B3.3 - maintaining internal environments

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
• causes enzyme reactions to occur too slowly
• 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 temperature)

- internal receptors (blood temperature)

Question 7

what does a change in temperature result in?

Answer 7

the 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 layer of insulating air being trapped around body

Question 10

how does vasodilation cool you down?

Answer 10

• increases blood flow to capillaries (surface of skin)

- increasing heat loss via radiation

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
• blood vessels = 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 the capillaries (less heat lost)

Question 15

how does shivering keep you warm?

Answer 15

• occurs when your muscles contract and relax quickly
• cells respire more quickly
• transfer extra energy by heating

Question 16

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

Answer 16

• affects concentration gradient in blood (negative impact on osmosis)

Question 17

what are the negative effects on the body of blood glucose levels are too low? - not conc. gradient

Answer 17

• organism cannot produce enough energy

- prevents cell from respiring effectively

Question 18

describe what happens when you eat food

Answer 18

1) glucose released by digestion passes into bloodstream

2) blood sugar levels rise

Question 19

what happens when blood glucose levels are too high? - body’s response

Answer 19

• pancreas detects change
• releases (hormone) insulin
• insulin travels in blood to liver
• liver is stimulated to turn glucose into glycogen
• glycogen stored in liver

Question 20

what happens if blood glucose levels are too low? - body’s response

Answer 20

• pancreas detects change
• releases glucagon (hormone)
• hormone makes liver change glycogen into 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, glucose and glucagon?

Answer 22

• glucose is released during digestion (sugar)
• glycogen is glucose stored in the liver
• glucagon is the hormone released by the pancreas to stimulate glycogen to be changed into glucose

Question 23

Which organ helps to restore our glucose levels to normal when they fluctuate?

Answer 23

liver/pancreas

Question 24

what does insulin do?

Answer 24

• bind to cells in body

- tells them to absorb excess glucose and turn it into glycogen

Question 25

causes of type 1 diabetes

Answer 25

- Cannot produce insulin or very little insulin produced | - Immune system has destroyed pancreatic cells that make insulin

Question 26

causes of Type II diabetes

Answer 26

- Cells do not produce enough insulin - cells do not respond properly to insulin (may be resistant) - cells won’t take in glucose from bloodstream

Question 27

how is type 1 diabetes controlled?

Answer 27

- injecting insulin

Question 28

how is type 2 diabetes controlled?

Answer 28

- healthy, low sugar diet | - regular exercise

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 would move into cells - cells would burst/swell - 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, excess salts, excess water, waste products

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 which urine passes to the outside of your body?

Answer 37

urethra

Question 38

what is the ring of muscle that control the opening and closing of the bladder?

Answer 38

urethral sphincter

Question 39

what happens during filtration in the kidneys?

Answer 39

- small molecules are absorbed into the tubule | - large molecules remain in the capillaries (proteins/cells)

Question 40

what is absorbed during selective reabsorbtion?

Answer 40

- some water - all glucose [- some ions ]-allegedly - any salts needed

Question 41

how does the body maintain water levels? - how is water lost

Answer 41

breathing/ sweating/ amount of water in urine

Question 42

describe the capsule of the kidney

Answer 42

- outer membrane - protect kidney’s shape - protect 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? (1)

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 to first from the renal artery?

Answer 48

glomerulus (a knot of capillaries)

Question 49

how does filtration occur?

Answer 49

1) exit of glomerulus blood vessels are narrow = high blood pressure 2) pressure forces small molecules out of capillary wall (glomerulus) to Bowman’s capsule 3) travel to nephron tubules 4) large molecules stay in bloodstream/ glomerulus

Question 50

how does selective reabsorption occur?

Answer 50

1) filtrate moves through nephron tubules/ loop of Henlé | 2) glucose/ water/ salts are absorbed by body into capillaries

Question 51

how is urine collected?

Answer 51

1) urine collects in collecting duct 2) travels in ureter (tube) 3) stored in bladder

Question 52

what is the volume of urine produced controlled by?

Answer 52

a negative feedback loop

Question 53

what detects the water potential of blood?

Answer 53

hypothalamus (when passes through brain)

Question 54

how does the hypothalamus react to water potential?

Answer 54

- by producing ADH | - getting the pituitary gland to secrete it

Question 55

what happens if the blood water potential is too low? To change this

Answer 55

- more ADH produced - increased permeability of kidney tubules - less water lost = less urine produced = 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

1) digestion of protein results in an excess of amino acids 2) In the liver, amino acids go through deamination, and the waste product is ammonia. 3) ammonia is then converted into urea

Question 58

what happens if the blood water potential is too high? - body response

Answer 58

- The hypothalamus triggers the pituitary gland to stop the release of (ADH). 2) reduces permeability of the kidney tubules. 3) This means that less water reabsorbed back into the bloodstream. = more dilute urine

Question 59

when is urea formed?

Answer 59

excess of animo acids

Question 60

what does a reduction of water potential in blood plasma or increase of salt concentration trigger?

Answer 60

thirst response

Question 61

what happens if you drink too much water? (6)

Answer 61

- more urine produced - cells may burst (osmosis) - concentration of sodium in blood 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 = high water concentration (low ion) - a hypotonic drink would have low levels of glucose and salt cell = low water potential (high ion) GAIN WATER - lysis

Question 64

what is a hypertonic solution?

Answer 64

solution = low water potential (high ion) cell = high water potential (low ion) SHRINK - lose water

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 ions concentration (constant)

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/water levels

Question 69

what is the function of the kidneys?

Answer 69

- regulate the volume and concentration of urine | - remove waste + regulate body water content

Question 70

3 things that can cause the body to overheat

Answer 70

- exercise - exposure to very high temperatures - some infections

Question 71

At what temperature do your enzymes denature

Answer 71

If your core temperature rises above 40-42C