Response to stimuli

Question 1

What is the sequence from stimuli to response?

Answer 1

Stimulus
Receptor
Coordinator
Effector
Response

Question 2

What is Taxis?

Answer 2

This is a response that is effected by the direction of the stimulus.

Question 3

What is Kinesis?

Answer 3

A response in which the organism does not move towards or away from a stimulus and the more unpleasant the stimulus, the more rapidly the organism moves and the more frequently it changes direction. It is an increase in random movements.

Question 4

What is tropism?

Answer 4

It is the growth movement of part of a plant in response to a directional stimulus. In almost all parts of the plant grows positively or negatively in response to something.

Question 5

What is the central nervous system?

Answer 5

This is the nervous system that is made up of the brain and spinal cord.

Question 6

What is the peripheral nervous system?

Answer 6

This is made up from pairs of nerves that originate from the brain or spinal cord.

Question 7

The peripheral nervous system is split into which to neurones?

Answer 7

Sensory neurones and motor neurones.

Question 8

What is a sensory neurone?

Answer 8

A sensory neurone carries electrical impulses from receptors towards the central nervous system.

Question 9

What is a motor neurone?

Answer 9

A motor neurone that carries electrical impulses away from the central nervous system to effectors.

Question 10

What is the sequence of the reflex arc?

Answer 10

1. The stimulus
2. A receptor create a nerve impulse in a sensory neurone
3. A sensory neurone passes the nerve impulse to the spinal cord
4. A relay neurone links the sensory neurone to the motor neurone in the spinal cord
5. A motor neurone carries the nerve impulse from the relay neurone in the spinal cord to the effector (muscle or gland)
6. An effector receives the impulse and either causes secretion in glands or contraction in muscles
7. The response, pulling away from an object

Question 11

Why are reflexes important?

Answer 11

They are involuntary and so don’t require a decision from the brain and so leaving the brain free to carry out more complex responses.
They protect your body from harmful stimuli.
They are fast because the neurone pathway is short with very few, typically one or two synapses.

Question 12

What is the sympathetic nervous system?

Answer 12

In general they speed up activity and acts like an emergency controller as it stimulates the effectors when we exercise strenuously or experience powerful emotions. They cause the fight or flight response.

Question 13

What is the parasympathetic nervous system?

Answer 13

This generally inhibits the effector and slows down activity. It controls normal resting conditions.