Week 7.0 - Coitis and fertilisation Flashcards Preview

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Flashcards in Week 7.0 - Coitis and fertilisation Deck (77)
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1

How long does it take for spermatogonia to mature into spermatozoa?

-upto 74 days (50 in testis 12-24 in epididymis)

2

When does spermatogenesis begin/end?

-From puberty until death

3

How many of the sperm produced per day become viable sperm?

-50%

4

Does production of sperm stay the same throughout life?

-Decreases in quantity and quality with age

5

Which hormone acts on the leydig cells? What is the result of this?

-LH
-Production of testosterone

6

Which hormone acts on the sertoli cells? What is the result of this?

-FSH
-Antigen binding protein production leading to the concentration of testosterone in luminal fluid enabling spermatogenesis

7

If the pituitary gland is removed, how is spermatogenesis stimulated?

-FSH and testosterone

8

What is the function of oestrogen in the testis?

-Increase sperm viability

9

What is nuclear condensation and when does it happen?

-Extrusion of the cytoplasm and condensation of the nucleus from spermatid to spermatozoon

10

What does the acrosome contain? Why?

-Golgi apparatus and hydrolytic enzymes to enable sperm to penetrate ovum

11

Identify the main feature of the midpiece of a spermatozoon
Why is this needed?

-Mitochondria packed around either side
-Motility is a highly energy dependant process

12

What is the tail of a sperm made from?

-Flagellum produced by microtubules

13

What signals for the cytoplasm and organelles to be stripped from the permatid?

-Testosterone

14

What is different between the mature spermatozoa in the seminiferous tubules and the mature spermatozoa in the epididymis?

-Lack motility in the seminiferous tubules

15

What is spermiation?

-Release of spermatozoa from sertoli cells into seminiferous lumen

16

How are spermatozoa transported from seminiferous lumen to epididymis?

-Testicular fluid (produced by sertoli cells) and peristaltic contraction

17

How long can mature spermatozoa stay in the epididymis?

-Several months, eventually phagocytosed

18

How do the spermatozoa get into ductus deferens?

-Upon sexual arousal the epididymal wall contracts and expels the sperm into the ductus deferens

19

What are the phases of coitus?

-Excitement phase
-Plateau phase
-Orgasmic phase
-Resolution phase

20

What is the refractory period in males?

-After ejaculation it is not possible to ejaculate again upon further stimulation

21

Describe the excitement phase of the male sexual response

-Sensory and psychological stimulation
-Inhibition of sympathetic outflow (thoracolumbar)
-Activation of parasympathetic outflow (sacral)
-Ach-> M3 on endothelial cells of penile bvs -> increased Ca-> activation of eNOS -> NO production
-Arterial vasodilation in corpora cavernosa
-Increased penile blood flow
-Penile filling (full of blood but not erect)
-Penile tumescence (erection)

22

What happens to the testes and scrotum upon sexual arousal?

-Testes elevate and engorge and scrotal skin thickens and tenses

23

Describe the plateau phase of male sexual response

-Activation of sacrospinous reflex
-Contraction of ishiocavernosus -> compresses crus of penis and impedes venous return -> venous engorgement
-Rise in intracavernosus pressure higher than systolic pressure -> decreased arterial inflow
-Stimulation of secretion from accessory glands
-Loss of erection unlikely

24

Which accessory glands are stimulated in the plateau phase of male sexual response?

-Cowpers glands
-Littre's glands

25

What are the two stages of orgasmic phase in male sexual arousal?

-Emission
-Ejactulation

26

Describe the emission stage of orgasmic phase in male sexual response

-Stimulation of sympathetic reflex
-Contraction of smooth muscle in ductus deferens, seminal vesicle and prostate
-Internal and external urethra contracts
-Semen becomes pooled in urethral bulb

27

Describe the ejaculation stage of orgasmic phase of male sexual response

-Sympathetic spinal reflex with cortical control
-Further contraction of glands and ducts and sphincters
-Filling of urethra stimulates pudendal nerve-> contractions of the genital organs, ischiocavernosus and bulbocavernosus -> expulsion of semen

28

Describe the resolution phase of the male sexual response

-Activation of sympathetic outflow
-Contraction of arteriolar smooth muscle in corpora cavernosa
-Increased venous return
-Detumescence and flaccidity
-Testes descend and scrotum thins and relaxes
-Refractory period entered

29

Describe the excitement phase of the female sexual response

-Sensory and psychological stimulation
-Activation of parasympathertic outflow; inhibition of sympathetic outflow
-Vasocongestion causes vaginal lubrication to begin
-Clitoris becomes engorged with blood
-Uterus elevates, inner 2/3 of vagina lengthens and expands
-Increased muscle tone, HR and BP

30

Describe the plateau phase of female sexual response

-Further increase in muscle tone, HR and BP
-Labia minora deepen in colour
-Clitoris withdraws under its hood
-Barthlin glands secretions lubticates vestibule for entry of penis
-Orgasmic platform forms in lower 1/3 of vagina, upper 2/3 fully distended and uterus is fully elevated