Sperm origins and role Flashcards
acrosome=
sits on top of the spermatoza and contains enzymes that digest through the egg
what does the male contribute to the egg
nucleus DNA and centrioles
where are the mitochondria arranged in the sperm
in the midpiece in a specific structure surrounding the sperm tail
what is the key cell of the testicular cords
sertoli cells
when do the male germ cells arrest
in mitosis
what is the highly coiled structure in the testes
seminiferous tubule
where do the seminiferous tubules drain into
retes testes
what are the retes testes formed from
the wolffian duct
where does the retes testes drain into
the epididymis and then into the vas deferens
where are spermatozoa made
in the seminiferous tubules
where are spermatozoa matured
epididymis
in males what develops into the testes and what degenerates
the medulla develops into testes, cortex degenerates
what cells line the seminiferous tubule
sertoli cells
where have sertoli cells originated from
coelomic epithelia
what gene do sertoli cells express
SRY gene
what type of cell are sertoli cells
epithelial
what junctions join the sertoli cells to form a continuous barrier
gap and tight junctions
what is the job of sertoli cells
to nourish and support another cells division
what is the compartment called in the middle of the seminiferous tubule
adluminal compartment
what compartment is on the outside of the tube
basal compartment
what cells support the sertoli cells
myoid cells
what forms the blood testes barrier
tight junctions formed between sertoli cells (myoid cells help)
what does the blood testes barrier ensure
stops sperm being recognised by antibodies
what cells lie outside of the seminiferous tubules
leydig cells
what can tell us how developed a spermatozoa is
there position in the gaps between the sertoli cells
what do meiosis and mitosis both begin with
diploid cells
end product of mitosis
2 diploid cells
end product of meiosis
4 spermatozoa
when do the prospermatogonia resume mitosis
at puberty under the direction of GnRH
what does the first mitotic division of prospermatogonia form
spermatogonium type A1
how many mitotic divisions
5
what is the does A4 spermatogonium produce
intermediate spermatogonium
what do intermediate spermatogonium divide to become
spermatogonium type B
when does mitosis stop
when resting primary spermatocytes are formed
where does the mitosis of sperm happen
basal layer of the sertoli cells
what do the Type B spermatogonia do
they breach the tight junctions and stimulaneously enter meiosis
where does all meiosis take place
adluminal compartment
what are the gametes called at the start of meiosis
primary spermatocytes
what are the gametes called at the end of meiosis 1
secondary spermatocytes
in meiosis 2 what so secondary spermatocytes become
early spermatids
for each type B spermatogonium how many spermatids are there
4
what is special about the spermatids
they are undergoing cell division but aren’t separating into individual cells they are maintaining cytoplasmic bridges
GO TO MA TOZ
spermatogonia
spermatocytes
spermatids
spermatozoa
what confers individuality between the clones
chiasmata
what happens to the golgi apparatus in spermatid specialisation
they move to the proximal end of the cell and secrete the acrosome vesicle
what happens to the centrioles in spermatid specialisation
both move to distal end of cell and most distal one forms the flagellum
what forms the flagellum
most distal centriole
where do mitochondria become concentrated
around the developing flagellum
what do the sertoli cells enable the cytoplasm to do
enable excess cytoplasm to be pinched off
what does the head of the sperm contain
the nucleus with very little cytoplasm
what does the midpiece of sperm contain
the centrioles one of which is extended into the flagellum and the mitochondria
how many days to make a spermatozoa from a stem cell
64
what are the two key roles of the testes
spermatogenesis and hormone production
where do the sperm travel from the seminiferous tubules
into the retes testes and then into the epididymis
what happens to sperm in the epididymis
they become concentrated, matured and stored
can a spermatozoa out of the seminiferous tubules swim
no
when can spermatozoa swim
after a period of time away from the seminiferous tubules in the epididymis
which cells does LH bind to
leydig cells
what cells does FSH bind to
sertoli cells
what happens when LH binds to leydig cells
androgen (testosterone) is produced
what happens when FSH binds to sertoli cells
production of androgen receptors
inhibin produced
positively supports leydig cells
what does inhibin do
acts on pituitary to inhibit FSH
what cells are leydig cells comparable to in females
theca cells
what is the production of testosterone from leydig cells crucial to maintain
blood testes barrier
what is the more potent version of testosterone
5 alpha-dihydrotestosterone
what kind of soluble is testosterone
lipid soluble
what does sertoli cells do to testosterone
converts dihydrotestosterone and binds to androgen receptor
when do androgen levels rise and spermatogenesis begin
at puberty
what do granulosa cells and sertoli cells both support
the production of gametes
what structure contributes the majority of semen volume
seminal vesicle
what does the seminal vessel contribute to semen
nutrients to keep the sperm alive
fructose, ascorbic acid, prostaglandins
what does the prostate contribute to semen
PSA (prostate specific antigen)
what does the bulbourethral gland contribute to semen
mucus to lubricate sex
ejaculate semen comes from (4)
seminal vesicle
prostate
cowpers gland
vas deferens
what is prostate function dependant on
androgen
3 drugs treating prostate cancer/ enlargement
goserelin
bicalutamide
finasteride
what is Goserelin (drug)
GnRH antagonist
what is bicalutamide (drug)
androgen receptor antagonist
what is finasteride (drug)
reductase inhibitor
oligozoospermia=
low sperm count
aspermia =
complete absence of semen
Azoospermia
complete absence of sperm
asthenozoospermia
low sperm motility
teratospermia=
abnormal morphology
what temp do sperm work at
2 degrees below body temp
what is the first step in a erection
corpus cavernosa fills with blood
what happens because of sensory stimulation in an erection
nitric oxide is produced which acts as a vasodilator
what does Nitric oxide increase the production of
cyclicGMP
what does cyclicGMP do
vasodilator increases blood in the corpus cavernosa
detumescence=
end of sensory stimulation
what happens in detumescence
sensory stimulation lost
nitric oxide levels fall
production of PDE5
what does PDE5 do
breaks down cGMP and causes vasoconstriction
how to treat elevated levels of PDE5
viagra
proper name for viagra
sildenafil
