Nerve Cells 1

Question 1

There are ___ types of cells in the nervous system. They are:

Answer 1

Two.

• Neurons.
• Supporting cells.

Question 2

The nervous system is divided into:

Answer 2

–Central nervous system (CNS):
•Brain.
•Spinal cord.
–Peripheral nervous system (PNS):
•Cranial nerves.
•Spinal nerves.

Question 3

The basic structural and functional units of the nervous system is…

Answer 3

Neuron

Question 4

Neurons can’t divide by mitosis. True or false?

Answer 4

True

Question 5

Properties of neurons

Answer 5

• They respond to physical and chemical stimuli.
• They produce and conduct electrochemical impulses.
• They release chemical regulators.

Question 6

A nerve is…

Answer 6

A bundle of axons located outside CNS, most are composed of both motor and sensory fibers.

Question 7

Parts of a neuron

Answer 7

Cell body (perikaryon)
Dendrites
Axon

Question 8

Which part of the neuron is the “Nutrition center”?

Answer 8

Cell body

Question 9

Cell bodies within the CNS are clustered into ____, and in PNS in ____.

Answer 9

Nuclei, Ganglia

Question 10

Functions of dendrites

Answer 10

They provide receptive area and transmit electrical impulses to cell body.

Question 11

Functions of axons

Answer 11

They conduct impulses away from cell body.

Question 12

What happens in axoplasmic flow?

Answer 12

Proteins and other molecules are transported by rhythmic contractions to nerve endings.

Question 13

What happens in axonal transport?

Answer 13

Microtubules are employed for transport and may occur in orthograde or retrograde direction.

Question 14

Functional classification of neurons is based on…

Answer 14

…direction of impulses conducted

Question 15

Classes of neurons based on function

Answer 15

• Sensory or afferent – Conduct impulses from sensory receptors into CNS.
• Motor or efferent – Conduct impulses out of CNS to effector organs.
• Association or interneurons – Located entirely within the CNS and serve an integrative function.

Question 16

Which functional class of neurons are located entirely within the CNS?

Answer 16

Association or interneurons:

Question 17

Structural classification of neurons is based on…

Answer 17

…the number of processes that extend from cell body.

Question 18

Classes of neurons based on structure

Answer 18

– Pseudounipolar - Short single process that branches like a T
– Bipolar neurons - Have 2 processes.
–Multipolar neurons - Have several dendrites and 1 axon

Question 19

Examples of the neurons that make up the structural classes of neurons

Answer 19

– Pseudounipolar, e.g. sensory neurons
– Bipolar neurons, e.g. Retina of the eye
–Multipolar, e.g. Motor neuron.

Question 20

Supporting cells in the nervous system are located in the CNS alone. True or false?

Answer 20

False. They’re in CNS and PNS

Question 21

Types of supporting cells in the CNS

Answer 21

Oligodendrocytes
Microglia
Astrocytes
Epyndymal cells

Question 22

Types of supporting cells in the PNS

Answer 22

Schwann cells

Satellite cells

Question 23

What is a diffusion potential?

Answer 23

It is the potential difference generated across a membrane when a charged solute ( an ion) diffuses down its concentration gradient.

Question 24

What is the Equilibrium Potential?

Answer 24

The diffusion potential that exactly balances or opposes the tendency for diffusion down the concentration difference

Question 25

At electrochemical equilibrium, the chemical and electrical driving forces acting on an ion are equal and opposite, and no further net diffusion occurs. True or false?

Answer 25

True

Question 26

What is the Nerst Equation?

Answer 26

The Nernst Equation is used to calculate the equilibrium potential for an ion at a given concentration difference across a membrane, assuming the membrane is permeable to that ion.

Question 27

What is the Resting Membrane Potential (RMP)?

Answer 27

RMP is the potential difference that exists across the membrane of excitable cells, such as nerve and muscle, in the period between action potentials.

Question 28

The RMP is established by...

Answer 28

diffusion potentials, which results from concentration differences from various ions across the cell membrane.

Question 29

The concentration differences resulting from RMP is established by what mechanisms?

Answer 29

Primary and secondary active transport mechanisms.

Question 30

Each permeant ion attempts to drive the membrane potential towards another’s equilibrium potential. True or false?

Answer 30

False, it’s towards its own

Question 31

Which ions exert the greatest contribution to RMP and which ones exert the least?

Answer 31

Those with the greatest permeability or conductance exert the most while those with lower permeability will make little or no contribution.

Question 32

The RMP of excitable cells falls between ___.

Answer 32

-70 to -80mV

Question 33

Which ions are most permeable at rest? On the other hand, the RMP is far from those of Calcium and Sodium because the permeability to this ions at rest is low.

Answer 33

Those of potassium and chloride to whom the RMP of excitable cells are closest

Question 34

On the other hand, the RMP is far from those of Calcium and Sodium because the permeability to this ions at rest is low.

Answer 34

Hh