CNS Organization

Question 1

Explain the ANS.

Answer 1

It is entirely motor and innervates smooth muscles and glands.

It does depend on normal sensory input.

Sympathetic & Parasymmpathetic

Question 2

What are the characteristics of Dendrites?

Answer 2

Serval per neuron
Short compared to axon
Can be branched
Receptors for neurotransmitters 
Conduct local potentials

Question 3

What are the characteristics of the axon?

Answer 3

Long
One per neuron
Conduct action potential (nerve impulse)

Release neurotransmitters

Ends in branched processes = telodendria. 
Have terminal boutons
These have synaptic vesicles w/
Neurotransmitters 
Cell membrane is axolemma= atop last

Question 4

Spinal nerves give off two small branches before the primary rami, what are they?

Answer 4

White ramus
communicants

1. Carries myelinated preganglionic

Gray ramus communicants

1. Carries unmyelinated postganglions fibers back to spinal nerves.

Question 5

What does the splanchnic nerve innervate?

Answer 5

Viscera

Question 6

What is the resting potential of the cell body?

Answer 6

-65 my

Question 7

What is the potential of an excited cell body?

Answer 7

-45 my

Question 8

What is the potential of an inhibited cell body?

Answer 8

-70mv

Question 9

Explain the somatosensory axis pathway?

Answer 9

Peripheral rectors
Afferent neurons
Spinal cord/brain stem

Reticular substance= importance of information.

1. Medulla
2. Pons
3. Mesencephalon

Cerebellum
Thalamus
Somesthetic areas of the cerebral cortex

Question 10

What are the components of the skeletal motor nerve axis pathway? (The processing areas)

Answer 10

Telencephalon
1. Basal ganglia=
Putamen
Globus pallid us
Subthalamic nuclei

Diencephalon
1. Thalamus

Spinal cord reflexes

Question 11

Define electronic conduction?

Answer 11

Direct spread of electrical current by ion conduction in the dendritic fluids w/out generating an AP.

Question 12

Explain why dendritic characteristics do not allow for AP?

Answer 12

Few voltage-gated Na channels

Thresholds are too high

Dendritic membranes are partially permeable to K and Cl

Much potential is lost

Question 13

Describe the excitatory state of the dendrite?

Answer 13

Defined as the summated degree of excitatory drive to neuron.

1. Excitatory state w/higher degree compared to inhibition
   And vs viscera.

Question 14

Describe firing rate?

Answer 14

Neuron will fire repetitively as long as it is above threshold.

Firing rate depends on normal excitatory rate and changes due to superimposition of other excitatory or inhibitory signals.

Question 15

What CN’s carry parasympathetics?

Answer 15

CN 3, 7, 9, 10

Oculomotor
Facial
Glossopharyngeal
Vagus

Question 16

Explain Paravertebral ganglia.

Answer 16

Located on side of vertebral column in thoracolumbar region

Postganlionic sympathetic cell bodies

Synapses between preganglionic myelinated sympathetic and postganglionic non-myelinated sympathetic neurons

Question 17

What do Splanchic nerves supply?

Answer 17

Viscera

Question 18

Explain prevertebral ganglion.

Answer 18

Located anterior to abdominal aorta

Synapses between preganglionic myelinated sympathetic neurons and postganglionic non-myelinated neurons.

Question 19

Define decremental conduction.

Answer 19

Signal becomes weaker as it travels from initiation

In opposition of AP which are renewed along length of axon. They don’t decrease in strength.