Term
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Definition
| Long, thin cell body (soma). On one end, cell body and nucleus. That end is covered with dendrites (branching structures). The axon (long arm in middle) can be microscopic or up to meters long. At end of axon, a few branches that end in axon terminals. These attach to neuromuscular juncture. |
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Term
| Myelinated vs unmyelinated nerves; structure of Schwann cell in each case. |
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Definition
Myelinated: surrounded by multiple Schwann cells, which are 80% myelin.
Unmyelinated: surrounded by a single Schwann cell. |
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Term
What are the relative concentrations of anions, K+, Na+, and Cl- inside and outside neurons at rest.
How do they contribute to a resting action potential? |
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Definition
Inside Axons: Large number of negatively charged anions (mostly large anions-, K+, a little Na+, Cl-
Outside axons: Lots of Na+, Cl-, a little K+, almost no large anions-
At rest, a slight negative charge inside the axon relative to the outside. Measures about -70 mV, outside is 0 mV. |
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Term
| Voltage-gated and chemical-gated ion channels |
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Definition
Voltage-gated ion channels: open and close based on voltage
Chemical-gated ion channels: open and close based on specific chemicals. |
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Term
| sequence of events and what happens during propagation of an action potential |
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Definition
Axon hillock: where action potential is initially propagated.
Along the axon membrane: voltage gated channels: open or close based on voltage.
At rest: -70 mV, membrane and protein channels that allow Na+ to rush into the cell are closed.
If resting potential is brought close to 0 or positive, Na+ channels open and Na+ (highly concentrated outside) rushes in. The K+ rushes out because the Na+ is freeing it chargewise. Very localized and very temporary.
Action potential runs down axon in waves. Goes down axon in wave of depolarization. |
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Term
| propagation of action potentials in unmyelinated and myelinated neurons. |
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Definition
saltatory (jumping)conduction in an unmyelinated nerve: up to 2 m/s
Saltatory conduction in a myelinated nerve: ~100 m/s |
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Term
| Advantages of myelinated neurons compared to unmyelinated neurons. |
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Definition
| Advantages: much more efficient in terms of time and size of the neurons |
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Term
| transmission of action potentials between cells. |
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Definition
Invertebrates/unmyelinated cells: action potential must go down full length of axons.
Vertebrate/Myelinated: have nodes of Ranvier. Open areas between myelin on mylenated axon. AP is propagated from node to node. Looks like dancing from node to node (saltatory). In myelinated neuron, very, very fast. |
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Term
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Definition
| connects to sensory receptors |
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Term
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Definition
| connect to effector organs (muscles, glands, etc) |
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Term
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Definition
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Term
| central nervous system (CNS) |
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Definition
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Term
| peripheral nervous system |
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Definition
| nervous system outside of CNS |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| to voluntary or skeletal muscle |
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Term
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Definition
| to smooth muscle. No conscious control |
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Term
| structure of central nervous system and spinal cord in humans. |
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Definition
innermost to outermost
grey matter is surrounded by white matter. Spinal canal in middle creates a bowtie shape of grey matter.
All of these make up spinal cord.
3 layers of meninges (tough protective tissue). Spinal trunk nerves radiate from spine, connecting with sympathetic ganglia. |
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Term
| structure of a reflex arc |
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Definition
Knee example:
Knock on patella tendon, pulls down on it. Stretch receptors in quadriceps is part of sensory neuron. Activates, goes to the dorsal root ganglion, to the monosynaptic synapse. Part of motor neuron, connects to muscle (effector), which jerks. |
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Term
| functions and structure of the autonomic sympathetic nervous system |
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Definition
Readies for action. Controls reflexes, including fight-or-flight.
Sympathetic ganglion: (close to spinal cord)
Acetylcholine released from preganglionic neuron ending; norepinephrine released from postganglionic neuron ending
Effects: dilated pupils
stop saliva secretion
dilate bronchioles
Speed up heartbeat
secrete adrenaline
shuts down digestive and excretory systems |
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Term
| functions and structure of the parasympathetic nervous system |
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Definition
normal ('peaceful') activity.
Parasympathetic ganglion: close to effector organ: Acetylcholine is neurotransmitter released by both pre- and postganglionic neuron endings
Has ends in either brain or sacral spinal cord. Synapses close to the effector organ.
Effects:
Constricted pupils
secrete saliva
constrict bronchioles
slow down heartbeat
activates digestive and excretory systems |
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Term
| taste and functions of taste |
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Definition
Taste: sweet, salt, sour, bitter, umami
Taste papillae --> Taste buds --> taste receptors
Taste pores have microvilli that detect particular tastes. In salty: salt flows into bud. If enough, will release neurotransmitter into synapses. |
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Term
| structure and function of olfactory |
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Definition
| Olfactory epithelium in nose. Has cilia that grab scent molecules, relay them to receptor cells, then go on to olfactory bulb of brain. |
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Term
| structure and function of pacinian corpuscles |
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Definition
(touch receptors)
Pacinian corpuscle: picks up initial feeling, then drops off (in terms of action potential). Allows to adapt to wearing clothes, etc.
Among the most sensitive receptors we have.
adaptive receptors: designed to pick up and be very sensitive to changes in pressure. Once change stops, stops sending action potential |
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Term
| structure and function of lateral line receptors. |
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Definition
(in fish)
Openings in the scales (or areas where not completely covered). Lead to canal deeper in tissue. There is a cupula (sensory receptor) with hair cells and afferent axons. Anything that causes disturbance in water causes waves. Waves hit the lateral lines, gives it direction and strength of wave. |
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Term
| traits of action potentials |
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Definition
1. All or nothing
2. Information is relayed by frequency of action potentials. AP is not large, but there is a lot of them
3. Up to ~1000/sec.
4. 1-2 ms refractory period |
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Term
| How does multiple sclerosis affect neurons |
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Definition
| breaks down myelin sheath |
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Term
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Definition
| discrete groups of neuron cell bodies outside of the CNS |
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Term
| Steps in release of neurotransmitters. |
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Definition
1. Presynatic action potential arrives at synapse.
2. AP causes influx of Ca++. Open and closing of terminal opens and closed based on voltage.
3. Ca++ induces vesicular exocytosis and acetylcholine is released.
4. Acetylcholine binds to receptor, causing postsynaptic membrane excitation.
5. Postsynaptic excitatory potential
6. Postsynaptic AP if enough EP are rcvd
7. Acetylcholinesterase breaks AC into acetate and cholines.
8. Choline is reabsorbed into the presynaptic terminal
9. Acetylcholine, resynthesized from acetate and choline, is stored in vesicles. |
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Term
| How do nerve gas and some insecticides effect the nervous system? |
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Definition
acetylcholinesterase inhibitors. Acetylcholine can't be break down and the channels stay open, so you get uncontrolled APs. Twitchy death.
Cure: acetylcholinesterase injection. |
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