Organisation of the Nervous System

Question 1

What does the nervous system consist of

Answer 1

brain and cranial nerves
spinal cord and spinal nerves
ganglia (small masses of nervous tissue)

Question 2

Give a brief overview of the nervous system

Answer 2

sensory receptors detect internal/external stimuli - carried to brain and spinal cord through spinal and cranial nerves > the NS integrates the sensory info and makes decisions for appropriate responses > once integrated the NS elicits an appropriate motor response by activating effects through cranial and spinal nerves - muscles contract and glands secrete

Question 3

The Central Nervous System (CNS) consists of …

Answer 3

Brain and Spinal Cord

Question 4

Describe the role of the CNS

Answer 4

processes incoming sensory info and responds with nerve impulses that stimulate muscles to contract and glands to secrete - also the source of thoughts, emotions and memories

Question 5

The Peripheral Nervous System (PNS) consists of …

Answer 5

Spinal nerves and their branches, Cranial nerves and their branches, Ganglia and sensory receptors

Question 6

The PNS is divided into …

Answer 6

Somatic NS
Autonomic NS
Enteric NS

Question 7

Describe the sensory and motor neurons in the somatic NS

Answer 7

sensory neurons convey info from receptors in head/body/limbs/special senses to CNS
motor neurons conducts impulses from CNS to skeletal muscles ONLY

Question 8

Describe the consequence of the motor response of the Somatic NS

Answer 8

because these motor responses can be consciously controlled, the action of this part of the PNS is VOLUNTARY

Question 9

Describe the sensory and motor neurons in the autonomic NS

Answer 9

sensory neurons convey info from autonomic sensory receptors in visceral organs such as stomach/lungs to CNS
motor neurons conduct impulses from CNS to smooth muscle, cardiac muscle and glands

Question 10

Describe the consequence of the motor response of the Autonomic NS

Answer 10

because its motor responses are not normally under conscious control, the action of the ANS is INVOLUNTARY

Question 11

The motor part of the ANS consists of 2 branches …

Answer 11

sympathetic division

parasympathetic division

Question 12

Describe these 2 divisions

Answer 12

most effectors receive nerves from both divisions, have opposing actions, sympathetic neurons increase h.r., parasympathetic neurons decrease h.r.
sympathetic = ‘fight-or-flight’
parasympathetic = ‘rest-and-digest’

Question 13

Describe the Enteric NS

Answer 13

‘brain of the gut’, INVOLUNTARY, approx 100 million neurons that extend most of the length of the GIT that function independently of the ANS and CNS, sensory neurons monitor chemical changes within GIT as well as stretching of its walls