N1: Overview of the Nervous System

Question 1

What is the Peripheral Nervous System composed of?

Answer 1

Cranial nerves and spinal nerves

- ganglia and nerves

Question 2

What is the Central Nervous System composed of?

Answer 2

Brain and spinal cord

• gray matter and nuclei (collection of neurons)
• white matter and tracts (collection of axons)

Question 3

What are the “functional” categories”?

Answer 3

somatic (motor/efferent or sensory/afferent) and visceral (motor/efferent or sensory/afferent)

Question 4

What is the Autonomic Nervous System categorized under?

Answer 4

Visceral-> motor/efferent-> parasympathetic (rest or digest, S2-S4) or sympathetic (fight or flight, T1-L3)

Question 5

Where is the Central Sulcus located?

Answer 5

In between the frontal lobe and the parietal lobe

Question 6

Where is the Sylvian fissure (lateral fissure) located?

Answer 6

Separated the temporal lobe from the frontal lobe and the parietal lobe

Question 7

Where is the Parieto-Occipital Sulcus?

Answer 7

Between the parietal lobe and occipital lobe

Question 8

Where is the calcarine fissure located?

Answer 8

Separates the occipital lobe in half

Question 9

Spinal cord organization?

Answer 9

31 pairs of spinal nerves:
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1-2 coccygeal
Conus Medullaris (cone shape at the end)
Cauda Equina (nerves that extend farther out)

Question 10

Spinal nerves?

Answer 10

posterior root
-sensory neurons (pseudounipolar)

posterior root ganglion
-cell bodies of sensory neurons

anterior root
-motor neurons (multipolar)

Posterior side= sensory side, anterior side= motor

Question 11

Cerebral hemisphere anatomical orientation?

Answer 11

anterior (rostral)
superior (dorsal)
posterior (caudal)
inferior (ventral)

Roy doesn’t carry violins.

Question 12

Brainstem and spinal cord anatomical orientation?

Answer 12

anterior (ventral)
superior (rostral)
posterior (dorsal)
inferior (caudal)

Violins Roy doesn’t carry

Question 13

What is a neuron?

Answer 13

neuron = functional unit of the nervous system

• cell body
• dendrite(s): bring in signals
• axon: several feet long

Question 14

Types of neurons?

Answer 14

multipolar neurons

• 99% of all neurons
• whole bunch of processes sticking out

pseudounipolar neurons
- sensory ganglia

bipolar neurons

• retina, cranial nerve I, cranial nerve VIII
• only 2 processes

Question 15

6 layers of the cerebral cortex?

Answer 15

1. Molecular
2. External granular
3. External pyramidal
4. Internal granular
5. Internal pyramidal
6. Multiform

Question 16

Cell body composition?

Answer 16

contains nucleus, nucleolus,
Nissl bodies (ribosomes and endoplasmic reticulum), Golgi complexes,
mitochondria, neurofilaments, microtubules

Question 17

Dendrites composition?

Answer 17

contains same organelles as cell body except nucleus

Nissl bodies and Golgi complexes only in proximal portion

Question 18

Axon composition?

Answer 18

contains mitochondria,
neurofilaments and microtubules,
but no protein-making machinery

Question 19

Components of a neuron?

Answer 19

A. Nissl bodies
B. axon hillock- point where axon begins
C. initial segment- always unmyelinated
D. internodal segment
E. node of Ranvier- gap between unmyelinating cells

Question 20

CNS glial cells?

Answer 20

oligodendrocytes and astrocytes

Question 21

Oligodendrocytes?

Answer 21

• branched processes radiate from cell body
• myelination of CNS axons
• 1 oligodendrocyte can myelinate multiple segments on multiple axons
• multiple sclerosis demyelinates neurons of CNS

Question 22

Astrocytes?

Answer 22

• numerous thin stellate processes radiate from cell body
• regulation of extracellular ionic environment
• guidance of migrating neurons during brain development
• regulate the blood-brain barrier
• glioblastoma multiforme severe type of brain tumor

Question 23

PNS non-neuronal cells?

Answer 23

Schwann cells

• myelination of PNS axons
• single internodal segment
• axons can regenerate to target

Question 24

PNS ganglia?

Answer 24

sensory ganglia

autonomic ganglia

Question 25

Sensory ganglia?

Answer 25

-sensory
-pseudounipolar neurons
-neuron density higher
-satellite cells greater (support cells for PNS neurons)
-no synapses
These look more crowded

Question 26

Autonomic ganglia?

Answer 26

-motor
-multipolar neurons
-neuron density lower
-satellite cells fewer
-synapses
These look less crowded

Question 27

Myelin sheath?

Answer 27

• up to 50 plasma membrane layers
• oligodendrocytes in CNS, Schwann cells in PNS
• cover internodal segment

Question 28

Schwann cells?

Answer 28

-myelinated axons are enclosed
by up to 50 plasma membrane layers
of Schwann cells
-unmyelinated axons are enclosed
by invaginations of plasma membrane
of Schwann cells

Question 29

Neuromuscular synapse?

Answer 29

• neurotransmitter is ACh (+)

- junctional folds in skeletal muscle

Question 30

CNS synapse?

Answer 30

• axosomatic: axon to cell body
• axodendritic: axon to dendrite
• axoaxonic: axon to axon

neurotransmitters include glutamate (+) and GABA (-)