Anatomy, Male Reproductive System

Functions of male reproductive system

1. production of male gametes (sperm)

2. synthesis of androgens (testosterone)

3. delivery of sperm into female reproductive tract

name some internal accessories of male reproduction system

1. epididymus

2. ductus deferens

3. urethra

4. seminal vesicles

5. prostate gland

6. bulbourethral glands / cowper’s glands

7. semen

Epididymus

sperm travels from _______ via ____

where does it sit?

seminifours tubules via rete testis

behind / above testis within scrotum

how long does the sperm mature in the epidiymus to become mobile

what happens during ejaculation

3 weeks

smooth muscle contracts forcing sperm → ductus deferens

ductus deferens / vans

when is this cut?

a tube that carries sperm from the epididymis to the urethra during ejaculation.

in a vasectomy

enters pelvic cavity (inguinal canal), over bladder, joins seminal vessicel to form ejaclatory duct

urethra

the tube that carries urine out of the body.

it also carries semen during ejaculation.

seminal vesicles

they are glands on the ___

posterior bladder. secrete 60% of the semen volume.

produces seminal fluid - visous alkaline fluid containing fructose (energy for sperm), prostaglandins (alters uterus to help sperm travel), coagulating enzyme, (turns semen into a bolus that can be propelled during ejaculation)

• sperm / testicular fluid / seminal fluid mix in ejaculatory duct during ejacualtion

prostate gland

what does it secrete

secretes about 30% of semen volume

• prostatic fluid contains : citrate (to feed sperm)

• prostate specific antigen : to liquify semen (sperm to swim)

boulbourethral glands / cowper’s glands

• what does it produce

*william

• produces thick / clear alkaline mucus after erection but before ejaculation to nutralize acidic urine in the urethra and to lubricate glands penis

semen

what is the makeup

transport for the sperm

protects / activates / facilitates movement of sperm

• 10% sperm + testifcular fluid, 60% seminal fluid, 30% prostatic fluid

name the male external accessories

1. scrotum

2. testes

3. interstitual cells (leydrig cells)

4. penis

scrotum

what is it

what temp

a sac of skin + superficial fascia contains testes. separated by a CT septum. 3 F lower in temp.

• cremastor muslce - elevates testes if cold. lowers testes if warm

• Dartos muslce - changes scrotal surface area. contracts when temp drops, relaxes when temp increases.

testes

name the 2 layers its covered in

the site of what

what cells does it contain

1. tunica vaginalis - membranous outer layer derived from parital peritoneum

2. tunica albuginea - fibrous capsule. extends into testis and divides it into 250 lobules

• seminiferous tubules - each lobule has 1-4. site of spermatogenesis

• interstitual cells (*franz leydrig cells) - within CT between seminiferous tubules and secrete androgens -mainly test

• spermatic cord - sheath of CT (includes nerves / BV / vas deferens of each testis. penetrates abdominal wall at inguinal canal)

organs that produce sperm and the hormone testosterone.

penis

functions to deliver sperm into female reproductive tract

1. corpus spongiosum - erectile body that surrounds urethra

2. corpus cavernosum - surrounds the above structure

signifiicance of nitric oxide, cGMP

Nitric oxide (NO) helps relax smooth muscle in blood vessel walls. This increases blood flow to the penis during an erection.

cGMP is the chemical messenger made after nitric oxide is released. It keeps the smooth muscle relaxed so the erection can continue.

Viagra (sildenifil, Cialis, levitra)

delivers urine and semen out of the body through the urethra.

what is the production of sperm called

spermatogenesis

the seminiferous tubules contain ___ made of 2 types of cells:

epithelium

1. spermatogenic cells (spermatogonia)

2. sustenacular cells (sertoli cells)

spermatogenic cells (spermatogonia)

located where

contains what

what do they do

innermost surface against basement membrane

46 chromosomes

in male embyos, hormones stimulate them to undergo mitosis → form 2 new cells

• Type a and b

a = remain undifferentiated. b = become primary spermatocyte

stops? → puberty

sustenacualr cells (sertoli cells)

sustain mother the spermocytes

• columnar cells that extend from basement membrane →lumen

• support / nourish / regulate spermatogenic cells

• form tight junctions to help form blood-testis-barrier

why? - isolate sperm from the immune system

what happens during puberty

test increases

primary spermatocytes reproduce by meiosis

*become secondary spermatocytes then spermatids → mature into sperm cells

• spermatids pushed to lumen

what is spermiogenesis

process of sperm cells maturation

what is a sperm

cell is tiny, tad pole shaped. 0.06 mm long

flat head, cylindrical mid peice, long tail

oval head

has a nucleus + chromatin (23)'

has a covering at the end called (acrosome) - contains enzymes that help the sperm penetrate the cell layers that surround the oocyte

midpeice

central core + many mitochondria in a spiral

tail

flagellum

contains several mitochondria enclosed in cell membrane

propels the sperm

Hormonal Control of Male Reproductive Function Notes

What part of the brain controls the changes associated with puberty?

the hypothalamus

released by the hypothalamus, GnRH / gonadotropin, does what

GnRH triggers the anterior pituitary to produce / release what

releasing hormones, travels to anterior pituitary

1. Lutenizing hormone (LH)

2. Follicle Stimulating Hormone (FSH)

LH - lutenizing hormone

• intersittual cells stimulating hormone (ICSH)

• promotes development of interstitual cells (leydig cells) in testes → then secretes male sex hormones androgens

• stimulates production of testosterone

testosterone

• some produced in adrenal glands

• steroid hormone

• production starts in puberty / continues rest of male life

Follice Stimulating Hormone FSH

• stimulates sustenacular cells (setolic cells) to proliferate / grow / mature / respond to test