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ANA 113 Lecture 36
Male Reproductive System
Question | Answer |
---|---|
Primary sex organs (gonads) | testes- produce the gametes (sperm) and produce and secrete the sex hormone testosterone |
Secondary sex organs | aid in the formation of semen and the transport of the sperm. includes the epididmis, ductus deferens, ejaculatory duct, seminal vesicles, prostate gland, bulbourethral glands and the penis |
Secondary sex characteristics | body physique, patterns of body hair and low voice pitch |
Location of testes | outside of pelvic cavity within the scrotal sac (scrotum) |
Function of testes | production of sperm, production of testosterone |
Structure of testes | small oval structure, surrounded by CT |
seminiferous tubules | funtional unit of testes, site of sperm production (thousands/second) (miosis) |
spermatogonia | developing sperm in various stages |
Sertoli cells | "nurse cells" lines semiferous tubules and produces nutrients required to maintain developing cells (sperm) |
Interstitial cells of Leydig | produce and secrete testosterone (in testes) |
Structure of mature sperm | has head body and tail, -acrosome -23 chromosomes (22 autosomes, 1 sex), life expectancy:48-72 hours after ejaculation at body temp, approx. 50-150 million per mL of ejaculate *only 200-400 reach ovum |
Acrosome | located at the tip of the head, contains enzymes which help penetrate the ovum |
spermatic cord | the testes "life line", It is a CT sheath which contains the :vas deferns, testicular artery, pampiniform plexus of the veins, nerves, lymphatics |
vasectomy | cutting and ligating of the ductus deferens, prevents sperm from entering hrough this tube and passing into the urethra |
Where do the testes develop embryologically? | the abdominal cavity, then descend into the scrotal sac the inguinal canal (passageway through the abdominal wall) |
What are the 3 main components of the spermatic cord? | Epidiymis, ductus deferens (vas deferens), and the ejaculatory duct |
Epididymis | attached to the posterior surface of the testes. consists of coiled tubes (17 ft)and contains millions of sperm in their final stages of development. function: stores sperm and transports sperm from epididymis to the ductus deferens |
Ductus deferens | (vas deferens)-contains only sperm. passes through the scrotal sac outside the pelvic cavty) within the spermatic cord to enter the pelvis. composed of fibromuscular tube. funtion: transports sperm from the epididmyis to the ejacculatoy duct |
Ejaculatory duct | begins on the posterior side of prostate, passes through the prostate gland to join the prostatic urethra. formed by the union of the the ductus deferens and the duct of the seminal vesicles |
Accessory glands | produce the components of semen (seminal vesicles, prostate gland and bulbourethral glands) |
seminal vesicles | posterir to the bladder, near the base. glandular organ which contains smooth muscle, which contracts to release contents |
function of seminal vesicles | -produces an alkaline secretion rich in fructose (sugar), used to provide energy for the sperm (60%) -secretes prostaglandins, capible of causing uterine contractions to help the sperm move through this organ |
Prostate gland | just inferior to the neck of the bladder, surrounds the first portion of the urethra (prostatc urethra) |
Function of the prostate gland | secretes an alkaline fluid which contains enzymes, helps to neutralize acidic environment of the vagina. (about 30%) |
Bulbourethral glands | (cowper's glands) small glands with a duct openng into the urethra, located in muscular layer of the pelvic floor. |
Functon of the bulborethral glands | secretes a mucous-like fluid which lubricates the urethra |
What makes up the male external genitalia? | Penis and scrotum |
Scrotum | located somewhat posterior to the penis, sac-like struture coveredby fasca (CT) and skin, contains muscle fibers (cremaster muscle) |
Function of the scrotum | reglates the temperature and position of the testes, supporteds and protects testes |
What happens to the scrotum when it's cold? | contracts, draws testes closer to body wall |
What happens to the scrotum when it's warm? | relaxes, lowers testes |
Structure of the penis | Shaft, glands, and contains penile urethra |
Shaft of the penis | major portion of the penis, contains highly vascular tissue, composed of sponge-like erectile tissue |
glans of the penis | expanded, terminal portion of the penis. contains opening of the urethra, foreskin (retractable portion of skin removed during circumcision) |
Erection | occurs when vascular spaces becime engorged with blood ad blood is not permitted to drain, erectile tissue becomes rigid |
Ejaculation | under sympathetic control, affects smooth muscle of the glands and vessels of the reproductive system |