Anatomy Final Reproductive System

reproductive system is composed of

primary sex organs

accessory reproductive organs

primary sex organs

testes and ovaries

-produce sex cells (gametes)

-secrete steroid sex hormones

—> androgens (males): testosterone, dihydrotestosterone (DHT) and androstenedione (precursor)

—> estrogens and progesterone (females)

gametes

sperm

oocytes (eggs)

steroid sex hormones androgens

males

testosterone, dihydrotestosterone (DHT) and androstenedione (precursor)

dihydrotestosterone (DHT) steroid sex hromone

most active

steroid sex hormones female

estrogen

progesterone

accessory reproductive hormones

ducts, glands, and external genitalia

testosterone —>

DHT

testes

-are located in the scrotum

-hang outside the body

testes function

produce sperm

sperm is best produced

in cooler temperatures (<37 degrees)

scrotum

layer of smooth muscle called dartos muscle

dartos muscle

if too cold: muscle contracts

if too hot: muscle relaxes

sperm are delivered to exterior through a

system of ducts

path of sperm delivery to exterior

epididymis —> ductus (vas) deferens —> ejaculatory duct —> urethra

vasectomy

cuts the vas deferens to inhibit sperm from leaving

spongy tissue of the penis

-corpus cavernosum

-corpus spongiosum

prepuce

foreskin

the testes are surrounded by 2 tunics

-tunica vaginalis

-tunica albuginea

seminiferous tubules

site of sperm production (in the walls)

sperm passes through ____ in the testes

-seminiferous tubules

-rete testis

-efferent ductules

-epididymis

interstitial (leydig) cells

-outside the seminiferous tubules

-produce androgens (EX: testosterone)

testosterone is converted to

more active form DHT by 5-alpha reductase

functions of testosterone

-facilitates spermatogenesis

-stimulate libido and development of secondary sex characteristics (hair growth in axillary anf pubic regions, deeper voice, facial hair)

spermatic cells

give rise to sperm

meosis are

primary for spermatic cells

mitosis

spermatogonia form spermatocytes

meiosis

spermatocytes form spermatids

spermatogenesis

-spermatids become sperm (spermatozoa)

-haploid (n)

—> sex chromosome is either X or Y

major regions of the sperm

-head

-midpiece

-tail

head of sperm

1) nucleus

2) acrosome

acromosome head of sperm

containing enzymes that enable sperm to penetrate the egg

midpiece of sperm

produce mitochondira

tail of sperm

flagellum (microtubules)

sustentacular (sertoli) cells

present in testicles

• Provide nutrients and signals to dividing cells throughout
spermatogenesis
• Dispose of excess cytoplasm sloughed off during
spermiogenesis
• Produce chemical mediators to regulate spermatogenesis
—>• ABP – promotes spermatogenesis
—>• Inhibin – inhibits spermatogenesis
• Forms blood-testis barrier

ABP

chemical mediator that promotes spermatogenesis

inihibin

chemical mediator that inhibits spermatogenesis

accessory sex glands produce

the remaining components of semen

accessory sex glands

-seminal vesicles

-prostate

-bulbourethral

semen consists of secretions from

-seminal glands

-prostate glan

-bulbourethral glands

seminal glands (70%)

Secretions are alkaline which neutralizes vagina acidity
• Fructose nourishes sperm (only place fructose is produced; can be
used in rape kit)
• Prostaglandins promote widening of external os of cervix

why can fructose be used in a rape kit

it is th only place in the body fructose is produced (seminal glands)

fructose

nourishes sperm

prostaglandins

promote widening of external os of cervix

prostate gland

secretes milky fluid containing:

-citric acid

-seminalplasmin

-PSA

citric acid prostate gland

nutrient for sperm health

seminalplasmin prostate gland

antibiotic that combats urinary tract infection; may also prevent female immune system from attacking sperm

PSA prostate gland

enzyme to liquefy semen

-prostate specific antigen

bulbourethral glands

produce pre-ejaculatory fluid (pre-cum)

pre-ejaculatory fluid

-lubrication of urethra and tip of penis

-neutralization of acidity in urethra

-clearing the urethra of urine or debris

The hypothalamic-pituitary-gonadal (HPG) axis

anterior pituitary

1. Hypothalamus releases gonadotropin-
releasing hormone (GnRH)
—>. Massive increase Begins during puberty
2. GnRH stimulates the anterior pituitary
to secrete FSH and LH
3. FSH causes Sertoli cells cells to release
androgen-binding protein (ABP), which
makes spermatogenic cells receptive
to testosterone
4. LH stimulates Leydig (Interstitial) cells
to release testosterone

FSH

follicle stimulating hormone

-causes sertoli cells to release anddrogen-binding protein (ABPT) which makes spermatogenic cells receptive to testosterone

LH

leutinizing hormone

-stimulates Leydig(interstital) cells to release testosterone

the penis consists of

-root

-shaft

-glans penis

-prepuce

-3 cylindrical bodies of erectile tissue

-urethral regioms

3 cylindrical bodies of erectile tissue

-corpus spongiosom

-corpora cavernosa

urethral regions of the penis

both urine and semen pass through

1)prostatic urthra (prostate)

2) membranous urethra

3) spongy (penile) urethra (outside body)

Male secual response consists of

-erection

-ejaculation

erection

– Parasympathetic
reflex promotes
release of nitric oxide
(NO) – a vasodilator
– NO causes erectile
tissue to fill with
blood

blood fills spongy tissue

ejaculation

– Sympathetic spinal
reflex causes
• Ducts and accessory
glands to contract
and empty their
contents
• Bladder sphincter
muscle to constrict,
preventing the
expulsion of urine

men with decreased testosterone levels in 50s

o Due to decreased number of interstitial (Leydig) cells
o Decline more gradually than women’s hormone drop
o Most men have few symptoms
o Some with mood swings, decreased sex drive, hot flashes

prostate elargement

o experienced by most men with age

o interferes with sexual and urinary functions

erectile dysfunction

o inability to achieve or maintain erection

o associated with aging, other risk fatcors

female gonads

ovaries

-produce female gametes (ova)

-secrete female sex hormones (estrogen and progesterone)

accessory ducts in female reproductive system

-uterine tubes

-uterus

-vagina

the ovaries are held in place by several ligaments

-ovarian ligament

-suspensory ligament

-broad ligament

-round ligament

follicle

oocyte surrounded by granulosa cells

stages of developement for follicle

– Primordial follicle
– Primary follicle
– Secondary follicle
– Late secondary follicle

graafian follicle

-fluid-filled antrum forms

ovulation

ejection of the oocyte

corpus luteum

develops from reptured follicle

female duct system

-uterine (fallopian) tubes

-uterus

-vagina

fallopian tubes

-ampulla

-isthmus

ampulla fallopian tubes

– Infundibulum - distal expansion
near ovary
– Usual site of fertilization
– Ciliated fimbriae of
infundibulum create currents to
move oocyte into uterine tube

Infundibulum ampulla

distal expansion near ovary

isthmus fallopian tubes

constricted region where tube joins uterus

oocyte is carried along by

peristalsis and ciliary action

uterus

cervix & uterine wall

cervix

narrow neck to vagina

– Cervical canal connected to
– Vagina via external os
– Uterine body via internal os

cervical glands

secrete mucus

blocks sperm entry except during midcycle

3 layers of the uterine wall

1) perimetrium

2) myometrium: smooth muscle

3) endometrium: mucosal lining

myometrium

: smooth muscle

contracts during labor to push the baby out

endometrium

: mucosal lining

grows during menstrual cycle; shed during menstruation

functions of the vagina

as birth canal,

recieves penis,

passageway for menstruation

vagina

thick-walled, fibromuscular tube

3 tunics of the vagina

-mucosa

-muscularis

-adventitia

mucosa tunic of vagina

o Nonkeratinized stratified
squamous epithelium
o Acidic secretions prevent
infection
o Form vascularized
membranous barrier, hymen
which covers part of external
vaginal opening

hymen

vascularized membranous barrier that covers part of external vaginal opening

female external genitalia

-labia majora

-labia minora

-greater vestibular glands

-clitoris

labia majora

outer fatty skin folds

labia minora

inner skin folds

-protect the vaginal and urethral openings from mechanical irritation, dryness and infections

greater vestibular glands

release mucus into the vestibule for lubrication

clitoris

-contains erectile tissue

-glans clitoris: exposed

glans clitoris

exposed

oogenesis —> production of female gametes

gonadotropin releasing hormone (GnRH) female reproductive

– Secretion from hypothalamus begins to rise towards very
end of previous menstrual cycle
– Leads to the increase in production/secretion of FSH and
the production of LH

follicular stimulating hormone (FSH) female reproductive

-causes the development of the follicle

-causes granulosa cells fo the follicle to secrete estrogen

lutenizing hromone (LH) female reproductive

– Before day 10, it’s secretion is blocked by low levels of
estrogen (negative feedback)
– After day 10, it’s secretion is increased by high levels of
estrogen (positive feedback)
• This leads to ovulation

gonadotropin hormone levels female reproductive

-GnRH

-FSH

-LH

Ovsarian hormone levels

-estrogen

-progestogens