NERVOUS SYSTEM Flashcards

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1
Q

Neurons

A

-functional units of nervous system
-functions to transmit information

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2
Q

Cell body

A

-houses the nucleus and cytoplasm
-neuron control center
-receives graded potentials

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3
Q

Axon

A

-propagation of the action potential

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4
Q

Dendrite

A

-receives information
-transmits graded potentials toward the cell body

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5
Q

Synaptic knob

A

-location where a neuron is connected to another neuron or effector

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6
Q

Axon hillock

A

-receives graded potentials
-initiates the action potential

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7
Q

Synapse

A

-specialized junction where neurons connect and transmit signals to each other
-a single neuron can contain thousands of synapses

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8
Q

Synaptic cleft

A

-small gap between neurons where communication takes place
-separates the presynaptic ending and the postsynaptic cell

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9
Q

Myelin

A

-insulating layer of fatty substances and protein that surrounds nerves
-enables electrical impulses t travel quickly
functions include:
-speeds up communication in the brain
-water balance
-cognitive function: helps neurons respond to signals involved in memory formation
and other cognitive functions

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10
Q

Neurofibril node

A

-gaps in myeline sheaths

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11
Q

Multipolar neurons

A

-multiple processes from cell body
-many dendrites and 1 axon

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12
Q

Bipolar neurons

A

-1 dendrite and I axon from cell body

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13
Q

Unipolar neurons

A

-single short process from cell body

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14
Q

Sensory (afferent) neurons

A

-convey action potentials (APs) into the CNS through cranial or spinal nerves
-most are unipolar

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15
Q

Motor (efferent) neurons

A

-convey APs away from the CNS to effectors in the periphery
-most are multipolar

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16
Q

Interneurons

A

-located within the CNS between sensory and motor neurons

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17
Q

Resting membrane potential

A

-difference in charge inside and outside of the cell
-voltage measured across the plasma membrane
-set up by leak channels
-Na/k pump
-voltage difference from inside and outside the cell at rest due to the RMP is -70mV

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18
Q

Electrochemical gradient

A

-when ion channels are open, they allow specific ions to move across the plasma membrane
-movement of ions depends on both the chemical gradient (concentration gradient) and the electrical gradient (electro chemical gradient)
-ions move form high concentration to low concentration=> chemical
-cations (+) move to negatively charged areas and anions (-) move to positively charged areas=> electrical

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19
Q

Ligand-gated ion channels

A

-open when a neurotransmitter latches onto its receptor

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20
Q

Mechanically gated ion channels

A

-open in response to mechanical deformation

21
Q

Voltage-gated ion channels

A

-open in response to change in the transmembrane electrical potential

22
Q

Graded potentials

A

-communication
-established on the receptive segment by opening chemically gated channels
-spreads for a short distance
-can vary in magnitude and direction
-can be added up resulting in a larger or smaller graded potential (summation)
-dendrites and cell body is the only places it can be generated
-can change the membrane potential

23
Q

Depolarizing graded potentials

A

-membrane potential gets more positive
-also called post-synaptic potential (EPSP)

24
Q

Hyper-polarization graded potential

A

-when the membrane potential gets more negative
-farther away from the threshold value
-also called inhibitory post-synaptic potentials (IPSP)

25
Q

Action potentials

A

-communication
-electrical signal travels the length of the axon
-always the same (all or non)
-if a neuron receives a threshold stimulus, an AP is produces and spreads down the axon of the neuron
-graded potentials depolarize the neuron from -70mV to threshold (-55mV)

26
Q

Depolarizing phase

A

-Na+ channels open
-cell becomes more positive
-graded potentials above the threshold causes a series of events:
-voltage gated Na+ channels open
-Na+ rushes into the cell
-inside of cell more positive
-membrane potential reaches
+30 mV
-depolarization

27
Q

Repolarizing phase

A

-K+ channels open
-cell returns to negative RMP
-Na+ channels close
-K+ voltage gated channels open
-K+ moves out of the cell
-cell returns to a more negative
state until RMP of -70mV is restored
-repolarization

28
Q

After-hyperpolarization phase

A

-K+ channels remain open
-causes hyperpolarization
-membrane potential becomes even
more negative
- -90mV
-once K+ channels close the membrane potential returns to resting levels

29
Q

Absolute refractory period

A

-period during which a cell cannot generate another AP
-occurs due to Na+ channels
inactivation
-must first return to resting
state

30
Q

Relative refractory period

A

-period where a second action potential can be initiated but requires larger stimulus
-due to K+ channels being open and
causing hyperpolarization

31
Q

Neurotransmitter

A

-CNS and PNS both have excitatory and inhibitory neurotransmitters
-acetylcholine (Ach)
-common neurotransmitter
-released by the PNS and CNS neurons
-ACH is excitatory at the NMJ but inhibitory at other synapses
-many amino acids can act as neurotransmitters
-glutamate
-released by nearly all excitatory
neurons in the brain
-GABA
-inhibitory transmitter for 1/3 of all
brain synapses
Which can cause:
-Excitatory postsynaptic potential (EPSP)
-Inhibitory postsynaptic potential (IPSP)

32
Q

Excitatory postsynaptic potential (EPSP)

A

-membrane potential becomes more positive

33
Q

Inhibitory postsynaptic potential (IPSP)

A

-when membrane potential gets more negative
-farther away from the threshold value

34
Q

Neuroglia

A

-support and maintain neuronal function
-greatly outnumber the neurons
-non-excitable cells

35
Q

Astrocytes

A

-helps form BBB
-maintain the chemical environment
-Ca2+ and K+

36
Q

Oligodendrocytes

A

-produce myelin in the CNS

37
Q

Microglia

A

-participate in phagocytosis

38
Q

Ependymal cells

A

-form and circulates the CSF

39
Q

Satellite cells

A

-support cells in the PNS
-regulates ions and nutrients

40
Q

Neurolemmocytes (Schwann cells)

A

-produce myelin in the PNS

41
Q

Central Nervous system

A

-CNS consists of the brain and spinal cord

42
Q

Peripheral nervous system

A

-PNS consists of all nervous tissue outside the CNS

43
Q

Somatic NS

A

-SNS
-consists of:
-somatic sensory (afferent) neurons
-stimuli from special senses,
skin and proprioceptors
-somatic motor (efferent) neurons
-transmit signal to skeletal
muscles
-voluntary
-effectors are the skeletal muscles
-interneurons

44
Q

Autonomic NS

A

-ANS
-consists of:
-sensory neurons
-convey information from
receptors in visceral orans to
CNS
-motor neurons under involuntary
control
-transmit signals to smooth and
cardiac muscles and glands
-consists of two branches- sympathetic and parasympathetic

45
Q

Enteric NS

A

-ENS
-the operation of the “brain to the gut”
-controls the function of the GI tract
-can operate independently from the CNS

46
Q

Be able to draw a neuron and label all parts

A
47
Q

Be able to draw a synapse and label all components

A
48
Q

Be able to draw the graph of membrane potential over time for an action potential, and label the phases

A