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
