Endo 11 - Endocrinology of Pregnancy

Question 1

Where is tubular fluid reabsorbed?

Answer 1

Rete testis and early epididymis

Question 2

What hormone controls the reabsorption of tubular fluid?

Answer 2

Oestrogen

Question 3

Where is oestrogen mainly found in the male reproductive tract?

Answer 3

Tubular fluid produced by sertoli cells

Question 4

What stimulates the release of nutrients into the epididymal fluid?

Answer 4

Androgens

Question 5

What is the role of these secreted nutrients into the epididymal fluid?

Answer 5

provide energy for the impending journey

coat spermatozoon to protect from hostile environment

Question 6

In which part of the male reproductive tract is fluid reabsorbed and nutrients put in?

Answer 6

Epididymis

Question 7

Where is a vasectomy performed?

Answer 7

Lower end of the vas deferens

Question 8

What structures contribute to the seminal fluid?

Answer 8

Seminal vesicle 2/3

Prostate 1/3

Question 9

Why is fibrinogen and fibrinolytic enzymes needed in the seminal fluid?

Answer 9

After ejaculation, semen clot and must be broken down

Question 10

Describe the capability of spermatozoa in the vas deferens

Answer 10

Limited movement

limited capacity to fertilise ovum

Question 11

When do sperm reach full activity?

Answer 11

In the female reproductive tract

Question 12

What is the name given to when sperm reach full activity and capability?

Answer 12

Capacitation

Question 13

Name 3 changes that occur during capacitation

Answer 13

Loss of glycoprotein coat
whipping of tail
change in surface membrane characteristics

Question 14

What two things are the changes during capacitation dependent upon?

Answer 14

Oestrogen

Calcium

Question 15

Which receptor do spermatozoa bind to on the zona pellucida?

Answer 15

ZP3

Question 16

Once bound, what stimulates the influx of calcium into the spermatozoon?

Answer 16

Progesterone

Question 17

The calcium influx into the spermatozoa stimulates…

Answer 17

a calcium-dependent acrosome reaction

Question 18

Once the calcium dependent acrosome reaction has taken place, what recognition site can the spermatozoa bind to?

Answer 18

ZP2

Question 19

Once bound to ZP2, what does the spermatozoa do next?

Answer 19

acrosome release, allowing penetration of zona pellucida so spermatozoon can enter

Question 20

Where does fertiisation usually occur?

Answer 20

In the fallopian tubes

Question 21

What does fertilisation result in the expulsion of?

Answer 21

Second polar body

Question 22

When does the zonal reaction take place?

Answer 22

Straight after fertilisation

Question 23

What happens in the zonal reaction?

Answer 23

cortical granules release molecules that degrade the zona pellucida inc the ZP2/3
prevents further binding of sperm

Question 24

What chemical is needed for the zonal reaction?

Answer 24

Calcium

Question 25

What is the zygote called when is starts dividing?

Answer 25

Conceptus

Question 26

Describe how the conceptus receives nutrients before implantation?

Answer 26

From uterine secretions

Question 27

How long is the phase of the free-living conceptus?

Answer 27

9-10 days

Question 28

What stage of the menstrual cycle is this taking place in?

Answer 28

Luteal - so progesterone and oestrogen are high

Question 29

What does the conceptus compact to form?

Answer 29

8-16 cell morula

Question 30

What are the two parts of the blastocyst?

Answer 30

Inner cell mass | Trophectoderm

Question 31

What does the inner cell mass of the blastocyst become?

Answer 31

embryo

Question 32

What does the trophectoderm become?

Answer 32

chorion - which becomes the placenta

Question 33

What hormonal change helps the transfer of the conceptus to the uterus?

Answer 33

Increasing progesterone:oestrogen ratio

Question 34

What is a decidua?

Answer 34

thick layer of mucous membrane which lines the uterus during pregnancy

Question 35

What hormonal environment is needed for implantation?

Answer 35

progesterone dominance over oestrogen

Question 36

Name 2 molecules which are important in implantation

Answer 36

Leukaemia inhibitory factor | IL -11

Question 37

What does leukaemia inhibitory factor do?

Answer 37

stimulates adhesion of blastocyst to the endomtrial cells

Question 38

What cells produces LIF?

Answer 38

Endometrial secretory glands

Question 39

What cells produce IL -11?

Answer 39

Endometrial cells

Question 40

What is the reaction called when the trophoblast cells invade the uterine tissue?

Answer 40

Decidualisation

Question 41

What are the main changes that take place in this decidualisation reaction?

Answer 41

- increased vascular permeability - oedema of the tissue - growth of capillaries etc

Question 42

Which chemical factors are involved in decidualisation?

Answer 42

IL -11 | Histamine

Question 43

What is the role of HCG?

Answer 43

peaks at 8 weeks | mimics LH stimulating the production of oestrogen and progesterone

Question 44

What change takes place after about 5 weeks?

Answer 44

hormone production goes from corpus luteum to the placenta

Question 45

How do oestrogen and progesterone production change throughout pregnancy>?

Answer 45

Continue rising | Progesterone dominant

Question 46

What is human placental lactogen and what is its role?

Answer 46

growth hormone which has prolactin effects | important for growth and development of the fetus

Question 47

At what point would a oophorectomy have no effect on pregnancy and why?

Answer 47

6 weeks | hormone production is taken over by placenta

Question 48

What steroid precursor is provided for by the mother for the foetus?

Answer 48

Pregnenalone

Question 49

Which androgen is formed by the maternal and foetal adrenals?

Answer 49

Dehydroepiandrosterone (DHEAS)

Question 50

What is DHEAS used for?

Answer 50

Precursor for oestrogen production

Question 51

Which oestrogens are produced by the placenta using DHEAS?

Answer 51

Oestradiol | Oestrone

Question 52

Why are Oestradiol and oestrone not good markers for foetal health?

Answer 52

dependent on precursor production from mother adrenals and fetal so not a good measure

Question 53

What is the main oestrogen of pregnancy?

Answer 53

Oestriol

Question 54

How is oestriol produced?

Answer 54

DHEAS from foetal adrenals is conjugated in foetal liver to form 16-hydroxy DHEAS converted to oestriol in placenta

Question 55

What can be used to gage health of foetus?

Answer 55

Oestriol

Question 56

Describe how maternal hormones change during pregnancy?

Answer 56

Most increase during pregnancy | e.g. thyrotrophin, corticotrophin, prolactin, GH, PTH

Question 57

Which hormones decrease during pregnancy?

Answer 57

Gonadotrophins | hGH

Question 58

What biochemical change is needed for contraction of uterus during parturition?

Answer 58

increase in intracellular calcium concentration

Question 59

How does oestrogen increase the chance of contractions?

Answer 59

Oestrogen triggers Prostaglandins | Prostaglandins stimulate the release of calcium from IC stores

Question 60

How does oxytocin increase the chance of contraction?

Answer 60

opens calcium channels on endometrium

Question 61

What is the effect of progesterone during parturition?

Answer 61

keeps effects of oestrogen under control | so inhibits

Question 62

What change occurs when the foetus reaches a particular size?

Answer 62

Switch in steroid synthesis from progesterone to oestrogen | so oestrogen dominance

Question 63

What does the oestrogen dominance do?

Answer 63

Stimulate prostaglandin production which stimulates release of intracellular calcium which promotes muscle contraction

Question 64

What 2 hormones are involved in milk?

Answer 64

Oxytocin and Prolactin

Question 65

What is the role of prolactin in milk?

Answer 65

Milk production

Question 66

What is the role of oxytocin in milk>?

Answer 66

Milk ejection

Question 67

What are prolactin and oxytocin both stimulated by?

Answer 67

Suckling