b3.3

Question 1

What temperature may you have a risk of hypothermia by?

Answer 1

35°C

Question 2

How does exposure to extreme cold affect the body?

Answer 2

Core temperature may reduce; enzyme reactions slow; respiration does not release energy fast enough; cells begin to die

Question 3

What does exposure to high temperature lead to?

Answer 3

Body overheats; enzymes may denature; body reactions cannot occur

Question 4

State a key fact about homeostasis

Answer 4

It is a negative feedback loop

Question 5

What area in your brain is responsible for regulating body temperatures?

Answer 5

Thermoregulatory centre (hypothalamus)

Question 6

What is a change in temperature detected by?

Answer 6

Skin receptors (external); internal receptors (blood temperature)

Question 7

What does a change in temperature result in?

Answer 7

Brain sends impulses to effectors

Question 8

What happens when you get too hot?

Answer 8

Body hair lowers; vasodilation; sweat glands produce sweat

Question 9

How does body hairs lowering cool you down?

Answer 9

Prevents a layer of insulating air being trapped around the body

Question 10

How does vasodilation cool you down?

Answer 10

Increases blood flow to capillaries at skin surface

Question 11

How does sweating cool you down?

Answer 11

Water in sweat evaporates; energy is transferred by heating from body to environment

Question 12

What happens when you get too cold?

Answer 12

Body hairs rise; vasoconstriction; shivering begins

Question 13

How does body hair rising keep you warm?

Answer 13

Traps a layer of insulating air close to the skin

Question 14

How does vasoconstriction keep you warm?

Answer 14

Reduces blood flow through capillaries

Question 15

How does shivering keep you warm?

Answer 15

Muscles contract and relax quickly; cells respire faster; extra energy transferred as heat

Question 16

What are the effects on the body if blood glucose levels are too high?

Answer 16

Affects concentration gradient in blood

Question 17

What are the negative effects on the body if blood glucose levels are too low?

Answer 17

Organism cannot produce enough energy; cells cannot respire effectively

Question 18

Describe what happens when you eat food

Answer 18

Glucose released by digestion passes into bloodstream; blood sugar levels rise

Question 19

What happens when blood glucose levels are too high?

Answer 19

Pancreas detects change; releases insulin; insulin travels to liver; liver converts glucose to glycogen; glycogen stored in liver

Question 20

What happens if blood glucose levels are too low?

Answer 20

Pancreas detects change; releases glucagon; glucagon stimulates liver to convert glycogen to glucose; glucose released into blood

Question 21

What causes blood sugar levels to drop?

Answer 21

Exercise (glucose used more during respiration)

Question 22

What is the difference between glycogen

Answer 22

glucose

Question 23

Which organ helps to restore glucose levels to normal?

Answer 23

Liver/pancreas

Question 24

What does insulin do?

Answer 24

Binds to cells; tells them to absorb excess glucose and convert to glycogen

Question 25

Causes of Type 1 diabetes?

Answer 25

Cannot produce insulin or very little insulin; immune system destroys pancreatic cells

Question 26

Causes of Type 2 diabetes?

Answer 26

Cells do not produce enough insulin; cells resistant to insulin; cells cannot take in glucose

Question 27

How is Type 1 diabetes controlled?

Answer 27

Injecting insulin

Question 28

How is Type 2 diabetes controlled?

Answer 28

Healthy

Question 29

How does vasodilation work?

Answer 29

Muscular walls relax

Question 30

How does vasoconstriction work?

Answer 30

Muscular walls contract

Question 31

What happens if too much water is present in plasma?

Answer 31

Water moves into cells; cells swell or burst (lysis)

Question 32

What happens if too little water is present in blood?

Answer 32

Water diffuses out of cells; cells shrink

Question 33

What does urine contain?

Answer 33

Urea

Question 34

What brings ‘unclean’ blood to the kidneys?

Answer 34

Renal artery

Question 35

What carries ‘clean’ blood away from the kidneys?

Answer 35

Renal vein

Question 36

What is the tube through which urine passes from the kidney to the bladder?

Answer 36

Ureter

Question 37

What is the tube through which urine passes to the outside of your body?

Answer 37

Urethra

Question 38

What is the ring of muscle that controls the opening and closing of the bladder?

Answer 38

Urethral sphincter

Question 39

What happens during filtration in the kidneys?

Answer 39

Small molecules absorbed into tubule; large molecules remain in capillaries (proteins/cells)

Question 40

What is absorbed during selective reabsorption?

Answer 40

Some water; all glucose; required salts

Question 41

How does the body maintain water levels?

Answer 41

Water lost via breathing

Question 42

Describe the capsule of the kidney?

Answer 42

Outer membrane; protects kidney shape; protects from damage

Question 43

Where is the cortex of the kidney?

Answer 43

Outer part

Question 44

Where is the medulla of the kidney?

Answer 44

Inner part

Question 45

Where is urine produced?

Answer 45

Microscopic tubules (nephrons)

Question 46

Where is the top of the nephron found?

Answer 46

Cortex

Question 47

Where is the loop of Henlé found?

Answer 47

Medulla (lower section)

Question 48

Where does blood go first from the renal artery?

Answer 48

Glomerulus (knot of capillaries)

Question 49

How does filtration occur?

Answer 49

High blood pressure in glomerulus forces small molecules into Bowman’s capsule; large molecules stay in blood

Question 50

How does selective reabsorption occur?

Answer 50

Filtrate moves through nephron tubules; glucose

Question 51

How is urine collected?

Answer 51

Urine collects in collecting duct; travels via ureter; stored in bladder

Question 52

What is the volume of urine produced controlled by?

Answer 52

Negative feedback loop

Question 53

What detects the water potential of blood?

Answer 53

Hypothalamus

Question 54

How does the hypothalamus react to water potential?

Answer 54

Produces ADH; pituitary gland secretes ADH

Question 55

What happens if blood water potential is too low?

Answer 55

More ADH produced; kidney tubules more permeable; less water lost; more concentrated urine

Question 56

What happens if there is too much urea in the bloodstream?

Answer 56

Harms cells and tissues

Question 57

How is urea formed?

Answer 57

Protein digested to amino acids; excess amino acids deaminated in liver to ammonia; ammonia converted to urea

Question 58

What happens if blood water potential is too high?

Answer 58

Pituitary stops releasing ADH; kidney tubules less permeable; more dilute urine

Question 59

When is urea formed?

Answer 59

From excess amino acids

Question 60

What does a reduction of water potential in blood plasma trigger?

Answer 60

Thirst response

Question 61

What happens if you drink too much water?

Answer 61

More urine produced; cells may burst; sodium concentration drops; muscle cramping; seizures; confusion

Question 62

What happens in extreme cases of too much water?

Answer 62

Death; water moves into brain cells

Question 63

What is a hypotonic solution?

Answer 63

Solution has high water concentration (low ions); cell has low water potential; gains water; lysis

Question 64

What is a hypertonic solution?

Answer 64

Solution has low water potential (high ions); cell has high water potential; loses water; shrinks

Question 65

What is a solution that has the same water and ion concentration as cells?

Answer 65

Isotonic

Question 66

How does homeostasis affect the blood?

Answer 66

Regulates water and ion concentration

Question 67

What controls osmosis and diffusion between cells in the body?

Answer 67

Ion levels in plasma vs cells

Question 68

What do kidneys control in the body?

Answer 68

Ion and water levels

Question 69

What is the function of the kidneys?

Answer 69

Regulate urine volume/concentration; remove waste; regulate body water

Question 70

3 things that can cause the body to overheat?

Answer 70

Exercise; high temperature exposure; some infections

Question 71

At what temperature do your enzymes denature?

Answer 71

Above 40–42°C