Chapter 3 Physiology in Chapter 3 Physiology in pregnancypregnancy

pregnancypregnancy:the condition of being with child :the condition of being with child or gravid.from the fertilization to the or gravid.from the fertilization to the expelling of the fetus with placenta and expelling of the fetus with placenta and membranes.membranes.

Sec.1 fertilization, development,transport Sec.1 fertilization, development,transport and implantation of fertilized ovumand implantation of fertilized ovum. .

Sec.2 the formation and function of fetal Sec.2 the formation and function of fetal attachment.attachment.

Sec.3 the maternal changes during Sec.3 the maternal changes during pregnancy.pregnancy.

Sec.1 fertilization, Sec.1 fertilization, development,transport and development,transport and

implantation of fertilized ovumimplantation of fertilized ovum 1.1.fertilizationfertilization:semen enters vagina:semen enters vagina→spermatozoons co

ntact with endometrium,the α-/β-amylase remove the decapacitation factor on spermatozoons’ acrosomal enzyme,then the spermatozoons with the ability of fertilization(capacitation) in uterrus and fallopian tubes,the spermatozoons meet the ovum at the ampulla→external mem. Of acrosome rupture→acrosomal enzyme released(acrosome reaction) →the spermatozoons penetrate the radiate corona and zone pellucida→Fusion

2.implantation:fertilized ovum→vitelline sphere (early blastosphere) →into uterine cavity→late blastosphere→implantation including apposition,adhesion,penetration.

The necessary factors:The necessary factors: (1)the zone pellucida disappear. (2)the syncytiotrophoblastic cells appear. (3)synchronic development of blastosphere and

endometrium. (4)enough progesterone. 3.decidua formation:thicker,more vascular and e

dematous than premenstrual endometrium.

Sec.3 changes during pregnancy ( 一 )changes of reproductive tract. 1.uterus (1)corpus:a increase in size (7*5*3→35*22*

25cm),the capacity (5→5000ml),the weight(50→1000g),the thickness(1→0.5-1cm);the rate of the hypertrophy of different parts varies(fundus→inferior portion→cervix) so that the contractility decreases from fundus to cervix , the fetus is delivered.

with the pregnant weeks,more vascular(500-700ml/min)

(2)isthmus:softer and longer(1→7-10cm) (3)cervix:increased vascularity,edema of the entire c

ervix,hyperplasia of cervical glands. 2.ovary. 3.fallopian tubes. 4.vagina: violet coloration;desquamation of epitheli

um with more glycogen↑→acidity↑. 5.vulva:pigmentation. ( 二 )breasts

An increase in size and a nodular sensation due to thAn increase in size and a nodular sensation due to the hypertrophy of the mammary alveoli,the nipples se hypertrophy of the mammary alveoli,the nipples soon become larger ,more deeply pigmented and mooon become larger ,more deeply pigmented and more erectile.scattered around the areola are some roure erectile.scattered around the areola are some roundish nodules called Montgomery tubercles which rendish nodules called Montgomery tubercles which result from the hypertrophy of the sebaceous glands.sult from the hypertrophy of the sebaceous glands.

三三 ..circulatery systemcirculatery system 1.heart:the growing uterus pushes the diaphragm up1.heart:the growing uterus pushes the diaphragm up

ward,with the result that the heart is displaced to thward,with the result that the heart is displaced to the left,upward and somewhat in the direction of the ae left,upward and somewhat in the direction of the anterior chest wall.a certain degree of rotation is belienterior chest wall.a certain degree of rotation is believed to take place.the capacity increases by 10%, the ved to take place.the capacity increases by 10%, the heart rate increases by 10-15bpm.heart rate increases by 10-15bpm.

2.output:increases from 10weeks,the peak at 32-34w.2.output:increases from 10weeks,the peak at 32-34w. 3.Bp.:few changes if any. 3.Bp.:few changes if any.

4.venous pressure:increased vp, in the legs is demonstrable in later months of pregnancy,which co4.venous pressure:increased vp, in the legs is demonstrable in later months of pregnancy,which contributes to the ankle edema,varicose veins in the legs and vulva during gestation.ntributes to the ankle edema,varicose veins in the legs and vulva during gestation.

Supine hypotension syntromSupine hypotension syntrom:supine position for a long time :supine position for a long time →inferior vene cava compressed→back-volume↓→output↓→Bp↓→cm. of hypotension.

( 四 )blood system 1.volume:increasing from 6-8w,peak at 32-34w, about 1500ml(1000ml of plasma,500ml of erythroc

ytes→hemodilution) 2.composition:RBC→3.6*1012/L,Hemoglobin→110g/L, WBC→10*109-12*109/L,coagulating factors→

most inceasing→hyper-coagulation,plasmal protein decreases mildly due to hemodilution.

(( 五五 ))urinary systemurinary system both RPF. and GFR.increase by about 35% and 50% both RPF. and GFR.increase by about 35% and 50%

respectively ,the metabolites of the gravida /fetus crespectively ,the metabolites of the gravida /fetus can be excreted.under the influence of progesterone,an be excreted.under the influence of progesterone,a condition of atonia in relaxation or loss of irritabilia condition of atonia in relaxation or loss of irritability not only of uterus,but also of the ureters,large boty not only of uterus,but also of the ureters,large bowel and bile ductswel and bile ducts→dilatation of ureters and renal pelvis associated with stasis of urine → acute nephropyelitis especially in the right side.

( 六 )respiratory system:in a word,the ventilation volume increases;the immunologic competence↓.

( 七 )digestive sys:estrogen→gingiva-hyperplasia progesterone→atonia of stomach and bowel→ heart burn,vomit,constipation

(( 八八 ))skinskin 1.the pigmentation of the areola,linea alba, vulva,occasional1.the pigmentation of the areola,linea alba, vulva,occasional

ly irregularly shaped,brownish patches of varying size appely irregularly shaped,brownish patches of varying size appear on the face and neck,ar on the face and neck,the the cloasma cloasma or the mask of pregnancyor the mask of pregnancy,which fortunately usually disappe,which fortunately usually disappears after delivery.ars after delivery.

2.during late months of pregnancy,reddish,slightly depresse2.during late months of pregnancy,reddish,slightly depressed streaks often develop in the skin of abdomen,and sometimd streaks often develop in the skin of abdomen,and sometimes also in the skin covering the breasts and the thighs.these es also in the skin covering the breasts and the thighs.these striae gravidarum occur in about 1/2 of all pregnancies.striae gravidarum occur in about 1/2 of all pregnancies.

(( 九九 ))endocrine changesendocrine changes 1.pituitary gland:the anterior lobe hyperplasia1.pituitary gland:the anterior lobe hyperplasia (1)high level of E and P(1)high level of E and P→inhibites Gn releasing (2)PRL:increases from 7w,peak ante-delivery 2.adrenalin cortex:the level cortisol and aldosterone

increases by 3 and 4 times respectively

3.thyroid gland:the enlargement usually concomita3.thyroid gland:the enlargement usually concomitant with normal pregnancy due to hypertrophy of adnt with normal pregnancy due to hypertrophy of adenomatous tissue,to an increase blood supply and enomatous tissue,to an increase blood supply and to the formation of new follicles.but most thyroxin ito the formation of new follicles.but most thyroxin is connected with thyroxin binding globulin,so no hys connected with thyroxin binding globulin,so no hyperthyroidism occurs.perthyroidism occurs.

(( 十十 ))metabolic changesmetabolic changes 1.BMR:mildly rising .1.BMR:mildly rising . 2.weight: from 13w increases by 350g per week,abo2.weight: from 13w increases by 350g per week,abo

ut 12.5Kg during the entire pregnancy.ut 12.5Kg during the entire pregnancy. 3.metabolism of carbohydrate3.metabolism of carbohydrate (1)fasting-sugar higher due to higher insulin-secreti(1)fasting-sugar higher due to higher insulin-secreti

onon (2)insulin-resistant factors(2)insulin-resistant factors 4.fat metabolism 4.fat metabolism

Deposit of fat increasing charaterized by a hyperlipeDeposit of fat increasing charaterized by a hyperlipemia and a tendency to ketosis.mia and a tendency to ketosis.

5.protein metabolism:positive nitrogen balance5.protein metabolism:positive nitrogen balance 6.water metabolism:water-retention of about 7L6.water metabolism:water-retention of about 7L 7.mineral metabolism:in the late months of gestatio7.mineral metabolism:in the late months of gestatio

nn→ calcium and iron supplyingcalcium and iron supplying→to avoid deficiency of c

alcium and iron. ( 十一 )bone,joint and ligament 1.bone:no changes normally. 2.joint and ligament:relaxin→loosening of joints an

d ligaments→the birth canal widened.thanks

implantation

Hegar

Decidua change

True basal

capsular

Striea gravidarum