3.4.1 - Control systems involve stimulus and response

What do responses to changes depend on?

Responses to changes can vary in complexity depending on the type of organism involved and the circumstance they are responding to.

What does responding to change involve?

Responding to change involves a stimulus and a receptor.

What are the type of responses different receptors can carry out?

Two types of receptors- produce electrical activity, or secrete substances.

How does a nerve impulse cause a rewponse?

Nerve impulses sent by a receptor travel to a coordinator. The coordinator sends the impulse to an effector. Which produces a response.

What are taxes and kinesis?

Taxes and kineses are simple responses that enable mobile organisms to stay in a favourable environment.

What is kinesis?

Kinesis- non-directional response to a stimulus. Rate of movement is affected by the intensity of the stimulus.

What is taxis?

Taxis- directional response to a stimulus. Organism moves directly away from or towards the stimulus.

What are the three main type of neurones in a reflex arc?

Sensory, relay and motor

What do sensory neurones do?

Sensory- carry impulses from receptors to the CNS (brain/spinal chord).

What do relay neurones do?

Relay - (intermediate neurones found within the CNS, connects sensory and motor neurones.

What do motor neurones do?

Motor - carry impulses from the CNS to the effectors.

What is a reflex arc?

Reflex arc- pathway along which impulses are transmitted from a receptor to an effector without involving 'concious' regions of the brain.

Why is a reflex response quicker than a nervous response?

Since the response doesn't involve the brain, a reflex response is quicker than any other type of nervous response.

Describe a reflex arc pathway

stimulus, receptor, sensory neurone, relay neurone, motor neurone, effector, response