Control in Humans

Question 1

What are some internal conditions that are controlled?

Answer 1

water content:

• leaves lungs when we breathe out
• leaves as sweat via skin
• leaves as urine via kidneys

Ion content:
-lost in sweat via skin

blood sugar:
-gives body constant supply of energy

Question 2

What are hormones?

Answer 2

• chemical messenger that regulate functions of organs and cells
• carried in blood stream
• secreted by glands

Question 3

What are the hormones in menstrual cycle?

Answer 3

FSH (follicle stimulating hormone):

• secreted by pituitary gland
• causes egg to mature in ovaries
• stimulates ovaries to produce oestrogen

LH (luteinising hormone):
-stimulates release of egg

oestrogen:
-inhibits further production of FSH

Question 4

What are the uses of hormones in contraception?

Answer 4

oral contraception:

• contain oestrogen and progesterone to inhibit egg maturation
• first birth-control pills contained large amounts of oestrogen - women suffered significant side effects
• progesterone-only pills lead to fewer side effects.

Question 5

What are the uses of hormones in fertility treatments?

Answer 5

fertility drugs:
-FSH is given to women, whose own level is too low to stimulate eggs to mature.

IVF:

• mother is given FSH and LH to stimulate the release of several eggs
• eggs are collected and fertilized with father’s sperm
• embryo implanted in the mother’s uterus