Nervous Tissue Flashcards

0
Q
  1. List the two types of cells that compose nervous tissue
A
  1. Neurons

2. Neuroglia

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1
Q
  1. What structures make up the CNS & PNS?
A
  • brain & spinal cord

- spinal nerves, cranial nerves, ganglia, & sensory receptors

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2
Q
  1. a) Describe the general function of neurons and neuroglia
A
  • conduct nerve impulses by secreting neurotransmitters

- maintain homeostasis, form myelin sheath, & provide support and protection for neurons

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3
Q
  1. List the 3 classes of neurons and describe the function of each
A
  1. Sensory Afferent Neuron- receives internal/external sensory stimuli & transmits impulses to CNS
  2. Interneurons- integrate the sensory information “makes decision”
  3. Motor Efferent Neuron- transmits impulses within and away from CNS (muscles/glands)
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4
Q
  1. List the parts of a neuron and describe the function of each
A

Dendrites- receives stimulus & sends info to soma
Soma- decides what to do with the info
Axon- conducts action potential away from the soma

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5
Q
  1. Describe the differences between multi-polar, bipolar, and unipolar neurons.
A

Multi-Polar - many dendrites, one axon

Bipolar- one dendrite, one axon

Unipolar- single process divided into T-like formation

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6
Q
  1. List the neuroglia found in the CNS and give the function of each
A

Astrocytes- supports & anchors neurons to capillaries
Oligodendrocytes- form myelin sheath around axon
Ependymal- ciliated cells that line the cavities of the brain & spinal cord
Microglia- help get rid of other micro organism/debris

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7
Q
  1. List the neuroglia found in the PNS and give the function of each
A

Schwann Cell- produce myelin cheats around 1 axon & helps with regeneration of nerve fibers

Satellite Cell- supply nutrients & support the structural function to the surrounding neurons

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8
Q
  1. What causes MS?
A

Degeneration of myelin sheath

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9
Q
  1. Describe gray matter
A
  • Composed of neuron cell bodies, processes, Unmyelinated axons & neuroglia
  • Helps rout sensory & motor neurons to interneurons
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10
Q
  1. Describe white matter
A
  • composed of myelinated & unmyelinated axons

- form connections between nerve fibers

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11
Q
  1. Define RMP
A

At rest, the inside of a neuron is more negative than the outside (polarized)

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12
Q
  1. a) What is the RMP of a neuron?
A

-70mV

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13
Q
  1. b) How is the RMP established?
A

Unequal distribution of ions across the membrane

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14
Q
  1. c) Describe the ion composition of the ICF & ECF
A

ICF- slightly neg

ECF- slightly pos

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15
Q
  1. d) How is the RMP maintained?
A

Na+/K+ pump

3 Na+ out & 2 K+ in

16
Q
  1. Define action potential and threshold stimulus
A
  • an impulse that is sent across an axon

- weakest stimulus capable of proud in a response in an excitable tissue

17
Q
  1. List the characteristics of an action potential
A
  • All or none
  • self propagating
  • not graded (will not increase w/ stimulus)
  • travels short/long distances w/out losing strength
  • one direction
18
Q
  1. Describe the events that occur during the depolarization phase of an action potential
A
  • threshold stimulus is reached (-55mV)
  • voltage gated Na+ channels open
  • Na+ enters cell
  • RMP (-70mV) > 0mV > +35mV
  • Polarity reversed > (+) inside (-) outside
19
Q
  1. Describe the events that occur during the repolarization phase of an action potential
A
  • voltage gated K+ channels open
  • K+ exits cell
  • RMP restored (-) inside (+) outside
20
Q
  1. a) How is the RMP restored?
A

Voltage gated K+ channels open as Na+ channels close, causing K+ to rush out of the cell.

21
Q
  1. b) What causes hyperpolarization?
A

After repolarization, the gates stay open longer and K+ leaks out, causing the cell to become super neg.

22
Q
  1. Define absolute refractory period & relative refractory period
A
  • Na+ enters, K+ leaves (occurs during depolarization)
  • when partial repolarization has occurred and a greater than normal stimulus can stimulate a second response (occurs during hyperpolarization)
23
Q
  1. Be able to interpret graph
A

.

24
Q
  1. Describe Saltatory Conduction vs. Continuous Conduction
A

Saltatory:

  • myelinated
  • voltage gated ion channels are located on nodes
  • faster conduction

Continuous:

  • unmyelinated
  • voltage gated ion channels along entire plasma membrane
  • slower
25
Q
  1. Compare and contrast a graded potential and an action potential
A

Graded Potential:

  • vary in size w/ stimulus strength
  • localized & loses strength
  • reversible

Action Potential:

  • will not increase w/ stimulus
  • travels long distances w/out losing strength
  • one direction