Neurons, synapses and neurotransmitters.

Question 1

What type of nerves originate or terminate in:
A - Dorsal Horn
B - Ventral Horn

Answer 1

A - sensory peripheral nerves terminate
B - peripheral motor nerves (lower motor neurons) originate

Question 2

What activities does the somatic nervous system influence?

Answer 2

Somatic nervous system receives inputs from sensory receptors in skin and mucosa dealing with touch, pressure, pain temperature and with all voluntary movement conducted through striated muscles.

Question 3

What activities does the autonomic nervous system influence?

Answer 3

Autonomic nervous system involuntary activities – sensation from internal organs (e.g. baroreceptors and chemoreceptors monitoring blood pressure and blood chemistry) and involuntary motor activities (e.g. secretion from glands and smooth muscle activity).
It is an important part of the homeostasis mechanisms that control the internal environment of the body.

Question 4

By which route do afferent (sensory neurons) enter the spinal cord?

Answer 4

Afferent (sensory nerves) enter the spinal cord by dorsal roots.

Question 5

By which route do efferent (motor) neurons leave the spinal cord?

Answer 5

Efferent (motor nerves) leave via ventral roots.

Question 6

What are the likely consequences of injury to a spinal nerve (e.g. by compression from a slipped disc?

Answer 6

Injury to a spinal nerve = lower motor neuron lesion = flaccid paralysis of the muscles it controls + loss of sensation from areas supplied by that nerve.

Question 7

What are the likely consequences of transection of the spinal cord?

Answer 7

Transection of the spinal cord = complete loss of motor activity below level of damage and complete loss of sensation below level of damage. No motor information can get to muscles via spinal cord below level of injury and no sensation can get up the spinal cord to the brain.