ANATOMY

GENERAL ANATOMY

NERVOUS SYSTEM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What is the purpose of the myelin sheath on the axon?
A
To maintain temperature
B
To improve conductivity
C
To protect the axon
D
To release neurotransmitters
Explanation: 

Detailed explanation-1: -Summary. Myelin can greatly increase the speed of electrical impulses in neurons because it insulates the axon and assembles voltage-gated sodium channel clusters at discrete nodes along its length. Myelin damage causes several neurological diseases, such as multiple sclerosis.

Detailed explanation-2: -By acting as an electrical insulator, myelin greatly speeds up action potential conduction (Figure 3.14). For example, whereas unmyelinated axon conduction velocities range from about 0.5 to 10 m/s, myelinated axons can conduct at velocities up to 150 m/s.

Detailed explanation-3: -Myelin is an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells. If myelin is damaged, these impulses slow down.

Detailed explanation-4: -The myelin sheath is a layer of fatty tissue surrounding the axon of a neuron that both acts as an insulator and allows faster transmission of the electrical signal. Axons branch out toward their ends, and at the tip of each branch is a terminal button.

Detailed explanation-5: -The myelin sheath transformed the way neural impulses are transmitted, by forcing action potentials to “jump” rapidly between periodic breaks in myelin (nodes of Ranvier), thus dramatically increasing transmission speed and elevating nervous function well beyond that of invertebrates.

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