homeostasis

Question 1

definition of homeostasis

Answer 1

• Homeostasis is the regulation of the internal conditions of a cell/ organism
• to maintain optimum conditions for function
• in response to internal and external changes.

Question 2

in simple terms homeostasis is all about…

Answer 2

keeping internal conditions as constant as possible in order for enzymes to work

Question 3

3 ways homeostasis is used in the human body

Answer 3

to keep
- blood glucose concentrations
- body temperature
- water levels

constant

Question 4

what can the automatic control systems in the human body involve

Answer 4

nervous system or hormones

( nervous system or endocrine system )

Question 5

how an automatic control system works

Answer 5

• receptor cells detects stimulus
• receptor cells now pass

information to coordination centre
(e.g brain, spinal cord, pancreas)

• The coordination centre receives and processes the information from the receptor cells.
• The coordination centre now sends instructions to the effector.
  ( muscle or gland)
• effector carries out response and restores optimum level

Question 6

what is a stimulus

Answer 6

a change to the environment internally or externally changes In the environment

• body’s internal conditions)
  e.g concentrations of glucose in blood

or

• external conditions of body
  e.g temp of skin

Question 7

how does an automatic control system work in the nervous system

Answer 7

receptors detect a stimulus and send electrical impulses down neurones ( nerve cells) to the central nervous system -
( coordination centre)

Question 8

what happens when you touch a hot object
e.g flame

Answer 8

first the stimulus is detected by a receptor
( stimulus is heat - receptor is skin)

Electrical impulses now pass from the receptor along a sensory neurone to the central nervous system.

at the synapse a chemical is released
this diffuses to a relay Nerone in the central nervous system where it triggers an electrical impulse. this now passes across the relay neurone to another synapse

the electrical impulse passes from motor neurone to an effector ( muscle ) - muscle contracts and pulls hand away from heat - the response

Question 9

reflexes are automatic and rapid because

Answer 9

there is no decision making by the conscious part of the brain - help to protect us from danger