male reproductive physiology test 3 Flashcards
the head of the sperm cell contains what two things?
genetic information
acrosome
what is the acrosome?
vesicle full of enzymes which can break down the outer layer of the ovum, or acrosome rxn. allows for fusion of the sperm with the ovum membrane and deposition of the haploid genetic information.
why are the centrioles in the sperm important?
they are delivered with the genetic material and form a centrosome which is involved in in the initial zygotic divisions
what is the axoneme?
cytoskeletal component of the sperm flagella which is formed from microtubules. Movement of these by motor proteins in relation to one another allows locomotion
complexes of mitochondria are located near the axoneme, why?
well you need energy to power that flagella.
the cell membrane of the sperm contains many chemotactic sensors in order to give it some direction. what is the called?
gradient sensing
where does spermatogenesis occur?
seminiferous tubules
spermatogonia proliferate to replace them selves, undergo meiosis, and differentiate into?
haploid sperm
what is the importance of sertoli cells?
they nurse the developing sperm, by supplying nutrients, translocating the differentiating sperm cells and forming the blood-testis barrier aka Sertoli Cell Barrier
why is the Sertoli Cell Barrier(blood-testis barrier) important?
sperm cause an auto-immune response when exposed to blood. thus the testes tubules are said to be immunologically privileged.
why do leydig cells do?
produce testosterone in response to LH initiating puberty and spermatogenesis.
when the tail is added and decouples from the Sertoli and enters into to the seminiferous tubule is the sperm cell motile?
nope
inhibin produced by sertoli cells has a negative feed back in excess of what?
FSH secretion
inhibin inhibits FSH from anterior pituitary
LH hormone stimulates what cell?
leydig to produce testosterone that promotes division of spermatogonia
FSH stimulates what cell?
Sertoli cells to produce estrogens from testosterone by sertoli cells
-estrogen regulates spermatogenesis
how does the sperm get to the epididymis?
by the way of tubulus rectus and rete testis
tubulus rectus
connection of seminiferous tubule with the rete testis
Rete testis
tubule which delivers maturing sperm to the epididymis and serves to reabsorb some tubular fluid concentrating sperm.
are sperm capable of motility once they are in the?
epididymus for a day, but they are inhibited by factors in the fluid
where do the sperm go after they leave the epididymus?
off to the ductus deferens to await deployment
how many sperm are made per day?
120 million mostly parked in the vas deferens
-they can be stored here for a month and maintain functionality
T/F spermatogenesis is most efficient at high temperatures.
false they are most efficient at lower temperatures
what 3 things do the seminal vesicles secrete?
fructose
prostaglandins: causes reverse peristaltic contractions to propell sperm inwards
fibrinogen: to form a clot later on
where does the stuff from the seminal vesicle go?
into the ejaculatory duct where they meet the sperm
how much of the final product do the seminal vesicles contribute?
60-70%
what three things does the prostate gland add to semen?
clotting enzyme
pro-fibrinolysin(plasminogen)
various alkaloids
how much of the total semen product does the prostate gland contribute?
25-30%
what do the blubourethral glands (cowper’s galnds) do?
produce a mucous like secretion that forms the pre-ejaculate that has a lubricating function
what is a dangerous things that blubourethral glands can do?
they can contain sperm from prior ejaculations, but more importantly they can transmit infectious agents in the pre-ejaculate.
how much of the final product do the coper’s glands add to semen?
1%
what is in semen?
sperm
secretions from seminal vesicles, prostate gland and cowper’s glands and small mucous glands.
what important factors are in semen?
fuel (sucrose)
alkaloids
clotting factors
clot removing factors
how long can sperm last in utero?
2-3 days
when the sperm enters that vagina what happens to enable it to be fertile?
mobility inhibitors are washed away and become fully motile
- cell membrane around acrosome weakens
- calcium permeability increases=more vigorous motion in flagella
what causes erection?
parasympathetic innervation from the sacral spine via the pelvic nerves
-autonomic response
pre-ejaculation is due to what type of innervation?
parasympathetic
what causes the vasodialation in the penis?
Ach, nitric oxides and other transmitters
what are the erectile tissues of the penis?
corpora cavernosa
corpus spongiosum
the sympathetic impluses from T12-L2 causes what to happen?
contraction of ductus deferens moving the sperm towards the seminal vesicles.
what causes ejaculation?
rhythmic contraction of the ischiocavernosus and bulbospongiosus (blubocavernosus) which expels the semen from the urethra.
why is a male considered an imposed phenotype?
females are default
thus many male sexual organs are derived from female ones that therefore are embryonic equivalent.
