Neurophysiology part 1

Question 1

What are myelin sheath gaps?

Answer 1

Aka nodes of Ranvier made of nonmyelinated fibers

Question 2

What are myelin sheaths in CNS nerve fibers formed by?

Answer 2

Processes ofoligodendrocytes, not whole cells

Question 3

Each cell can wrap up to how many axons once?

Answer 3

60 axons

Question 4

Myelin sheath has____ present with no ________?

Answer 4

Gap w/no outer collar of perinuclear cytoplasm

Question 5

The thinnest fibers are myelinated or unmyelinated in CNS?

Answer 5

Unmyelinated BUT are covered by long extensions of adjacent neuroglia

Question 6

Multipolar neurons are the _____?

Answer 6

Most abundant in body & major neuron type in CNS

Question 7

Multipolar neurons can be found in what 2 cells?

Answer 7

Purkinje cell of cerebellum and pyramidal cell

Question 8

Bipolar are ___?

Answer 8

Rare

Question 9

Biopolar neurons can be found in what three cells ?

Answer 9

Olfactory mucosa cell, retinal cell, and ear: the special sensory organs

Question 10

In what nervous system are unipolar mainly found in?

Answer 10

The PNS

Question 11

Unipolar are common only in ____ and ____?

Answer 11

Dorsal root ganglia of the spinal cord AND sensory ganglia of cranial nerves

Question 12

Most multipolar neurons are what type of neurons?

Answer 12

Interneurons that conduct impulses within the CNS, integrating sensory input or motor output.

Question 13

Multipolar neurons may be ___ chain of ___ or a single neuron ______.

Answer 13

one chain of CNS neurons or a single neuron connecting sensory & motor neurons.

Question 14

Some multipolar neurons are also ___, and what do they do?

Answer 14

Motor neurons that conduct impulses along the efferent pathways from the CNS to an effector (muscle/gland)

Question 15

All bipolar neurons are what type of neurons? where are they located?

Answer 15

Sensory neurons share are located in special sense organs.

Question 16

Bipolar cells of the retina are involved in transmitting visual inputs from the eye to the brain via an intermediate chain of neurons. This is an exam of___?

Answer 16

Bipolar neurons as sensory neurons

Question 17

What other type of neurons are sensory neurons?

Answer 17

Most unipolar neurons

Question 18

Sensory neurons of unipolar neurons conduct impulses along what pathway to the CNS for what?

Answer 18

Afferent pathways to the CNS for interpretation

Question 19

Sensory neurons of unipolar neurons are called ____ or ____?

Answer 19

Primary or first-order sensory neurons

Question 20

Membrane ion channels contain ____ ____ that serve as what type of membrane ion channels?

Answer 20

large proteins that serve as a selective membrane ion channel

Question 21

An example of an ion as a selective membrane ion channel is?

Answer 21

A potassium ion channel that allows only potassium ions to pass

Question 22

What are the two main types of ion channels?

Answer 22

Leakage- non gated, always open

Gated- open and close from a protein changing shape

Question 23

What are the names of the 3 types of gated channels?

Answer 23

1. Chemically gated
2. Voltage gated
3. Mechanically gated

Question 24

Chemically gated aka ligand-gated channels open only with what condition?

Answer 24

The binding of a specific chemical like a neurotransmitter

Question 25

Voltage gated channels open and close in response to ____?

Answer 25

changes in membrane potential

Question 26

Mechanically gated channels also ___ and ___ in response to what influence?

Answer 26

open and close in response to physical deformation of receptors like sensory receptors

Question 27

When gated channels are open, ions diffuse quickly along what two types of concentration gradients?

Answer 27

Chemical and electrical concentration gradients

Question 28

Along chemical concentration gradients, ions disuse quickly from ___ concentration to ___ concentration?

Answer 28

High to lower

Question 29

Along electrical gradients, ions diffuse quickly ______?

Answer 29

toward opposite electrical charge

Question 30

What is the definition of an electrochemical gradient?

Answer 30

Electrical & chemical gradients combined

Question 31

Ion flow creates and ____ current and voltage ___ across membrane?

Answer 31

electrical current and voltage changes