Reproduction part 2

Question 1

What is the main function of the menstrual cycle?

Answer 1

The main function of the menstrual cycle is to prepare the uterus/uterus lining for the implantation of an embryo.

Question 2

What is the length of menstrual cycle in a healthy adult female and what are the natural variation and its reason?

Answer 2

The average length of menstrual cycle is 28 days. The natural variation is from 21 days to 35 days. Some reasons for variation include: stress, hormones, lifestyle and individual health conditions.

Question 3

What pauses the menstrual cycle?

Answer 3

Pregnancy pauses the menstrual cycle.

Question 4

What are the four hormones involved in the menstrual cycle?

Answer 4

Oestrogen, progesterone, follicle stimulating hormone and luteinising hormone.

Question 5

What is the function of oestrogen?

Answer 5

Oestrogen helps to repair and thicken the uterine lining, especially during the follicular phase.

Question 6

What is the function of progesterone?

Answer 6

Progesterone maintains the thickness of the uterine lining during the luteal phase.

Question 7

What is the function of the follicle stimulating hormone?

Answer 7

The follicle stimulating hormone stimulates ovaries to produce oestrogen and helps follicles develop, leading to ovulation.

Question 8

What is the function of luteinising hormone?

Answer 8

The luteinising hormone triggers ovulation, causing the dominant follicle to release the mature ovum into the oviduct.

Question 9

What are the two main phases of the menstrual cycle?

Answer 9

Follicular phase, followed by luteal phase ( which last around 14 days of the menstrual cycle)

Question 10

When is the fertile period?

Answer 10

The fertile period is three days before ovulation and 2 days after ovulation. Fertile period: Fertilisation can occur and lead to pregnancy. lower limit: Sperm can only survive 3 days. Upper limit: Ovum can only survive 2 days.

Question 11

Describe more about the follicular phase.

Answer 11

The follicular phase is for the first 14 days.
Days 1 to 5
When uterine lining in breaks down due to low levels of the two hormones: Oestrogen and progesterone

Menstruation, the monthly discharge of blood and uterine tissue through the vagina, begins the menstrual cycle.

Days 6 to 14
Follicle stimulating hormone stimulates follicles in ovaries:
To secrete oestrogen which causes thickening of the uterine lining, and its enrichment with blood vessels.
Such that one dominant follicle develops into the *Graafian follicle
Luteinising hormone stimulates ovulation, causing the *Graafian follicle to erupt.

Question 12

The luteal phase is taken to be ___ days.

Answer 12

The luteal phase is taken to be 14 days.

Question 13

How many times does oestrogen increase during the menstrual cycle?

Answer 13

2 times

Question 14

Which of the following describes what changes can be observed in the blood concentrations of oestrogen, progesterone and the thickness of he uterine lining durin the fertile period of the menstrual cycle?

A increasing then decreasing (oestrogen concentration) increasing (progesterone concentration) increasing (thickness of the uterine lining)
B decreasing then increasing (oestrogen concentration) increasing (progesterone concentration) increasing (thickness of the uterine lining)
C increasing (oestrogen concentration) decreasing (progesterone concentration) increasing (thickness of the uterine lining)
D increasing (oestrogen concentration) increasing (progesterone concentration) decreasing (thickness of the uterine lining)

Answer 14

A

Question 15

What is/are the male hormones?

Answer 15

Testosterone, progesterone and oestrogen

Question 16

What is/are the male sex hormones ?

Answer 16

testosterone

Question 17

What are female hormone?

Answer 17

Testosterone, progesterone and oestrogen

Question 18

What are the female sex hormones?

Answer 18

Oestrogen and progesterone

Question 19

The progesterone level will always increase after the fertile period True or false.

Answer 19

false, for the menstrual cycle, if pregnancy doe snot happen then after the follicular phase, then the progesterone and oestrogen would decrease immediately

Question 20

What does course of pregnancy refer to?

Answer 20

Course of pregnancy is referring to the entire period after fertilisation, it does not include the entire menstrual cycle.

Question 21

Which of the following statement is more accurate and true about sexual reproduction in humans?

A Progesterone levels remain high in the female during the course of pregnancy.

B The embryo implants in the placenta.

C The fertilised egg develop to form a zygote.

D The haploid cells fuse together during fertilisation to form a gamete.

Answer 21

A—> although A is correct, it can still be improved. This is because A only works if fertilisation occurs and pregnancy is sustained (no abortion) It should be amended to: progesterone levels remain high in the female after fertilisation during pregnancy.

B is false because the embryo implants in the uterus. The placenta develops after implantation to nourish the embryo.

C A fertilised egg is called a zygote, and it undergoes cell division to develop in to an embryo.

D is false. Two haploid cells (sperm and egg) fuse to form a zygote, not a gamete. A gamete is a haploid reproductive cell (sperm or egg).

Question 22

Which of the following shows the correct effects of increasing oestrogen and progesterone levels in female reproductive cycle?

A causes egg to mature in ovary (increasing oestrogen level) promotes menstruation (increasing progesterone level)

B maintains and thickens uterine lining (increasing oestrogen level) stimulates ovulation (increasing progesterone level)

C promotes menstruation (increasing oestrogen level) maintains and thickness uterine lining (increasing progesterone level)

D repairs uterine lining after menstruation (increasing oestrogen level) prevents menstruation (increasing progesterone level)