Sperm Release Pathway: The Parasympathetic Step

1. Brain perceives sexual stimulus

2. NO (nitrous oxide) released in smooth muscle lining arterioles of erectile tissue

3. Arterial muscles relax, arterioles dilate

4. Arterioles fill with blood

5. Engorged arterioles compress venules

6. Blood is trapped in erectile tissue arterioles. Erection achieved.

Sperm Release Pathway: The Sympathetic Step

7. Prolonged sexual stimulus results in spinal reflex impulse…

8. Causes contraction of:*vas deferens *bulbourethral gland

*prostate gland * seminal vesicles

9. Semen empties into urethra10. Urethral sphincter muscles contract11. Semen forcefully ejected from urethra

Ejaculation

Female Reproductive System

I. Female Reproductive Structures

Ovaries Oviducts Uterus Cervix Vagina Brain

A. Ovaries

Primary Reproductive Organ/Female Gonad Paired Attached medially to uterus by ovarian

ligament Filled with ovarian follicles Each ovarian follicle contains an immature

oocyte (gamete)

Follicle membrane

Immature oocyte OVARIAN FOLLICLE

Onset of Puberty

Hypothalamus released GnRH (Gonadotropin Releasing Hormone)

Pituitary Gland releases: FSH ESTROGEN LH RELEASE

Release of Estrogen at onset of Puberty…

SECONDARY SEX CHARACTERISTICS Breast development Widening of pelvic girdle Body hair

MENARCHE First ovulation followed by menstrual period

The Ovarian Cycle

Results in the release of: gamete hormones required for pregnancy

Repeats ~ 28 days

OVULATION: major event of Ovarian Cycle! release of mature oocyte from ovary

3 Phases of Ovarian Cycle

1. Follicular Phase

2. Ovulation

3. Luteal Phase

1. Follicular Phase Days 1 - 14 Granulosa cells (Epithelium/CT) of follicle

provide nutrition/support/protection to oocyte

Follicle increases in size around oocyte Follicle secretes Estrogen hormone Zona pellucida forms around oocyte

Thick protective, nutritive membrane

Increased granulosa cells surround oocyte

“Corona radiata”

Zona pellucida

nucleus

Corona Radiata

2. Ovulation Day

• Day 14 Wall of ovary bulges and bursts

• Oocyte (w/ corona radiata) expelled from ovary!

Ovulation

Identify:

Ovary

Follicle

Oocyte

Corona Radiata

3. Luteal Phase

Days 15 – 28 Follicle remains in ovary after ovulation Granulosa cells secrete hormones:

Progesterone Estrogen

Follicle has been transformed into…

CORPUS LUTEUM!

The fate of the Corpus Luteum…

If sperm are present and oocyte becomes fertilized…

Corpus Luteum continues production of progesterone (pregnancy hormone) for 1st three months of pregnancy!

If fertilization of oocyte does NOT occur…

Corpus luteum stops hormone production and breaks down

B. It Starts with the Brain…

C. Fallopian Tubes

Aka: oviducts / uterine tubes Attached medially to uterus Lateral region surrounding ovary…

Ampulla : common site of fertilization Possesses ciliated finger-like projections that hang

over ovary…

Fimbriae !

Fimbriae

Ampulla

D. The Uterus

“womb” Thick muscular lining Resembles a pear in shape and size Functions to receive, retain, and nourish the

fertilized ovum

The Uterus is…

Divided into regions Fundus: rounded superior region Body: largest region Cervix: narrow inferior region

Fundus

Body

Cervix

The Uterus is… Composed of three layers:

Perimetrium: outer visceral layer Myometrium: middle muscular thickest layer Endometrium: inner epithelial layer

site of implantation of fertilized ovum

The Uterus is… Highly vascular! Uterine Arteries: branch to provide blood to

myometrial and endometrial layers of uterus!

The Vagina Extends from cervix to external environment Functions to:

Allow for passage of infant (“birth canal”) Allow for passage of menstrual flow Receive penis during intercourse

(female organ of copulation) Acidic pH in adults protection against

infection hostile environment

for sperm

The fate of the Ovum... Post-Ovulation

Menstruation

Occurs ~ 14 days post ovulation Occurs ONLY if fertilization of ovum does NOT occur Endometrium layer of uterus is shed Results in bleeding from vagina for ~3-5 days Endometrial layer will immediately begin rebuilding

vascular tissue during days 1-14 of Ovarian Cycle (due to estrogen!)