Topic 40 - Structure of a nerve, types and nerve fibres

Question 1

Types of nerves?

Answer 1

Myelinated

Unmyelinated

Question 2

Myelinated nerves?

Answer 2

increase transmission speed, use nodes of Ranvier,

Question 3

Unmyelinated nerves?

Answer 3

slower transmission, typically shorter nerves.

Question 4

Myelinated nerves classifications:?

Answer 4

• A fibres: longest insulated segments, motor neurons are the fastest (alpha type), followed by tactile, muscle spindles, and pain receptors (slowest, gamma type).
• B fibres: shorter internode lengths (vegetative preganglion).
• C fibres: slowest (vegetative postganglion).

Question 5

Myelinated nerves location:

CNS?

Answer 5

CNS: myelin sheath is composed of oligodendrocytes.

Question 6

Myelinated nerves location:

PNS?

Answer 6

myelin sheath is composed of Schwann cells, peripheral nerves consist of thousands of axons organized into connective tissue fascicles. Within a fascicle each neurolemmocyte is surrounded by endoneurium. Fascicles are surrounded by perineurium, multiple fasciles are then bound by epineurium.

Question 7

What is a ganglion?

Answer 7

An assembley of neurons at the periphery along the course of a nerve. Surrounded by a CT-capsule, giving riseto several septa.