Homeostasis

Question 1

Define the term ‘homeostasis’

Answer 1

the regulation of the body’s internal environment, maintaining it within its normal limits

Question 2

What is negative feedback?

Answer 2

the process by which, when something deviates from the normal range, it is detected, and responses are triggered to return it to its normal range

Question 3

Identify 3 processes of homeostasis that are controlled through negative feedback loops

Answer 3

body temperature
glucose
osmoregulatoin (control of fluid levels)

Question 4

What detects changes in temperature?

Answer 4

receptors in skin - external changes

receptors in internal organs - internal changes

Question 5

Where is the temperature control centre?

Answer 5

in the hypothalamus in the brain

Question 6

Describe how our body produces heat to warm us up if we get too cold

Answer 6

blood vessels to our hands and feet constrict (vasoconstriction) so less heat is lost through the skin as it doesn’t go as close
we shiver (muscle contractions) that produce energy, which generates heat
piloerection - hair stands on end to trap warm air
sweat ducts stop producing sweat
we put on clothes, drink hot drinks etc

Question 7

How does our body cool us down if we get too hot?

Answer 7

vasodilation of blood vessels to the skin, so heat can be lost through conduction, convection, radiation
we sweat more, so heat can be lost through the evaporation of sweat
we remove clothers, drink cool drinks etc

Question 8

How does heat loss compare with smaller and larger people?

Answer 8

smaller bodies have a higher surface area to volume ratio, so they lose heat quicker.

Question 9

What term means ‘regulation of body temperature’?

Answer 9

thermoregulation

Question 10

What does thermoregulation mean?

Answer 10

regulation of body temperature

Question 11

Name 2 problems associated with failure of the homeostatic mechanisms that control body temperature

Answer 11

pyrexia

hypothermia

Question 12

What is pyrexia?

Answer 12

when you get too hot and have a high temperature (fever)

Question 13

What is hypothermia?

Answer 13

when your body temperature gets too cold

Question 14

What is a normal body temperature?

Answer 14

37 degrees C

Question 15

What term means that your body is too cold?

Answer 15

hypothermia

Question 16

What term means that your body is too hot?

Answer 16

pyrexia

Question 17

Where are glucagon and insulin produced?

Answer 17

in the pancreas

Question 18

What happens if we have too much glucose in our blood?

Answer 18

the pancreas secretes insulin, to tell the muscles and liver to take up glucose and store it as glycogen

Question 19

What happens if we don’t have enough glucose in our blood?

Answer 19

the pancreas secretes glucagon to tell the muscles and liver to break down glycogen into glucose and release it back into the blood stream

Question 20

What term means that our blood glucose levels are too high?

Answer 20

hyperglycaemia

Question 21

What term means that our blood glucose levels are too low?

Answer 21

hypoglycaemia

Question 22

What condition occurs when your body can’t control it’s blood glucose levels?

Answer 22

diabetes

Question 23

Which term means control of fluid levels?

Answer 23

osmoregulation

Question 24

Which body system is responsible for maintaining the composition and volume of body fluids?

Answer 24

renal system (kidneys)

Question 25

Which hormone is secreted if we don’t have enough water, to tell our kidneys to reabsorb more of it?

Answer 25

ADH

Anti-diuretic hormone

Question 26

How can we increase our fluid levels if we become dehydrated?

Answer 26

drink more water

our kidneys can reabsorb water, and excrete less out

Question 27

What are the effects of dehydration?

Answer 27

• organ failure, as water is needed for them to function normally
• reduced blood pressure, as water makes up most of blood
• brain damage, as there is less fluid to cushion the brain
• headaches, due to less water around the brain
• confusion/ dizzyness, as the brain functions slows down
• cystisis, due to more concentrated urine