The Reproductive System

Gonads

ovaries and testes

-produce sex steroid hormones

-females: estradiol, progesterone

-males: testosterone

Gametes

ova and sperm

gonads

Where are gametes produced?

Seminiferous tubules

Where spermatogensis occurs

-lined by Sertoli cells

Spermatogenesis

production of sperm

Sertoli cells

protect and nuture developing sperm

-control the release of testosterone (needed for spermatogenesis

Leydig cells

produce testosterone

-located between the seminiferous tubules

-under influence of lutenizing hormone (LH)

Luteinizing hormone (LH)

causes the secretion of testosterone in the testes

Spermatocytogensis

the first phase of spermatogenesis, -sperm cells multiply by miotivc division in order to produce pprimary permatocytes

-number of chromosomes is diploid

Spermiogenesis

spermatids transform into nonmotile spermatozoa

-formation of tail, condensation of nuclear chromatin, development of acrosomal cal

Spermiation

non-motile spermatozoa are released into the lumen of the seminiferous tubules

-under control of LH

Epididymis

houses sperm during maturation

-mature, motile sperm are stored in the tail and vas deferens

Vas Deferens

"ductus deferens"

-transports mature sperm to the urethra during ejaculation

-connects to tail of the epididymus

head of sperm

contains genetic material (haploid number of chromosomes)

-acrosome of head has enzymes that help sperm penetrate the egg

midpiece of sperm

contain mitochondria for generation of energy

tail of sperm

propels sperm froward

Accessory sex glands

seminal vesicles, prostate gland, bulbourethral glands

Seminal vesicles

secrete prostaglandins, which stimulate contraction of uterine muscles to move semen

-fluid, mucus, amino acids, fructose secreted provide energy for sperm

Prostate gland

-largest accessory gland

-prostate fluid is thin, milky, alkaline

Bulbourethral glands

"Cowper's glands"

secrete a viscous fluid before emission of sperm/semen

Fertilization

fusion of ovam and sperm

-signals beginning of gestation

Parturition

act of giving birth

Zona pellucinda

an extracellular matrix that surrounds the plasma membrane of the egg cell. It helps protect the egg, and has an essential role in fertilization by sperm. It is surrounded by the corona radiata.

Granulosa cells

protect the developing oveum

-have FSH receptors

-produce aromatase

Aromatase

enzyme that converts testosterone to estrogen

Ovulation

release of an ovum and parts of its follicle from the ovary

luteinizing hormone (LH)

ovulation occurs under the influence of?

Corpus luteum

secretes progesterone and estrogen

Progesterone

produced by copus luteum

-helps prepare uterus for implantation of ovum

-helps maintaine pregnancy

Oviducts

"fallopian tubes"

site of fertilization

Endometrium

inner lining of the uterus

Myometrium

smooth msucle layer of the uterus

-stretches to accomidate fetus

Cervix

gatewat to the uterus and terminal portion of femal repro system

estrogen and other hormones

growth of duct structures of mammary glands is under the influence of?

progesterone

Development of secretory tissue is under the influence of?

Prolactin

Stimulates milk production in mammary glands

Oxytocin

Stimulates uterine contractions and milk ejection

Estrous cycle

period of time an animal shows sexual receptivity to the next (estrus to estrus)

Estrus

period of sexual receptivity

-increased levels of estrogen (causes LH) surge-->ovulation occurs

Metestrus

period during which the corpus luteum develops

-starts after ovulation

-under influence of LH

Diestrus

A period of sexual inactivity between recurrent periods of estrus

-corpus luteum is fully developed, secreting large amounts of progesterone and small amoutns of estrogen

prostaglandins secreted by the endometrium

The corpus luteum degenerates under the infulence of?

Proestrus

begins after regression of corpus luteum

-marked by rapid growth og follicles

Follicle stimulating hormone

FSH

-stimulates production of ova and sperm

-stimulates follicualr growth and secretion of estrogen by growing follicles

Anestrus

period of inactivity between breeding seasons in seasonally polyestrous animals

21 days

length of cow estrus cycle?

21 days every 6 to 7 months

length of dog estrus cycle?

Monestrous

one estrous cycle per year

Polyestrous

more than one estrous cycle per year (most domestic animals)

during estrus and immediately following

When are most animals onyl sexually receptive?

Induced ovulators

ovulate in response to copulation

follicular and luteal

What are the phases of the ovatian cycle?

Follicular phase

several follicles begin to grow/secrete estrogen

ends when one or more follicles mature and ovulate

Luteal phase

phase of the ovarian cycle during which the corpus luteum is developed and active

proestrus and estrus

What parts of the estrus cycle make up the follicular phase?

metestrus and diestrus

What parts of the estrus cycle maye up the luteal phase?

prolonged estrus, pseudopregnancy

What occurs if the corpus luteum does not regress?