Reproductive 3 - Female Intro, Folliculogenesis, Oogenesis

What are three general characteristics of the female reproductive system?

- Cyclic changes in activity (menstrual cycle)

- Restricted periods of fertility (ovulation)

- Limited gamete production (pool established at birth)

What is menarche

the first menstrual period

What are the cyclic changes of the female reproduction?

Menstrual cycle - uterus changes during menstruation (uterine lining)

What is the time period of menstrual cycles?

From menarche in the teenage years to menopuase around age 45-50

Is menopause instantenous

No - various hormonal changes

How does obesity affect the hormonal reproductive axis?

Obesity can cause early puberty

What are the female gonads

Ovaries

What composes the female reproductive tract

Uterus, uterine (fallopian) tubes, vagina

What is the composition of the ovaries

Connective tissue with follicles

Location of the ovaries

Suspended by ligament tissue in the peritoneal cavity

Do the fallopian tubes connect to the ovaries?

No. There is a gap

Function of the ovaries

Site of ova maturation

Role of the fallopian tubes

Transport ova from ovaries to the uterus

Role of fallopian tube fimbriae + infundibulum

Pick up the ovum released by the ovary

What is the site of fertilization in females

In the fallopian tube (ampulla)

How does the ovum move through the fallopian tube

- Initially, peristaltic contractions of smooth muscle

- Mostly caused by ciliary actions of fallopian tube epithelial cells

How long does it take for ova to get to the uterus

4 days

Layers of the uterus (outer to inner)

perimetrium, myometrium, endometrium

Perimetrium composition

Epithelial cells and connective tissue

Myometrium composition

smooth muscle

Role of myometrium

involved in contraction during childbirth

Endometrium composition

Epithelial cells, connective tissue, glanfd

What do the endometrium glands contain

Glycogen

What is the cervix

Canal leading to vagina

What is the birth canal

Cervix + Vagina

What is an ovarian follicle

Fluid filled sac on the ovary containing the oocyte. Dense cells surround

What is the ovary covered by

Capsule

What is the corpus luteum

a hormone-secreting structure that develops in an ovary after an ovum has been discharged but degenerates after a few days unless pregnancy has begun.

What is the corpus albicans

degenerated corpus luteum

What causes the change in structure and function of the ovary

Hormones from the hypothalamus and the pituitary gland

Role of corpus luteum

Endocrine gland - produces progesterone

What is the ovarian cycle

Cycle that looks at the development of the follicle, discharge, and formation of the corpus luteum

What hormones cause changes in the ovary, and what does this cause?

LH and FSH cause ovarian changes. These ovarian changes accompany changes in estrogen and progesterone, which cause changes in endometrium

How long is the menstrual cycle

28 days on average

What are the 2 phases of the ovarian cycle

follicular phase and luteal phase

What is follicular phase

Ovarian phase associated with development of follicles (around first 14 days)

What is the luteal phase

Ovarian phase associated with the corpus luteum

What is day 1 of the uterine cycle

First day of menstrual bleeding

What is the uterine cycle

Cycle associated with changes in the endometrium due to ovarian and hormonal changes

What are the phases of the uterine cycle

menstrual phase, proliferative phase, secretory phase

Menstrual phase

Uterine cycle phase associated with shedding of the endometrial layer

Proliferative phase

Uterine cycle phase associated with endometrium + blood vessel growth, and development of a functional layer

Secretory phase

Uterine cycle phase associated with further endometrial vascularization + uterine gland development

What ovarian phase coincides with the menstrual + proliferative phase?

Follicular phase

What ovarian phase coincides with the secretory phase?

Luteal phase

What is the difference between oogenesis and folliculogenesis?

Oogenesis is the development of the oocyte (female gamete)

Folliculogenesis is the development of the ovarian follicle (that the oocytes sit in)

How many oocytes are in a follicle

1 - primary oocyte stage

What is primordial follicle

A primary oocyte surrounded by a single layer of follicle cells

Granulosa cells

the majority of the cells surrounding an oocyte in a follicle. They can multiply, divide, undergo mitosis, and they develop as the oocyte develops

What do granulosa cells secrete

Granulosa cells secrete estrogen during the follicular phase of the ovarian cycle (before ovulation).

Theca cells

Ovarian connective tissue layer that has developed and differentiated

Layers of theca cells

Theca interna, theca externa

What is the earliest stage of follicle growth

Primordial follicle

What is a primary follicle

Fully grown oocyte surrounded by several layers of epithelial cells

Role of granulosa cells in primary follicle

Secrete proteins and glycoproteins around the oocyte = zona pellucida

Preantral follicle

large oocyte, multiple layers of granulosa cells, thin layer of theca cells (connective tissue has divided)

Early antral folicle

Follicle contains an Antrum (follicle structure with fluid filled space)

Mature follicle characteristics

very large, multiple layers of granulosa and theca cells, large antrum - ready to ovulate. Contains cumulus oophorus

Cumulus oophorus

a mound of granulosa cells on one side of the antrum that covers the oocyte and secures it to the follicular wall

If you take a cross section of an ovary, what follicles will you see

Several follicle in several stages of growth

In each menstrual cycle, how many follicles mature to pre-antral and early antral stage?

10-25

Of the 10-25 follicles that begin to grow at the beginning of of the follicular phase of the menstrual cycle, the dominant follicle is selected by...

The follicle that secretes the most estrogen

Once the dominant follicle is chosen, what happens to the rest of the follicles?

Undergo atresia (programmed cell death)

What hormone dominates the first 14 days of menstrual cycle

Estrogen - known as the estrogenic phase. Occurs during the ovarian follicular phase and the uterine menstruation + proliferative phase

What hormone dominates the last 14 days of the menstrual cycle

Progesterone - known as the progestational phase. Occurs during the ovarian luteal phase and the uterine secretory phase

What hormone causes granulosa cell differentiation + mitosis

FSH

How does the oocyte get nutrients and paracrine factors

Granulosa cells send out cytoplasmic processes through the zona pellucida and form gap junctions. Nutrients and paracrine factors are send through these junctions to aid in growth

How many oocytes are available at ovulation at birth?

2-4 million - come from initial pool in gestation

At puberty, how many oocytes are available for ovulation?

100-200 thousand

How many oocytes go through ovulation during a female lifetime?

Around 400 - the rest go through atresia