Objective To describe the process of oogenesis, the ovarian cycle, and the uterine cycle

Oogenesis The process by which oocytes are created Oogonia (haploid cells) undergo mitosis and create primary oocytes which are surrounded by a follicle. That follicle is called a primordial follicle.

Oogenesis The process of oogenesis begins before a female is born. About 1-2 million primordial follicles are present at birth. Fewer than 500 will ever mature in a females lifetime

Female Hormonal Cycles Uterine/Menstrual Ovarian 1.Menstrual Phase 2.Proliferative Phase 3.Secretory Phase 1.Follicular Phase 2.Ovulation 3.Luteal Phase

The Ovarian Cycle

The Follicle Phase Each month, several primordial follicles begin maturing into primary follicles. Only one is fully developed and released each month.

The Follicular Phase Description- Follicle Grows, Primary Oocyte matures Stimulated by- Follicle Stimulating Hormone (FSH) Outcome- Follicle releases estrogen

The Ovarian Cycle

Ovulation Description- Secondary Oocyte released from follicle Stimulated by- surge in Leutinizing Hormone (LH) Outcome- Follicle becomes corpus luteum

The Ovarian Cycle

The Luteal Phase Description- Corpus Luteum secretes progesterone (and some estrogen) ---> Progesterone inhibits LH and FSH secretion ---> Progesterone and estrogen levels drop Outcome- Corpus Luteum disintegrates

The Ovarian Cycle

Put it into perspective The Ovarian cycle ended with an oocyte being released from its follicle. Where does it go? Where was this process happening?

The Uterine Cycle (Menstrual) While the ovaries were undergoing the change we just learned about, the uterus is changing too.

The Uterine Cycle

Endometrium Inner lining of the uterus Thickens to support embryo (in possibility of pregnancy) Rich in blood vessels to provide oxygen and nutrients

Menstrual Phase The first 4-5 days of the Uterine Cycle The outer layer of the endometrium breaks down The blood and tissue lost during this phase are discharged through the cervix and the vagina

Proliferative stage The functional level of the endometrium begins to grow back as soon as the menstrual cycle ends This is caused by rising levels of estrogen What other stage has a rising level of estrogen ?

Secretory Stage Progesterone levels begin to rise which causes the endometrium to become a dense network of blood vessels and nutrients to fertilize an egg If fertilization does not occur, the endometrium breaks down.

Synthesize: Estrogen levels are highest during the proliferative phase and progesterone are highest during the secretory phase. Use this information to state the primary effect each of these hormones have on the uterus. Estrogen- Progesterone-

Quick Check In the female reproductive cycle, the endometrium is the thickest a.during the menstrual phase b.during the proliferative phase c.shortly before ovulation d.during ovulation e.in the secretory phase

The hormone progesterone is produced A) in the uterus and stimulates the ovary B) in the uterus and inhibits secretions by the ovary C) in the ovary and targets the endometrium of the uterus D) in the ovary and initiates the shedding of the uterine lining E) in the anterior pituitary and inhibits estrogen secretion by the ovary

Ovulation is the follicular response to a burst of secretion of A) LH. B) progesterone. C) inhibin. D) prolactin. E) estradiol.

Putting it All Together Use the information from the previous slides to explain how the ovarian cycle effects the uterine cycle.

Check Your Understanding 1. The ovarian cycle includes the a.luteal and secretory phases b.menstrual and proliferative phases c.follicular and luteal phase d.follicular and proliferative phases e.proliferative and secretory phases

2. In humans, the follicular cells that remain behind in the ovary following ovulation become A) the ovarian endometrium that is shed at the time of the menses. B) a steroid-hormone synthesizing structure called the corpus luteum. C) the thickened portion of the uterine wall. D) swept into the fallopian tube. E) the placenta, which secretes cervical mucus.

3. Which of the following statements correctly describes a phase of the uterine cycle A)During the follicular phase a growing oocyte matures into a follicle B)Progesterone and estrogen levels are highest during the menstrual phase C)The uterine lining is thickest during the secretory phase D)The uterine lining thickens during the luteal phase E)The corpus luteum degenerates during ovulation