Neural Tissue Flashcards
0
Q
Nervous system characteristics
A
- System that coordinates all body systems
- Accomplished by the transmission of signals
- Body part —> central nervous system
- Central Nervous system –> body system
- Electrochemical signaling
1
Q
What are the 2 communication systems?
A
- Nervous system
2. Endocrine System
2
Q
Endocrine system characteristics
A
- Slower scaled system
- Uses chemicals in the blood stream called hormones
3
Q
General make up of the nervous system (5)
A
- Organs
- Connective Tissue
- Blood Vessels
- Neurons
- Neuroglia
4
Q
2 groups or divisions of the Nervous System
A
- Central Nervous System
2. Peripheral Nervous System
5
Q
The brain and the spinal cord
A
Central Nervous System
6
Q
The cranial and spinal nerves and ganglia
A
Peripheral Nervous System
7
Q
Components of the Central Nervous System (5)
A
- Brain and Spinal Cord
- Covers by meninges
- Starts as a hollow tube
- Bathed in cerebrospinal fluid
- Integration center
8
Q
Components of the Peripheral Nervous System (3)
A
- Consists of all cranial and spinal nerves that contain sensory and motor fibers
- Connects CNS to muscles, glands, and all sensory receptors
- Brings information to and from CNS
9
Q
2 divisions of the Peripheral Nervous System
A
- Afferent Division = sensory
2. Efferent Division = motor
10
Q
2 divisions of the Efferent Division
A
- Somatic Division
2. Autonomic Division
11
Q
General function of the Nervous System (5)
A
- Receptors- detect stimuli
- Sensory- afferent PNS
- Integrative- CNS
- Motor- Efferent PNS
- Effector- Muscle/gland
12
Q
2 types of Nervous Tissue
A
- Neurons
2. Neuroglial Cells
13
Q
- Structural and functional units
- Excitable
- Amitotic
A
Neurons
14
Q
- Accessory nerve cells
- Act like connective tissue
A
Neuroglial Cells
15
Q
3 Parts of a Neuron
A
- Soma
- Dendrites
- Axon
16
Q
What is the Soma
A
- Cell body
- Mononucleate
18
Q
The soma consists of… (4)
A
- Nissl Bodies - ribosomes clusters, give gray color
- Axon Hillock- connects soma to axon
- Perikaryon- Region around the nucleus
- Neurofibrils- Cytoskeleton that extend into dendrites/axons and gives it its shape
19
Q
Dendrite characteristics (4)
A
- Respond to neurotransmitters
- Short, branched, unmylelinated
- Specialized for contact with other neurons
- Conducts impulses toward the cell body
20
Q
Axon characteristics (4)
A
- only 1 per cell
- Conducts nerve impulses AWAY from the soma
- Can give off collaterals
- Many wrapped in myelin sheath, glial cells wrapped around the axon
21
Q
Where do axons end?
A
In synaptic terminals
22
Q
What do axons produce?
A
Neurotransmitters
23
Q
Neurotransmitters may contact these 3 things…
A
- Another neuron
- Muscle fibers
- Glands
24
Q
The movement of cellular materials (NOT SIGNALS) through the axon
A
Axonal Transport
AKA Axoplasmic flow
25
Away from soma, neurotrasmitters, organelles, and nutrients
Anterograde
26
Towards soma, degraded materials to be recycled and extracellular substances
Retrograde
27
-Cytoplasm of the axon
Axoplasma
28
What does the axoplasma consist of? (2)
- Few organelles
| - Cytoskeletal proteins
29
What is the role of the cytoskeletal proteins? (3)
1. Form cytoskeleton
2. Maintain shape
3. Generate axonal transport
30
-Plasma membrane of axon
Axolemma
31
What does the axolemma consist of? (4)
1. Collaterals
2. Telodendria
3. Synaptic terminal
4. Synaptic Vesicles
32
Side branches of axolemma
Collaterals
33
Terminal Extensions of axolemma
Telodendria
34
Part of axolemma that contains synaptic vesicles where neuron contacts postsynaptic cell
Synaptic Terminal
35
Structural classification of neurons (4)
1. Anaxonic
2. Bipolar
3. Unipolar
4. Multipolar
36
- Small neurons
- Axons can not be distinguished from dendrites
- In CNS- especially interneurons that coordinate special senses
Anaxonic
37
- Several small dentrites converge onto one
- Dendrite and axon separated by soma
- Unmyelinated
- Sensory neurons of special sensory organs
Bipolar
38
- Several small dendrites converge into one large one
- Dendrite and axon continuous
- Usually myelinated
- Majority of sensory neurons in PNS
Unipolar
39
- Many dendrites extend from soma
- Long axon
- Myelinated
- Majority of motor neurons in PNS
- Spinal interneurons in CNS
Multipolar
40
Characteristics of Afferent Neurons (4)
- Have sensory function
- Cell body usually are outside CNS
- Have receptor ends on dendrites or are associated with receptor cells in sense organs
- Carry impulses from peripheral body parts --> brain or spinal cord
41
Receptors in Afferent neurons... (3)
1. Exteroceptors
2. Proprioceptors
3. Interoceptors
42
Receptor that does...
- touch
- temperature
- pressure
- light
- chemicals
Exteroceptors
43
Receptor that...
| -monitors muscle and skeletal position
Proprioceptos
44
Receptor that...
| -monitor internal systems (digestion, respiration, and urinary system)
Interoceptors
45
Neurons that...
- Only in CNS
- Classified based on effects (excitatory, inhibitory)
- Most abundant
- Link 2 or more neurons
Interneurons
46
Neurons that...
- Have motor function
- Cell body is usually inside CNS
- Carries impulses from the brain or spinal cord to peripheral body parts
Efferent Neurons
47
The 2 divisions of efferent neurons...
1. Somatic
| 2. Autonomic/Visceral
48
Type of efferent neurons that controls skeletal muscle
Somatic Neurons
49
Type of efferent neurons that are in smooth muscle and glands
Autonomic/Visceral
50
Neuroglial Cells in PNS (2)
1. Satellite Cells
| 2. Schwann Cells
51
Neuroglial Cells in CNS (4)
1. Astrocytes
2. Oligodendrocytes
3. Ependymal Cells
4. Microglia
52
CNS Neuroglial Cell that...
- Largest and most common
- Star shaped
Astrocytes
53
Functions of Astrocytes (5)
1. Structure and repair
2. Metabolism
3. Regulate ions and nutrients
4. Guide nutrients to targets
5. From blood brain barrier
54
CNS Neuroglial Cell that...
| -Like astrocytes but smaller
Oligodendrocytes
55
Functions of Oligodendrocytes (2)
1. Form myelin in CNS
| - Sequester debris
56
CNS Neuroglial Cell that...
- Smallest and least common
- Derived from myeloid cells
Microglia
57
Functions of Mircoglia (3)
1. Help support neurons
2. Phagocytosis
3. Increase in number during injury or disease
58
CNS Neuroglial Cell that...
- Columnar/cuboidal
- Microvilli on luminal surface
- Joined by gap junctions
Ependymal
59
Functions of Ependymal (3)
1. Help produce cerebrospinal fluid
2. Form porous layer
3. Monitor CSF composition
60
PNS Neuroglial Cell that...
- Associated with soma
- Assist with exchange of nutrients
- Isolates neuron from extraneous stimuli
Satellite
61
PNS Neuroglial Cell that...
- Produce myelin in PNS
- Encloses axons of longer peripheral nerves
Schwann Cells
62
Functions of Schwann cells... (3)
1. Support neurons
2. Prevent contact
3. Myelinate large PNS axons
63
Characteristics of unmyelinated axons... (3)
1. Appear gray
2. Many axons associate with a single schwann cell
3. CNS- no glial cells
64
Characteristics of Myelinated Axons... (3)
1. Appear white
2. CNS- Oligodendrocytes myelinate part of several axons
3. PNS- Schwann cell myelinates part of one axon
65
Myelin Structure (3)
1. Myelin
2. Neurilemma
3. Nodes of Ranvier
66
Part of myelin structure that...
| -Plasma membrane of Schwann cell wrapped around an axon
Myelin
67
Part of myelin structure that...
| -Part of the Schwann cell that contains the cytoplasm
Neurilemma
68
Part of myelin structure that...
| -Gaps in myelin sheath
Nodes of Ranvier
69
Process that starts at week 14 and completed by age 2 or 3 years
Myelination process
70
Myelin Functions (2)
1. Isolate Axons
| 2. Increase rate of action potential
71
Regeneration of Nerve fibers in PNS
- Can regenerate a fraction of the axons
- Schwann cells participate in process
- Called Wallerian degeneration
72
Process of Nerve Fiber Regeneration (9)
1. Injury separates axon from the cell body (distal portion of the axon will deteriorate along with myelin sheath
2. Macrophages clean up
3. Some Schwann cells remain and reproduce
4. Get thin basement membrane & layer of CT around Schwann cells
5. Forms hollow tube leading to original connection of axon
6. Proximal end sprouts
7. Sprout may grow into tube
8. Remaining Schwann cells produce new myelin around growing axon
9. New axon grows 3-4 mm/day
73
Characteristics of repair in CNS (5)
1. More limited
2. Degeneration occurs after injury
3. Oligodendrocytes do not proliferate
4. Proximal end sprouts but has no tube that follows
5. Astrocytes produce scar tissue and chemicals blocking regrowth
74
4 Factors of Nerve Impulse
1. Irritability
2. Excitability
3. Action Potential
4. Nerve Impulse
75
Ability to respond to stimuli
Irritability
76
Ability to transmit an impulse
Excitability
77
An electrical impulse changing the permeability of a membrane
Action potential
78
Action potential moving down an axon
Nerve Impulse
79
Impulse travels faster when... (2)
1. Axon is myelinated
| 2. Has a larger diameter
80
Functions of synapse
Control and transmission point
81
Synapse is the site of communication between... (4)
1. Sensory structure and neuron
2. Neuron & effector
3. 2 neurons
4. Any 2 cells with gap junctions
82
2 types of Synapses
1. Electrical
| 2. Chemical
83
Characteristics of Electrical Synapse
- Gap functions cause the exchange of charged ions between 2 cells
84
Example of Electrical Synapse
Intercalated disks in cardiac muscle
85
Characteristics of Chemical Synapse
-Chemicals are released by one cell and travel to another
86
Examples of Chemical Synapses (2)
1. Neuromuscular Junction
| 2. Neuron-neuron contact
87
How chemical synapses work
1. Synaptic vesicles house neurotransmitter
2. Only exist in the presynaptic cell
3. Release neurotransmitter into the synaptic cleft
4. Receptors on post-synaptic membrane register the neurotransmitter
5. Proliferates AP from one cell to the next
6. Communication in one direction only
88
- Receive impulses from afferent fibers (input)
- Impulses carried away on efferent neurons (output)
- Afferent fibers can branch many times as they enter a pool
Neuronal Pool
89
Types of Neuronal Pools (5)
1. Convergence
2. Divergence
3. Serial Processing
4. Parallel Processing
5. Reverberation
90
Type of Neuronal Pool that...
| -One neuron to another in a series
Serial Processing
91
Type of Neuronal Pool that...
- When impulse leaves a pool it may spread out into several output fibers
- Allows impulse to be amplified
Divergence
92
Type of Neuronal Pool that...
- Single nerve in pool may receive impulses from 2 or more incoming fibers
- if lead to the same nerve, they are said to converge
- Allows summation o impulses from different sources
Convergence
93
Type of Neuronal Pool that...
| -Processing information from several neurons at once
Parallel Processing
94
Type of Neuronal Pool that...
| -Positive feedback continues activity of circuit
Reverberation
95
- Process in which one neuron may receive either excitatory & inhibitory stimuli from multiple neurons
- The net effect of all this input results in a net charge and if this charge is positive enough it will result in an AP
Facilitation
96
The point where an action potential can be produced is...
Threshold
97
- If a neuron is excited but still below threshold
- No impulse but the nerve is more excitable to next impulse
- This nerve is said to be....
Facilitated
98
Central Nervous System Structures... (3)
1. Nuclei
2. Center
3. Tracts
99
Collection of neuron cell bodies
Nuclei
100
Collection of neuron cell bodies working together
Center
101
Bundles of axons
Tracts
102
Peripheral Nervous System structures
1. Ganglia
| 2. Nerves
103
Collection of cell bodies (PNS)
Ganglia
104
Bundles of axons (PNS)
Nerves
