covering contained excretory a single allantois with its cord is healed up. ladik in of the of umbilical distal portion and the place is ruptured, broken shell, Slaik adherent to the LVelled membrane Membraness Functions of Extraembryonic glanduiar embryo. Its and absorption) the sac 1. Function of Yolk Sac of absorbed the yolk nutrition (digestion is by soluble form. It organ for into $ac is the primary the yolk OIkY which convert wall enzymes retes digestive twall and is sent to the embryo. 454 Chordate

2. Function of Chorion association with allantois. It acts as an organ of respiration and lies in 3. Functions of Amnion the it serves Since, the amniotic cavity forms watery pool around embryo, following functionens: 1. It protects the embryo from the danger of dessication. 2. It protects the embryo against external shocks. 3. It protects the embryo from adhesion with itself and embryonic membranes. 4. It helps in the absorption of albumen.

4. Functions of Allantois Allantois serves as a receptacle for excretory products. It is connected with the gut. The higly vascular allanto-chorion comes in contact with the shell membrane and forms embryonic respiratory surface for the embryo. rine muscle niotic sac nbryonic utrition 30

Chorionicc vili-

Umbilical cord Foetal blood Chorion

Maternal blood sinus (Pool)

Uterine cavity Maternal blood vessels

Fig. 22.3 foetus Human showing placental association with the maternal uterine wall.

Occurrence Dlacenta is not found exclusively in mammals but also occurs in animals belonging to different groups which are basically oviparous. For example, is formed in Peripatus (Onychophora), Saloa (Tunicata), Mustelhus laevis (Elasmobranchia) and certain lizards and snakes (Reptilia). The forms with maternal uterine wall is different in all these cases. nature of foetal tissue that placenta

Composition of Placenta in close approximation placenta consists of two different parts lying Structurally, uterine endometrium. of is furnished by the Part of This part placenta 1. Maternal Placenta membranes of the embryo. from the extra embryonic is derived vascular 2. Foetal Part of Placenta: It Its supply with the endometrium of uterus. establishes contact by the ne foetal membrane, chorion, allantoic circulation provided or from the circulation of yolk sac from the vitelline COmes either following two types can be the aantois. Based on this, the placenta of

wall and that part ot Yolk-sac Placenta uterine 1. Chorio-Vitelline or between the sac. The established yolk connection is vessels the the vitelline blood of and In of placenta, network of (Marsupialia-Didelphis this type has a yolk-sac and mammals chorion which is lined with the metatherian and highiy vascular some a large In develop as yolk-sac small. these is known allantois emains relatively without yolk, association villi of small and foetal the are Such a absorbed by the vascular. is Macropus), though eg makes it milk. It chorion and uterine yolk-sacyolk-sac.I It uses with the fluid, the viscous the embryo. Placento wall secretes a carried to placenta. The uterine circulation is vitelline yolk-sac placenta and through Vascular yolk Embryo Amnion sac and chorion Non-vascular yolk sac and Extra-embryonic chorion coelom

Ectoderm Mesoderm

Endoderm

Allantois

Yolk sac

in Didelphis. Fig. 22.4 Yolk-sac placenta

2. Chorio-aliantoic Placenta (True Placenta) the connection 1s estabiished between the ute In chorio-allantoic or allanto-chorionic placenta, terine biood has a net-work of allantoic vessels. The volk wall and the chorion lined with allantois and in some marsupials (Dasyurus and Parameler remains rudimentary and non-functional. it is found an all eutherian mammals. Ailantochorionic Villi

Embryo

Amnion

Amniotic cavity Umbilicuss Extra-embryonic Allantois Coelom

Yolk sac

loderm Chorion Allantoic E mesoderm

3alinshy Fig. 22.5 Embryo showing allanto-chorionic vili that form placenta with the uterine wall (arter pe Implantation fertilizedf in and Theegg is fallopian tube immediately starts The to reach the uterus. On dividing. Simultaneously, it descends egeuctviduct reaching the uterus the zona .nthe now enters pellucida it down ohe embryo the stage. It surrounding gets ute blastocyst gets attached to the dissolv to the is uterine wall. This issolveufblastocystblastocyst uterine wall Known as implantation. The time taken for attachattachment fferent of groups of mamn being 6 days in rats and 8-10 days in mar implantation Vvariesin diff Before implantaticlantation, thelthe blastocyst is nourished by a secretion of the tubular uterine glands, called contains substances as milk. It organic used nutrients. uterine the of Placenta (Placentation) Formation the implantation, at first e embryo obtains its nourishment by enzymatically breaking down the After around it. Later a is which uterine lining on, placenta developed through embryo cells ofthe immediatelymaternal blood stream. nutrition: elements from extracts penetrates deep into the uterine wall. At this time the extraembryonic membrane The hlastocyst called villi that the is produced into finger-like projections, penetrate on that surrounds trophoblast villi are from allantois which forms in the uterine wall. Later on, these penetrated denressions These allantochorionic villi become highly blood vessels of the foetal placenta. tissue and receive the oannective the area of contact form crypts and the uterine wall, which in and grow into and maternal part vaccular structure of embryonic (allantochorionic villi) This interdigitating The trophoblastic villi. of is known as placentation. The process of formation placenta is called placenta. the of uterine wall or (uterus wall) dissolution or erosion of some of layers more intimate by association may become villi or both. whereas in trophoblastic and uterine wall is superficial attachment of the embryo the uterine in implantation, the villi eroding deep into Thus, intimate with trophoblastic association is more maternal blood vessels. placentation the tissue to reach the the connective Wall, eventuaily breaking through or of following layers Structure of Placenta etc. is formed in cow, goat, placenta as found he primitive type of true most Derived from allantois and maternal tissues embryonal capillaries 1. Foetal blood connective tissue chorion 2. Foetal | Derivedfrom Embryonal Layers Foetal chorionic epithelium 3.

1. Uterine epithelium uterus wall of uterus) Derived trom (mucous epithelium

2. Uterine connective Maternal Layers 2. blood capillaries 3. Maternal

be Classification of Placenta and can A. wall varies greatly Based on of the uterine Mode Implantation sac to chorionic suc uterine In placental mar relation ofof of main the chorionic lininglining of main mals, with the lt is| inta contact Ustinguishednguished into following three types lieslies in implantation. sac central chorionic called The is also .Superficial Implantation:n: implantation cavity but itIS is not not burriburried in it. This type of ungungulates, carnivores and monkeys. Blood capillaries Endothelium

-Connective tissue

Foetal Chorion part Uterine mucosal epithelium

-Connective tissue Maternal parn Endothelium

and foetal components. Fig. 22.6 T.S. Placenta showing its maternal fold or which 2. Eccentric Implantation: The chorionic sac lies in a pocket looses off irom main uterine cavity. It is found in beaver, rat and squirrel. 3. Interestitial Implantation The chorionic sac penetrates into the substance ofthe ute lining and establishes deep contact, e.g., hedgehog. guinea pig, apes and man. tern

Chorion Amniotic fold Uterine cavity Embryo Wall of uterus

Yolk sac A B C Fig. 22.7 Classification of placenta based on mode of A. rat; C. in implantation. Superficial in B. Eccentre Interstitial guinea pig and man. monkey; B. Classification Based on the Degree of Association The degree of closeness between foetal and maternal tissues varies Based on the degree of their intimacy three within the eutherian manu types of placenta are 1. Nondeciduate Placenta: In nondeciduate recognized: superficial. The foetal chorionic placenta the implantation of in epithelium lies in contact with embryo tne u birth the foetal villi are drawn out the uterine epithelium. At ne no occurs. completely without tearing or bleeding This type f IS called causing any injury to the placenta nondeciduate or uteriu d in pigs, cattle, horse and other ruminants. nondeciduous placenta. It 2. Deciduate or

In betwen foetal and tissueDeciduous Placenta: deciduous matemal is inimale. The placenta, the degree of contact that the foetal more wallof the uterus choriornic to becomes eroded to blood, At the time of parturil10n,epilhelu whenmay 1oetal comie part oflie placentain separates the from the uterinevarious ntopart the ontao ue ma ether connective tissue or nto there is more or less taeacentu. extensive and this fype is as haemorrhage learng of tissues known deciduous and the from the The uterine wiall as uterine wall. pl Into three regions: decidua. lt can be differentiated basalis thepart iofor decidua decidua betwedbetween ULltIOIn JUS Decidua rionic esicle and ,, Decidua.ecidu capsularis: the of the muscles cularis: part decidua which of the wall of utterus. uterus. surrounds the Orthe chorionic sac cavity and it from thehe separates Deciduacav parietalis : the otalis: part which forms the inner lining of the rest of the , pec is found in uterus. deciduous placenta man, rabbit, dog, cat, etc. In 3. Contra-ddate ecidu Placenta: Parameles and Talpa the associa Contr intimate as in (mole)fithe association hetween foetal Ssue is deciduous But atat the andmaternal placenta.5ut the time of both naterna e re lost and absorbed inin situsilu parturition maternal as well as foetal ed by maternal contra-deciduatote placenta. leucocytes. This modified deciduate 1s Ccalled nlacenta lassification Based on Distribution of Villi on Chorion villi scattered all over thes surface of chorion. Diffused type with , Examples: Ungulates-horse, mare, lemur, pig, etc. Arealae of villi

ChorionicC folds A Diffused Cotyledon or areala of villi Compound villi '. C B Zonary Cotyledonary C

Compound villi

v

Discoidal Primary placenta Incomplete with compound villi E Zonary D

Secondary U:u placenta C.Zonary F Cotyledonary;

Diffused; B. ofvilli. A. distribution Fig. based on the 22.8 types of placenta Bidiscoidal. Differer Discoidal; F. D.incomplete zonary; E. Cotyledonary type with villi distributed in isolated patches as in goat and rumi goat and rumin sheep, cattle. like LOnary type with villi arranged in a definite band or girdle encircling the middle . chorionic sac. of blastosy. Examples: It is found in carnivores like cats, dogs, etc. areas. It is called1 Discoidal type with villi located in one or two discoidal monodiscoidmonodiscoia.. placena when the villi form one patch and bidiscoidal if the villi are present in itwotwo disc.opladisc-s Examples Discoidal placenta is found in mouse, rats, rabbit, monkey, anthropo shapedt D. apes andd manatea Histological Classification of Placenta Based upon the histological relationship of embryonic villi with the uterine wall and erosion the uterine and thethe degree mammalian placentae are classified into five types dege

Foetal tissue OR0COCODO0DDo0E

Maternal tissue

Epitheliochorial Syndesmochorial' Endotheliochorial

Foetal tissue

8

Maternal tissue e

Haemochorial Fig. 22.9 Different of Haemoendothelial types placentae found in mammals based on the intimacy of foetal and mat utrluon J07 : In EpitheliO-chorialPlacenta this type of 1. placenta the pitheliumremair in close contact but b contact both of them retain their embryonic trophoblast and the uterine .epressions of the uterine original layers. The pocket like wall (Fig. chorio-allantoic villi in the 22.9). lie (a) endothelium of foetal blood vessels. Foetal layers (b) chorionic connective tissue (c) ectoderm of chorion (chorionic (d) uterine epithelium epithelium). Maternal layers (e) endometrial connective tissue ( endothelium of maternal blood vessels. The chorio-allantoic villi lie in the pocket-like depressions of the uterine wall. Since, epithelium of uterine wall lies in contact with the chorionic-epithelium. This type of placenta is called uterthelio-chorial placenta. It is found in and ehorial placenta. marsupials, ungulates (pig horse, etc.) and lemurs. It is the type placenta. most primitive of amdesmo-chorial Placenta: In this type of placenta the chorionic villi erode the uterine wall " uterine epithelium is ruptured and the chorionic epithelium lies in contact with the connective sothat the uterine wail, eg, Sneep and cow, (i.e, ruminant ungulates). tissue of the Endotbelio-chorial Placenta: Not only the uterine epithelium but the uterine connective 3 to the extent that the chorionic of villi comes in contact with the tissue is also eroded epithelium i cat and other carnivores. endothelium of maternal blood vessels, e.g., dog, uterine conmective tissue endothelial wall 4, Haemo-chorial Placenta: Here, epithelium, and the ofthe matermal blood capillaries are eroded with the result that the chorionic epithelium comes in direct blood which circulates in the lacunae formed in thickened trophoblast of the contact with the maternal vill, eg., man. In this uterine uterine connective tissue, 5. Haemo-endothelial Placenta: type epithelium, are eroded with the result the endothelium of maternal blood capillaries and the trophoblastic epithelium rabbit. foetal capillaries lie freely in maternal blood, e.g, PHYSIOLOGY OF PLACENTA for nutrition, the mammalian embryo The mammalian are with almost no yolk. Therefore, eggs Hence, a close contact is the maternal through the placenta. depends on their supplies from body are entirely maternal and foetal vascular supply n maternal and foetal tissue and the estabished between the the blood circulation maternal blood does not enter of the never in direct contact. The COmmunication but barrier. Morphologically, a placental the or Vice-versa. The two circulations are separated by the cOryo tissues placenta lying between maternal of the maternal and foetal of the lt Pna barrier is composed different types of placenta. may of placental barrier varies in dblood spaces. The composition epithelium, connective maternal tissues, i.e., trophoblastic the three of foetal and T all layers connective tissue and endothe hum ot fi d uterine epithelium, mondothelium of foetal capillaries, and the endothelial layer of toetal mareti somesOme blood capillaries or in the last stages only nmembrane, allowng al as semipermeable Physiologically, the placental barrier acts substances SuDstances to pass through but keeping out others. nourishment oxygen mother for its and completely on carbon dioxide Therefore, in the embryo depends wastes, and mammals, removes nitrogenous for Supply Mother also and kidneys Supply the developing period. intestine,intestine, liver,liver, lungs lungs and kIncys throughout e as ,stomach, essenual. from the mother, therefore, acts Is ne embryo. Cpregnant nourishment ofmother foetus.foetus, that health and proper It is,ererore, therefore, obvious good Functions materials present in is the interchange of function of placenta the placenta either l0o0 primary to through he substances have pass by mother All the is and embryo. oftransmission associated withith the mplesimpe &fibse etc. The mode or active transport, inorganic materials sucesize of of m nOcytosis by water soluble ials such mol of carbon-dioxide, a olecules oxygen, and soluble organic substances Ch of potassium and magnesium ike gucose phospha sodium, wastes, etc. pass placern8lucochlorides a vitamins and nitrogenous throughough place Onosaccharides, hormones, absorbed ta and are by the cellslls of tro by i of polysaccharides, lipids proteins troph Macromolecules carries out following functions- POblag Wnich are obtained by pinocytosis. Thus, the placenta oblastic in the transportation of 1.Nutrition: Placenta brings about nutrients disaccharides, amino acids and small lipid molecules) from maternal blood stream into(monosaceh thchthe and carbon Respiration: Placenta helps in the exchange of oxygen dioxide betwa foetus. 2. maternal blood diffuses into foetuoe noner and thus, helps in respiration. Oxygen from the oxygen concentration is comparatively less than in maternal blood. Similarly, diffusion ofblood,C Whw foetus blood into the maternal blood stream is also facilitated. of CO, f 3. Excretion: The nitrogenous waste products produced as a resultof of metabolicmetabolic activit.activities embryo diffuse through placenta into maternal blood stream. 4. The in the blood of mother Immunity: antibodies developed against certain diseae. diphtheria, measles, smallpox, scarlet fever, etc., are passed from mother into the foetus. These in passive inmmunity and insusceptibility to these diseases. roduse 5. Transport of Pathogens: Certain pathogenic organisms like viruses diffuse If mother is through placemcemta during pregnancy infected with some virus, its to cause organisms manage enter the foetus an infection. Viruses causing syphilis, measles, smallpox, if mother gets infected chickenpox, rubella, etc. infect the foen during pregnancy. Some of them even enter the may cause congenital foetus during early pregnancy. deformities, if thess 6. Transport of Drugs: Some drugs taken by mother barrier and may even cause during pregnancy cross the developmental deformities. The placemi by ladies as a sleeping sedative and to avoid nausia and drug, thalidomide, which was usei was found to morning sickness cause deformities in limb during early pregnancy (25 to 44 of development of the as defective . The children foetus, perforation of anus and borm to such mothers had developmer phocomelia. The children are flipper-like limbs, a condition called thalidomide babies. know. teratogenic. Drugs like quinine and aspirin at as 7. of Storage Substances: Placenta participates in the stores materials such metabolism of proteins. as fat, glycogen and iru an 8. Secretion of Hormones: Like endocrine progesteron, estrogen, glands, placenta secretes 1ones such of and gonadotropin, placental many hormmou pregnancy lactogens, etc. ntenan and prevents premature Progesteron helps in contraction of muscles of parturition. Relaxin helps in ne tn uterus and urethra. birth by relaxation of pelvie 9. Protection of Foetus s* pregnancy is against Bacterial impermeable to Infection of firsthalfe of many of bacteria and Mother: PlacePlacentanta during influences maternal ill macromolecules. It, during earant health on therefore, placenta becomes more the foetus. reduces chances permeable and However,r, in there are chances thethe later halfhalf ofor pregn of passing the pifoser to foetus germs from mou Infertility

the inability to . Infertility is infertile. ina Indian society ceive and to be In thethe Indian she is said animals. society infertility conceive to many ertility is able to common woman is not lf a only but is to human beings callod confined taken place then it is d not has never a curse. miscarriaoa to be Ifconception child birth or primar onsidered secondary. after a miscarriage then it is or place thnt be primary not take in the male or in Infertility may does found either le in the hand conception defects emale. on the other if due to may be determined. ertility, Infertility cannot be infertility. correct cause secondary checked the alled are nless both the partners REASONS FOR INFERTILITY

are few important ones given below Males in the males a attributed to infertility causes are after an attack of mumps, Though many in the testes usually of spermatozoa T.B. Deficiency in the production of Gonorrohoea or due to an attack male genital tract An obstruction in the gland. unfavourable secretion of theprostate An structural malformation of the penis. intercourse due to a semen during A faulty delivery of from the hypophysis. Insufficient secretion of the gonadotropins become erect during intercourse. Failure of the penis to testes. Cryptorchism orundescended due to inflammatory diseases. .Occlusion of the vas deferens in the A low percentage of live spermatozoa ejaculate. Exposure ofthe scrotum to very high temperature.

Females ms. of from the neck of the uterus which may block the entry Speu . An unfavourable secretion Presence of a tumour in the uterus whic may prevent implantation. Obstruction of the uterine and fallopian tubes due to disease. of A failure the ovary to Infection and produceduce eges. damage of the ovaries .Improper development of the vagina and Inflammation of the oviduct, non-canalization. The hymen may be rigid and prevent the entry of .Improper development of the external penis. Psycosomatic like tubal genitalia. reasons spasm, etc. .Veneral eases the damaging reproductiveve .Early onset of menopause. system like leucorrhoea, .Sexualincompatability. gonorrthoea and syphilis. h the couple may be barren due to any of the ers is to be made to locate the above said exact reason. reason a careful Once located it is study of possible to cure in both TESTS FOR some cases. INFERTILITY OR STERILITY 1. Tests for Man

The first test is the examination of the semen of the man. This has to be done within emission from the collected one hour ofi body. Sperms directly from man as well as those collected from the neck of cervix of the woman immediately after intercourse must be examined. The fetilization of the sperms depends on the following six factors potential .Volume of the entire ejaculate. .Total number of sperms in the ejaculate. .Number of spermatozoa. Percentage ofmotile spermatozoa. Quality of motility. Percentage of spermatozoa with abnormal shape. count of 10,000,000 ml is considered to be normal, even a a count 60,000,000 per found it is Though sperm of 75% to 60% activity is about fertilization. If about per ml is sufficient to bring satisfactory.

2. Tests for Woman or tube is open not. lis1s out whether the fallopian the female is that of finding which will go through e main test for the the uterus is sent into tested under pressure can be by test gas movements Rubins test. In this and its e of gas tests tail then C avdomen. The presence twice. If both and enter the conducted substance tube must be fallopian Rubins test radio-opaque symptoms. The of Or cinical the injection by test involves PE conducted. This is to be photography. uterinrine it X-ray the Hysterosalsalpingography following by examination of tubes and then chemical into the iterus and as fallopian as well and uterus the vagina CAamination of secretionsetion also must be done. REMEDIAL MEASURES

1. In Males In males if there is any blockage in the vas deferens it can be removedd by surgery. The ssna can be improved by hormonal treatment. erm counmt 2. In Females

n temales, most of the structural malformations can be corrected by surgery.

The secretions, forming plug-like structure at the neck of cervix can be removed. In case the Rubin test shows positive reaction for blockage of Fallopian tubesubes inflation h dioxide is tried. This removes the blockage in the tubules. by carbon In case of faulty ovulation or fertility related to an ovulation, ovulation can be induced Synthetic drng, clomiphene citrate. Women who fail to respond to this drug aretreed by drug are by a human menopausal gonadotropins. treated with But, human chorionic gonadotropin (HCG) is not used because it may cause follicles ovulation from simultaneously resulting in multiple births. many Bromocryptine, Metrodin and may be used to induce ovulation Cyclofenil when the Drolae level is raised in blood. actim Women with blocked or infected fallopian tubes can resort to in vitro transfer of sperms. fertilisation or emhn.bryo Women whose husbands have low count or no the sperm sperms, can be artificially husband's donor's sperm. inseminated with Study Questions 1. Give reaons for infertility in man and woman. 2. Summarise tests for women fertility. 3. Write short note on infertility. Birth Contro

also the . Sanger. She started the movement in Mrs. Margaret first coined by term birth control was he 1916, she said: delivered in with inten. O.d.A. In famous speech, to be planned an her to be desired, sity of love child is to be wanted, The first right of every that gives its title to being." the world and in India in nar: birth control in the need for This statement clearly explains explosion. Thouoh is the population for birth control Though and compelling reason 1nis calis tor population The main in way. practical ann not increase any a and bounds the resources do approach increases in leaps birth control. available today is to the problem and the only answer CONTROL REASONS FOR BIRTH To control increasing population. To maintain a healthy family. children. For better education and better care of the without difficulty. To help parents to rear the children any In the interest of health of the mother. child births affect the mother's income. Ifboth parens are working then frequent Financial considerations ofthe parents. or in Caesarian births. In special cases like Rhesus incompatibility After sudden ilness or after major operations, etc. .To have only the limited number ofchildren the couple wants to have.

MEASURES OF BIRTH CONTROL There are two kinds of birth control measures: (a) Contraception (b) Abortion. Contracepulv Contraception: In this method attempts are made Various devices have been used n madede to prevent Various to prevent to destroy the sperm, after onception. se methods are sperm, themconception the contraceptive methods in preventvent them from intercourse opular the takes The reaching ovum or place. The aims of . Abstinence prevent ovulation itself. .Coitus interruption .Rhythm method

.Douching Contraceptive chemicals .Condom or sheath .Diaphragms .Intrauterine devices Alteration of the nature of the cervical mucousa

.Pills Stilbesterol .Tubectomy Tubal rings Vasectomny 1. Abstinence: When the couple refrain from the act of sexual intercourse it is called abstinence. even sanction. Mahatma Gandhi also This is 100% successtul and has religious recommended this method, but it is very difficult to be followed by young people. Withdrawal: This method no artificial devices and is one of 2. Coitus Interruption or requires In this method the male withdraws his penis from the vagina during the earliest birth control methods. an in coitus or intercourse. This before the ejaculation takes place. This involves interruption mating just this method. 1. Some spermatozoa There are two main drawbacks in method is not always successful. semen o0ze out without the knowledge before climax is reached and also some may may be released even the and physiological problems to both partners. man. 2. It involves psychological of the of the sperm and the the perishable nature Method: This is based on study of the a sperm 3. Rhythm released from the ovary. Normally on which the ovum is it Ovum and also the approximate day undergoes many changes when or four days. The egg and an ovum for three Survives for about a day the uterus it is over-mature and is not n the time it reaches tube. the fallopian tube and by through the fallopian With passes through fertilized when it passes known, and it must be of ovulation 1s to be fertilized. Therefore, if the exact date USition to avoid impregnation, Dasic facts in hand it is possible be fertilized. Se fit condition to menstruation tne time when the egg will be in a which begins as with the day on to be avoided, involves 28 days that has woman is the day women of a This sonme nenstrual cycle the 14th day. occurs in occurs on ovulation ovulation because first day. such a perfect cycle after. This is intercourse three days not be any ihwhich and before and also there should on andso also a fewodays Thus, iod. The days 1 menstrual cycle. period. 28th day are betweenbetween 12th and 16th day of the called the danger h8th to This period is and 10th to both inclusive. 9th day the 17th dayday days safe days. Thus, Ist to ne are called the rcourse can take place not take place. However, safs fertilization may normally ol pe saie period wnen An average pregnancie iod aed thee has occurred. 25 when pregnancy womcn studied in coT l00. safeand there.are cases in 100 the that may occur urse ol year(i.e. the numbecr pregnancies duc to the tolloWing reasons: of failure rate is one beern gynaecologists. This yeax by carnnot use this method. About menstrual cycle who have irregular 16% Women be uscd by them. of he wc this method cannot Ve iTegular cycles and as menstruation may not occur s cannot be followed for a After childbirth this method and when it occurs it wil! be iregular. lew m menstrual cycle and make it irrepula. effect on the ar Mental upsets have a definite 45 to 50 the menopause perlOd years of Women who are about to reach age menstrual cycle and cannot use this meth hes menstruation will stop) have irregular hod. ln many women menstrual cycle is also irregular in their yung age when they are ne . also cannot follow this method ally height of their reproductive activities. They It is difficult for many women to keep track oftheir menstrual cycles and also thei. . also their safe and may commit mistakes. pe Restricting love making to a few days and abstinence to other days is practicable

MENSTRUAL CALENDER

. menstruation... 3 7 9 11 12 13 14* 15 16 17 18 19 21 22 23 24 25 26 27 28 *Ovulation 1-Menstrual cycle begins again. Bold letters indicate danger period. On the whole this is not a good method to be recommended. 4. This is one oldest Douching: of the method which is not followed much now. It the very invon douching of the vagina with a spermicidal solution. An irritator is used for this This done purpose. hastu immediateiy after the intercourse. The spermicidal chemicals immobilize the washed out the flow sperm which by of liquid. This is also not a safe method and the rate be 40 per 100 women. pregnancy may about 5. Contraceptive Chemicals: Many contraceptive chemicals are available in the form of ur jellies, and foaming tablets. The creams andjellies are to be applied before intercourse with the applicator. The foam tablets, if neip inserted, form foam which spreads into the vaginal cavty. chemicals have the power to immobilize and kill the spermatozoa and thereby prevent However, ifthe sperms are directly ejected into the neck tertla of the cervix and have easy access to pregnancy may Occur as the sperms escape the direct ne a very safe method. effect of the spermicidal chenicals. This 6. Condom or Sheath: A tight fitting sheath made is pensl time of intercourse. Some of the sheaths of rubber used to cover the are lubricated to erecea flow of semen into the facilitate easy This vagina. This is the most fitting. shean p these sheaths are at popular method in use and is cheap. tu supplied subsidised rates to very ilut help the normal rate ot pregnancy rate is I per 100 women. common man. The Sometimes the nor orr l torn during intercourse. sheaths may be or have Otherwi1se this is a safe method. damaged noc 1. Diaphragm The diaphhragm isis in t lastic ring atthe rim. This is in the form before meant to of a womenomen D intercourse and close thethe opern:Ound.roun thin hythe incan be gm eloses hethe entra left opening to the membra made the wall entrance to the inside up of rubber with betweenpuyhe wall of the without cervix.The diap Space uterus space and any iaphragm can spermicidal cre vagina of be idal creams ana jellys can be rim. To sometimesbe fecling inserted applied to doublydo ssperms may discomfort. :lure of the doubly sure find their Though the The rate of failure of thethe device that no way device is only 6 diaphragm before such through the human error. per 100 insertion. entry takes women per place, 8. Intra-utertorine year. The main Devices (UD): These cause forfor uterus men devices failure isis side the of and allowed to are in the inside f remain there form of four types coils known, viz. for plastic coils are Lippes considerable that are two loop, time even inserted have nylon threads attached at Birnberg bow, up to one loops one end. These Saf-T-coil and year. There coil by just ing the and threads the coil. the finger feeling it. The help wearer toMargulies These can be loa led with a loop is know the inserter loop by it placed in presence of inserter a straightening and then it position an original shape. The is by inserter. The regains shape prevents inserted into the conception by one or uterus where the makes the egg move down the more of the loop followingng ways he falop1an tube very fast time taken for the egg to reach thereby prevents fertilization. the uterine wall is remains unprepared to receive it. very short the wall (endometrium The irritation caused by the loop which to happens be a foreign makes Zygote to move down. body even an implanted The DH value of the cervical is altered canal slightly due to the precsence thread makes fertilization difficult. of the and this The presence of the mechanical device also affects the movement of the sperm. .The endometrium is also prevented from forming the necessary layers to help implantat the irritating act of the loop. This method is very cheap and efficient. In a country like India where the women are nor much the is the educated and shun other methods which involve personal care and efficient handling. loop answer. The failure rate is very low being only 2 to 5% per 100 women per year.

in the intra-uterine devices. They are: There are certain disadvantages and 10 to 15% women the wearer in about of the The UD is expelled without the knowledge of risk of pregnant. they run the becoming lUD. presence of the occurs in spite of the In cases pregnancy about 1% of the oceur. intermittent menstruation may in some women who wear the IUD, based on method is the preipie the Mucous: This women Cervical In a nomal of the Nature of cervical canal. of Alteration into the The nanre the crevical canal. sperm from vagina of the movement of liningotthe taken is 0.5 g retarding the mucous medicine and aided by common is facilitated The the movement of sperms chemicals. n cervieca the certain chemical changes altered taking some the mucous can be by about physicalnarure. lining medicine brings atfected. The of This is mortality chlormo every day. sperm heavy o chlormadinone ace movement the aso acetate the of There is with the can: thereby the sperm. interteres value increases movement of however and the pH the method hov to retard This the also changed reduced. mucous lining is is also u Spemssperms andand thereby the number of sperms much recommenaed. Strual cycle and is not very P pills use OVulatio the of in ththe form progesterons tion by t behind ratecpills

principle and at the be taken main oestrogens to one a The are like capaue pills occurs norn day 1u. The pills: hormones The he method. Menstruation 2R îrom ertain for administration of cert woman contraception day. reason a ts oral 26th tot calledled the till the lffor some is also days However, ifsfshe forget This for 21 5th day. apil menstruation the day. started on succeeding pills are take the day of has to be the methodshods only. Ifthe the pill two pills taker take contraceptive day and again must side effectects were aileg then she other many on reglat day Though on the use particular to depend ny then she has cent only. safe. for 2 or 3 days one per is less than pills is the use of powerful hormo the rate failure that the of proved like rape, hormonewithinlbe Stilb en studies havej cases be taken statistical particular and must be taken within f some besteri pills, In days ays t Stilbesterol: for and nauseati taken five unpleasant Use of has to be very 1. This treatment is This destroying the to prevent nception. conception by used be delayed. o and should not prevents This method is. th5ezygote or t intercourse hormone embryo. ethod is, there on alternative. This implanted no even the cases there is or before implantation multicellular embryo the blocking of the fallon an emergency device. and aubes. T method involves has to be h a surgical operation done This is knots. This ingt 12. Tubectomy: between the childbirth whe twice and cut few after tubes are tied within a days fallopian done and hp is fairly easyif additional hOspitalization wall. The operation involve be cove abdominal reach. It does not and easy to tubes remain prominent withinAn the advanced maternity method period. that has been deviced recently involves the use of a flexible instnmarslectical and the the fallopian tube tube is eles and uterus into introduced the vagina the tube and the can be through to the tissue in tube is hldl. cauterization causes slight danmage cauterized'. The cauterization has to be done in both thehi into the uterus. The the entry of the eggs failure rate is nil preventing and is very safe. The almost alternatively. This does not require hospitalization tubes are latest methods in which the fallopian folded and in 13. Tubal Rings: It is one of the called laparoscope. This has become very popular nen by synthetic rings with the help ofan instrument can it done if fulfill the follow Women are first screened before this operation. They get they conditions: (a) ifthey have completed 15 days after child birth, (b) should not have uterine tumou and shouldn= uterine adnexa, (c) general health condition must be good, (d) should not be obese, (e) have any fluid in the abdomen. Before operation the woman is given what is called Lytic cocktail that contains Oxygen and Nir. Oxide. Tais will make her feel dizzy. After giving a local anaesthesia, a neddle is introduced beo umbilicus into the peritoneal cavity and about 1.5 to 2 litres of air or carbon dioxide is injected to pusha intestines to one side.A small incision of about I cm is made and the Trocher Canula of the Lapans is introduced. It is possible to see the interior of the abdominal cavity clearly through the it contains a and lens laporos light system. The fallopian tube is pulled and folded and the over the fold. This synthetic ring5 keeps the fallopian tube in a folded and tied condition. br in this The Both the fallopian t ringed way. ring is made of a up synthetic material and does not cause irritation. It can be allowed to remain uithi in the body for The few minutes and the is years. whole operation is patient kept under observation for compic srate m method is 100%. 6 hours in the hospital. The suc 14. This is a Vasectomy: very simple deter man. The deferens is cut and surgical method the of the vas vas then both the involving cuttingtting th e testi ends are folded he tst and tied so that the sperm move out. Th operatio cannot does not man does no need my loose his sexual any ho ejaculatoctonTheted. The failure rate inin this potency and durializatin latea method isis les d durinospitalization ing interc and is and asectom. less urse a f fairly Bothth ubectomyctomy and V than one auid popular now. TuD tomy are per cent. uid free from After operation have beenVasectomy are methods everse is performed butmethods which are not spermatozoaspermatozoa is finaldecision is taken to they are not when a stop child birth. common.reversible. A few This successfulsuccessful cases method must be of adapted only Abortion is the moval of the ABORTION foetus othermeasures: and there is no premature from her measu alternative.native. It is mother' s uterine abortion.on.In In. India it isis lo and wall. It is are against India painful legal and is done in involves opted only when all abortion. Government hospitalization. Manyy Hospitals. There are religions 1. D and C : and three Dilatation In methods for r of a Curettage: this able the entry spoon-spoon-like called method the cervix is apparatus the curette. dilated or lawly scrapped and remOved from its The embryo and spread open to attachment to the uten the 2. Vacuumeum Suction: It is erus. covering membranes Suction: another method in which This is the is Taspirator. operation less embryo sucked an painful than the previous by instrument, the 3. Use of Abortifacients: This method. method invovles the neaf sacs injection of the surrounding the embryo. Of all the hormones called three methods this is the prostaglandins use. least painful and is now in Though the common person may confine himself or herself to the use of ontral. an for only one method of intelligent person may opt more than one An birh nill after the methods. educated woman may immediately marriage and may change over to the start with the diaphragm after the first child. The this case may use the condom. After some the man in years same woman use the when want to end may intra-uterine device and finally they child-bearing either can of them go in for serilization. It is that in vears to come some other better method be possible may found which may prove to be useful for all all persons. times and for

Study Questions- 1. Discuss necessity of birth control. 4. Enumerate various methods of birth control. Discuss one of them in details. Which method is the safest?

. Describe clearly what do you understand by rhythm method of contraception. 4. Describe various physically used contraceptive devices. bi use is not encouraged now for dre contraceptive pills? How they are used? Why their being control? 6. Write shoret notes on: (a) Tubectomy (b) Vasectomy c) Laparoscopy (d) Condom (e) Menstrual calenders.