l2- Neurons

Question 1

types of neurons

Answer 1

motor- (sd,la) sensory (ld, sa), relay (sd,sa)

Question 2

sensory neurons

Answer 2

• found in receptors such as the eyes, ears, tongue and skin
• carry messages from PNS to CNS
• impulses reach brain =translated into ‘sensations’, such as vision, hearing, taste and touch.
• not all sensory neurons reach the brain, as some neurons stop at the spinal cord, allowing for quick reflex actions.

Question 3

Relay neurons

Answer 3

• found between sensory input and motor output/response.
• found in the brain and spinal cord and allow sensory and motor neurons to communicate.

Question 4

motor neurons

Answer 4

• found in CNS and control muscle movements.
• connect CNS to effectors (muscles, glands)
• When motor neurons are stimulated they release neurotransmitters that bind to the receptors on muscles to trigger a response, which lead to movement

Question 5

purpose of neurons

Answer 5

provide the NS with its primary means of communication

Question 6

structure of typical neuron

Answer 6

• CELL BODY includes NUCLEUS which contains genetic material of cell
• DENDRITES carry nerve impulses from neighbouring neurons towards cell body
• AXON carries impulses away from cell body to AXON TERMINAL via SCHWANN CELLS
• axon covered in fatty layer of MYELIN SHEATH- protects axon and speeds up electical transmission of impluse
• NODES OF RANVIER- gaps in myelin sheath that force impluse to jump along gaps to speed up transmission (or would be slow)
• AXON TERMINAL- communicate with next neuron in chain across synapse