B5 Homeostasis

Question 1

Define homeostasis

Answer 1

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

Question 2

What does the body control during homeostasis

Answer 2

Carbon dioxide
Urea
Water
Salt
Oxygen
Temperature

Question 3

Define receptor

Answer 3

Detects change in internal or external environment

Question 4

Define stimulus

Answer 4

A change in the environment of something

Question 5

Define coordination centre

Answer 5

Receives and processes information from the receptors. They send out signals and coordinate the response of the body

Question 6

Define effector

Answer 6

This part changes the conditions

Question 7

Define response

Answer 7

The action taken by a processing centre as a reaction to a stimulus

Question 8

What makes up the nervous system.

Answer 8

Central nervous system (CNS) consists of brain and spinal cord
peripheral nervous system (PNS) consists of nerve cells and receptors

Question 9

What does the nervous system enable us to do?

Answer 9

Avoid danger
Find food
Eventually find a mate

Question 10

How does the nervous system coordinate a response?

Answer 10

Stimulus
Receptor Sensory neurone
Coordinator Motor neurone
Effector
Response

Question 11

Define neurone

Answer 11

Cells that carry minute electrical impulses around the body

Question 12

Define nerve

Answer 12

Bundle of hundreds or even thousands of neurones

Question 13

Define dendrites

Answer 13

Detect changes in the environment (stimuli) and starts the electrical signal in the cell

Question 14

Define cell body

Answer 14

Contains the cells nucleus

Question 15

Define axon

Answer 15

Long extension of the cytoplasm that carries the electrical impulse from the cell body to other neurones

Question 16

Define myelin sheath

Answer 16

Covers the axon and acts as an insulator and helps to speed up nerve impulses

Question 17

Define axon terminal

Answer 17

Connect to another cell (neurone or an effector)

Question 18

Describe the difference between the function of a receptor and the function of an effector

Answer 18

A receptor detects the stimulus and sends electrical impulse to sensory neurone for example a skin receptor. An effector is the response to the stimulus for example a muscle or a gland.

Question 19

What is the place where two neurones meet called?

Answer 19

A synapse

Question 20

How do electrical impulses travel along neurones?

Answer 20

Electrical impulses travel along the axon to the end of the firs neurone. Neurotransmitters are released into the synapse. The neurotransmitter diffuse across the synapse and bind to the receptor on the cell membrane. This causes another electrical impulse to be transported across the second neurone.

Question 21

What is the method for reaction time?

Answer 21

1. Use writing hand and non writing hand, Working with a partner.
2. Person A holds out their hand with a gap between their thumb and first finger.
3. Person B holds the ruler with the zero at the top of person A’s thumb.
4. Person B drops the ruler without telling Person A and Person A must catch it.
5. The distance on the ruler level with the top of person A’s thumb is recorded in a suitable table.
   Repeat this five times.
6. Swap places, and record another ten attempts.
7. You can use the conversion table to help convert your ruler measurements into reaction time or just record the catch distance in cm.