Nervous Tissue Flashcards
(84 cards)
1
Q
Provides for generation of nerve impulses (AP) that communicate with and regulate most body tissues
A
Nervous tissue
2
Q
Maintaining homeostasis is shared by what two systems?
A
Nervous system
Endocrine system
3
Q
How does the nervous system regulate body activities?
A
Responding rapidly using nerve impulses
4
Q
How does the endocrine system respond to body activities?
A
Slowly by use of hormones
5
Q
Neurology
A
Deals with normal functioning and disorders of the nervous system
Neurologist
6
Q
The central nervous system is made up of what?
A
Brain
Spinal cord
7
Q
The peripheral nervous system is made up of what?
A
Cranial nerves
Spinal nerves
Peripheral nerves
8
Q
What are the functions of the nervous system?
A
Sensory
Integrative
Motor
9
Q
How does sensory function in the nervous system?
A
- Receptors (detect changes inter/external)
- Sensory never cells (neurons) carry sensory info from receptors to the brain and spinal cord
- Sensory neurons are AFFERENT neurons
10
Q
How does integrative function in the nervous system?
A
- Analyze and store info
- Make decisions
- Integrative neurons are interneurons, relatively short neurons in the brain, spinal cord, and ganglia that connect nearby neurons
11
Q
How does motor function in the nervous system?
A
- Respond to decision
- Motor neurons carry information from brain and spinal cord to effectors (muscles or glands)
- Motor neurons are EFFERENT neurons
12
Q
What is the general organization of the nervous system?
A
Somatic
Autonomic
Enteric
13
Q
Somatic
A
- Sensation from body walls, limbs, head, special senses
- Motor control of skeletal muscle (voluntary)
14
Q
Autonomic
A
- Sensation from internal organs like heart, lungs, bladder
- Motor control of smooth and cardiac muscle, glands (involuntary)
15
Q
Enteric
A
- Sensation from gastrointestinal tract
- Motor control of smooth muscle and glands of GI (involuntary)
16
Q
Consists of all nervous tissue outside the CNS
A
PNS
- Somatic nervous system (SNS)
- Autonomic nervous system (ANS)
- Enteric nervous system (ENS)
17
Q
An association (bundle) of neural axons in the peripheral nervous system (Includes dendrites and other tissue)
A
Nerve
18
Q
Group of neuronal cell bodies in the PNS (plus associated tissue)
A
Ganglion
19
Q
Association (a bundle) of neuronal axons in the CNS
A
Tract
20
Q
An ossification (a bundle) of (unmyelinated) nerve cell bodies in the CNS)
A
Nucleus
21
Q
Network of nerves
A
Plexus
22
Q
Cells that possess electrical excitability (can do an AP)
A
Neurons
23
Q
Cells of the nervous system that support, nourish, and protect the neurons
A
Neuroglia
24
Q
Are there more or less neuroglia than neurons?
A
Yes
25
What are the basic parts of a neuron?
The cell body
Nerve fibers comprising
- an axon
- dendrites
26
The cytoplasm of an axon
Axoplasm
27
The plasmalemma of axon
Axolemma
28
Dendrites (little trees)
- the receiving position of a neuron
| - typically short, tapering, highly branched
29
Axon
- Single axon per neuron
- Propagates impulses to another neuron, muscle, or nerve
- Aprox three feet long in humans
30
What happens if the axon is cut
The distal fragment dies
31
What does the axon contain?
Mitochondria
Microtubules
Neurofibrils
Does not contain RER so protein synthesis does not occur in axon
32
What are neurofibrils and what do they do?
Intermediate filaments
Provide cell shape and support
33
What are microtubules and what do they do?
Tubulin
Participate in moving material between the cell body and axon
34
In a typical neuron what are the specialized cells that aren’t in the most common cells?
Nissan bodies
| - prominent clusters of rough ER
35
The axon typically arises from an elevation in the cell body called
Axon hillock (= small hill)
36
What is the first part of an axon called before the axon hillock?
Initial segment
37
Where do impulses (AP) generally arise from?
The tigger zone
| - junction of the hillock and initial segment
38
What may branch off main axons?
Axon collateral
39
Axon and collaterals end by dividing into? Which end in ether?
Axon terminals (telodendria)
Synaptic end bulbs
Or
Varicosities
40
Synaptic end bulbs and varicosities are what?
Bulb-shaped structures
String of swollen bumps
41
What is a present in many neurons, yellowish brown pigment, accumulates with age
Lipofuscin
42
What is slow axonal transport?
One-way only, from cell body to axon terminals
Transports axoplasm to growing or regenerating axons
43
What is fast axonal transport?
Two-way transport, both toward and away from cell body
A lot faster then slow
Transport organelles and materials that used to form axolemma membranes, synaptic end bulbs, and synaptic vesicles
44
Where is the multipolar neuron found and what does it have?
Brain and spinal cord, motor neurons
Several short dendrite, one axon
45
Where is the bipolar neuron found and what does it have?
In special sensory organs
One main dendrite, one axon
46
Where is the unipolar neuron found and what does it have?
Typical sensory neuron
Axon and dendritic are fused into a single process for a short distance, then split
Peripheral process
Central process
47
Receptors, with dendrites at distal end; carries impulses toward the CELL BODY
Peripheral process
48
Carries impulses toward the CNS
Central process
49
What are GABAergic neurons?
Purkinje cells
50
What is the primary neural cell type in the corticospinal tract?
Pyramidal neurons
51
Characteristics of neuroglia
- Not excitable cells
- Smaller
- Play supporting role
- Make up 1/2 volume of CNS
- Neuroglia multiply to fill in the spaces formerly occupied by neurons
52
Neuroglia of the CNS
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
53
Neuroglia of PNS
```
Schwann cells (neurolemmocytes)
Satellite cells
```
54
What do astrocytes do?
Regulate composition of ECF in CNS
Help form the blood brain barrier
Take up excess neurotransmitters
Influence formation of neural synapses
55
What do oligodendroctes do?
Myelinated axons in the CNS
56
What do microglia do?
Phagocytes of the CNS
57
What do ependymal cells do?
Line the ventricles of the brain
Produce, monitor, and aid in circulation of CSF
Help form the blood-CSF barrier
58
What do Schwann cells do?
Myelinated axons in the PNS
59
What is myelination produced by?
Schwann cells (PNS)
Oligodendrocytes (CNS)
60
What is Myelin?
Multilayered complex of lipids and proteins
61
Myelin prevents loss of electrical signal; speeds up conduction of nerve impulses
Insulate axons
62
Can a Schwann cell and or oligodendrocyte be associated with a unmyelinated neuron
Yes
63
What does myelination require?
Glial cell to have wrapped its plasma membrane around the axon many times
64
What is the outer nucleated cytoplasmic layer of the Schwann cell?
Nurolemma
65
Unmyelinated axons can be associated with Schwann cells, they lay in grooves on surface of cell but what is there none of?
Myelin sheath
Neurolemma
66
What is contained in the neurolemma?
Nucleus and all the cytoplasm
Not be confused with axolemma
67
Only on nerve fibers supplied by potentially myelin-producing cells; gaps between myelinating cells (where no myelin)
Nodes of Ranvier
Found in PNS and CNS
68
What surrounds the nerve fiber of the Schwann cells?
Endoneurium
69
What is NOT present in the CNS because the olugodendrocyte cell body and nucleus cell body do NOT envelope the axon
Neurolemma
Also do not have node of ranvier
70
A region predominantly filled with myelinated tract fibers. Why is it colored this?
White matter
The myelin produces whiteish color
71
A region predominantly filled with neuronal cell bodies. Why is it colored this?
Gray matter
Little or no myelin
Nissl bodies impart a gray color
72
Electrical voltage difference across membrane
Membrane potential
73
How do neurons communicate with one another? Two types of electrical signals
Action potentials (nerve impulses)
Graded potentials
74
Which electrical signals are for short distance (localized)?
Graded potentials
75
For both short and long distance communication within the body. All or none.
AP
76
Both electrical signals depend on two features
Existence of a resting membrane potential
Presence of specific ion channels
77
Opposite charges are separated in space their attractive for is?
Potential
Measured in volts
78
Flow of charged atoms or molecules and what are two types?
Current
Electrical current: flow of electrons
Body current: flow of ions
79
Not gated; randomly open and close
Leakage channels
80
Neurotransmitter; channels open and close in repose to ligand binding
Ligand-gated channels
81
Response to mechanical stimuli (pressure)
Mechanically gated channels
82
Open and close in response to changes in the membrane potential
Voltage-gated channels
83
Voltage difference measured across the plasma membrane when the neuron isn’t signaling
Resting membrane potential
84
Average resting membrane potential
-70mV
