Chapter 12 Flashcards

1
Q

CNS

a) components
b) number of neurons
c) functions

A

a) brain and spinal cord
b) 85 billion neurons in brain, 100 billion neurons in the spinal cord
c) processes sensory information and sends signals for muscles to contract or glands to secrete.

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2
Q

Somatic division of the PNS is composed of what 2 types of neurons?

A

1) sensory neurons to the CNS from the head, body, and limbs and from receptors of the special sense of visions, hearing, taste, and smell
2) motor neurons that conduct impulses from the CNS to skeletal muscle only (voluntary)

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3
Q

Autonomic division of the PNS is composed of what 2 types of neurons?

A

1) sensory neurons to the CNS from receptors such as the stomach, heart, and lungs
2) motor neurons from the CNS to smooth muscle, cardiac muscle, and glands (involuntary)

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4
Q

PNS

A

All nervous tissue outside the CNS: ganglia, enteric plexuses, receptors.

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5
Q

Ganglion

A

Small masses of nervous tissue outside the CNS but closely associated with the brain and spinal nerves

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6
Q

Enteric plexuses

A

Networks of neutrons located in the walls of the organs of the gastrointestinal tract which help regulate the digestive system.

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7
Q

ENS

A

The brain of the gut.

100 million neurons.

Involuntary - propels food through the GI tract

Secretes hormones.

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8
Q

Sympathetic division of the autonomic system

A

Fight or flight

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9
Q

Parasympathetic division of the autonomic system

A

Rest and digest

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10
Q

What is contained in the cell body of a neuron?

A

Nucleus, cytoplasm, organelles

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11
Q

Nissl bodies

A

Clusters of rough ER - site of ribosomes for protein synthesis - NO protein synthesis in the axon

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12
Q

Dendrite

A

Nerve finer that emerges from the cell body. Act as the receiver or input portion of a neuron. Multiple and branched.

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13
Q

Axon

A

Single nerve finer that acts as the output portion towards another neuron, muscle cell, or gland. Contains mitochondria but no rough ER, therefore no protein synthesis

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14
Q

Axon hillock

A

Where the axon joins the cell body

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15
Q

Initial segment

A

Their portion of the axon closest to the axon hillock

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16
Q

Trigger zone

A

Where nerve impulses arise (between the axon hillock and the initial segment).

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17
Q

Synapse

A

The site of communication between 2 neurons or a neuron and an effector (muscle or gland)

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18
Q

Multipolar: structure and common locations

A

Several dendrites, single axon. Brain, spinal cord, motor neurons

19
Q

Bipolar: structure and common locations

A

Single dendrite, single axon. Eyes, ears, nose

20
Q

Unipolar: structure and common locations

A

Dendrites and axon fused together. Sensory receptors for touch, heat, pain

21
Q

Sensory neurons

A

Unipolar. Afferent pathways

22
Q

Motor neurons

A

Multipolar. Efferent pathways

23
Q

Interneurons

A

Mainly in the CNS. Afferent and efferent pathways. Multipolar

24
Q

2 types of nerve cells

A
  1. neuron

2. neuroglia

25
4 types of neuroglia in the CNS
1. astrocyte 2. ogliodendrocyte 3. microglia 4. ependymal
26
Astrocyte
Neuroglia of the CNS Largest and most numerous Support, growth, protection, chemical balance
27
Ogliodendrocyte
Neuroglia of the CNS Smaller than astrocyte with fewer processes. Forms and maintains myelin sheath (lipid/protein coating that insulates and increases speed)
28
Microglia
Neuroglia of the CNS Acts as phagocytes, removes debris and repairs damage
29
Ependymal
Neuroglia of the CNS Columnar, cuboidal cells that live in the ventricles of the brain and spinal cord that monitor and circulate cerebrospinal fluid.
30
2 types of neuroglia in the PNS
1. Schwann cell | 2. satellite cell
31
Schwann cell
Neuroglia of the PNS Forms myelin sheath Participates in axon regeneration
32
Satellite cell
Free floating neuroglia of the PNS Provides structure and support
33
Nucleus vs ganglion
Both are clusters of neuronal cell bodies. Nucleus is in the CNS, ganglia in the PNS
34
Nerve vs tract
Bundles of axons. Tract in the CNS, nerve in the PNS
35
Myelin
White in colour. Electrically insulates, and increases speed. Myelin increases through maturity.
36
Nodes of ranvier
Gaps in the myelin sheath.
37
Neurolemma
The outer covering of the schwann cell which encloses the myelin sheath. Only in the PNS.
38
White matter
Primarily composed of myelin. Surrounds grey matter in the spinal cord BUT is surrounded by grey matter in the brain
39
Grey matter
Unmyelinated portions of tissue: cell bodies, dendrites, neuroglia.
40
Graded potential
Communication between electrically excitable cells used in short distances
41
Action potential
Communication between electrically editable cells used in long distances
42
Leak channel
Randomly alternates between open and closed. Located in nearly all cells: dendrites, cell bodies, axons
43
Current
The flow of ions exchanges via ion channels