Nervous System - Homeostasis

Question 1

What is homeostasis?

Answer 1

• regulation of the internal conditions of a cell or organism to maintain optimum conditions for functions in response to internal and external changes

Question 2

The automatic control is given by what 2 systems in the body.

Answer 2

-nervous
- endocrine systems

Question 3

What are the 3 homeostatic control mechanisms?

Answer 3

• receptor cells
• coordinations centres
• Effectors

Question 4

What is the function of receptor cells?

Answer 4

• detect stimuli (changes in environment)

Question 5

What parts of the body are coordination centres and what is their function?

Answer 5

• Brain, Spinal Cord, Pancreas
• Receive and process information from receptors

Question 6

The human nervous system is divided into 2:

Answer 6

• Central nervous system : Brain + spinal Cord
• Peripheral nervous system : all other nerves

Question 7

What are nerves?

Answer 7

cells called neurones that carry electrical impulses around the body

Question 8

What are receptor cells?

Answer 8

specialised cells that detect changes in the environment

Question 9

What are effectors and what is their functions?

Answer 9

-muscles or glands
- bring about response to restore optimum levels

Question 10

Reflex arc -

Answer 10

The nerve pathway involved in a reflex action (doesn’t involve the brain)

Question 11

Reflex -

Answer 11

rapid + automatic response for body protection

Question 12

Reflex action -

Answer 12

automatic + rapid response to a stimulus

Question 13

Key characteristics of reflexes:

Answer 13

• automatic + rapid response
• Involuntary
• stimulus always leads to the same response

Question 14

Describe the reflex arc pathway.

Answer 14

1. Stimulus
2. Change detected by receptor
3. sensory neurone receives electrical impulse from receptor. Then sends to relay neurone across the synapse
4. relay neurone (central nervous system) receives electrical impulse and sends to motor neurone
   5.motor neurone receives electrical impulse and sends it to effector
5. effector produces a response:
   - muscle contracts
   - glands release hormones
6. Causes physical response / action

Question 15

What is the acronym for the reflex arc?

Answer 15

Stimulus
Receptor
Sensory neurone
Relay neurone
Motor neurone
Effector
Response

Question 16

Name 3 examples of internal conditions controlled by homeostasis:

Answer 16

• water potential
• blood glucose concentration
• temperature

Question 17

what do the brain and the spinal cord act together as

Answer 17

coordinators - coordinate the response

Question 18

what are the 2 different effectors and what do they do when they carry out a response?

Answer 18

effector produces a response:
- muscle contracts
- glands release hormones

Question 19

how many neurones and synapses are there in the relay arc and how does this affect the speed of the electrical impulses

Answer 19

3 neurones + 2 synapses
electrical impulse can travel quicker - only has to trave across 2 synapses