BIO12 - REPRODUCTIVE SYSTEM

testes (testicles - 2)

produce sperm & sex hormones

- made of connected tissues w/ seminiferous tubules

scrotum

holds test away from body @ cooler temp (34C)

- skin (balls)

- ideal temp for spermatogenesis

epididymis

carries & stores sperm cells from testes; helps sperm mature

- coiled tubules behind testes

vas deferens

transports mature sperm to urethra to prep for ejaculation

- tubules

prostate gland (1)

produces fluid to nourish & transport sperm (seminal fluid)

- muscular tube

SEMINAL FLUID: basic fluid containing bicarbonate (HCO3) to neutralize vagina's acidity

cowper's gland (2)

produces thick clear mucus before ejaculation (seminal fluid)

- small glands bellow prostate

SEMINAL FLUID: mucus rich fluid for lubrication

penis

copulation organ

- connective tissue

seminal vesicle

provides sperm w sugary fluid for movement

SEMINAL FLUID: basic fluid for acidity of vagina; fructose for sperm energy; prostaglandins (hormone) to contract female uterus

Spermatogenesis

formation of sperm in seminiferous tubules in testes

spermatocyte

makes up tubules

- undergoes meiosis to produce sperm & supported by sertoli cells

sperm structure

HEAD:

nucleus (chromosomes & DNA)

acrosomes (enzymes 4 outer layer egg penetration)

MIDPIECE:

circular mitochondria (energy 4 movement)

TAIL:

microtubules (flagellum)

interstitial cells

between seminiferous tubules

- secrete male sex hormones androgen & testosterone

sperm pathway

TESTES - sperm maturation

EPIDIDYMIS - sperm storage

VAS DEFERENS - sperm transport & some storage

URETHRA - penis 4 ejaculation

semen makeup & gland contributors (3)

SEMEN = sperm + seminal fluid

1. seminal vesicles

2. prostate gland

3. cowper's glands

penis structure & function

- foreskin cover (unless circumsized)

- spongy erectile tissue compressed when arteries fill w blood (erection)

- sphincter controls contractions 4 ejaculation when semen in urethra & prevents urine from entering

- post ejaculation, returns to flaccid state during refractory period

male orgasm

1. penis erectile tissue fills w blood, becomes erect for intercourse (erection)

2. sperm release (ejaculation) approx 4million/3.5mL of semen

3. orgasm physiologically & psychologically experienced by brain & reproductive organs

neuroendocrine control in male reproductive system (flowchart)

Hypothalamus -> Gonadotropic

Releasing Hormone (GnRH) -> anterior pituitary -> 2

FOLLICLE STIMULATING HORMONE (FSH) -> spermatogenesis & hormone production (seminiferous tubules) -> sperm + inhibin

(inhibin has negative feedback loop to hypothalamus & anterior pituitary)

LUTENIZING HORMONE (LH) -> androgen + testosterone (interstitial cells) -> sperm maturation + secondary sex characteristics (voice, facial hair, big ass Adam's apple)

(testosterone has negative feedback loop to hypothalamus & anterior pituitary)

ovaries

produce eggs + sex hormones

- connective tissue

oviducts

transports eggs

- tubules

uterus

houses developing embryo

- muscular sac

cervix

connects vagina to uterus

- muscle/muscular

vulva

external parts of vagina

- skin (labium minora & majora)

clitoris

erectile tissue, leads to female orgasm

- tissue

vagina

copulation organ & birth canal

- muscular tube

labium minora & majora

VULVA

MINORA: internal small folds covering vagina

MAJORA: external big folds covering vagina

ovaries structure & function

protects developing ova (eggs)

- where follicles undergo oogenesis

oogenesis

2 million follicles located in outer cortex of ovaries @ birth

- 400 of 2M follicles mature via oogenesis (changing from follicles to eggs to implant into uterus)

ovum

mature egg cell from follicles developed during puberty

corpus luteum

from follicles

FERTILIZED: persists for 3-6 months producing female hormones (estrogen & progesterone)

- degenerates in 10 days

UNFERTILIZED: degenerates in 10 days

ovum path

OVARIES - produced

OVIDUCT - transport

UTERUS - implants if fertilized

VAGINA - period if not fertilized

female orgasm

1. erectile tissue (clitoris, labia minora, vaginal wall) fill with blood, clitoris is erect

2. vaginal wall blood vessels release fluid lubricating vagina for sex

3. no ejaculation, wide range of physiological & psychological sensations in reproductive organs + brain

neurendocrine control of female sexual development & hormones (flowchart)

Hypothalamus -> Gonadotropic

Releasing Hormone (GnRH) -> anterior pituitary -> 2

FOLLICLE STIMULATING HORMONE (FSH) -> follicles -> estrogen + egg maturation growth & thickening of endometrium (uterine lining)

(estrogen is negative feedback loop to hypothalamus & anterior pituitary)

LUTENIZING HORMONE (LH) -> corpus lutenum -> progesterone grows + thickens uterine lining

(progesterone is negative feedback loop to hypothalamus & anterior pituitary)

ovarian cycle

day 1-13:

FOLLICULAR PHASE - FSH -> follicle -> estrogen grows endometrium & egg (uterine lining)

day 14:

OVULATION - peak FSH & LH levels

day 15-28:

LUTEAL PHASE - follicles become corpus luteum -> progesterone growth & thickens endometrium

- continues for 3-6 months if pregnant

- last ~10 days b4 degeneration

uterine cycle

day 1-5:

MENSTRUATION - estrogen + progesterone decrease & shedding of endometrium

day 6-13:

PROLIFERATIVE PHASE - estrogen increase -> growth/regrowth + thickening of endometrium

day 14:

OVULATION - peak FSH & LH levels

day 15-28:

SECRETORY PHASE - progesterone increase -> growth + thickening of endometrium

NOT FERTILIZED - menstruation starts & cycle repeats

pregnancy

fertilization occurring in oviducts

1. zygote (fertilized egg) goes from oviduct to uterus

2. zygote implants into endometrium

3. develops outer membrane producing Human Chorionic Gonadotrophic Hormone (HCG)

4. HCG prevents corpus luteum degradation

placenta development

blood vessel network to exchange nutrients + wastes

- responsible for producing HCG hormone & progesterone + estrogen (negative feedback signal 2 anterior pituitary to stop GnRH production so new follicles don't mature to maintain endometrium)

birth (flowchart)

"water breaks" - release of mucus plug from cervix

1. cervix dilates

2. hypothalamus

3. posterior pituitary

4. oxytocin

5. uterine contractions

(5 -> 1 positive feedback system until baby is out)

female breasts

MAMMARY DUCT: 15-25 lobules, leads to nipples

NIPPLES: surrounded by areola + contains saliva resistant lubricant

AREOLA: contains glands containing saliva resistant lubricant

milk production

hypothalamus

prolactin releasing hormone

anterior pituitary

prolactin hormone

milk production in mammary

(circles back to hypothalamus - positive feedback for suckling infant)

milk release

hypothalamus

posterior pituitary

oxytocin

contraction of lobules

release milk

(circles back to hypothalamus - positive feedback areola stimulation by infant)

menopause

ovarian & uterine cycles stop (45-55)

- hormones are produced but ovaries don't respond, leads to decreasing hormone lvls over time