Topic 7

Question 1

state the name of the hormone that regulates the water content of the blood

Answer 1

ADH

Question 2

where in the brain is the thermoregulatory centre?

A) cerebellum
B) cerebral cortex
C) hypothalamus
D) pituitary gland

Answer 2

C) hypothalamus

Question 3

the hormone progesterone is produced by the:
A) corpus luteum 
B) pituitary 
C) thyroid 
D) uterus

Answer 3

A) corpus luteum

Question 4

a student was investigating the effect of sweating. the temperature of the water in each flask was recorded every minute for 10 minutes

state two variables that would need to be controlled in this investigation

Answer 4

1. starting temperature of water

2. volume of water

Question 5

the thyroid gland is part of the 
A) circulatory system 
B) digestive system
C) endocrine system
D) urinary system

Answer 5

C) endocrine system

Question 6

explain the role of vasodilation in thermoregulation

Answer 6

vasodilation acts to cool down the body as more blood flows near the surface of the skin causing and less blood flows through the shunt valve. this causes increased thermal energy loss

Question 7

explain how negative feedback, involving the thyroid gland, controls metabolic rate

Answer 7

low levels of thyroxine causes TRH to be produced, and this causes TSH to be released from the pituitary gland. TSH causes thyroxine to be produced by the thyroid gland

Question 8

explain how hormones control the menstrual cycle

Answer 8

four hormones involved in the menstrual cycle are oestrogen, progesterone, LH and FSH. at the start, FSH causes the egg to develop in the follicle and FSH is released from the pituitary gland. as oestrogen and progesterone levels are low, oestrogen begins to rise and its released from ovaries causing the lining to build up. high levels cause a surge of LH which is released from the pituitary gland causing ovulation - an egg is released from the ovary and progesterone produced from the corpus luteum. this causes the uterus lining to be maintained. if an egg is fertilised oestrogen and progesterone levels remain high to maintain the lining of the uterus

Question 9

explain how the release of adrenalin can result in the improved performance of an athlete

Answer 9

adrenalin acts to increase heart rate and blood pressure so there is an increased blood flow which causes the release of glucose from glycogen. as a result the rate of respiration increases

Question 10

explain how substances are exchanged between the blood entering the nephron and the filtrate leaving the collecting duct

Answer 10

the blood is filtered into the nephron through the glomerulus and the bowman capsule. it enters the first tubule and substances are reabsorbed by diffusion. the waste products pass to the collecting duct where urine is formed.
the blood is filtered into the nephron through the glomerulus and the bow mans capsule, this is called ultrafiltration. it enters the first tubule and substances are reabsorbed by diffusion and substances like glucose are selectively reabsorbed. the filtrate moves through the loop of henle where some water and ions are reabsorbed. the waste products pass to the collecting duct where urine is formed