ENDOCRINE ORGANS AND RESPIRATORY SYSTEM
ENDOCRINE ORGANS
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
length of axon
|
|
number of neuroglia associated with it
|
|
where the impulse originates from
|
|
presence or absence of myelin
|
Detailed explanation-1: -Axon diameter, internode distance, and myelin sheath thickness all influence the speed of action potential propagation. Moreover, these factors are to a certain degree correlated with each other.
Detailed explanation-2: -1 Answer. The two main factors are insulation by the myelin sheath and the diameter of the axon.
Detailed explanation-3: -Environmental factors influencing myelination Conversely, negative environmental influences like poor nutrition (D), premature birth (E), and social isolation (E) can cause abnormalities in myelination (bottom axon).
Detailed explanation-4: -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-5: -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.