male reproductive system

why is the reproductive system in the body if it is not essential to the life of the individual?

the system produces, stores, provides nourishment, and transports gametes(reproductive cells) to ensure the continued existence of the human species

scrotum

fleshy pouch that covers the testes, the testes are suspended inside the scrotum, these small pockets are part of the peritoneal cavity

descent of testes

as a fetus the testes form inside the body next to the kidneys, move gradually anterior and inferior thru the abdominal musculature

cryptorchidism(abdominal testes)

3% of male births, 30% of premature male births, one or both testes do not descend, surgically repaired

spermatic cords

extends from the pelvic cavity to testes, contains vas deferens, blood and nerve supply

lingual canal

passageway thru abdominal musculature for spermatic cords, this causes a weak area that can lead to an inguinal hernia in males, very rare in females

cremaster and dartos muscles

2 degrees F cooler than body temp. pulls testes closer to body

tunica vaginali and tunica albuginea

connective tissues covering testes

seminiferous tubules

tightly coiled tubes, place of sperm production

interstitial cells

found in spaces between seminiferous tubules, production of sex hormones- androgens(mostly testosterone)

rete testes

passageway that leads from seminiferous tubules

efferent ductules

connect rete testes to epididymis

epididymis

beginning of male reproductive tract, coiled tube, contains head, body and tail

epididymis functions

1. monitors and adjusts the fluid produced by the seminiferous tubules

2. recycles damaged spermatozoa

3. stores, protects and matures spermatozoa after detaching from Sertoli cells

ejaculatory duct

empties vas deferens and seminal vesicles into urethra near prostate gland

vas deferens(ductus deferens)

begins at tail of epididymis, part of spermatic cord, ascends thru inguinal canal

urethra

passageway from the bladder to the tip of the penis, used by both the urinary and reproductive systems

accessory glands functions

1. activating spermatozoa

2. provides nutrients needed for motility

3. propels spermatozoa and fluids along reproductive tract

4. produces buffers against vaginal acidity

seminal vesicles

drains into ejaculatory duct, contributes 60% to total volume, contains fructose(energy), prostaglandins(controls smooth muscle), fibrinogen(forms clot inside vagina)

prostate glands

encircles urethra as it leaves the bladder, contributes 20-30% to volume, contains antibiotic to prevent urinary infection, common area for male cancer

bulbourethral gland(cowper’s gland)

2 small round glands found at the base of the penis, empties into urethra- helps make semen alkaline, contributes 5% to volume

semen

(ejaculate), 2-5 ml, regenerates in 36 hours

spermatozoa

20-100 million per ml, only 60% are normal(actively swimming), makes up 5%

seminal fluid

mixture if fluids from accessory fluids from accessory glands, makes up 95%

enzymes

dissolves vaginal secretions, an antibiotic to kill bacteria(E-coli), coagulates semen by fibrinogen- fibrin, fibrolysin dissolves clot after 15-30 minutes

penis

external organ containing the urethra

root

attaches penis to the body wall

body(shaft)

middle part

glans

expanded distal end, surrounds external orifice

prepuce(foreskin)

attaches to neck and extends over the glans

circumcision

surgical removal of foreskin, done to prevent infection and/or religious beliefs, mostly done in America after second day after birth

erectile tissue

maze of vascular tissue, when dilated with blood causes erection

corpora cavemosum

paired structures, extends length of shaft, each surrounds a central artery

corpus sponglosum

surrounds urethra, extends to tip of penis, expands the glans

mitosis

cell division, 2 daughter cells, 46 chromosomes, diploid

meiosis

involves I and II, produced 4 gametes, 23 chromosomes, haploid

spermiogenesis

development from spermatid to sperm cell, rids itself of cytoplasm and organelles, grows flagellum

sertoli (sustentacular) cells

1. blood- testis barrier-prevents immune system from attacking developing sperm cells

2. supports mitosis and meiosis by circulating FSH and testosterone

3. provides nutrients and chemical stimuli that promote cell development

4. secrete inhibin- regulates production

5. secretion of androgen- binding protein, attracts testosterone

6. helps in fetal development of testes

sperm cell

essentially a mobile carrier of genetic material, lacks glycogen and other organelles(reduces weight), absorbs energy(fructose) from surroundings

acrosomal cap

front tip of sperm, helps enter egg

nucleus

contains genetic material

neck

contains mitochondria to provide energy for tail

tail

flagellum, provides movement, swimming action

GnRH

FSH→ LH

FSH

1. provide spermatogenesis

2. secrete androgen- binding protein(ABP)

inhibin

inhibits FSH production, increase in FSH causes release, negative feed back loop

LH

secretion of testosterone

1. stimulates spermatogenesis and maturation

2. affects CNS including sex drive

3. stimulates protein synthesis and muscle growth

4. establishes and maintains secondary sex characteristics

5. maintains accessory glands