Cells and control - Nervous System

What are sensory receptors?

Groups of cells that detect stimuli and initiate responses to them (e.g. eye receptors and skin)

Describe how neurones are involved in the transfer of information to and from the CNS.

1. Sensory neurones - carry info as electrical impulses from sensory receptors to CNS

2. Relay neurones - carry electrical impulses from sensory neurones to motor neurones. Found in CNS

3. Motor neurones - carry electrical impulses from CNS to effectors (e.g. muscles)

What are dendrons, axons and myelin sheaths used for?

Dendron - carry nerve impulses towards the cell body

Axons - carry nerve impulses away from cell body

Myelin sheath - fatty layer that speeds up electrical impulse

Burn the following image into your brain because I cba to type it out.

Picture

What is the function of synapses?

Nerve signal transferred by neurotransmitters which diffuse across the synapse.

Explain process of reflex arc.

1. Stimulus detected by receptors, impulses sent along sensory neurone to relay neurone in CNS

2. When impulse reaches synapse between relay neurone and motor neurone, same thing happens, they trigger neurotransmitters to be released.

3. When impulses reach synapse between relay neurone and motor neurone, same thing happens. Neurotransmitters released and cause impulses to be sent along the motor neurone.

4. Impulses then travel along motor neurone to effector

5. If effector = muscle, it will contract

   If effector = gland, it will secrete a hormone