2.2 - Hormonal Control Of Reproduction

Question 1

How is puberty triggered?

Answer 1

A releaser hormone produced in the hypothalamus stimulates the release of hormones by the pituitary gland to trigger the onset of puberty.

Question 2

What hormones are produced by the pituitary gland?

Answer 2

• follicle stimulating hormone (FSH)
• luteinising hormone (LH)
• interstitial cell stimulating hormone (ICSH)

These hormones control the onset of puberty.

Question 3

What are males described as?

Answer 3

Continuously fertile - constantly produce sperm

Question 4

What are the 3 common hormones involved in the production of sperm?

Answer 4

• follicle stimulating hormone (FSH)
• interstitial cell stimulating hormone (ICSH)
• testosterone

Question 5

Follicle stimulating hormone (FSH) function - sperm production

Answer 5

Promote sperm production in seminiferous tubules.

Question 6

Interstitial cell stimulating hormone (ISCH) function

Answer 6

Stimulates interstitial cells to produce testosterone.

Question 7

Testosterone function

Answer 7

Stimulates sperm production and activates the prostate gland and seminal vesicles to release their secretions.

Question 8

What is negative feedback control?

Answer 8

Negative feedback control is a system of maintaining a steady state in various body systems.

Question 9

What is use use of Negative feedback control in males

Answer 9

In the male reproductive system, negative feedback control is used to regulate sperm production.

Question 10

Negative feedback control of testosterone - what hormones are released from the pituitary gland and what does this cause?

Answer 10

FSH and ICSH released from the pituitary gland stimulates the seminiferous tubules and interstitial cells.

This causes the interstitial cells to produce testosterone.



Question 11

Negative feedback control of testosterone - what does high levels of testosterone cause?

Answer 11

High levels of testosterone have inhibitory effect on the pituitary gland which inhibits the release of FSH and ICSH.

Testosterone levels then decrease and the cycle begins again.

Question 12

How is female fertility described?

Answer 12

Females are fertile around the time of ovulation. Female fertility is cyclical.

Question 13

What are the four hormones involved in the control of the menstrual cycle?

Answer 13

• follicle stimulating hormone (FSH)
• luteinising hormone (LH)
• oestrogen
• progesterone

Question 14

How long does the menstrual cycle take?

Answer 14

The menstrual cycle takes approximately 28 days.

Question 15

What phases does the menstrual cycle consist of?

Answer 15

• follicular phase
• luteal phase
• (menstrual phase)? Let’s achieve says?

Question 16

What is the first day of menstruation regarded as?

Answer 16

The first day of menstruation is regarded as day one of the menstrual cycle.

Question 17

What is menstruation?

Answer 17

Menstruation is the shedding of the endometrium, the blood lining of the uterus.

Question 18

When does the follicular phase occur?

Answer 18

The follicular phase occurs in the first half of the menstrual cycle.

Question 19

What does follicle stimulating hormone stimulate in the follicular phase of the menstrual cycle?

Answer 19

During the follicular phase, FSH stimulates:

• Development of a follicle an ovary
• Production of oestrogen by the follicle

Question 20

Follicular phase - what does oestrogen stimulate?

Answer 20

Oestrogen stimulates proliferation (growth) of the endometrium preparing it for implantation.

Question 21

Follicular phase - what else does oestrogen affect?

Answer 21

Oestrogen stimulates the proliferation of the endometrium preparing it for implantation AND affects the consistency of cervical mucus causing it to become thinner and waterier in consistency making it more easily penetrated by sperm.

Question 22

What does peak levels of oestrogen cause?

Answer 22

Peak levels of oestrogen stimulates a surge in the secretion of luteinising hormone which triggers ovulation.

Question 23

When does ovulation occur?

Answer 23

Ovulation occurs around the midpoint of the menstrual cycle at approximately day 14.

Question 24

When does the luteal phase occur?

Answer 24

The luteal phase occurs after ovulation, during the second half of the menstrual cycle.

Question 25

What hormone has a affect on the follicle and what does the follicle develop into?

Answer 25

Luteinising hormone causes the follicle to develop into the corpus luteum which secretes progesterone.

Question 26

What affect does progesterone have in the luteal phase?

Answer 26

Progesterone promotes further development and vascularisation of the endometrium preparing it for implantation if fertilisation occurs.

Question 27

What is the process of vascularisation?

Answer 27

Vascularisation is the process by which there is an increase in blood vessels in the endometrium making it spongy.

Question 28

Negative feedback control - menstrual cycle - what do high levels of oestrogen and progesterone cause?

Answer 28

High levels of oestrogen and progesterone have an inhibitory effect on the pituitary gland.

Question 29

Negative feedback control - menstrual cycle - What affect does decreasing the levels of FSH and LH have?

Answer 29

Decreasing the levels of FSH and LH prevent further follicles from developing.

Question 30

Negative feedback control - menstrual cycle - What happens if fertilisation does not occur?

Answer 30

If fertilisation does not occur, the ovum degenerates and a lack of LH leads to the degeneration of the corpus luteum which stops secreting progesterone.

Question 31

Negative feedback control - menstrual cycle - If fertilisation does not occur and the corpus luteum stop secreting progesterone what is the effect of this?

Answer 31

A subsequent drop in progesterone leads to menstruation.

Question 32

Negative feedback control - menstrual cycle - if fertilisation doesn’t occur, what does a lack of LH cause?

Answer 32

If fertilisation doesn’t occur, the ovum degenerates and a lack of LH leads to degeneration of the corpus luteum which stops secreting progesterone.

The subsequent drop in progesterone levels leads to menstruation.

Question 33

Negative feedback control - what does a drop in progesterone levels cause

Answer 33

The subsequent drop in progesterone levels leads to menstruation.

Question 34

Negative feedback control - what happens to the corpus luteum if fertilisation occurs

Answer 34

If fertilisation does occur, the corpus luteum will continue to produce progesterone preventing further FSH from being released and new follicles developing.