2. Homeostasis Pt7

Question 1

What happens when blood glucose concentrations are too low?

Answer 1

-glucagon secreted by the pancreas into the blood

Question 2

What parts of the body use osmoses?

Answer 2

-water leaves the body via the lungs during exhalation
-water, ions & urea are lost from the skin as sweat
-there’s no control over water, ion or urea lost by the lungs or skin
-excess water, ions & urea are removed via the kidneys in the urine
(If body cells gain or lose too much water by osmosis they don’t fu cation efficiently)

Question 3

How does the digestion of proteins work?

Answer 3

• the digestion of proteins results in excess amino acids which need to be excreted
• in the liver the amino acids are deaminated to form ammonia
• ammonia is toxic and so is converted to urea fir safe excretion

Question 4

What controls the water level in the body?

Answer 4

• ADH which acts in the kidney tubules
• ADH is released by the pituitary gland when the blood is too concentrated
• & it causes more water to be reabsorbed back into the blood from the kidney tubules
• which is controlled by negative feedback

Question 5

What happens if the concentration of water in the body is too high?

Answer 5

• a receptor in the brain detects it’s too high
• the coordination centre in the brain receives the information & coordinates a response
• the pituitary gland releases less ADH, so less water is reabsorbed from the kidney tubules

Question 6

What happens if the concentration of water is too low?

Answer 6

• a receptor in the brain detects it’s too low
• the coordination centre in the brain receives the information & coordinates a response
• the pituitary gland releases more ADH, so more water is reabsorbed from the kidney tubules

Question 7

What’s the main reproductive hormone produced in females?

Answer 7

Oestrogen is the main reproductive hormone produced in the ovary
At puberty eggs begin to mature & one is released approximately every 28 days, this is called ovulation

Question 8

What’s the main reproductive hormone produced in males?

Answer 8

Testosterone is produced in the testes & stimulates sperm production

Question 9

Explain how injections, skin patches & implants can control fertility?

Answer 9

They release progesterone to inhibit the maturation and release of eggs for a number of months or years

Question 10

What’s sterilisation?

Answer 10

Involves cutting or tying Fallopian tubes in a female or the sperm ducts in a male.
It’s permanent

Question 11

What are the disadvantages of fertility treatments?

Answer 11

• it’s emotionally & physically stressful
• the success rates aren’t high
• it can lead yo multiple births which are a risk to both the babies & the mother

Question 12

What does adrenaline do?

Answer 12

• produced in the adrenal glands in times of fear or stress
• it increases the heart rate & boosts the delivery of oxygen & glucose to the brain & muscles
• preparing the body for ‘fight or flight’

Question 13

What does thyroxine do?

Answer 13

• produces from the thyroid gland
• it stimulates the basal metabolic rate
• it plays an important role in growth & development