Human Reproduction (Female Reproductive System)

Question 1

What is oogenesis?

Answer 1

Egg production where the human female will produce about 1 million primordial follicles in each ovary.

Question 2

Where does oogenesis begin?

Answer 2

In the ovaries during the 3rd month of detail life and continues shortly after birth.

Question 3

What are the primordial follicles capable of?

Answer 3

They are capable of becoming a mature ovum (egg) although normally only 300-400 will mature and ovulate during the course of the woman’s reproductive life.

Question 4

One follicle every 28 days is capable of…?

Answer 4

Fertilization beginning at puberty.

Question 5

How do the remaining follicles get absorbed?

Answer 5

By the ovaries until their depletion ends in the females reproductive years - menopause.

Question 6

Primordial and the ovulated ovum have completed what?

Answer 6

PF - Prophase 1

OO - Telophase 1

Question 7

Completion of meiosis is triggered by what?

Answer 7

Penetration of the oocyte by the sperm, because of this meiosis is a process that may take 40 years or more to finish in human females.

Question 8

Day 1-4

Answer 8

Menstruation (Menses) Declining levels of estrogen and progesterone in the bloodstream cause the uterine lining (endometrium) to shed the thick glandular layer built up during the previous cycle (in anticipation of a pregnancy that did not occur)

Question 9

Day 4-14

Answer 9

Proliferation. The low levels of estrogen and progesterone enable the pituitary gland (under the brain) to secrete follicle stimulating hormone (FSH) and luteinizing hormone (LH). These stimulate about 15-20 pimordial follicles to develop. By 14th day, some will have become mature Graafian follicles. The other follicular cells secrete increasing quantities of estrogen. This estrogen will cause the regeneration of the endometrium, which becomes thicker and more glandular during this period.

Question 10

Day 14

Answer 10

Ovulation. Triggered by a sudden ovulatory surge of LH (which ruptures the dominant folic) the cell (oocyte) that will become the egg is released from the ovary into the abdominal cavity.

Question 11

Day 14-28

Answer 11

Secretion. The follicular cells that remain in the ovary grow into a yellowish mass which is called the corpus lutetium. This begins to secrete increasing quantities of progesterone and estrogen. Estrogen levels remain high, due the secretion from the corpus luteum w/contributions from the ovarian follicles that matured during the proliferative phase but lost to the ovulatory race. Now both estrogen and progesterone stimulate the uterine lining, causing it to become even more vascularized and to secrete nutrients within its numerous endometrial glands.

Question 12

What is another effect of high levels of estrogen and progesterone?

Answer 12

To inhibit pituitary secretion of FSH and LH which prevents new primary follicles from beginning to develop.

Question 13

What happens when fertilization does not occur?

Answer 13

The corpus luteum and remaining follicles will waste away which causes the levels of estrogen and progesterone to decline.

Question 14

How many spermatozoon participate in fertilization?

Answer 14

1, but multitudes will be necessary to hydrolyze the protective layer around the oocyte. Where chances are that there won’t be enough surviving sperm to accomplish this 48 hours after delivery, which means that there is about a 3 day period each month during which intercourse could result in fertilization (2 days prior to ovulation, 1 day after)

Question 15

How does implantation occur in the uterine lining?

Answer 15

Occurs 4 days after the fertilized ova, reaches the uterus. Becomes a blastula, made up of hundreds of cells.

Question 16

List different menstrual cycles for different mammals

Answer 16

Humans - 28 days average
Elephants (cow) 16 weeks
Sheep (ewe) - 17 days
Cattle (cow) - 21 days
Pigs (sow) 21 days

Question 17

What are induced or reflex ovulators?

Answer 17

Penetration of the penis causes ovulation, no evidence that semen itself is trigger. Happens in cats, llamas, rabbits, minks and other mammals are induced or reflex ovulators.

Question 18

What is seasonal ovulation?

Answer 18

Animals such as deer and sheep are seasonal ovulatory. They want their young to be born in spring when there’s a lot of green vegetation for the mother to turn into milk. In late spring and summer when the young are being weaned from milk to vegetation, there are a lot of mature plants and seeds for the young to feed on. For this reason deer and relatives mate in the fall (rutting season) so the young can be born in the spring.