Repro- Male physiology Flashcards
function of the epididymis
store sperm (3 months) and matures
why are testes located in the scrotum outside the abdominal cavity
testicular temperature has to be lower than that of the body to allow sperm production
Where is the site of sperm production
seminiferous tubules
What is the rete testes?
site where all of the seminiferous tubules merge
what is the tunica albuginea?
a fibrous capsule that divides testes into lobules
Name 3 types of cells within the seminiferous tubules.
- germ cells - produce sperm
- sertoli cells - support sperm producing cells and produce inhibin
- leydig cells - produce testosterone (surround tubules)/inbetween tubules
purpose of sertoli cells (sustentacular cells)
- support the sperm producing cell (support spermatogenesis) - facilitate production of sperm
- produce inhibin
purpose of interstitial (leydig cells)
release testosterone
sertoli cells support the sperm producing (germ cells) , but they also secrete inhibin - what is its function?
It inhibits the synthesis and release of the follicle-stimulating hormone in the anterior pituitary gland (negative feedback)
good indicator of infertility if
- inhibin b is low and FSH high (spermatic damage)
What is the function of the testes?
- sperm production (germ cells) - average cycle is 3 months
- testosterone production - for secondary sex characterisitcs and control of spermatogenesis (leydig cells)
Where is testosterone released from?
testes
Where is FSH and LH released from?
anterior pituitary
Which two hormones inhibit the secretion of GnRH and LH/FSH in men?
Testosterone (Leydig cells) and Inhibin (Sertoli cells)
via negative feedback
inhibin exerts negative feedback on what structure?
Anterior pituitary!! - reduced LH and FSH
Are sperm cells haploid or diploid ?
haploid (23n)
Spermatogonia undergo constant mietosis
a. True
b. False
a. True
Basal component of seminferous tubules -> move to Luminal component.
The process of maturation into mature sperm cells is called?
Spermatogenesis
(Spermatid -> Sperm “spermatozoa”)
gains strutural changes and functional capacity
The process of clonal expansion and maturation through mitotic and meiotic process is called?
Spermatocytogenesis
- Primoridial germ cells (Spermatogonium) (43y)
- Mitosis (16 days)
- Primary Spermatocyte 1 (2n)
- Meiosis 1 (24 days)
- Secondary Spermatocyte 2 (1n)
- Meiosis 2 (hours)
Spermatogonium become primary spermatocytes after one meiotic division
a. true
b. false
b. false
one mitotic duplication (2n) - 46Y (diploid chromosomes)
Primary spermatocytes become secondary spermatocytes after the first ______ division?
a. meiotic
b. mitotic
a. meiotic
become two cells with haploid chromosome (1n)
Secondary spermatocytes become spermatid after the second _____ division?
a. meiotic
b. mitotic
a. Meiotic
spermatid with two cells with halpoid chromosomes (23) (1n)
the maturation of spermatids into functional sperm cells is called?
spermatogenesis
oligospermia
low sperm count
normal - 15million/ml
What disease can cause the absence of ductus deferens ?
cystic fibrosis
High FSH and LH and Low Testoersone woud indicate there was a _____ cause of infertility?
a. hypothalamic or pituitary cause
b. testicular cause
b. testicular cause
(hypergonadotrophic hypogonadism)
LH effect in males
stimulates testes to produce testosterone
FSH role in males
stimulates sperm production (spermatogenesis)
function of sertoli cell
support sperm producing germ cells
which muscle contracts to propel sperm out
bulbospongiosus - somatic NS, pudendal nerve S2-S4
where is sperm stored and matured?
epididymis
what do the seminal vesicles produce
a fluid that makes up the majority of semen
contains nutrients (e.g. fructose for energy), proteins, amino acids and other substances which support sperm
the fluid is alkaline and helps neutralise acidic enviroment in male urethra and female reproductive tract
What two structures combine to form the common ejaculatory duct?
duct of the vas deferens and seminal vesicles fuse
function of the cremaster muscle
pulls testes superiorly (elevates) towards the superficial inguinal ring (brings closer to warm enviroment when exposed to cold/protect from physical harm).
What is the rete testes
collection point for sperm from seminiferous ducts before entering epididymis
Function of the bulbourethral gland ?
Secretes an alkaline mucous which lubricates the glands penis and neutralises acidic tract of the urethra
What is the name of the erectile tissue that fills with blood during erectile response?
corpus cavernosum
Where is FSH and LH released from?
Anterior pituitary gland
How does GnRH reach the anterior pituitary gland?
via the hypophyseal portal system
LH stimulates what cells?
Leydig cells (produce testosterone)
testosterone stimulates germ cells to produce sperm
Sertoli cells allow spermatogonium to enter the lumen of seminiferous tubule
a. true
b. false
a. true
open up the tight junctions (release chemicals) after cells have been replicated (mitosis)
outline how spermatozoa are developed after the 1st mitosis (replication)
primary spermatocyte -> meosis 1
secondary spermatocyte -> meosis 2
spermatids
———– spermogenesis (become more motile and functional)
spermatozoa
what is used to make testoterone
cholesterol
(converted to testosterone by leydig cells under the influence of LH)
leydig cells are found in the interstitium surround semniferous tubules
which cell creates anitgen binding protein (ABP)
sertoli cells
(ABP causes testosterone to be less lipophillic - so it can stay in the lumen of semniferous tubules and help sperm to develop)
** helps keep testosterone around/stable concentrations
functions of sertoli cells
- keep testosterone around (make less lipophillic) via ABP
- opens up tight junctions (allow movement of spermatogonia to centre lumen)
- nutrients - to sperm producing cells
- helps with spermatids -> spermatozoa
where is the DNA stored in sperm
head
what is the acrosome of sperm
has hydrolytic enyzmes that eat through egg layers
what stimulates sertoli cells
FSH and testosterone
sertoli cells also can release inhibin - what does it do
has negative feedback on the anterior pitiutiary - decreases FSH production/LH
anterior pituitary
which part of the nervous system is responsible for erection
PNS - points
pelvic splanchic nerve S2-S4
blood vessels in corpus cavernsum dilate (dilatory tissue starts expanding)
which part of the nervous system is responsible for ejaculation?
SNS !! - shoots
smooth muscle squeezes epididymis - sperm sent to vas deferens -> seminal vesicles expell semen -> common ejaculatoru duct
how do sertoli cells support spermatogenesis
- secrete antigen binding protein
- secrete tubular fluid
- form blood -testes barrier
- nourish developing sperm
what do the inferior and superior vesical arteries supply in men?
bladder
seminal glands
prostate
(branches of internal iliac)
what do the seminal vesicles produce
70% of semen
contains
- fructose (energy)
- prostaglandins (acts on smooth muscle of uterus)
- enzyme coagulase (coagulates fluids and allows sperm to latch onto walls of vagina)
what does the prostate gland release?
30% of semen
- citrate
- PSA (prostate specific antigen)
- fibrinolysin
what is capacitation of sperm
increased motility of sperm!!
occurs as sperm is moving towards the egg
there is increased cleaning of the sperm head - only modified glycoproteins are kept
What is the acromsomal reaction
the acromosome of sperm releases chemicals which borrow a hole through the zona pellucida of egg
allows sperm to bind with ZP3 receptors
What is the fast block on sperm
Na+ (sodium ions) flow into the cell
this inhibits further sperm from binding
++++++ positive charge blocks++++++
caused when sperm touches oocyte membrane
oocyte cell membrane and sperm membrane then fuse
What is the slow block on sperm
when the pronucleus is pushed into the ovvum
it triggers SER to release Ca2+ ions
lysosomes are activated which fuse with cell membrane and release enzymes which break down the zona pullucida and harden the cell membrane so other sperm cannot attach
order of events of sperm binding to egg
1, capacitation (increased motility)
2. acromsome reaction
3. fast block
4. slow block
5. fertilisation
when is fertilisation finished?
23Y fuses with 23X
zygote formed 46n
(meosis 2 - metaphase 2 finished)
What is the acrosome reaction
Sperm binds to the zona pellucida of the secondary oocyte
Hydrolytic enzymes are released by the sperm
What is the cortical reaction?
The sperm and secondary oocyte fuse
Cortical granules are released in the zona pellucida to cause it to harden and trigger removal of remaining sperm (no other sperm can bind)
what is spermination
sperm is released from connection to sertoli cells and enter the lumen of the seminiferous tubules
what is capacitation
physiological changes the sperm undergoes once in the female reproductive tract to increase motility - to prepare for acromsome reaction
