Anatomy of a Neuron

Question 1

Cell Body

Answer 1

The large central portion which contains
the nucleus and other organelles

Contains:
* Ribosomes and rough endoplasmic
reticulum responsible for protein
synthesis
* Golgi apparatus for protein synthesis
* Mitochondria to meet the metabolic
demands.
* Neurofibrils and microtubules provide
the structural support

Question 2

Dendrites

Answer 2

The short expansions from the cell body that receive messages/impulses
from other neurons

Question 3

Axon

Answer 3

The single extending structure that moves the nerve impulse from the cell body to a target cell. Starts at axon hillock

Question 4

Myelin Sheath

Answer 4

Insulation and protection of neurons.
Formed by Schwann cells.

Question 5

Nodes of Ranvier

Answer 5

Gaps in myelin sheath, key to speed and timing of action potential along the
axon. Allows for saltatory conduction

Question 6

Myelination

Answer 6

= speed up impulse
transmission = very fast

Question 7

Axon Hillock

Answer 7

Origin of axon, where action potential originates.
“All or nothing”

Question 8

Neuroglial cells

Answer 8

Anchor nerves and vessels in place
Monitor extracellular fluid
Influence nerve impulse transmission

Question 9

3 functional types of neurons

Answer 9

 Sensory neurons in PNS (pick up
stimulus)

 Motor neurons in PNS (transmit
impulses from spinal cord to
muscle – control movements)

 Interneurons in CNS (connect
motor and sensory impulses)

Question 10

Interneuron

Answer 10

• 99% of neurons in the body are interneurons
• Mostly in the CNS
• Primary function: integration; relay information

Absent from interneuron illustration
There are some neurons in the body that are not
myelinated; tend to be very short

Question 11

Support Cells

Astrocytes

Answer 11

Provide structural support and clear excess neurotransmitters; make up large percentage of CNS cell