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Flashcards in Physiology of pregnancy Deck (23):
1

Describe the duration of human pregnancy?

280 days (40 weeks) from last menstrual period 

266 days (38 weeks) from fertilisation 

2

How is foetal age estimated?

Length and US measurements of foetus 

3

Describe the physical signs of pregnancy?

Cessation of mestruation

Morning sickness

Increased frequency of urination

Increased breast size

Fatigue

Darkening of areolae

4

How is pregnancy determined biochemically?

Human chorionic gonadotropin in blood and urine 

5

Where does hCG arise from?

Produced by trophoblast 

6

Why are physiological adaptations required in pregnancy?

Maintain uteroplacental perfusion

Maintain foetal demands 

7

What are the functions of the umbilical veins and arteries?

Umbilical vein carries well-oxygenated blood to the embryo

Umbilical arteries return embryoinic blood to placenta

8

How does material from the mother reach the embryo/foetus?

Placenta

Some material via diffusion, other materials must be transported 

9

Which organs does the placenta substitute for in utero?

Lungs

Kidneys

GIT

10

Describe the endocrine function of the placenta?

hCG: rescues corpus luteum

Human placental lactogen: breast development, maternal metabolic effects

Oestrogen and progesterone: pregnancy maintenance and breast development

11

Describe the difference between monozygotic and dizygotic multiple pregnancies?

Monozygotic: single fertilised ovum, genetically identical

Dizygotic: 2 oocytes ovulated and fertilised by 2 separate sperm, not genetically identical

12

Describe the changes to the cervix prior to parturition?

Softening

 

13

Describe the changes that occur to the reproductive system during labor?

Rhythmic uterine contractions

Cervical dilation 

14

How are the uterine contractions maintained during labor?

Positive feedback

15

What occurs during parturition after the baby is delivered?

Placental release and expulsion

16

Descirbe the regulators of parturition?

Trigger for labor unknown

Stretch of cervix stimulus

Oxytocin

Positive feedback 

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17

Describe the mammary gland development in puberty, pregnancy and late pregnancy?

Puberty: oestrogen stimulates growth of ducts and fat deposition

Pregnancy: oestrogen, GH and cortisol stimulate further gland development

Late pregnancy: progesterone stimulates conversion of ducts to secretory epithelium 

18

Describe lactation before birth?

Prolactin-inhibiting hormone blocks prolactin

High sex steroid levels supres milk production 

19

Describe lactation after birth?

High prolactin and low oestrogen > lactation 

20

Describe the effect of suckling?

Inhibits prolactin inhibiting hormone > prolactin > milk production

Oxytocin > milk ejection

Inhbits GnRH and ovarian cycle 

21

Why does suckling inhibit GnRH and the ovarian cycle?

Want all of the energy going into breastfeeding, not carrying another child 

22

Describe the hormonal control of milk secretion and release?

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