B12 - Homeostasis in action

Question 1

What is the optimum temperature in the body

Answer 1

37 degrees

Question 2

Why is controlling body temperature important

Answer 2

to make sure enzymes work

Question 3

What are three things that cause internal body temperature to change

Answer 3

fevers from disease, transfer of energy during exercise, change in external temperature

Question 4

What part of the body controls temperature
- where is it

Answer 4

thermoregulatory centre
- hypothalamus in brain

Question 5

how does the thermoregulatory centre get information about the temperature of the skin

Answer 5

temperature receptors in the skin that send impulses to the thermoregulatory centre

Question 6

How does the body cool down

Answer 6

• vasodilation happens
• more sweat is produced as energy is transferred to the environment
• hairs lie flat

Question 7

What is vasodilation

Answer 7

when capillaries near the skin get bigger to allow for more blood flow

Question 8

What is vasoconstriction

Answer 8

capillaries close to skin get smaller so less blood flows

Question 9

How does the body keep warm when it is cold outside

Answer 9

vasoconstriction
- no sweat
- shivering which required energy to be transferred

Question 10

What are the two main poisonous waste products

Answer 10

urea and carbon dioxide

Question 11

How is carbon dioxide produced in the body

Answer 11

respiration

Question 12

Why must carbon dioxide in the body
- how is it removed

Answer 12

dissolved carbon dioxide produces an acidic solution that affects enzymes
- using a concentration gradient to the lungs, then it is exhaled

Question 13

What is urea

Answer 13

the nitrogenous water produced by the breakdown of excess amino acids in your liver

Question 14

How is urea moved from the body

Answer 14

it passes from the liver cells into the blood. it is filtered out of blood by the kidneys and passed out in urine

Question 15

What are the three ways water is lost from the body

Answer 15

breathing, sweat, urine

Question 16

Why is urine produced

Answer 16

to balance water and mineral concentrations, to remove urea

Question 17

are
-exhalation
- sweat
- urine
controlled water loss

Answer 17

exhalation and seat are not, urine is

Question 18

What happens if body cells lose or gain too much water

Answer 18

they do not function efficiently

Question 19

What is the function of the kidneys

Answer 19

remove toxins from blood and maintain the water balance

Question 20

What do kidneys do if you drink too little / much water

Answer 20

little - concentrated urine is produced, water is conserved
lots - dilute urine is produced with lots of water

Question 21

How are mineral ions excreted

Answer 21

through urine, sweat

Question 22

How do the kidneys work

Answer 22

• glucose, mineral ions, urea and water move out of blood into kidney
• around 99% goes back to blood, rest becomes urine
• this trickles down into bladder

Question 23

What blood vessel brings blood to the kidney

Answer 23

renal artery

Question 24

What blood vessel brings blood to the kidney

Answer 24

renal vein

Question 25

Why do blood cells and proteins not enter the kidneys

Answer 25

too big to leave the blood

Question 26

What happens to the substances taken in by the kidney

Answer 26

all the glucose is reabsorbed
- water and minerals are reabsorbed based on what is necessary
- all urea is excreted

Question 27

What is the process of controlled amounts of water and minerals being reabsorbed called

Answer 27

selective reabsorption

Question 28

What type of system controls the amount of water in the blood
- Which hormone does it involve

Answer 28

negative feedback system
- ADH Anti-diuretic hormone)

Question 29

How does the system of water balance in the body work

Answer 29

• if the blood is too concentrated with solutes, the pituitary gland releases lots of ADH
  -this makes the kidneys reabsorb more water
• If it is too dilute less ADH is produced
• large volume of dilute urine is produced

Question 30

Why do kidneys fail

Answer 30

accidents, genetic problems

Question 31

What is the effect of not having functioning kidneys

Answer 31

toxins such as urea build up and damage cells

Question 32

What are the two effective methods of treating kidney failure

Answer 32

dialysis
kidney transplant

Question 33

What is dialysis

Answer 33

a process where the kidney’s function is done artificially

Question 34

How does a dialysis machine work

Answer 34

blood leaves the body and flows between a partially permeable membrane
- on the other side is dialysis fluid with the same concentration of useful substances
- there is no net movement of substances such as glucose
- excess substances are removed via diffusion down a concentration gradient

Question 35

How long do dialysis sessions tend to last

Answer 35

around 8 hours, a few times a week

Question 36

What are the drawbacks of dialysis

Answer 36

a very controlled diet is needed, with a relatively low protein intake

• long time must be spent at a dialysis machine
• the balance only lasts a relatively short time so you might feel unwell
• over years keeping balance can get harder
• causes damage to the body

Question 37

Why are organs sometimes rejected

Answer 37

the donor’s antigens are different to the recipients so the immune system might attack it

Question 38

How can the risk of rejection be reduced

Answer 38

• similar antigens
• immunosuppressants

Question 39

What is the issue with using immunosuppressants

Answer 39

they prevent the patient from dealing with normal diseases so they feel more ill

Question 40

What are the drawbacks of having a kidney transplant

Answer 40

• won’t last forever
• long waiting lists
• requires immunosuppressants

Question 41

What are the advantages of dialysis

Answer 41

• much more available

Question 42

What are the advantages of having a kidney transplant

Answer 42

• can have a normal life
• less expensive than dialysis