Nervous System Exam 1 Flashcards

(91 cards)

1
Q

What are the two divisions of the nervous system and what are they composed of

A

Central Nervous System: brain and spinal cord
Peripheral Nervous System: nerves that connect the brain or spinal cord with the body’s muscles, glands, sense organs, tissues

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2
Q

What are the two types of principle cell types of the nervous system

A

Neurons and Glial Cells

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3
Q

What are neurons

A

-Functional units of the nervous system
-Excitable cells that transmit electrical signals from one cell to another
-Do NOT DIVIDE

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4
Q

Parts of Neurons:
Dendrites
Cell Body
Node of Ranvier
Schwann Cells

A

Dendrites: receive signals from other cells
Cell Body: organizes and keeps cell functional
Node of Ranvier: Allow diffusion of ions
Schwann Cells: produces the myelin sheath

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5
Q

Parts of Neurons:
Axon
Axon Hillock
Axon Terminal
Myelin Sheath

A

Axon: transfers signals to other cells and organs
Axon Hillock: generates impulse in the neuron
Axon Terminal: forms junctions with other cells
Myelin Sheath: increases the speed of the signal

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6
Q

Axonal Transport:

A

cellular process responsible for movement components to and from the soma

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7
Q

Anterograde transport vs Retrograde transport

A

Anterograde: from soma to axon terminal
Retrograde: from axon terminal to soma

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8
Q

Retrograde Transport

A

Fast transport:
-moves membrane vesicles and cellular material to be degraded
-moves substances that enter the neuron
-mediated by dynein

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9
Q

Anterograde Transport

A

Slow axonal transport
-moves neurofilaments and microtubule proteins
Fast axonal transport
-moves organelles with membranes along the surface of microtubules
-mediated by kinesin

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10
Q

Neurons are classified based on structure and function define each

A

Structural classification: according to the number of processes extending the body
Functional classification: based on the direction of the nerve impulse with respect to the CNS

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11
Q

Multipolar Neurons

A

several short dendrites and a single long axon (neuron in the brain and in the spinal cord)

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12
Q

Bipolar Neurons

A

Single axon and one main dendrites

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13
Q

Unipolar Neurons

A

have cell body to one side and a single axon divided into branches (sensory neurons in skin, muscles, joints)

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14
Q

Afferent Neurons or Sensory

A

From receptors on organs to the CNS (brain)
Unipolar

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15
Q

Interneurons

A

connect sensory neurons and muscles
located in CNS
multipolar

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16
Q

Efferent Neurons or Motor

A

Info from CNS to periphery organs
effectors are muscles and glands
multipolar

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17
Q

How do glial cells support neurons (neuroglia)

A

-form myelin sheath around neuronal axons
-making the cerebrospinal fluid
-participating in phagocytosis (eating of things)
-Blood-Brain Barrier

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18
Q

Types of glia cells in PNS and CNS

A

PNS: satellite cells, schwann cells
CNS: oligodendrocytes, astrocytes, microglia, ependymal cells

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19
Q

Satellite Cells in PNS

A

-surround neuron cell bodies in ganglia
-regulate O2 and CO2 nutrient, and neurotransmitter levels around neurons in ganglia
(surround the body of neurons and get rid of things)

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20
Q

Schwann Cells in PNS

A

-surrounds axons ONE at a time
-responsible for myelination of peripheral axons
-participate in the repair process after injury

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21
Q

Oligodendrocytes in CNS

A

-myelinate axons
-structural framework
- surrounds many axons at once
- has small cell bodies

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22
Q

Astrocytes in CNS

A

-BBB
-structural support
-regulate ion, nutrient, gas concentration
-absorb and recycle neurotransmitters
-form scar tissue after injury

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23
Q

Microglia Cells in CNS

A

remove cell debris, waste, and pathogens by phagocytosis

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24
Q

Ependymal Cells in CNS

A

-Line ventricles (brain) and the central canal (spine)
-Assist in producing, circulating, and monitoring of CSF

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25
BBB
-semi-permeable -composed of blood vessels and glial cells, tight junctions -astrocytes processes cover capillaries -joins cell walls of vessels -prevent diffusion of material between endothelial cells
26
What is myelination and what is it composed of
It is the process of forming a myelin sheath which increases nerve impulse speed 80% lipids, 20% proteins and water
27
How is myelination formed in CNS and PNS
CNS - oligodendrocytes PNS - Schwann Cells
28
Myelination in CNS axons
cell bodies of oligodendrocytes do not surround the axons no neurolemma formed involved in forming myelin sheath synthesis of large amounts of plasma membrane
29
Unmyelinated Axons in PNS
bundle of axons that are wrapped very thinly by Schwann cells
30
Node of Ranvier
Gaps in myelin sheath facilitates in rapid conduction of nerve impulses electrical impulses hop node to node important in signal transduction
31
Electrical signals in neurons depends on what two things
depends on the variety of ion channels existence of resting membrane potential
32
Types of ion channels
Leaky - random open and close Gated - ligand, mechanically, voltage
33
Where are leaky channels in neurons
dendrites can be in cell bodies and axons
34
Where are ligand-gated channels located
in dendrites of sensory neurons in dendrites and cell bodies of interneurons and motor neurons (at synapse)
35
Where are mechanically gated channels located
auditory receptors, internal organs, skin -vibration, touch, pressure
36
Where are voltage-gated channels located
mainly neuronal axon unmyelinated axons, Node of Ranvier (myelinated), axon hillock
37
What are nerve impulses
electrical signals by which neurons talk to one another and other cells of the body
38
What are nerve impulses also referred to as
action potential: brief reversal of the membrane potential
39
Depolarization Repolarization Hyperpolarization
Depolarization: potential moves from RMP to less negative or positive values Repolarization: potential returns to the RMP (negative) Hyperpolarization: potential moving away from the RMP in a more negative direction
40
When there is RMP how is it stimulated
No stimulation, no nerve imoulse
41
What two things does the magnitude of RMP depend on
Differences in specific ion concentrations inside and outside the cell Differences in membrane permeability to the different ions --> number of open channels
42
What two things does the Goldman Field equation consider
concentration of ion inside and outside the cell permeability
43
What does the Nernst Equation predict
equilibrium potential
44
What does action potential depend on
-Distribution of ions -Changes in membrane permeability to ions -It is short-lasting
45
What happens in each of the 6 stages of resting membrane potential and action potential
1: Resting membrane potential 2: Depolarization makes less negative Na+ leaks in 3: All channels of Na+ are open (-) to (+) 4: Na+ close and K+ open (+) to (-) 5: Not all K+ close at once, hyperpolarization 6: action potential, goes back to the starting point
46
Does the action potential change with different amounts of stimulus within a cell
no, the amplitude is always the same
47
How are refractory periods a safety mechanisms
system can only open with enough closed pumps
48
What is an absolute refractory period
Channels are in the open and inactive state which can not create a action potential because more channels can not open
49
What is a relative refractory period
Pumps are in the closed and inactive state which with enough stimulus can open pumps
50
What is continuous propagation
non-myelinated axons ions flow to adjacent segments short distance slow
51
What is saltatory propagation
myelinated axons action potentials in nodes of ranvier action potentials jump from node to node faster
52
What is synaptic transmission
a neuron communicates with a target cell across a synapse
53
What are electrical synapses
allows ions to move through one neuron to another through gap junctions
54
What are chemical synapses (steps of Ca2+)
-Needs Ca to depolarize (pre-synaptic) -increase of Ca vesicles move -fuse vesicles to the membrane and makes pore -neurotransmitters leave in synapse and move to other cell to produce an effect (post-synaptic) -creates an action potential
55
What are the three types of chemical synapses
Axodendritic: Axon and dendrite Axosomatic: axon and somatic Axoaxonic: axon and axon
56
Nerve impulse vs synaptic transmission
Nerve Impulse: production of action potential, change in membrane potential, flow of ions Synaptic transmission: release neurotransmitters at the synapse
57
Neurotransmitters are what kind of messengers
chemical messengers
58
Difference between excitatory and inhibitory transmitters
EPSP: promotes an action potential in receiving neuron (Ca+2) IPSP: prevents an action potential (Cl- or K+)
59
What are the three types of removal of neurotransmitters (after effects)
-Reuptake: NT is transported back to presynaptic terminal, transport into nearby glial cells to get degraded -Enzymatic Transformation: at the synaptic cleft (acetylcholine), inside the cell -Diffusion: away from active site *All are metabolized to get rid of, or they can be reused
60
Ionotropic: Receptor Speed Function Effect Example
Ligand-gated Fast The functional domain of extracellular NT binding site and membrane-spanning domain forms ion channels (+) Effect: depolarization or hyper-polarization Ex: Acetylcholine
61
How does depolarization and hyper-polarization relate to an excitatory and inhibitory transmitter
depolarization: excite (ESPS) hyper-polarization: inhibit (ISPS)
62
Metabolic Receptor
7 times through the membrane slow GCPRs specific amino acids *ion channel not apart of the receptor
63
How does a GCPR work Directly
1. Ligand binds to receptor 2. Exchange GDP for GTP on alpha 3. Dissociation between alpha and beta/gamma 4. Subunits bind to effectors (can inhibit or activate) - alpha to E 5. Hydrolysis of GTP to dissociate subunits from effectors 6. Formation of inactive state (subunits bind to GCPR)
64
How does GCPR work indirectly
NT binds to receptor G protein binds to an effector (adenylyl cyclase) uses cAMP as a second messenger protein kinase activate channel
65
In GCPRs what is the state when there is positive vs negative charged
positive: active (positive charges into the cell) negative: inactive
66
Three postsynaptic potentials
Graded: small changes in membrane potential (small stimulus) Magnitude: depends on stimulus (number of channels) Summation: channels added together (small openings close enough to produce AP)
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CNS functions
Voluntary movement: muscle contraction Involuntary movement: breathing Process sensory information: pain Source of thoughts
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What are the three layers of the meninges
Dura Mater (outermost) Arachnoid Mater (middle) * Pia Mater (inner) * *CSF liquid between the two (continually made and into blood stream)
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Ventricles
cavities with CSF to cushion brain and spine
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What is the space between the Pia Mater and Arachnoid Mater called
subarachnoid
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What is the importance of the CSF
provide nutrients maintain electrolyte balance for neurons clears waste regulate intracranial pressures
72
What are in the external and internal portions of the brain
External: Cerebrum Brainstem - midbrain, pons, medulla oblongata Cerebellum Internal: Diencephalon - thalamus, hypothalamus
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Thalamus
The upper part of the diencephalon Central Relay Station: motor and sensory signals to cortex Regulates sleep and focus Damage can lead to coma
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Hypothalamus
Below the thalamus Maintain homeostasis (heart rate, temp, thirst) influences the endocrine system by pituitary gland
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Pituitary Gland
bottom of hypothalamus "master gland" controls release of hormones that maintain homeostasis
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Pineal Gland
roof of diencephalon produces melatonin (sleep regulator)
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Brain Stem 3 major parts
Midbrain: visual and auditory reflex Pons: part of respiratory center Medulla Oblongata: cardiac center (heart rate), vasomotor center (blood pressure), respiratory center *Site of cranial nerves (PNS)
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Spinal Cord (CNS)
Long, thin, tubular bundle of nervous tissue Functions: -axons take sensory information into the brain -motor info: neurons from brain & axon synapse to different muscles Coordinates reflex actions w/out brain
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Functions: Cervical Thoracic Lumbar Sacral Coccygeal
Cervical: innervate hands, arms Thoracic: innervate organs in upper chest and upper abs Lumbar: Innervate organs in lower abs, hips, legs Sacral: Innervate genitals and lower digestive track Coccygeal: Innervate skin
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What are PNS two main systems
Autonomic Nervous System: involuntary, regulates organs and tissues Somatic Nervous System: Voluntary, skeletal muscle
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PNS detects _______ and transmits information to the ___ and receive information from the ___
Stimuli, CNS, CNS
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What are the three divisions in the autonomic nervous system
Sympathetic: mobilizes body (fight or flight) Parasympathetic: conserves energy (rest and digest) Enteric: regulates GI track
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Most organs have duel intervention by sympathetic and parasympathetic systems. What are the two exceptions and which system are they located in
Blood vessels, sweat glands, Sympathetic (can't completely shut down)
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ANS has two neurons, what are they called
Preganglionic neuron from spinal cord and a postganglionic neuron
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Where are the two synapses in ANS
Between preganglionic and postganglionic Between postganglionic and effector (organ, tissue, gland)
86
ACh is released by preganglionic in both ANS systems. In the postganglionic which releases ACh and which system releases NE and E
Parasympathetic: acetylcholine Sympathetic: norepinephrine, epinephrine
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Length of synapses for sympathetic and parasympathetic and which receptor they use
sympathetic: short --> long, adrenergic parasympathetic: long --> short, cholinergic
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Fight or flight response sympathetic pathway functions (10)
Dilate Pupils* Inhibit Salvation Increase Heartbeat* Relax Airways (get air in)* Inhibit Stomach Activity* Release Glucose/ Inhibit Gallbladder Inhibit Intestines* Secrete E and NE Relax bladder* Genital contraction
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Two systems only have one neuron (preganglionic) what are they
Somatic system Adrenal System
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Somatic system
Preganglionic projects directly from CNS to skeletal muscle Motor neurons are myelinated NT is ACh (Na+ channel) Muscle Contraction and Tissues
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Adrenal system
Sympathetic System Preganglionic innervate chromaffin cells in medulla release ACh ACh bind to nicotinic receptors Releases E and NE get in blood vessels and go to organs aka hormones