Reproductive System

Question 1

OVARIAN CYCLE (DAYS 1-13)

Answer 1

• primary FOLLICLE develops into mature Graafian follicle
• The follicle secretes oestrogen (secondary sexual characteristics and endometrium development)

-*NB!! Oestrogen levels also stimulate the release of LH which in turn stimulates ovulation

Question 2

OVARIAN CYCLE (DAY 14)

Answer 2

• Rupture of Graafian follicle releasing the immature ovum due to the secretion of LH.
• Mature follicle bulges from the surface of the ovary and more fluid accumulates in it until it ruptures

Question 3

FORMATION OF CORPUS LUTEUM (DAY 15-28)

Answer 3

• LH promotes the development of a mass of yellow cells called the corpus luteum from the ruptured follicle
• This secretes progesterone that maintains the endometrium for implantation (which inhibits LH and FSH which allows only one follicle to be ovulated at a time)
• If fertilisation does not occur, this tissue degenerates, forming a white scar and LH and FSH is secreted again.

Question 4

UTERINE CYCLE

Answer 4

• ovulation takes place
• endometrium thickens
• developing follicle is not fertilized and menstruation occurs
• endometrium very thick
• endometrium destroyed and discarded
• ovulation takes place and new endometrium starts to form

Question 5

Zygote to Blastocyst

Answer 5

The zygote undergoes mitosis to form a ball of cells called the morula.

The morula undergoes more mitosis to form a hollow ball of cells called the blastocyst.

The blastocyst has an outer layer of cells called trophoblast which forms chorionic villi that grows into the endometrium.

This is called implantation

Question 6

Umbilical Artery (RED - away from heart)

Answer 6

• High in O2 (nutrients)

- Low in CO2 (waste)

Question 7

Umbilical Vein (BLUE - toward heart)

Answer 7

• Low in O2 (nutrients)

- High in CO2 (waste)

Question 8

Placenta

Answer 8

FUNCTIONS:

• Provides Nutrition of the embryo ensures maternal and fetal blood are in close contact (diffusion occurs across a thin membrane)
• Excretion
• Allows for Gaseous exchange
• A micro-filter preventing pathogen entry, and allowing antigens resulting in passive immunity for the baby
• Endocrine gland: after 12 weeks it secretes oestrogen and progesterone to maintain pregnancy

Question 9

Umbilical cord

Answer 9

Has 2 Functions:

• carry deoxygenated blood to the from foetus to placenta (artery)
• carry oxygenated blood away from placenta to foetus (vein)

Question 10

Amnion

Answer 10

• tough, extra-embryonic membrane lining the chorion surrounding the foetus
• encloses the amniotic cavity

Question 11

Chorionic villi

Answer 11

finger-like projections that develop around the blastocyst during implantation

Question 12

Chorion

Answer 12

Outermost extra-embryonic membrane surrounding the embryo

Question 13

Amniotic Fluid

Answer 13

• provides the watery medium in which the foetus can move freely and develop
• protects foetus from shocks, dehydration and temperature changes.

Question 14

Testes

Answer 14

produce sperm cells and the hormone testosterone

Question 15

Scrotum

Answer 15

It protects thetestes and holds them “outside” at 2 degrees lower than body temperature.

Question 16

Epididymis

Answer 16

tubule outside the testes but still in the scrotum.

It temporarily store spermatids until they mature into sperm cells

Question 17

Urethra

Answer 17

it transports urine and semen out of the body

Question 18

Vas Deferens

Answer 18

A muscular tupe passing from epididymis to the urethra.

It transports sperm from the epididymis to the urethra.

Question 19

Seminal Vesicles

Answer 19

it produces an alkaline fluid to neutralize vaginal acids which would kill sperm

Question 20

Prostate gland

Answer 20

produces nutrient rich fluid that provides energy for the sperm cells and also protects sperm cells from acidic environment of the vagina

Question 21

Cowper’s Gland

Answer 21

They produce mucus for lubrication and sperm motility