Ch. 28 - Male Reproductive System Flashcards
C/C cremaster and dartos muscles of the scrotum
C - sk that moves testes close to body
D - sm that decreases SA of scrotum
What do the testes contain?
each lobule is filled with 2-3 seminiferous tubules where spermatogenesis occurs
What are the 2 cell types in seminiferous tubules?
- spermatogenic cells (form sperm)
- sustentacular (support)
What cells are located in between seminiferous tubules? What is their function?
interstitial cells; secrete testosterone
What are the stem cells in seminiferous tubules?
spermatogonia (2n) located against basement membrane; develop into sperm toward lumen
What is the function sustentacular cells?
joined by tight-junctions to form blood-testis barrier
Describe the differentiation of spermatogonia
spermatogonia (2n) primary spermatocytes (2n) secondary spermatocytes (n, after meiosis I) spermatids (n, after meiosis II) spermatozoa (n)
What is the function of the acrosome on a sperm head?
has enzymes to help penetrate and fertilize a secondary oocyte
Describe the hormonal control of spermatogenesis
during puberty:
hypothalamus releases GnRH
ant pituitary secretes LH and FSH
- LH: stimulates testosterone secretion
- FSH: stimulates spermatogenesis
What is the pathway of sperm through ducts?
seminferous tubules
ductus epididymis
ductus deferens
What is the function of the epididymis?
site of sperm maturation; can be stored here or ejaculated
What is the function of the ductus deferens?
stores sperm and propels them from epididymis toward prostatic urethra during ejaculation
What is a vasectomy?
- incision to remove a portion of the vas deferens
- sperm still produced but cannot reach exterior; degenerate and removed by phagocytosis
What forms the ejaculatory duct?
union from seminal vesicle and ampulla of ductus deferens
- terminate in prostatic urethra
What are the 3 sections of the urethra?
- prostatic
- intermediate (through deep muscles of perineum)
- spongy (through penis)
Why does prostate enlargement lead to difficulty urinating?
prostate wraps around and compresses urethra
What are the 3 accessory sex glands?
seminal vesicles, prostate, bulbourethral glands
- secrete most of liquid portion of semen!
What is the function of seminal vesicles?
secrete an alkaline viscous fluid that contains fructose, prostaglandins, and clotting proteins
What is significant of the alkaline pH of the fluid produced by the sem vesicles?
neutralize acid in male urethra and in female repro tract for sperm viability
What is the function of the prostate?
secretes milky, acidic fluid into prostatic urethra containing citric acid and proteolytic enzymes
What is part of the acidic fluid produced by the prostate?
citric acid - used by sperm for ATP production
proteolytic enzymes - liquefy coagulated semen, act as antibacterial agents
What is the function of bulbourethral glands?
secrete an alkaline fluid into urethra to protect sperm by neutralizing acids from urine
- also secrete mucus as lubricant
What is semen?
mixture of sperm and seminal fluid
- secretions from seminiferous tubules, seminal vesicles, prostate, bulbourethral glands
- slightly alkaline (pH 7.2-7.7)
What is the penis composed of?
- body, root, glans penis
- 3 masses of erectile tissue
- 2 corpus cavernosa
- corpus spongiosum
What is the function of erectile tissue?
- spongy structures composed of blood sinuses lined by endothelial cells
- surrounded by sm muscle and elastic CT
- fill with blood during erection
What is the function of the corpus cavernosa?
dorsolateral; maintain erection
What is the function of the corpus spongiosum?
contain spongy urethra; keep it open during ejaculation
Describe how a parasympathetic reflex causes an erection
- sexual stimulation dilates the arteries supplying penis
- expansion of blood sinuses compress veins, trapping blood in penis to maintain erection
Describe how ejaculation is a sympathetic reflex
- peristalsis in epididymis, ductus deferens, seminal vesicles, ejaculatory ducts, and prostate propel semen into spongy urethra
- urination is prevented
What happens after ejaculation?
- arterioles supplying erectile tissue constrict
- smooth muscles within erectile tissue contract
- blood sinuses become smaller, reliving pressure from veins
- blood drains