THE REPRODUCTIVE SYSTEM

Organs & glands that: 1. produce & nurture sex cells; 2. transport these cells to site of fertilization; 3. ensure production of offspring with correct # of chromosomes

THE MALE REPRODUCTIVE SYSTEM

• Produce & nurture sperm cells & transport them to site of fertilization

• The male gonads are the TESTES

• ~ 5 cm long• Produce sperm

OTHER ORGANS• SCROTUM:

pouch that holds testicles; outside body to keep sperm @ lower temp

• SEMINIFEROUS TUBULES: tightly coiled tubes w/i testicles; where sperm are made

• EPIDIDYMIS: pouch that sits on testes; stores sperm while they mature

• VAS DEFERENS: duct leading from epididymis to urethra; transport sperm

GLANDS

• SEMINAL VESICLE: convoluted sac behind urinary bladder; secretes alkaline substances, fructose, prostaglandins

• PROSTATE GLAND: chestnut shaped;

just below bladder; secretes thin milky alkaline substance

• COWPER’S GLAND:

just below prostate; secretes a mucous lubricating fluid

Together these secretions form SEMEN…~7.5 pH

ON THE WAY OUT…

• URETHRA: tube leading to outside of male’s body (part of urinary tract, but there is a flap that closes opening to bladder during ejaculation

• PENIS: used to deposit sperm into female’s body

• PREPUCE: foreskin…loose skin…removed during circumcision

SPERM• Males produce

sperm throughout reproductive cycle

• Mobile & small compared to egg

• Spermatogenesis: formation of sperm cells (meiosis)

• Erection: erectile tissue…fills with blood (in penis)

• Ejaculation: forceful muscular release of sperm

Contain enzymes To penetrate egg

Contain mitochondriaFor energy

MALE HORMONES

• Called androgens• Produced in testes; controlled by

hypothalamus & pituitary glands• PUBERTY: release of hormones

makes a male reproductively functional

• The main male hormone is TESTOSTERONE

FUNCTIONS OF TESTOSTERONE

• Stimulate enlargement of reproductive organs & develop male characteristics…

• Increased growth of body hair• Enlargement of larynx; thickening of vocal

cords • Thickening of skin• Thickening/strengthening of bones• Increased red blood cell production• Affects sexual regions of brain• Increased muscular growth; narrowing of

waist; broadening of shoulders

FEMALE REPRODUCTIVE SYSTEM

• Produce & maintain egg cells;

• transport egg to site of fertilization

• Provide favorable environment for fetal development

• The female gonad is the OVARIES

• Solid, oval, ~3.5 cm• Produce eggs

FEMALE ORGANS

• FALLOPIAN TUBES: (also called oviducts): ~ 10 cm; funnel shape near ovary (infundibulum); transports egg to uterus; fertilization takes place here!

• UTERUS: hollow, muscular, pear shaped; bends forward over bladder; attachment for fertilized egg; fills with blood/nutrients; embryo/fetus develops here(expands to 500X normal size during pregnancy)

• CERVIX: neck of uterus

• VAGINA: ~ 9 cm long tube leading to outside of body; releases uterine secretions; receives penis; birth canal

EXTERNAL FEATURES• LABIA MAJORA rounded folds of fat tissue;

enclose/protect external reproductive organs (corresponds to male scrotum)

• LABIA MINORA flattened folds w/i labia majora

• CLITORIS small projection; most concentrated area of nerve fibers anywhere in body (8000)…corresponds to the male penis

• VESTIBULE small space…vagina opens at posterior end…urethra opens at mid-section

EVENTS

• OOGENESIS: formation of egg cells (during meiosis)

• OVULATION: release of egg from ovary to fallopian tube

• ORGASM: series of reflexes & rhythmic contractions that make it easier for sperm to move

• PUBERTY: the reproductive system becomes active

• MENSTRUATION: release of blood that has built up in uterus & unfertilized egg

• MENOPAUSE: end of female fertility; menstruation stops; caused by aging of ovaries & reduced estrogen production

• FERTILIZATION: union of sperm & egg

FEMALE HORMONES

• ESTROGEN• Stimulate

enlargement of reproductive organs

• Breast development• Increased fat

production• Increased

vascularization of skin

• PROGESTERONE

• Changes in uterus during reproduction

• Affect mammary glands

• Secretion of FSH & LH

Controlled by the hypothalmus

THE MENSTRUAL CYCLE• FOLLICLE STIMULATING HORMONE

(FSH) stimulates production of follicle around egg

• ESTROGEN stimulates production of LH

• LUTEINIZING HORMONE (LH) stimulates egg to mature

• LUTEOTROPHIC HORMONE (LTH) stimulates production of progesterone

• PROGESTERONE stimulates thickening of uterine lining; stops production of FSH

MAMMARY GLANDS

• Accessory organs• Produce &

secrete milk after birth

• 15-20 lobes • Dense connective

& adipose tissue separate each lobe

How the Egg is Deceived