Endocrinology of pregnancy Flashcards

1
Q

In relation to the size of a sperm cell, how long is the journey of a sperm from testes to oviduct?

A

100,000 times the length of a sperm (<1/10^6 make it)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens to most of the tubular fluid in men?

A

It reabsorbed within the rate testis and early epididymis under the control of oestrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What produces tubular fluid?

A

Sertoli cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What controls secretion of nutrients and other molecules into the epididymal fluid?

A

Androgens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the nutrients and other molecules for?

A

Provide journey for impending journey and coat the surface of the spermatozoon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where does a vasectomy occur?

A

Vas deferens at the bottom end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does concentration of spermatozoa compare in vas deferens compared to later on?

A

It is much higher at the vas deferens as lots of fluid is added along the way

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does semen consist of?

A

Spermatozoa
Seminal fluid
Leucocytes
Viruses (potentially)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Seminal fluid from

A

Mainly from seminal vesicles, prostrate, bulbourethral glands

small contribution from::
-epididymis/testis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are spermatozoa in the seminiferous tubule like?

A

Quiescent and incapable of fertilising an ovum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are spermatozoa in the vas deferens like?

A

Capable of limited movement (whiplash)

Limited ability to fertilise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When is full activity and fertilising capability achieved?

A

When in the female reproductive tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the process of reaching full activity and fertilising capability called?

A

Capacitation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What percentage of spermatozoa in ejaculate make it to the cervix?

A

1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do the spermatozoa achieve capacitation? (3 things)

A

Loss of glycoprotein coat
Change in surface membrane characteristics
Whiplash movements of the tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why can the spermatozoa lose the glycoprotein coat?

A

It has a protective function in the vagina but once in the uterus it isn’t necessary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where does capacitation occur

What two things are all the components of capacitation reliable on?

A

In ionic and proteolytic environment of fallopian tubes

Oestrogen and calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens to a sperm as it approaches an ovum?

A

There are changes in the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does a spermatozoon bind to?

A

ZP3 glycoprotein on zona pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens after the spermatozoon binds to ZP3?

A

Progesterone stimulates the calcium influx into the spermatozoon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does the calcium influx lead to in fertilisation?

A

Calcium dependent acrosome reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does the calcium dependent acrosome reaction enable?

A

An exposed spermatozoon recognition site to bind to a second glycoprotein (ZP2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What happens once ZP2 has bound?

A

The acrosome releases its enzymes allowing penetration of the zona pellucida so that the head of the spermatozoon can enter the ovum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Where does fertilisation normally occur?

A

Fallopian tubes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does fertilisation lead to?

A

Expulsion of the second polar body and the zonal reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the zonal reaction?

A

Cortical granules release molecules which degrade the zona pellucida, this prevents further binding of other sperm. This is also calcium dependent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the conceptus?

A

The product of the zygote starting to divide (baby early days)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What happens to the conceptus as it moves from fallopian tubes to uterus?

A

It continues to divide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How long does it take for the conceptus to travel from fallopian tubes to the uterus?

A

3-4 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How does the developing conceptus receive its nutrients until implantation?

A

Uterine secretions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How long does the free living phase last (between formation and implantation)?

A

9-10 days

32
Q

While this occurs, the woman is in her luteal phase, what does this mean?

A

There will be high oestrogen and progesterone

33
Q

What does the conceptus first compact to form?

A

8-16 cell morula

34
Q

What does the 8-16 cell morula then become?

A

A blastocyst

35
Q

What are the two parts of the blastocyst and what do they become?

A

An inner cell mass- becomes the embryo

Trophectoderm- becomes the chorion which becomes the placenta

36
Q

What facilitates the transfer to the uterus?

A

Increasing progesterone:oestrogen ratio due to the luteal phase

37
Q

What is the reason for implantation?

A

Establishing a system for getting nutrients form the mother to all cells in the embryo

38
Q

What does the initial attachment phase consist of?

A

Outer trophoblast cells making contact with the uterine surface epithelium

39
Q

What is the decidua?

A

Thick layer of modified mucous membrane which lines the uterus during pregnancy and is shed with afterbirth

40
Q

When does decidualisation of the underlying stromal tissue occur?

A

Within a few hours of implantation

41
Q

Which two molecules are of particular importance in attachment?

A
Leukaemia inhibitory factor (LIF)
Interleukin 11 (IL-11)
42
Q

Where does leukaemia inhibitory factor come from?

A

Endometrial secretory glands

43
Q

What does leukaemia inhibitory factor do?

A

Stimulation adhesion of the blastocyst to the endometrial cells

44
Q

Where does interleukin-11 come from?

A

Endometrial cells

45
Q

What is interleukin-11 released into?

A

Uterine fluid

46
Q

What is the decidualisation reaction?

A

Invasion of the underlying uterine stromal tissue by the trophoblast cells of the blastocyst

47
Q

What happens within hours due to the decidualisation reaction?

A

Increased vascular permeability in the invasion region

Localised changes in intracellular composition and progressive sprouting and growth of capillaries

48
Q

What factors are involved in the decidualisation reaction?

A

Mainly IL-11
Histamine
Certain prostaglandins
TGFbeta- promotes angiogenesis

49
Q

When does hCG reach a peak?

A

8 weeks

50
Q

When is hCG vital and why?

A

First 6 weeks as its job is to replace LH

51
Q

What happens in terms of hormones that leads to menstruation?

A

Levels of oestrogen and progesterone fall

52
Q

Why is hCG released during pregnancy?

A

It is needed to maintain the stimulation of oestrogen and progesterone

53
Q

What produces hCG?

A

Trophoblast cells

54
Q

How does hCG work?

A

It can bind to LH receptors on corpus luteum hence replacing the effects of LH

55
Q

Why are the ovaries no longer necessary in a pregnancy after 5 weeks?

A

The placenta will have taken over production of the hormones

56
Q

What happens to oestrogen and progesterone levels throughout pregnancy?

A

They increase and until the end, progesterone remains the dominant influence

57
Q

What is human placental lactogen?

A

It is produced by the placenta
Growth hormone
Prolactin like effects

58
Q

What are the three components important in providing steroids?

A

Mother
Foetus
Placenta

59
Q

What does the mother provide in terms of steroids?

A

The precursors

60
Q

What is the most common precursor?

A

Pregnenolone which leads to progesterone

61
Q

What causes steroid production in the foetus?

A

Progesterone

62
Q

What precursor does the foetal and maternal adrenals produce?

A

Dehydroepiandrosterone sulfate (DHEAS)

63
Q

What is DHEAS taken up by the placenta to produce?

A

Oestradiol and small amounts of oestrone

64
Q

What is the main oestrogen of pregnancy?

A

Oestriol

65
Q

If you wanted to look at the health of the baby, which oestrogen would you look at?

A

Oestriol because its source is completely foetal

66
Q

How is oestriol formed?

A

It comes from the conjugation of DHEAS in the foetal liver to form 16alpha-hydroxy DHEAS which then goes to the placenta which deconjugates it and uses it to form estriol

67
Q

What happens to most maternal hormones during pregnancy?

A

They increase

68
Q

What happens to the pituitary during pregnancy?

A

It enlarges

69
Q

What is responsible for the action of parturition?

A

Contraction of actin and myosin filaments

70
Q

What does the contraction of the filaments (parturition) require?

A

Calcium

71
Q

Why is oestrogen stimulating the production of prostaglandins important for parturition?

A

The prostaglandins stimulate the production and release of calcium into the cytoplasm from intracellular stores

72
Q

What effect does progesterone have in relation to parturition?

A

Opposite effect to oestrogen
Inhibits prostaglandin synthesis
Inhibits oestrogen receptors

73
Q

At parturition, oxytocin will be released, what effect will this have?

A

It will bind to its receptor and open calcium channels allowing calcium ions to move in from outside

74
Q

What does prolactin do?

A

Promotes milk synthesis

75
Q

What does oxytocin do?

A

Promotes milk ejection

76
Q

How are prolactin and oxytocin linked neurologically?

A

They have the same neuroendocrine reflex