Nervous System Flashcards

1
Q

What are the 2 divisions of the nervous system?

A

central nervous system and peripheral nerves system

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2
Q

What are the 2 divisions of the PNS?

A

sensory/afferent division and motor/efferent division

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3
Q

Describe the sensory/afferent division of the PNS

A

has sensory receptors that detect stimuli (change in internal or external environments)

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4
Q

Describe the motor/efferent division of the PNS

A
  • nerves convey impulses away from CNS
  • innervates (supplies nerves to) effectors = muscles + glands (endocrine or exocrine)
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5
Q

What are the cell types of the nervous system?

A
  • neurons
  • neuroglia
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6
Q

What do neurons do? Where are they located?

A
  • they conduct impulses
  • make up the CNS and PNS
  • mostly amitotic (irreplaceable)
    - exceptions for taste, olfaction, and memory
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7
Q

Describe the cell body structure of a neuron

A
  • has typical organelles
  • RER called Nissl Bodies
  • group//clusters in CNS = nuclei (grey matter)
  • groups/clusters in PNS = ganglia
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8
Q

What are the 2 processes from a neurons cell body called?

A

dendrites and axons

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9
Q

What do dendrites of a neuron do?

A

they receive incoming messages + relay to cell body

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10
Q

What are the parts of an axon in a neuron? What do they do?

A
  • overall, carry impulses away from cell body
  • axon hillock: where axon meets cell body
  • axon terminal: typically branched with synaptic end bulbs (enlarged tips)
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11
Q

Axon terminals may be:

A

1) myelinated: wrapped in many layers of cell membrane from Schwann cells (PNS) or oligodendrocytes (CNS)
2) unmyelinated: no myelin

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12
Q

Describe myelinated axons

A
  • electrical insulation
  • gaps in myelin sheath are called Nodes of Ranvier
  • myelinated axon bundles in:
    - CNS = tracts (white matter)
    - PNS = nerves
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13
Q

What do neuroglia (glial cells) do?

A

support neuron cells = can undergo mitosis (prone to cancer specifically brain tumour)

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14
Q

What are the 2 types of glial cells?

A

CNS neuroglia and PNS neuroglia

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15
Q

What are the 4 types of CNS neuroglia?

A
  • oligodendrocytes
  • microglia
  • astrocytes
  • ependymal - neural epithelia
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16
Q

What do oligodendrocytes produce? What are they a subtype of?

A

they produce myelin around axons and are a subtype of CNS neuroglia

17
Q

What do microglia do? What are they a subtype of?

A

they are protective, they become phagocytic if detect infected, dead, or damaged neurons (because immune cells can’t enter CNS)
- they are a subtype of CNS neuroglia

18
Q

What do astrocytes do? Where are they located? What are they a subtype of?

A
  • they surround blood capillaries to form part of blood brain barrier (BBB)
  • they help control capillary permeability
  • they are a subtype of CNS neuroglia
19
Q

What do ependymal (neural epithelia) do? Where are they located? What are they a subtype of?

A
  • they line brain ventricles and central canal of the spinal cord
  • they secrete cerebrospinal fluid (CSF) and circulate it by cilia
  • they are a subtype of CNS neuroglia
20
Q

What are the 2 subtypes of PNS neuroglia?

A
  • shwann cells
  • satellite cells
21
Q

Where are shwann cells do? What are they a subtype of?

A
  • they form myelin around axons in PNS
  • they are a subtype of PNS neuroglia
22
Q

Where are satellite cells located? What are they a subtype of?

A
  • they surround neuron cell bodies in ganglia for protection and support?
  • they are a subtype of PNS neuroglia
23
Q

What is structural/anatomical neuron classification based on?

A

based on # of cell processes off of cell body

24
Q

Describe unipolar neurons

A
  • has 1 process that divides into two: central and peripheral
  • peripheral end has dendrites (sensory receptors for pain, touch, etc) remainder is axon
  • always sensory
25
Describe bipolar neurons
- has 2 processes: 1 axon, 1 process with dendrites - sensory: retina, nose (olfaction)
26
Describe multipolar neurons
- has 3 or more: 1 axon, many dendrites - all interneurons and motor neurons
27
What are the functional types of neuron classification? What is it based on?
based on direction of impulse conduction a) sensory/afferent b) interneurons c) efferent/motor
28
Describe sensory/afferent neurons
- mostly unipolar - from sensory receptors to CNS
29
Describe interneurons
- within CNS (between sensory and motor) - 99% of neurons (mostly multipolar)
30
Describe efferent/motor neurons
- CNS to effectors (all multipolar)
31
What are the 3 neuron junctions?
1) neuronal junction 2) neuromuscular junction 3) neuroglandular junction
32
Describe neuronal junctions
- neuron to neuron - can be chemical (use neurotransmitters) or electrical (ions)
33
Describe neuromuscular junctions
- motor neuron to skeletal muscle
34
Describe neuroglandular junctions
- motor neuron to gland
35
What are they 4 most common chemical neuron synapses?
1) presynaptic neuron 2) axon terminal 3) synaptic cleft 4) postsynaptic neuron
36
What are presynaptic neurons?
- a type of chemical neuron synapses - they bring impulse
37
What are axon terminals?
- a type of chemical neuron synapses - have synaptic end bulbs: inside the bulbs (presynaptic membrane) are synaptic vesicles containing neurotransmitters
38
What are synaptic clefts?
- a type of chemical neuron synapses - space between neurons
39