Peripheral nervous system and Autonomic nervous system (4)

Question 1

The PNS consists of all the nervous tissue ____ the ____.

Answer 1

Outside

CNS

Question 2

What is the PNS made up of?

Answer 2

It is made up of the nerves that link the CNS to the receptors and effectors of the body.

Question 3

What do the 43 pairs of nerves that link the CNS to the receptors and effectors of the body consist? (2)

Answer 3

• 12 pairs of cranial nerves connected to the brain. These may be sensory (afferent) nerves or motor (efferent) nerves or mixed nerves made up of both sensory and motor nerves. They leave the brain and conduct impulses to and from the sense organs and muscles in the head and face.
• 31 pairs of spinal nerves which enter and leave the spinal cord between the vertebrae. These are all mixed nerves being made up of the fibres of sensory and motor neurons.

Question 4

What are the 2 functions of PNS?

Answer 4

• It collects information from receptors and transmits this information by way of impulses along sensory afferent neurons to the CNS- sensory function.
• It transmits impulses from the CNS by way of motor, efferent neurons to effectors to bring about an appropriate response – motor function.

Question 5

How is the motor division made up? (2)

Answer 5

1. Somatic nervous system that conducts impulses from CNS to skeletal muscles and therefore controls all voluntary muscular movements.
2. Autonomic nervous system that conducts impulses from the CNS to cardiac muscle, smooth muscles and glands and therefore controls the functioning of involuntary muscles and glands.