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What are the TWO structural organization of the nervous system and what does each consist of?
- Central Nervous System
- 1) Brain
- 2) Spinal cord
- Peripheral Nervous System
- 1) Cranial nerves
- 2) Spinal nerves
- 3) Ganglia
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"Receptors" relay information from what 5 body parts?
1) Skin
2) Eyes
3) Ears
4) Tongue
5) Organs
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"Sensory" neurons go which direction? "Motor" neurons go which direction?
Sensory: receptors to CNS.
- Motor: From CNS to the rest of the body. Sends motor information to effectors.
- *All muscle types and glands.
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What are the two branches of the Autonomic NS?
What is each one known as?
1) Parasympathetic NS (PSNS): "rest or digest" activities that occur when the body's at rest.
2) Sympathetic NS: "fight or flight" response; controls most of body's internal organs.
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What are the TWO parts of the MOTOR system (PNS, efferent)?
Which is Voluntary or Involuntary motor?
1) Somatic (body) Motor: "Voluntary" innervates skeletal muscles.
2) Autonomic (visceral) Motor: "Involuntary" innervates muscles (cardiac, smooth, glands)
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What types of cells are in the Nervous System?
(3)
What are their roles?
1) Neurons: functional unit of the NS, thought processes.
2) Interneurons: communication with neurons.
3) Glial cells: "support" cells..
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What is "neuroplasticity?"
The ability of neurons to "change."
*Not the same as Mitosis (cell division).
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What are the 3 structural classifications of Neurons and there important characteristics?
(i.e.dendrites, axon, cell body, etc.)
*What is the significance of neurons during infancy?
What do the "multipoloar neurons" turn on?
- 1) UNIPOLAR (pseudo-unipolar): From skin to CNS.
- -Dendrites pick up information from the skin.
- -Peripheral (outer) process (dendirtes to cell body) receives info.
- -Central process (axon): sends to CNS.
- 2) BIPOLAR: association w/ 5 senses.
- Dendrites: carries impulses "toward" cell body.
- Axon: "away" from cell body.
- Cell body (located in the middle): determines significance of info.
- 3) MULTIPOLAR (most celss): interneurons/motor neurons.
- -Turn on glands.
- -Collectively, "dendrites" (many)
- *As an infant, you have many neurons then undergo "remodeling" to lose adequate neurons (a reduction), so we function normally.
- *Brain cells DO NOT regenerate.
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What are the functional classifications of (afferent/efferent) neurons? (define)
*Afferent = "ascend up" (AA)
*Efferent" (motor) CNS --> rest of body
- Receptors for:
- Touch
- Pressure
- Pain
- = From the SKIN.
- Vision
- Hearing
- Balance
- Taste/Smells
*Central process carries sensation to CNS.
- Efferent Neuron: (cell bodies in CNS) Axons carry impulses to muscles and glands.
- -Skeletal, cardian, smooth, and glands (aka "effectors")
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What are the functional classifications of "interneurons" (inter = between)?
(association neurons)
Are they multipolar?
Receives impulses from sensory neurons and "decides" what to do with it.
Facilitates communication between sensory & motor neurons.
*Multipolar
*Joined together (afferent and efferent)
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What is a monosynaptic reflex?
Give an example.
A single chemical aynapse (versus a polysynaptic).
Patellar tendon reflex is an example (knee jerk reflex).
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Glial cells are also known as? Which systems are they usually found?
Are there more glial cells than neurons?
AKA: "neuroglia"
Found in CNS/PNS
*More glial cells than neurons, YES.
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Are glial cells capable of cell division?
Yes, they can undergo mitosis.
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What are the 4 types of glial cells in the CNS?
(2 types exist in the PNS)
1) Astrocytes (stars of the cells/multipolar)
2) Ependymal cells
3) Microglia
4) Oliogodendrocytes
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Of the 4 CNS types of glial cells, which is the MOST abundant?
Astrocytes.
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Astrocytes (1st type of glial cell), what are their functions? (4)
What is the bloodborne barrier?
1) Regulates tissue fluid composition.
2) Fill space from dead neurons.
3) Provide structural network
4) Assist w/ neuronal connections (initiate thought)***
BBorne barrier: controls substances entering the nervous tissue in the brain from the bloodstream.
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Ependymal Cell (2nd type of glial cell)
What is the importance of cerebral spinal fluid on the exterior of the brain? (comes out through holes of brain by stem)
The importance is "bouyancy" (maintains shape through bouyancy through cerebral spinal fluid).
- 1) Line the ventricles of the brain.
- 2) Helps form choroid plexus for production of CSF (cerebral spinal fluid)
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What is Cerebral Spinal Fluid?
What space does it occupy?
What is the importance of cerebral spinal fluid on the exterior of the brain? (comes out through holes of brain by stem)
Help produce fluid within cavities of the CNS.
*Occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord. In essence, the brain "floats" in it.
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What are Microglial Cells?
(3rd type of glial cell)
They're small cells.
"Clean Up" through phagocytosis
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Of the 4 CNS glial cell types, which contains the smallest amount (%)?
Microglial cells.
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What are the Oligodendrocytes?
(4th type of glial cells)
Provides myelination around more than one axon.
(Like tape around a pencil).
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Again, what are the 4 types of glial cells?
1) Astrocytes
2) Ependymal
3) Microglial cells
4) Oligondendrocytes (myelination)
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What is a Ganglion?
What do they regulate?
Group of cell bodies.
Located around bodies of Posterior Root Ganglion (PRG)
Regulate nutrients/wastes.
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What is the function of a Satellite cell?
(1st of 2nd type of glial cell in the PNS)
Regulate nutrients/waste.
Located around cell bodies of PRG (Post Root Ganglion).
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Schwann cell; define.
aka?
(2nd cell in the PNS)
They're areas between the nodes of ranvier.
AKA: neurolemmocytes.
They wrap around axons in PNS to provide myelin to a portion of the axon.
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Axon terminal is aka?
Telodendria.
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Why is Myelin needed?
Reversal polarity must happen down the entire axon. The axon is negative in the inside and positive on the outside.
Therefore, you need myelin to speed this process, "jumping" of node of ranvier to node of ranivier (Saltatory Conduction).
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What is a synapse?
Point of contact between one cell to another (dendrites/soma).
Located between Telodendria (axon terminal) and the effector or another neuron.
- (Post-synaptic nueron, cell body, axon, a.terminal/synapse/post-synaptic neuron)
- O---------------< Synapse O----------------<
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What is the purpose of Ca+2 influx into the terminal and the steps of a typical chemical synapse?
Signals chemcial messengers at the end of the signal.
Causes the NTs to migrate toward the cell membrane.
- 1) Arrival of nerve impulse @ knob induces Ca+2 influx.
- 2) Vesicles fuse to membrane.
- 3) NT released into synaptic cleft.
- 4) NT diffuses across cleft to plasma membrane of post-synaptic cell.
- 2) NT binds w/ post-synaptic receptors.
- 3) Na+ ions rush into the post-synaptic cell affecting charge across membrane.
- 4) Neuron's axon undergoes depolarization.
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Nerve Axon Structure.
Locating the Epi, Peri, and Endoneurion.
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Successful nerve regeneration after damage depends on what 3 factors?
1) Amount of damage.
2) Secretion of nerve growth factor by neurolemmocytes (Schwann cells; form tube of insulation for axons).
3) Distance between damaged axons & effector.
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Why doesn't regeration occur in the CNS?
List 3 reasons.
1) Oligondendrocytes do not release growth factor.
2) Large # of axons in the CNS interfere w/ regeneration.
3) Astrocytes may obstruct axon growth.
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