Term
| The general functions of the Nervous System |
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Definition
- Communication/Homeostasis
1.Sensation
2. Integration
3. Reaction |
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Term
| The nervous system can be divided into 2 major parts: |
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Definition
CNS: Central Nervous System
PNS: Peripheral Nervous System |
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Term
| The major anatomical components of the CNS |
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Definition
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Term
| Major anatomical components of the PNS |
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Definition
Nerves: cranial nerves and ganglia
Ganglia: Sensory and Autonomic (a type of motor) |
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Term
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Definition
sensation from the outside
"soma"=body |
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Term
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Definition
sensation from inside, organs (ex: nausea)
"viscus"=organ |
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Term
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Definition
| motor to cardiac, sm muscle, and glands (ex: sweat glands) |
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Term
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Definition
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Term
| Functional unit of Nervous System |
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Definition
| neuron, so each neuron can do the basic functions of the nervous system |
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Term
| 3 basic properties of neurons |
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Definition
1. excitability
2. conductivity
3. secretion |
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Term
| (basic properties of neurons): 1. Excitability (def) |
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Definition
| respond to stimuli (chemical, electrical, mechanical) |
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Term
| (basic properties of neurons): 2. Conductivity |
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Definition
| quickly conduct/transmit electrical signals over long distances |
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Term
| (basic properties of neurons): 3. Secretion |
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Definition
| releases a NT to affect another cell |
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Term
| 3 basic classes of neurons--based on function |
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Definition
1. Sensory/afferent
2. Interneurons
3. Motor/Efferent |
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Term
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Definition
-Conduct signals from receptors to the CNS
- Cell bodies in PNS, axons in CNS |
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Term
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Definition
| only in CNS, cell bodies and axons in CNS |
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Term
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Definition
-conduct signals from CNS to effectors (muscles and glands)
- cell bodies in CNS, axons in PNS |
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Term
| Most cell bodies are in _____ (PNS or CNS?) |
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Definition
CNS
-interneurons
-motor (but some motor cell bodies of motor neurons can be in PNS) |
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Term
| Cell body/Soma contains ________ |
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Definition
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Term
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Definition
| bundles of axons that support the cell, help the cell maintain the correct shape |
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Term
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Definition
| massive accumulations of rough ER (which synthesize proteins) |
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Term
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Definition
-receive incoming signals
-where other cell's axon usually makes contact
- carries info to the cell body |
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Term
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Definition
-carries info away from cell body
- a single process that transmits an AP
- sends signal to a target |
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Term
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Definition
-highly sensitive to electrical changes of membrane
-first part to depol |
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Term
| Axon collaterals (def and purpose) |
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Definition
def: branch of axon
purpose: so there can be multiple targets for a single neuron |
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Term
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Definition
| where axons terminate on their target (target can be neurons/muscles/gland/etc) |
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Term
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Definition
| baseline charge of the neuronal membrane |
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Term
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Definition
| decrease in polarity across the membrane |
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Term
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Definition
-sodium channels close after a fixed amount of time
- Re-establish polarity of membrane at rest |
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Term
| Distinguish between ganglia and nuclei |
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Definition
ganglion: clusters of cell bodies with a common function in the PNS
nuclei: cell bodies with common func in CNS |
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Term
| Distinguish between tract and a nerve |
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Definition
tract: clusters of axons with a common func in the CNS
nerve: axons with a common func in the PNS |
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Term
| 3 diff types of neurons based on shapes: determined by how many dendrites |
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Definition
1. Multipolar
2. Bipolar
3. Unipolar |
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Term
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Definition
-many dendrites, single axon
- most common type
- many diff functions |
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Term
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Definition
- one dendrite, one axon
*rare- only in the special senses (sight, hearing, etc, so some locations would be in retina, cochlea, etc) |
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Term
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Definition
-there are lots of these
- one process is both the dendrite and axon
- general sensory cells in dorsal root and cranial nerve ganglia
- in these, the cell body only really used to keep neuron alive
- aren't out in skin b/c they would be too vulnerable to damage out there |
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Term
| nerves out numbered __:__ by glial cells |
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Definition
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Term
| Four glial cell types found in the CNS |
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Definition
1. Astrocyte
2. Ependymal cell
3. Oligodendrocyte
4. Microglial cell |
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Term
| Astrocyte (functions-there are 3) |
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Definition
- "astro"=star
1. take up ions from ECF (via endocytosis)
2. surround blood vessels and form tunnels
3. form scar tissue when neurons are injured |
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Term
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Definition
- line the ventricles (which are fluid filled spaces in the brain)
- produce CSF (cerebro-spinal fluid) |
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Term
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Definition
- produce myelin in CNS
- myelinate axons in CNS |
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Term
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Definition
- equivalent to macrophages
- eat debris, clear it out so the astrocytes can come in and lay down scar tissue |
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Term
| Two types of glial cells found in the PNS |
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Definition
1. Satellite cells
2. Schwann cells |
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Term
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Definition
- encircle the cell bodies in the PNS and separate them from surrounding tissue
- found in ganglia
*nothing like this in the CNS b/c in the CNS is all nervous tissue |
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Term
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Definition
- myelinate axons in the PNS
- produce basement membrane
- associated with all axons in the PNS--surround all, but don't necessarily myelinate all |
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Term
| What determines whether or not an axon gets myelinated? |
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Definition
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Term
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Definition
| A lipid sheath around a nerve fiber, formed from closely spaced spiral layers of the plasma membrane of a Schwann cell or an Oligodendrocyte |
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Term
| How does myelination differ in the CNS and PNS? |
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Definition
- Each Oligodendrocyte helps myelinate multiple axons in the CNS
- multiple Schwann cells myelinate a single axon in the PNS |
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Term
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Definition
- gap between adjacent Schwann cells
- no myelin here
- only site in a myelinated axon capable of depol. |
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Term
| How does myelin speed up conduction process? |
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Definition
- a myelinated axon is functionally much shorter
- speeds up AP propagation
- unmyelinated: lots and lots of little segments of membrane, have to depol them all
- myelinated: can skip/jump from Node of Ranvier to Node of Ranvier |
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Term
| Diseases that cause demyelination |
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Definition
-ex: MS
-myelin gets thinner and shorter
- exposes parts of axons membrane that were covered with myelin: parts that aren't able to depol
- not only slower AP, but AP can't go at all! |
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Term
| How are unmyelinated fibers protected from their surroundings? |
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Definition
- have sunk under the surface of the Schwann cell
- a single Schwann cell surrounds many axons |
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Term
| How do unmyelinated axons conduct AP's? |
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Definition
-have ion channels and depol along entire length of the membrane
*slower |
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Term
| Neurons communicate with each other and with muscles and glands though _______. |
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Definition
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Term
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Definition
| -usually on dendrites of target cell, but can be any part of the target cell |
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Term
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Definition
| - axon terminates on dendrites of target cell |
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Term
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Definition
| - axon terminates on nerve cell body of target cell |
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Term
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Definition
- axon terminates on another axon
* usually inhibatory |
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Term
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Definition
- AP reaches the Axon terminal
- calcium enters the axon terminal, which stimulates exocytosis of NT's |
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Term
| To excite, send ____. To inhibit, send ____ |
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Definition
excite: sodium ions to depol
inhibit: chloride to hyperpolarize |
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Term
| Two types of circuits: convergent and divergent. Explain and give an advantage. |
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Definition
1. Convergent: many neurons converge on a single neuron. Heightens sensitivity but decreases ability to localize
2. Divergent: one neuron branches/diverges. AMPLIFIES signal being snet through system, good if you're in a crisis |
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