male reproductive Flashcards
sac of loose skin, fascia and smooth muscle that is divided into two pouches by a septum
scrotum
what is the function of the scrotum?
temperature regulation of testes
What is the name of the muscle that elevate or lower the testes in reponse to arousal, cold or warmth?
cremaster muscle
Why is the cremaster muscle important in sperm survival?
sperm requires 2-3 degrees lower temperature than the core body temperature to survive
Where are sperm formed?
within lobules are 2-3 seminiferous tubules where sperm are formed
What is the dense white capsule the testes are covered with called?
tunica vaginalis
sperm forming cells
spermatogonia
supporting cells for sperm formation
sertoli
What secretes testosterone?
interstitial leydig (interstitial endocrinocyte) cells which are between seminiferous tubules
What are 4 functions of serotoli cells?
- forms blood-testis barrier
- support developing sperm cells
- produce fluid and control release of sperm into lumen
- secrete inhibinwhich slows sperm production
sertoli cells extend from _____ _____ to ______
basement membrane
lumen
What is sperm morphology adapted for?
for reaching and fertilizing the egg
What is the acrosome in the sperm?
contains enzymes for egg wall penetration
Does sperm have a nucleus?
yes duh, to carry DNA
What is the midpiece of a sperm?
contains mitochondria to form ATP energy for motility
What is the tail of sperm called?
flagellum used for movement
Where does sperm maturation and development of the capacity of motility occur?
epididymis
How long can sperm be stored in a suppressed inactive state by inhibitory secretions?
in the epididymis for one month
What is sperm capacitation?
when the female genital tract fluids wash away inhibitory secretions
When does the acrosome reaction occur?
when the proteolytic enzymes and hyaluronidase open a penetrating pathway in the ovum wall
cryptorchidism
failure of the testes to descend- under testosterone stimulation- from the abdomen through the inguinal canal into the scrotum before or after birth of the fetus
- semineferous tubules and the spermatogonia will degenerate
- failure of spermatogenesis will cause sterility
What does increased temperature of the testes do?
causes degeneration of the semineferous tubule cells and the spermatogonia
What is the sperm count of a fertile male?
ejaculates ~3.5 mL with 120 million sperm per mL= 420 million sperm per ejaculation
What sperm count indicates infertility?
below 20 million/mL or less than 60 million total sperm /ejaculation
How can morphology of sperm change fertility?
sperms with 2 heads, two tails, abnormally shaped heads or tails, slow or non-mobile can cause infertility even with a normal sperm count
Where is gonadotropin-releasing hormone (GnRH) secreted from and what does it stimulate?
GnRH is secreted by the arcuate nuclei of the hypothalamus into the hypophyseal portal circulation to stimulate that anterioir pituitary gland secretion of LH and FSH
Where is the luteinizing hormone secreted from and what does it stimulate?
LH is secreted by the anterior pituitary cells called gonadotropes
stimulates the interstitial leydig cells to secrete testosterone by activating the cyclic adenosine monophosphate second messenger system
What is LH inhibited by?
testosterone-negative feedback control
Where is follicle stimulating hormone secreted from and what does it stimulate?
secreted by gonadotropes
stimulates the sertoli cells in the seminiferous tubules to secrete spermatogenic substances to intitiate spermatogenesis with testosterone
What is FSH inhibited by?
inhibin-negative feedback control
What does testosterone stimulate?
stimulates enlargement of the scrotum, testes and penis after puberty and develops the male secondary sexual characteristics
(affects body hair, voice, baldness, msucle development, bone, and RBC count)
Where is human chorionic gonadotropin secrete from and what does it stimulate?
secreted by the placenta and has the same effects on the sexual organs as LH
stimualtes the fetal testes to secrete testosterone which is critical for promoting formation of the male fetus sex organs
What do the seminal vesicles do?
secrete 60% of clear, alkaline seminal fluid, with fructose sugar, ATP and prostaglandins form normal sperm nutrition and function
What does the prostate do?
secretes 30% of milky, slightly acidic seminal fluid with an antibiotic to kill bacteria
What is Cowper’s gland?
secretes clear, alkaline mucus to buffer and lubricate urethra
What are the characteristics of semen?
mixture of sperms, mucus and seminal fluids
slightly alkaline
contains nutrients, clotting proteins and an antibiotic to nourish and protect the sperm
What is the life span of sperm?
24-48 hours at room temp
How is an erection initiated?
initiated by mental, visual, and physical stimuli that send afferent signals to the sacral region of the spinal cord via the internal pudendal nerve
In erection, what type of signal is transmitted from the spinal cord to the penis and via what nerve?
efferent parasympathetic signals
via pelvic nerve
What effects do the efferent parasympathetics signals have on the penis?
trabecular smooth muscles of the penis erectile tissue relaxes
deep artery of the penis dilates
–> corpus cavernosum and corpus spongiosum become engorged with blood and the penis becomes erect
Sexual stimulation causes the release of nitric oxide. What follows in the cascade leading to erection?
NO activates guanylate cyclase which converts GTP to cGMP, leading to vasodilation and an erection
What occurs during emission?
- Sympathetic efferent signal from spinal cord (T12-L2) to the genital organs via the Hypogastric nerve
- Contractions of the vas deferens and ampulla propel sperms into the internal urethra
- Contractions of the prostate gland and seminal vesicles propel the seminal fluids into the internal urethra
- Seminal fluids, mucus and sperms mix in the internal urethra forming the semen.
What occurs during ejaculation?
- Filling of the internal urethra with semen send sensory signals via the Pudendal nerve to the spinal cord sacral regions.
- Efferent sympathetic signals from spinal cord (L1-S4) excite rhythmic contractions of the internal genital organs.
- Ischiocavernosus and Bulbocavernosus muscles rhythmic contractions compress the bases of the penile erectile tissues and squeeze semen out through the urethra.
Nonfunctional testes in a male fetus causes what?
male pseudohermaphroditism
Hypogonadism before puberty causes ___ with infantile sex organs.
eunuchism
Hypogonadism after puberty causes what?
regression of the male secondary sexual characteristics
Hypothalamic GnRH deficiency causes what?
adiposogenital syndrome
In hypergonadism, interstitial leydig cells tumors cause what in young children?
very early puberty
excessive developement of the male sex organs & male secondary sexual characteristics
In hypergonadism, teratomas of germinal epithelium secrete what and cause what?
secrete estrogens male gynecomastia (overgrowth of the breast tissue)
Benign prostatic fibroadenoma
due to overgrowth of the prostate tissue causes urinary obstruction
What stimulates rapid growth and metastases in cancer of the prostate?
testosterone
How is cancer of the prostate treated?
by radiation, chemotherapy, testes removal or estrogen therapy
Causes and treatments of erectile dysfunction
caused by vascular diseases, low testosterone, neurological trauma and some drugs
treated by phosphodiesterase-5 (PDE5) inhibitors such as viagra, levitra and cialis that increase cGMP levels
How does viagra work?
inhibits PDE–> cGMP is maintained and NOT degraded, causing continued vasodilation and erection
