Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MD3002 Physiology > Coitus, fertilisation and pre-implantation > Flashcards

Coitus, fertilisation and pre-implantation Flashcards

1
Q

What are the 4 phases in the human sexual response?

A
  • EPOR
  • Excitement sexual arousal - psychological and physical stimulation of erogenous zones. Tumescence and erection of penis and clitoris, engorgement of female tract
  • Plateau intensification of arousal
  • Orgasm series of involuntary muscular contractions in both sexes with intense pleasurable sensations
  • Resolution - detumescence and time during which re-arousal is impossible (may not be true of women)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the parasympathetic system predominantely associated with?

A

Erection

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

What is the sympathetic system predominantely associated with?

A

Ejaculation

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

How long is sperm viable for?

A

24 - 72 hours

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

How long are oocytes viable for?

A

12 - 24 hours

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

For fertilisation to occur when does coitus need to happen?

A

No more than 3 days befpre ovulation and no more than 1 day after

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

In what trimester do most miscarriages occur?

A

1st 1 - 12 weeks

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

When in pregnancy is there a 50% survival rate?

A

24 weeks (2nd trimester)

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

At what week does pregnancy usually occur?

A

40th

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

What percentage of unprotected intercourse results in development to the blastocyst stage?

A

20%

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

WHat percentage of blastocysts fail to implant?

A

8 - 20%

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

What percentage of human conceptions actually survive to a successful birth roughly?

A

~ 15 - 20% (possibly less)

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

When does the embryonic period occur?

A

First 8 weeks

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

When does the foetal period occur?

A

8 - 40 weeks

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

What does the embryonic period include?

A
  • Preimplantation embryo
  • Implantation
  • Differentiation and development of the organ systems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the hair-like projections called that draw the oocyte into the fallopian tubes?

A

Fimbriae

17
Q

What structures beat the egg towards the interior of the duct?

A

Cilia

18
Q

Movement through the uterus and fallopian tubes is via what?

A
  • Sperm’s own propulsions and uterine contractions
19
Q

What is passage of sperm intocervix dependant on?

A

Oestrogen-induced changes in mucus consistency

20
Q

What causes many sperm to die from vagina to fallopian tubes?

A

100 - 200 million dies due to:

  • Acidic vaginal environment
  • Length and energy requirements of trip
21
Q

What do femal tract secretions cause in sperm for them to be capable of fertilisation?

A
  • Change from wavelike beats of sperm tail to whip-like action to propel sperm forward
  • Sperm’s plasma membrane is altered so it is capable of fusing with surface membrane of egg (acrosome reaction)
22
Q

What is capacitation and what does it include?

A

Capacitation destabilises the sperm surface membrane to enhance fusion with oocyte

  • Increase in Ca2+ permeability - rise in intracellular Ca2+
  • Removal of membrane proteins (glycoproteins)
  • Change in surface charge
  • Depletion of cholesterol
23
Q

Where does fertilisation usually occur?

A

The ampulla of the uterine tube

24
Q

When does fertilsation usually occur?

A

Few hours after ovulation and within 24 - 48 hours of ovulation

25
Q

What prevents other sperm from fertilising the egg?

A

Space between plasma membrane and glycoprotein/zona pelucida change in composition creates insulating layer

26
Q

What is the front part of the head of the sperm called?

A

Acrosome

27
Q

What does the increase in Ca2+ from the sperm to egg cause?

A
  • Fusion of corticol vesicles in egg which move towards the zona pellucida generating increase in space in viteline envelope creating insulating protective layer
28
Q

Describe the acrosome reaction

A
  • Induced by sperm head contacting the zona pellucida and binding to glycoproteins ZP2 and ZP3
  • Releases contents of acrosome which causes entry of more CA2+
  • Sperm then digests a path through the zona pellucida (proteolytic enzymes)
29
Q

When does ovulatgion occur in relation to the LH peak?

A

1 day after

30
Q

How many days after the LH peak does implantation occur?

A

6 - 7 days after

31
Q

What rescues the corpus luteum?

A

Human chorionic gonadotropin (hCG) from implanted blastocyt (trophoblast) rescues corpus luteum (occurs 9 - 10 days after LH peak)

32
Q

What hormone maintains contraction of smooth muscle near where fallopina tubes enter the wall of the uterus?

A

Oestrogen

33
Q

What is the size of the morula in comparison with the original fertilised egg?

A

the same

34
Q

When does progesterone rise after fertilisation and what does it cause?

A

Plasma progesterone levels rise 3 - 4 days after fertilisation, smooth muscle relaxes and conceptus is allowed to pass into the uterus

35
Q

When do cavities develop between cells?

A

4 - 5 days after fertilisation

36
Q

For how long does the conceptus/blastocyst lie free in the uterine cavity?

A

Approx 3 days

37
Q

What do trophoblasts give rise to?

A

The placenta

38
Q

What does the trophoblast differentiate into?

A
  • Inner cytotrophoblast

- Outer synctiotrophoblast (loses cell boundaries)

39
Q

What cells invade the endometrium?

A

Fingers of syncytiotrophoblast

MD3002 Physiology (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions