male reproductive system

the purpose of the reproductive system is to produce what?

gametes (specialized cells)

Gametes must come together through sexual intercourse which is also called what?

copulation

What is the first cell of a new individual called & what is it made of?

zygote, combined sperm & egg

what is the development of a fetus called?

gestation

What are the male gonads?

testes

Where are the testes found?

within the scrotum (testicles)

where is sperm produced?

testes

What is the path of sperm?

testes, epididymis, ductus (vas) deferens, ejaculatory duct, urethra

what are the accessory glands of the male reproductive system that help the sperm mature & fertilize an egg?

seminal vesicles, prostate, bulbourethral glands

In the male, the urethra is the same duct that carries what at different times?

semen & urine

After sperm is made in the testes, how does it flow through the body?

through the inguinal canal

into the pelvic cavity

up, over & behind the bladder

what is the scrotum?

sac of skin, fibrous membranes & fat which protect the testicle

For sperm to be viable, what temperature must it be kept at?

3 degrees lower than core body temperature

What structures divide the scrotum into two cavities?

scrotal septum

What is the dartos muscle?

smooth muscle that wrinkles scrotal skin to tighten & toughen the scrotum

What is the function of the wrinkles created by the dartos muscles?

trap warm air to help regulate temperature

What are the cremaster muscles?

skeletal muscles that elevate or lower the testes to maintain the proper temperature

If the temperature gets cold, the cremaster muscles will do what?

contract & pull the testicles closer to the body

If the temperature gets too warm, the cremaster muscles will do what?

relax & testicles are lower than the body

What are the testes surrounded by?

two tunics (tunica vaginalis and tunica albuginea)

What is the outermost layer of the testes?

tunica vaginalis

What is the innermost layer of the testes?

tunica albuginea; forms a fibrous capsule of the testes

What is the pampiniform venous plexus?

blood vessels & nerves merge to enter the testicle

How many lobules are in the testes?

250

What are the seminiferous tubules?

site of sperm production

Seminiferous tubules are separated into ______________ with a septum in between

lobules

Where does the sperm go after it travels through the seminiferous tubules?

rete testes then head of the epididymis

Where are immotile sperm stored?

epididymis within testicular fluid

How long is the epididymis when uncoiled?

20 feet

What moves sperm as they mature from the head to the body and finally to the the tail of the epididymis?

smooth muscle contractions

What happens when more sperm is produced than can be used?

epididymis will reabsorb some & return nutrients to the body

What happens when sperm mature after 20 days?

move into ductus deferens

What is the ductus deferens?

thick muscular tube that contracts by peristalsis

What encloses the ductus deferens?

connective tissue (spermatic cord)

Describe the path of the ductus deferens.

up through inguinal canal, into pelvic cavity, wraps around back of bladder

What is the structure called when the seminal vesicle duct & ductus deferens connect?

ejaculatory duct

When the fluid from the seminal vesicle has been conjoined with the sperm, what is produced?

semen

The urethra is the result of two __________________ __________ (left & right) joining.

ejactulary ducts

What is the prostatic urethra?

passes through the prostate gland

What is the function of the prostate?

adds secretions to the semen

When the prostatic urethra exits the prostate what is called? Is it long or short?

membranous urethra, short

When the urethra enters the penis, what is it called?

spongy urethra

What is the tissue called that surrounds the spongy urethra?

corpus spongiosum

What is the last accessory gland that adds secretions to the semen (it is located at the root of the penis)?

bulbourethral gland

During development, the testes form in the pelvic cavity & around the 7th month migrate through the inguinal canal. If they do NOT descend, what happens to the sperm?

will be too warm for sperm to mature & male becomes sterile

If the tests do not descend, what treatment is available?

surgery to remove testes out of pelvic cavity

What is a vasectomy?

cutting and ligating the ductus deferens (used to be called vas deferens)

Once the ductus deferens is cut, sperm CANNOT be ejaculated. The man still produces semen but is now what?

sterile

The sperm gets pushed into what structure during ejaculation?

ductus deferens

What does the ductus deferens & the duct of the seminal vesicle form?

ejaculatory duct

What do the seminal glands do?

contains smooth muscle that contracts during ejaculation so seminal fluid is added to sperm

The seminal fluid makes up what percentage of the semen?

60-70%

What does the seminal fluid contain to provide nourishment for the sperm?

fructose

What does the seminal fluid contain to stimulate peristalsis along the male & female reproductive tracts?

prostaglandins (helps to ensure sperm + egg physically meet)

What does the seminal fluid contain to temporarily clot inside the vagina?

clotting enzyme

What does the seminal fluid contain to neutralize the acids produced by the prostate gland + vagina?

alkaline fluid

Males have two of what structures? (hint: there are four different structures)

testicles, epididymis, ductus deferens, ejaculatory ducts

The ejaculatory ducts merge to form the ______________ ____________

prostatic urethra

What is the prostatic urethra surrounded by (this contracts during ejaculation)?

prostate

What does the prostate gland secrete?

a milky slightly acidic fluid that activates sperm a short after ejaculation (makes 20-30% of the semen volume)

What does the bulbourethral gland secrete?

pre-ejaculate alkaline mucus

What does pre-ejaculate do?

neutralizes traces of acidic urine in urethra & provides lubrication for sexual intercourse

What is the name of the structure that the sperm travels through (part of the membranous urethra)?

spongy urethra

What is the penis?

male sex organ designed to deliver sperm to the female reproductive tract

What three structures make up the penis?

root (near bulbourethral gland), shaft (body), glans penis (end)

There is one ___________ _________________ (the spongy urethra travels through this) and two _______________ _____________________.

corpus spongiosum, corpus cavernosa

What is the glans (of the penis)?

enlarged distal portion surrounding the opening of the urethra

What structure covers & protects the glans?

prepuce (foreskin)

The prepuce is sometimes surgically removed by what procedure (it is debated as it appears to be culturally driven)?

circumcision

What is an erection?

enlargement & stiffening of the penis due to more blood entering the erectile tissue that exits

Normally the arterioles within the penis are vasoconstricted, but during sexual excitement, the CNS activates what type of neurons?

parasympathetic neurons

What does the parasympathetic neurons release (in the penis)?

nitric oxide

What does nitric oxide do?

relaxation of smooth muscle, arterioles vasodilate, corpus cavernosa fills with blood

What is venous drainage blocked by?

enlarged corpora cavernosa (erectile tissue stays erect, corpus spongiosum keeps urethra open)

What happens during ejaculation?

movement of semen out of the body

What causes the ducts & accessory organs of the penis to contract?

sympathetic neurons

What constricts to keep urine from entering the urethra?

bladder sphincter

What might cause erectile dysfunction?

the parasympathetic nerves of the penis don't release enough nitric oxide, or problems with blood vessels

What is spermatogensis?

formation of male gametes (sperm)

Where does spermatogenesis occur (and when does it begin)?

seminiferous tubules (begins at puberty & through a male's life)

How much sperm does an adult male make in one day & how long does it take?

90 million sperm per day, 9 weeks to make sperm

What are sustentocytes?

large columnar cells that nourish the developing sperm

What are spermatogenic cells?

sperm forming cells

What are myoid cells and what do they do?

cells outside of the tubules & contract to squeeze sperm & testicular fluid through tubules

Where are interstitial endocrine cells (Leydig cells) located & what do they do?

located between tubules & produce androgens & some estrogen

If sperm cells haven't yet been made until puberty, then the immune system had no training to recognize them as self or non-self. What will the immune system consider sperm?

foreign

What is the job of the sustentocytes (in relation to the immune system)?

keep a blood testis barrier so no sperm cells escape into the blood & activate the immune system

What does androgen binding protein (ABP) do? What cells secrete ABP?

keeps testosterone levels high to stimulate spermatogenesis; produced by sustentocytes

What does inhibin do? What cells secrete ABP?

inhibits both FSH release & spermatogenesis

The ___________________________ __________ are in various stages of cell division as they become sperm.

spermatogenic cells

What is the process of mitosis?

cell divides into two identical cells (used to grow & replace worn out cells)

What is the process of meiosis?

The chromosome number is reduced from 46 total chromosomes to 23 pairs, so when the egg and sperm unite in fertilization the zygote will have the correct number of chromosomes

What is a cell with a complete set of chromosomes called?

diploid or 2n (the "2n" means you have two of each chromosome)

What is a cell with half the number of chromosomes called?

haploid or n

Where are spermatogonium (in relation to the tubule wall)?

stem cell that stays along wall of tubule

Where are primary spermatocyte (in relation to the tubule wall)?

pushed forward to the lumen

What is the process of spermatogenesis?

spermatogonia, primary spermatocyte, secondary spermatocyte, spermatid, sperm

As meiosis begins, each __________________ __________________ contains ________ individual chromosomes.

primary spermatocyte, 46

At the end of meiosis I, the daughter cells are called ________________ ______________________ and contain _____ chromosomes, each of which consist of a pair of duplicated chromatids.

secondary spermatocytes, 23

During meiosis II, the secondary spermatocytes will divide to become what?

4 haploid spermatids