B12 - Homeostasis in Action

Question 1

adaptations of polar bears in terms of temperature

Answer 1

layer of fur - insulates and reduces heat loss by radiation

Question 2

adaptations of a seal in terms of temperature

Answer 2

blubber - insulates and reduces heat loss by radiation

Question 3

adaptations of an elephant in terms of temperature

Answer 3

large surface area and thinner skin to raise heat loss

Question 4

homeostasis

Answer 4

keeping conditions in the body at a set point

Question 5

constant body temperature

Answer 5

37 degrees

Question 6

physical ways the body can gain/lose heat

Answer 6

*shivering
* sweating
* vasodilation
* vasoconstriction

Question 7

vasodilation

Answer 7

widening of blood vessels due to the relaxation of the blood vessels’ walls

Question 8

vasoconstriction

Answer 8

the narrowing of blood vessels by small muscles in their walls

Question 9

what do capillaries do to control body temperature

Answer 9

control blood flow to the skin

Question 10

how does sweat work

Answer 10

cools the body as it loses heat through evapouration of water molecules

Question 11

ways water is gained

Answer 11

• food and drink
• metabolism

Question 12

ways water is lost

Answer 12

• urine
• feces
• skin
• lungs

Question 13

dehydration caused by

Answer 13

hypertonic solution - blood has lower water concentration

Question 14

what happens if you eat too much protein

Answer 14

1. broken down into amino acids
2. amino acids converted into fats and carbohydrates (deamination)
3. ammonia produced as waste - toxic so converted into urea
4. urea also toxic and can lead to extensive damage to cells - removed from the body in the kidney

Question 15

urine

Answer 15

solution made by the kidney fro urea and water

Question 16

structure of urinary system

Answer 16

• liver - produces urea
• vena cava, aorta
• renal artery - brings blood containing urea and other substances in solution to the kidney
• ureter - tube that urine passes from kidney to bladder
• urethra - tube that urine passes through to leave the body
• renal vein - carries blood away from the kidney after the removal of urea and other substances from the blood
• diaphragm

Question 17

ultrafiltration

Answer 17

substances are filtered out of the blood - including water, glucose, urea - NOT protein and blood cells - too large

Question 18

reabsorption

Answer 18

useful substances are reabsorbed back into the blood - all glucose, some water, some ions

Question 19

adaptations of the kidney nephron for effective reabsorbtion

Answer 19

many microvilli containing many mitochondria for active transport

Question 20

what happens to urine on a hot day

Answer 20

darker, stronger scent

Question 21

what happens to urine on a cool day

Answer 21

paler, less scent

Question 22

what happens to the urine when a lot of salt is ingested

Answer 22

contains more ions

Question 23

what happens to the urine if you have diabetes

Answer 23

contains more glucose

Question 24

what happens to the urine if you drink more water

Answer 24

paler, less scent

Question 25

dialysis

Answer 25

procedure to remove waste products and excess fluid from the blood when the kidneys stop working properly

Question 26

when will you need a kidney transplant

Answer 26

if both of your kidneys fail - you can live with only one kidney

Question 27

advantages of a kidney transplant

Answer 27

• lasts many years
• cheaper than dialysis over a long period of time
• can live a normal life afterwards

Question 28

disadvantages of a kidney transplant

Answer 28

• large risk of infection
• very few tissue matches
• need to take immunosuppressant drugs

Question 29

advantages of dialysis

Answer 29

• no major surgery needed
• easy access, no donor needed

Question 30

disadvantages of dialysis

Answer 30

• low protein diet needed
• cannot lead a normal life afterwards
• start to feel ill before next treatment is due
• spend frequent long periods in the hospital