2.2 physiology and health

Question 1

What do hormones do?

Answer 1

Hormones are chemical messengers that are secreted from glands and then travel in the bloodstream to their target tissue

Question 2

What do hormones do when they reach there target tissue

Answer 2

When a hormone reaches its target tissue it binds to a specific complementary hormone receptor in the membrane of the cells. This then triggers a change within the target cell to bring about a response.

Question 3

State the role of the hypothalamus in the hormonal onset of puberty.

Answer 3

The hormonal onset of puberty is triggered when a releaser hormone produced in the hypothalamus is sent to the pituitary gland.

Question 4

Identify the reproductive system hormones released from the pituitary gland in males and females.

Answer 4

In males : FSH (Follicle stimulating hormone)
and ICSH (Interstitial cell stimulating hormone).

In females : FSH (Follicle stimulating hormone)
and LH (Luteinising hormone).

Question 5

Identify the role of FSH in male fertility

Answer 5

FSH : Released by the pituitary gland, FSH travels to the testes where it stimulates the production of sperm cells in the seminiferous tubules.

Question 6

What are the three hormones involved in male fertility?

Answer 6

FSH
ICSH
Testosterone

Question 7

State the role of ICSH in male fertility

Answer 7

ICSH : Released by the pituitary gland, LH travels to the testes where it stimulates the interstitial cells to make and release testosterone.

Question 8

State the role of testosterone in male fertility

Answer 8

Testosterone : Released by the interstitial cells this stimulates sperm production in the seminiferous tubules and activates the prostate gland and seminal vesicles to produce secretions

Question 9

What is sperm production controlled by?

Answer 9

Negative feedback control

Question 10

How does the testosterone concentration become an inhibitor (negative feedback control)

Answer 10

When the levels of testosterone rise above a threshold level, the testosterone concentration becomes an inhibitor, preventing the secretion of ICSH and FSH by the pituitary gland

Question 11

What happens when there is a prevention of the secretion of ICSH and FSH by the pituitary gland? (negative feedback control)

Answer 11

This subsequently causes ICSH and FSH levels to fall and there is then a reduction in the production of testosterone by the interstitial cells and a reduction in sperm production by the seminiferous tubules

Question 12

What are the consequences of a reduction in testosterone and sperm production by the seminiferous tubles (negative feedback control)

Answer 12

As a consequence of this inhibition, the testosterone concentration then decreases until it falls below a threshold level where it is no longer inhibitory to the pituitary gland.

Question 13

What happens when the testosterone concentration is decreased until its no longer able to inhibit the pituitary gland

Answer 13

ICSH and FSH are then secreted by the pituitary triggering the production of testosterone by the interstitial cells and switching on sperm production by the seminiferous tubules until the levels of testosterone increases above a threshold level…and so the cycle continues.

Question 14

Identify the four hormones involved in the control of the female menstrual cycle

Answer 14

FSH
LH
Oestrogen
Proestrogen

Question 15

FSH role in female menstrual cycle

Answer 15

Released by the pituitary gland, FSH travels to the ovaries where it stimulates the development of a follicle (maturation of an egg) and the production of oestrogen by the follicle during the follicular phase.

Question 16

LH in its role in female menstrual cycle

Answer 16

Released by the pituitary gland, LH travels to the ovary where it triggers ovulation (release of an egg from a mature follicle). LH then stimulates the formation of the corpus luteum from the empty follicle following ovulation.

Question 17

Oestrogen in its role in female menstrual cycle

Answer 17

Released by the ovary during the follicular phase, oestrogen travels to the uterus where it stimulates proliferation of the endometrium preparing it for implantation

Question 18

What effect does oestrogen have on the cervical mucus

Answer 18

Oestrogen also changes the consistency of cervical mucus making it less viscous so that it can more easily be penetrated by sperm

Question 19

What does peak levels in oestrogen after follicular phase mean

Answer 19

Peak levels of oestrogen at the end of the follicular phase stimulate a surge in the secretion of LH from the pituitary gland to trigger ovulation.

Question 20

Progestogen in its role in the female menstrual cycle

Answer 20

Released by the ovary from the corpus luteum during the first half of the luteal phase. Progesterone travels to the uterus where it promotes further development and vascularisation of the endometrium preparing it for implantation if fertilisation occurs.