Nerve Cells 1 Flashcards

1
Q

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

A

Two.

  • Neurons.
  • Supporting cells.
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2
Q

The nervous system is divided into:

A
–Central nervous system (CNS):
•Brain.
•Spinal cord.
–Peripheral nervous system (PNS):
•Cranial nerves.
•Spinal nerves.
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3
Q

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

A

Neuron

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4
Q

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

A

True

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5
Q

Properties of neurons

A
  • They respond to physical and chemical stimuli.
  • They produce and conduct electrochemical impulses.
  • They release chemical regulators.
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6
Q

A nerve is…

A

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

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7
Q

Parts of a neuron

A

Cell body (perikaryon)
Dendrites
Axon

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8
Q

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

A

Cell body

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9
Q

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

A

Nuclei, Ganglia

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10
Q

Functions of dendrites

A

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

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11
Q

Functions of axons

A

They conduct impulses away from cell body.

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12
Q

What happens in axoplasmic flow?

A

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

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13
Q

What happens in axonal transport?

A

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

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14
Q

Functional classification of neurons is based on…

A

…direction of impulses conducted

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15
Q

Classes of neurons based on function

A
  • 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.
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16
Q

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

A

Association or interneurons:

17
Q

Structural classification of neurons is based on…

A

…the number of processes that extend from cell body.

18
Q

Classes of neurons based on structure

A

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

19
Q

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

A

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

20
Q

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

A

False. They’re in CNS and PNS

21
Q

Types of supporting cells in the CNS

A

Oligodendrocytes
Microglia
Astrocytes
Epyndymal cells

22
Q

Types of supporting cells in the PNS

A

Schwann cells

Satellite cells

23
Q

What is a diffusion potential?

A

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

24
Q

What is the Equilibrium Potential?

A

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

25
Q

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?

A

True

26
Q

What is the Nerst Equation?

A

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.

27
Q

What is the Resting Membrane Potential (RMP)?

A

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

28
Q

The RMP is established by…

A

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

29
Q

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

A

Primary and secondary active transport mechanisms.

30
Q

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

A

False, it’s towards its own

31
Q

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

A

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

32
Q

The RMP of excitable cells falls between ___.

A

-70 to -80mV

33
Q

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.

A

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

34
Q

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

A

Hh