Reprod Lec 1- Male Flashcards
What is the function of the reproductive system? (3)
– production of gametes
– organs for mating
– fertilization
Organs of Reproductive System (3)
- gonads
- pathway of gamete transport
- accessory reproductive organs/glands
Function of Gonads (2)
– gamete production
– secrete sex hormones
descent of testes starts when ___to ___
3 months to birth
descent of testes starts when ___to ___
3 months to birth
testes are the ____
male gonads
testes contain ____ compartments each
250-300
testes contains ___ tubules ___
seminiferous tubules that are involved in sperm production
spermatogenesis begins at (what time?)___
puberty
seminiferous tubules contains ____
spermatogenic cells
mumps effect on spermatogenic cells (3)
- center lumen: small
- lining of cell: small
- small spermatogenic cells
cells of testis (3)
- Leydig cells (interstitial cells)
- sertoli cells (epithelial cells)
- smooth muscle (myoid cells)
cells of testis (3)
- Leydig cells (interstitial cells)
- sertoli cells (epithelial cells)
- smooth muscle (myoid cells)
Leydig cells (interstitial cells) action
-secrete testosterone
Sertoli cells (epithelial cells) action
-support sperm development
Smooth muscle (myoid cells) action
peristalsis (propel sperm)
tubule setup (4)
- smooth muscle
- basement membrane
- sertoli cell
- lumen containing sperm
blood-testis barrier (3 parts)
- tight junctions
- luminal compartment
- basal compartment
luminal compartment (3)`
- tight junction
- sertoli cell below that
- lumen
basal compartment (4)
- smooth muscle
- basement membrane
- sertoli cell above
- tight junction
Functions of Sertoli cells
1.Support sperm development: “trophic role”
2. Secrete luminal fluid
3. Secrete androgen-binding protein
4. target cell for testosterone and FSH
5. Secrete inhibin
6. Secrete paracrine factors that affect Leydig cell
function
7. Phagocytosis of old and damaged sperm
8. Site of immunosuppression (blood testis barrier)
androgen-binding protein is ___ and helps ____
- Androgen buffer
- Helps maintain steady [androgens] in lumen
sertoli cells secrete ____ that ___
Secrete paracrine factors that stimulate spermatogenesis
inhibin is a hormone (type of feedback loop for what hormone?)
-Hormone of negative feedback loop for FSH
2 hormones that target Sertoli cells
- testosterone
- FSH
Function of male gonads (2)
- production of sperms
- production of hormones
function of scrotum (1)
temperature regulation
function of epididymis (2)
– Maturation of sperm
– Storage site for sperm
function of vas deferens (2)
– Conduit
– Storage site for sperm
function of accessory sex gland (1)
-Production of seminal fluid
reproductive ability: childhood to onset of adolescence (upto 10-14 years)
• Inability to reproduce
reproductive ability: puberty (starts at around 10-14 years, later in boys) (3)
- Sexual maturation
- Reproductive organs mature (can produce gametes)
- Secondary sexualcharacteristics develop
testosterone is synthesized in ___
leydig cell
testosterone is transformed in ____ (4) in peripheral tissues
- testosterone
- dht (dihydrotesterone)
- E (estrogen)
- inactive molecules
sperm production from late teens up
-continuous (small decrease in old age)
release of testosterone (starting at hypothalamus)
-GnRH (hypothalamus) –> (+) Luteinizing hormone –> Leydig cell -> (+) testosterone
testosterone—> (-) LH, (-) GnRH
effect of androgens in males (6)
- spermatogenesis
- 2 sex characteristics
- increase sex drive
- protein synthesis in skeletal muscle (anabolic effect)
- increase growth hormone secretion
- creating male reproductive structures as embryo
summary of spermatogenesis
-spermatogonia (2n)—> primary spermatocytes (2nx2) –> secondary spermatocytes (nx2)—> spermatids (n)—> spermatozoa (n)
mitosis ensures ____
continuous supply of spermatogonia
meiosis (has two stages)- spermatogenesis
-chrosomenumber is halved.
spermatogenesis takes ____ (time?)
64 days
spermatogenesis occurs ___
- inside seminiferous tubules from basement membrane to lumen
- space in between adjacent sertoli cells through tight junction
Tight junction allows ____
spermatocytes to pass
Spermiogenesis (def.)
- last step in spermatogenesis
- physical change to form spermatozoa
- spermatid to spermatozoa
Spermiogenesis take ___ (how much time?)
24 days
head of sperm (2)
- Nucleus - Chromosomes
- Acrosome – Enzymes necessary for fertilization
midpiece of sperm (1)
- Mitochondria: source of energy
Tail of sperm (1)
Whiplike movements propel sperm
Spermatozoa released into lumen of seminiferous tubules is ___ and stay their for ___
- Immotile
* 20 days
Sperm maturation in epididymis (6-12 days)
- Acquire motility
• Wave–like tail movement initially
• Most of the fluid is reabsorbed
• Sperm is concentrated
sperm moves to vas deferens by ___ and ___
peristalsis and remains there until ejaculation
FSH stimulates
gametogenesis/spermatogenesis
LH stimulates
androgen secretion
pulse generator (male reproduction)
hypothalamus
frequency and amplitude for pulse changes every ___ in males
90 min
Inhibin is secreted by
Sertoli cells
60% of ejaculate volume is from (accessory gland)
seminal vesicle
30% of ejaculate volume is from (accessory gland)
prostate gland
semen =
sperm + seminal fluid
accessory sex organs secrete
seminal fluid
secretion of seminal vesicles (has clotting factor outside body)
-alkaline fluid with fructose, enzymes, prostaglandins
secretion of prostate gland
-citrate and enzymes like PSA (prostate specific antigen)
hypertrophy of prostate gland is ___
biomarker for cancer
secretion of bulbourethral gland
-secrete viscous fluid with mucus
neural control of male sexual response is controlled by (2)
- autonomic nervous system
- spinal reflexes
erection (neural input)
parasympathetic nervous system
emission (neural input)- moving toward through tract
-on prostate, vas deferens, seminal vesicles
sympathetic nervous system: sympathetic stimulation to the smooth muscle of the ducts
ejaculation (neural input)
-rapid contraction of skeletal muscle for semen expulsion (somatic control)
phases of male sexual response
- erection
- emission
- ejaculation
mechanism of vasodilation in erectile response
- activation of parasympathetic nerve
- increase NO
- Incr’d cGMP
- vasodilation
- Incr’d blood flow
- erection
mechanism of vasodilation in erectile response (viagra-sildenfail)
- cGMP broken down by phosphodiesterase -> no more erection
- viagra inhibits phosphodiesterase .
what accounts for low number of sperm o reach site of fertilization?
- acidic pH
- low energy
- lost in female tract
capacitation
- the change undergone by sperm in the female reproductive tract that enables them to penetrate and fertilize an egg
- acrosomal enzymes released in surroundings -dissolving of end
- whiplashing of tail after activation
sperm maturation in female tract
- capacitation
2. acrosome reaction
movement of sperm before capacitation
-wavelike
movement of sperm after capacitation
-whiplashing
