Male Reproduction Ch 20

Front 1

testes descend from abdominal cavity through inguinal canal into scrotum during last months of fetal life

Back 1

scrotum provides cool environment(optimal for spermatogenesis). the position of the scrotum can vary by spinal reflex mechanism

Front 2

seminiferous tubules carry out spermatogenesis

Back 2

leydig cells in the testis secrete testosterone. testosterone secreted into blood, carries by plasma proteins

Front 3

testosteroe secretion by fetal testis masculinizes reproductive tract and exteral genitalia

Back 3

secretion at onset of puberty signals growth and maturation of reproductive system

Front 4

testosterone is essential for spermatogenesis and maintainng male reproductive tract

Back 4

testosterone: development and maintenance of libido in adult male

Front 5

testosterone signals development of secondary sexual characteristics like voice change, hair, muscle growth

Back 5

testosterone's nonrepoductive functions: signals protein anabolism, bone growth at puberty followed by closure of epiphyseal plates.

Front 6

spermatogenesis produces highly specialized mobile sperm.

Back 6

spermatozoon=sperm
differentiated , haploid

Front 7

spermatogonium=undifferentiated, diploid

Back 7

spermIOgenesis: the packaging (remodeling) of cellular elements of spermatids. includes differentiation into 4 parts: head, acrosome, tail, and midpiece

Front 8

mitochondria located in midpiece

Back 8

nucleus is in the head

centriole located between head and midpiece

Front 9

sertoli cells found in wall of seminiferous tubules. throughout maturation, sperm cells intimately assiciated with sertoli cells

Back 9

function of sertoli cels: selective transport of materials into the lumen of the tubules. tight junctions between the sertoli cells form a blood-testes barrier (BTB) which allow selective transport of material. sertoli cells provide nourishment for sperm cells (barred by BTB)

Front 10

sertoli cells function cont:
phagocytosis of cytoplasm extruded during remodeling (destroy defective germ cells), secrete seminiferous tubule fluid into the lumens of the tubules; flushes released sperm into epididymis,secretes androgen-binding protein, maintaining high level of testosterone in lumen which is essential for sperm production, and sertoli cells are also the site of action for spermatogenesis by testosterone and FSH

Back 10

LH works on leydig cells, causes release of testosterone. FSH works on sertoli cells usual in promoting spermatogenesis

Front 11

testosterone is essential for mitosis and meiosis of germ cells

Back 11

there is a higher concentration of testosterone in the testes than the blood due to androgen-binding protein. the high conc. sustains sperm production

Front 12

FSH: important for spermatid remodeling
estrogen: imp. for spermatogenesis and normal sexuality
-small amount produced by adrenal cortex, and a portion of testosterone secreted by testes converted to estrogen by aromatase (widely distributed in male reproductive tract)

Back 12

GnRH activity increases at puberty

Front 13

winding series of tubules in male reproductive tract: transport sperm from the testis to outside the body

Back 13

accesory glands: secrete fluid into the tract for sperm viability and motility

Front 14

penis: penetration and deposition of sperm in female

Back 14

epididymis: attached to the rear of the testis. it is the exit route from the testis to the ductus deferens. here the sperm cells gain ability to move and fertilize. the epididymis concentrates sperm (100X) as they mature

Front 15

ductus deferens: passes from the scrotal sac up thru the inguinal canal into the abdomen. it is the storage site for concentrated sperm. the two ductus deferens unite behind the bladder forming a V. After bladder, ductus deferens form an ejaculatory duct. ejaculatory duct joins the urethra in the prostate gland under the bladder

Back 15

male accessory sex glands add to what is ejaculated. they contribute secretions that constitute the bulk of semen.

Front 16

semen

Back 16

sex gland secretions, sperm, mucus. provide support for viability of sperm in female reproductive tract, and thereby facilitate fertilization

Front 17

seminal vesicles: two, which join last part of each ductus deferens

Back 17

seminal vesicles: supply fructose to nurish ejaculated sperm. secrete prostaglandins which stimulate smooth muscle contraction, helping move sperm. provide bulk of semen. provide precursors (fibrinogen) for clotting of semen.

Front 18

prostate gland:
single, completely surrounds urethra at neck of bladder

Back 18

prostate gland:
secretes alkaline fluid that neutralizes acidic vaginal secretions. it also provides clotting enzymes and fibronolysin. cloitting enzymes act on fibrinogen to form fibrin, thus clotting the semen. this keeps the sperm in the vagina during penis withdrawl. fibrinolysin degrades seminal clot, releasing motile sperm within female tract.

Front 19

bulbourethral glands: two, both empty into urethra just before it enters the penis. it secretes mucus for lubrication for intercourse.

Back 19

prostaglandins:
locally acting chemical messengers. first discovered in semen. they are fatty acid derivatives found in most tissues. they havea wide variety of effects.

Front 20

prostaglandin effects:

Back 20

promoting sperm transport, promoting bronchodilation, increasing renal blood flow, inhibiting hydrochloric acid secretion in the stomach, enhancing cortisol secretion, and cause bursting of follicle so ovulation occurs