3. Female Reproductive System WEB

advertisement

Reproductive System Cont.

Female Anatomy & Physiology

Chapter 28

FEMALE ANATOMY

Ovaries = produce eggs

• Ovarian follicles = contain eggs in various stages of development and the cells that surround them; surrounding cells nourish the eggs & produce estrogen

Corpus luteum = remnants of a mature follicle after ovulation

(after egg is released); produces estrogen, progesterone, and relaxin

• Uterine tubes

(oviducts/fallopian tubes) = transport eggs from the ovary to the uterus; fertilization occurs in the oviducts

• Uterus = organ in which the fetus develops

• Endometrium = uterine lining

Cervix = lower end of uterus

• Vagina = passageway between the uterus and the outside

Vulva = external genitals of the female

Female

Reproductive

Cycles:

1. Ovarian Cycle

&

2. Menstrual

(Uterine) Cycle

Female Reproductive Cycles

Female reproductive cycles prepare the female body for pregnancy

1. Ovarian cycle = cyclic events that occur in the ovaries

2. Menstrual (uterine) cycle = cyclic events that occur in the uterus

• Last 28 days on average

• Influenced by

1. hormones secreted by pituitary gland: FSH and LH

2. hormones secreted by ovary: estrogen and progesterone

OVARIAN CYCLE

1. Follicular phase – prior to ovulation:

• One ovarian follicle becomes the dominant follicle and begins to mature when the pituitary gland releases FSH

Maturing follicle releases estrogen and causes the pituitary gland to release LH (this is an example of positive feedback : an increase in one hormone results in increase of another hormone)

2. Ovulation (day 14):

• levels of LH reach its peak and initiate ovulation

• Ovulation = egg is released from the dominant follicle

3. Luteal phase – after ovulation:

• Ruptured follicle becomes corpus luteum and secretes estrogen and progesterone

• High levels of estrogen and progesterone inhibit FSH and LH (this is an example of negative feedback : increase in one hormone results in decrease of another hormone)

MENSTRUAL CYCLE

• If the egg does not become fertilized, levels of estrogen and progesterone fall and cause endometrium to be shed = menstrual flow or menstruation (days 1-5)

• Starting with day 6, increasing levels of estrogen cause endometrium to thicken and prepare uterus for possible implantation of fertilized egg

FERTILIZATION

• Fertilization = union of sperm and egg; the resulting cell is called zygote

• Takes place in the uterine tube

• Implentation

= the zygote passes into the uterus where it attaches into the uterine lining (by the sixth day after fertilization)

IMPLENTATION

Download