Cell Types in Nervous System

Question 1

Theodor Schwann

Answer 1

• all tissues made of microscopic units called cells

- Cell Theory

Question 2

Two classes of cells

Answer 2

• Neurons

- Glial Cells

Question 3

Neurons

Answer 3

• Information processing agents
• 100 billion neurons
• Neuron has three parts
• –cell body (soma)
• –dendrites (extensions)
• –axon (long arm)

Question 4

Cell body

Answer 4

• contains cytoplasm and organelles

- endoplasmic reticulum, golgi apparatus, mitochondria, nissl body, and neurofibrils

Question 5

Dendrites

Answer 5

• extensions from cell body
• has spines
• communicates through them

Question 6

Axon

Answer 6

• all neurons have one axon
• transfers information away from cell body
• extends up to 1 meter
• covered in myelin sheath
• three parts
• –axon hillock (beginning)
• –axon proper (middle)
• –axoxn terminal/terminal bouton (end)

Question 7

Myelin Sheath

Answer 7

• surrounds axon and provides insulation
• interrupted at intervals called “Nodes of Ranvier”
• nonmyelinated parts called trigger zone/initial segment

Question 8

Long Axon

Answer 8

• Golgi Type I

Question 9

Short Axon

Answer 9

• Golgi Type II

Question 10

Axon terminal

Answer 10

• swollen disc containing synaptic vesicles
• terminal contacts with other neurons pass information
• has synapse

Question 11

Synapse

Answer 11

• gap between synapse and neuron = synaptic cleft (Sherrington - neurophysiology)
• transfer of information from one neuron to another is synaptic transmission
• synaptic contact innervates the other neuron