Lect. 20 - Male reproductive system Flashcards
organs of the male reproductive system (1, 3 ducts, 3 accessory sex glands, 2 supporting structures)
testes
vas deferens, ejaculatory ducts, urethra
seminal vesicles, prostate gland, bulbourethral gland
scrotum and penis
supporting sac for the testes
hangs from the root of the penis
scrotum
the scrotum is externally divided medially by a ridge called ___
raphe
the scrotum is internally divided by two sacs, each contain ___
one testis
what is the dartos muscle (action + role)
contraction causes wrinkling of the skin of the scrotum
helps regulate the temperature of the testes - required for sperm production
what muscles contracts when testes are exposed to cold to keep them closer to the body for heat
cremaster m. and dartos m.
small band of skeletal muscle in the spermatic cord
continuous with the internal oblique m. of abs
cremaster muscle
blood supply from the scrotum is from the ___ ___ a.
internal pudendal
paired oval glands
develop near the kidneys in the posterior portion of the abdomen
testes
the testes descend in the scrotum during the __ month of fetal development
7th
3 parts of the testes
tunica vaginalis
tunica albuginea
lobules
testes - serous membrane developed from the peritoneum
forms during the descent of the testes and partially covers them
tunica vaginalis
testes - forms a septum deep to tunica vaginalis which divides each testis into several internal compartment
tunica albuginea
testes - contain 1-3 coiled tubules called seminiferous tubules
lobules
structure where sperm is produced
seminiferous tubules
cells located within the seminiferous tubules
spermatogenic cells
sperm production begins in stem cells called ____
spermatogonia
where are spermatogonia located
line the periphery of the tubules
at puberty, the spermatogonia begin to undergo ___
mitosis
what is mitosis
division of the nucleus of the cell that ensures each new nucleus has the same number and kind of chromosome as the original nucleus = DIPLOID
the spermatogonia also undergoes _____
meiosis
what is meiosis
type of cell division restricted to sex-cell production involving two successive nuclear divisions that result in new cells with the haploid (n) number of chromosomes
Primary spermatocytes become ___ spermatocytes, then become ____ which finally mature into sperm cells
secondary, spermatids
main role of the blood-testis barrier
isolate spermatogenic cells from the blood
why is the blood-testis barrier essential?
because our immune system sees the spermatogenic cells as foreign substances and will want to destroy them
what is the blood-testis barrier formed by?
joined SERTOLI cells
role of sertoli cells (4)
- support and protect spermatogenic cells
- nourish spermatocytes, spermatids and sperm cells
- remove excess spermatid cytoplasm as development proceeds
- control the release of sperm into the lumen of the seminiferous tubules
“interstitial endocrinocytes”
Leydig cells
where are the leydig cells located + role
in the spaces between adjacent seminiferous tubules
- secrete testosterone
most important androgen (male sex hormone)
testosterone
how long is the process of spermatogenesis
65-75 days
spermatogenesis - process begins in the ___ (contain the diploid 2n chromosome number)
will undergo ___
some will develop into ___ ___ (2n), some will stay near the basement membrane for later sperm production
each primary spermatocyte will enlarge before undergoing ___ forming ____ ____
spermatogonia
mitosis
primary spermatocytes
meiosis, secondary spermatocytes
2 types of meiosis + infos
meiosis 1 = replication of DNA
meiosis 2 = no replication of DNA, formation of spermatids (haploid n)
a primary spermatocyte produces __ spermatids through 2 rounds of cell division (meiosis 1 and meiosis 2)
4
what is spermiogenesis
maturation of spermatids into sperm
t/f during spermiogenesis, no cell division occurs
true
what is spermiation
release of a sperm cell from its connection to a Sertoli cell
once ejaculated, sperm survives no more than __ __ in the female reproductive tratc
48 hours
matures at a rate of 300 million/day
highly adapted cell for reaching and penetrating a secondary oocyte
sperm
sperm cell - head content
contains the DNA and an acrosome
vesicle that contains enzymes which aid penetration of the sperm cell into the secondary oocyte
acrosome
sperm cell - midpiece content
contains mitochondria which provide ATP for locomotion
sperm cell - tails role
propel the sperm along its way
Once sperm is released in the lumen, it is propelled towards ___ ____ by the pressure generated by the continuous release of sperm and fluid (from the Sertoli cells)
straight tubules
ducts of the testes - straight tubules lead to ___ ___(ducts) which lead into a series of coiled ducts called ___ ___
all empty into a single ___ ___
Rete testis
efferent ducts
ductus epididymis
what structure lies on the posterior border of the testis
epididymis
head of epididymis
where the efferent ducts join the ductus epididymis
tail of epididymis
smaller, inferior portion which continues as the vas deferens
role of ductus epididymis (2)
stores sperm
helps propel sperm into the vas deferens by peristaltic contraction
what is the lining of the ductus epididymis made of?
lined with stereocilia that increase the surface area for absorption of degenerated sperm
Ascends along the posterior border of the
epididymis, passes through the inguinal canal and
enters the pelvic cavity. Loops over the ureter and passes down behind the bladder
Vas (ductus) deferens
what is the ampulla of vas deferens
dilated terminal portion
joining of the seminal duct and the ampulla of the vas deferens
form just above the prostate gland and pass inferiorly and anteriorly through it
ejaculatory duct
where do the ejaculatory duct terminate?
in the prostatic urethra
what is being ejected by the ejaculatory duct in the urethra (2)
sperm and seminal vesicle secretion
t/f urethra serves as a passageway for urine only
false, sperm also
the spermatic cord passes through which canal
inguinal canal
content of the spermatic cord (6)
- vas deferens
- autonomic nerves
- testicular artery
- testicular veins
- lymphatic vessels
- cremaster muscle
main role of the seminal vesicles
secrete an alkaline viscous fluid that helps neutralize acid in the female reproductive tract
structure that lies posterior to and at the base of the urinary bladder
seminal vesicles
structure that lies inferior to the urinary bladder
prostate gland
main role of prostate gland
secretes a milky, slightly acidic fluid that helps semen coagulate after ejaculation and subsequently breaks down the clot
t/f the size of the prostate gland slowly increases until puberty, then a rapid growth occurs until 50 yo
false, until 30 yo
other name for bulbourethral glands
cowper’s glands
structure that lies inferior to the prostate gland on either side of the membranous urethra (within the urogenital diaphragm)
bulbourethral gland
main role of cowper’s glands
secrete an alkaline fluid that neutralizes the acidic environment of the urethra and mucous that lubricates the linin of the urethra and penis during sexual intercourse
content of semen
mix of sperm and seminal fluid
what is seminalplasmin
antibiotic found in semen which can destroy certain bacteria in the semen and female reproductive tract
after __ to __, semen re-liquifies
10-20 minutes
structure that is the passageway for ejaculation of sperm and the excretion of urine
penis
main regions of the penis (3)
body, root and glans penis
t/f there is a pair of corpus spongiosum
false, only one
t/f there is a pair of corpus cavernosum
true
function of corpus spongiosum
keeping the spongy urethra open during ejaculation
penis - expanded portion of the base of the corpus spongiosum
attached to inf. surface of urogenital diaphragm
bulb of penis
penis - tapered portion at the proximal end (base) of the corpus cavernosum
attached to the ischial and inf.pubic ramus
crus of penis
bulb of the penis is enclosed by the ____ muscle
bulbospongiosus
crus of the penis is surrounded by the ____ muscle
ischiocavernosus
ejaculation is a parasympathetic or sympathetic reflex
sympathetic
peristaltic contractions in which 4 structures propel semen into the spongy urethra
ampulla of vas deferens, seminal vesicles, ejaculatory ducts, prostate gland
erection is a parasympathetic or sympathetic reflex
parasympathetic
upon sexual stimulation, the arteries supplying the penis ___ (constrict or dilate)
dilate = more blood