HSCI 210: Male Reproductive System

male reproductive system

produces sperm cells (to fertilize egg cell) & hormones (developing adult male characteristics)

penis

external male reproductive organ, contains urethra, part of urinary & reproductive system, a lot of venous/arteriole blood flow for erection & draining

root

crua + bulb, 2 ischiovancernosus & 2 bulbospongiosus

ischiocavernosus

muscle, upside down V shape that fills with blood during arousal

bulbospongiosus

contracts to empty urethra of residual urine/semen, contracts during orgasm/ejaculation

body/shaft

extends from pubic symphysis, 2 corpus cavernosa & 1 corpus spongiosum

glans

tip of penis, most distal portion

foreskin

covers glans, can be removed through circumcision, double layer of skin/fascia for shape/form

scrotum

2 pouch like sacs/external tissues that support testes, controls temperature of testes, wrinkly skin for flexibility (ascending & descending)

cold = moves closer/up to body to increase testes body temp, wrinkly

hot = moves away/down from body to decrease testes body temp, smooth

raphae

groove/ridge/seam in middle of scrotum

cremaster muscle

surrounds testicle & spermatic cords to elevate testicles (temperature regulation), extends from internal oblique muscle, skeletal muscle

dartos muscle

contracts & causes wrinkling to decrease surface area during cold (reduce heat loss), relaxes & causes smooth to increase surface area during hot (increase heat loss)

scrotal septum

divides dartos muscle left & right

corpus cavernosa

spongy erectile tissue on outside of penis, smooth muscle, endothelial cells, fils with blood to create rigidity during erection

corpus spongiosum

anterior tube that surrounds urethra & expands to form glands, thin/elastic outer layer to prevent urethra from being compressed during ejaculation (allows for passage of semen)

testicle/testes

glands held by scrotum that produce sperm cells & male sex hormones (testosterone), protrude outside body to have diff temperature form main body cavity (must be cooler than body to make sperm cells)

leydig cells

produce testosterone in testes

tunica albuginea

dense fibrous connective tissue around testes

seminiferous tubules

create sperm in testes

spermatogenesis

sperm creation

epididymis

narrow coiled tube on top of testes that temporarily stores immature sperm cells until they mature (develop tails & get stronger), produces special fluid to maintain maturing sperm (nutrition), can store sperm up to 30 days until ejaculated, pseudostratified columnar epithelium, ~6 meters

ductus/vas deferens

long muscular tube for sperm to be released from testes, connect epididymis to prostate gland, connects testes to seminal vesicles & urethra, smooth muscle, transports mature sperm to urethra for ejaculation

vasectomy

cut & tie off vas deferens, prevents sperm in semen, needs 20-30 ejaculations before all sperm cleared out, mature sperm still produced gets reabsorbed by macrophages (WBCs)

seminal vesicles

sac-like pouches attached to vas deferens, superior to prostate gland, produces sugar-rich fluid for energy for sperm (fructose/enzymes/prostaglandins), temporarily store sperm, ejaculation contracts & releases fluid into ejaculatory duct (makes up 60% of semen)

prostate gland

walnut sized gland under bladder & above penis, secretes fluid that nourishes/protects sperm, milky white color & alkaline to balance acidic environment of vagina, connects urethra to ejaculatory duct, blocks urine/semen to only allow one out at a time, turns into urethra (prostatic urethra)

benign prostatic hypertrophy (BPH)

increased prostate gland (noncancerous), compresses urethra

due to: aging/hormone changes

prostate cancer

tumor in prostate gland, check prostate through anus

cowper’s/bulbourethral gland

2 pea sized organs under prostate gland, releases fluid that flushes out foreign matter, lubricates & neutralizes acid in urethra so sperm can safely pass

urethra

passageway for urine & semen (doesnt allow mixing), surrounded by corpus spongiosum (prevents penis from collapsing)

prostatic urethra

urethra section near bladder

membranosus urethra

urethra section in prostate gland

spongy/penile urethra

urethra section in penis

bladder

holds urine, sits superior to prostate gland, urine exits through urethra

urine incontinenece

involuntary urine leakage

• weak pelvic floor muscles (skeletal muscle) → external urethral sphincter difficult to urinate

• enlarged prostate → presses on urethra (leaking urine)

rectum & anus

posterior to bladder, holds & releases feces

sperm head

has genetic material, 23 chromosomes & nucleus

acrosome

most external portion of sperm head, breaks ovum/egg outer layer

sperm body

mitochondria/energy

sperm tail

propel/move sperm

sperm pathway

1. testes (seminiferous tubules)

2. epididymis

3. ductus/vas deferens

4. seminal vesicles

5. prostate gland

6. cowper’s/bulbourethral gland

7. spongy urethra