Midterm 1: Neurons And The Brain Flashcards
1
Q
What is the neuron doctrine?
A
The nervous system consists of discrete individual cells
2
Q
What are neurons?
A
Neurons are specialized biological cells
3
Q
True or false: neurons are only present in the central nervous system and the peripheral nervous system
A
True
4
Q
What is the primary function of neurons?
A
Information processing and transmittal
5
Q
Name 3 qualities of the cell body
A
Contains genetic information, maintains the neuron’s structure, and provides energy to drive activities
6
Q
What are 2 functions of dendrites
A
Receives information from other neurons or from the environment and carries those signals to the cell body
7
Q
What are 4 functions of the axon hillock?
A
Information integration, controls the initiation of electrical impulses based on the inputs from other neurons or the environment, serves as a junction between the cell body and an axon, “trigger zone”, it is the start point of the nerve impulse
8
Q
What is the function of the axon
A
Input conduction; where electrical impulses (means of communication) from the neuron travel away to be received by other neurons
9
Q
What are 3 functions of the axon terminal?
A
Output zone; change in electrical impulses/action potentials within a neuron into chemical messages in the form of neurotransmitters
Neurotransmitters are released from terminal branches into synapses to relay messages to other neurons or types of cells like muscle cells
10
Q
What is a synapse?
A
Connecting neurons
Allows a neuron to pass an electrical/chemical signal to another neuron or a target effector cell
11
Q
What are 3 qualities of the myelin sheath?
A
Allows electrical impulses to transmit quickly and efficiently along nerve cells
Acts as insulation
Preserves the strength of the electrical signals as they travel
12
Q
What are oligodendrocytes?
A
Generates and maintains the myelin sheath around the axon
Allows fast saltatory conduction of action potentials
Provides motor neurons with metabolic potentials
13
Q
What are the nodes of Ranvier?
A
Allow for ions to diffuse out of the neuron
Propagates electrical impulses down the axon
14
Q
What are neural networks and 4 qualities of them
A
Computing systems that are modeled after the human brain
Occur in myelinated axons
Fast
Self-regenerating
Travel long distances
15
Q
What is saltatory conduction
A
Action potential jumps from one node of Ranvier to the next
16
Q
What does the cell membrane (lipid bilayer) do
A
Prevents flow of ions, proteins, and other water-soluble molecules
Lends myelin
17
Q
What is the difference in electrical potential across the membrane (3 points)
A
Results from difference in charge on each side of the membrane due to excess charged ions on one side
More negative ions inside of neurons
More positive ions outside of neurons
18
Q
What is the resting membrane potential?
A
- 70 millivolts
19
Q
What are 4 qualities of ion channels
A
Na+,K+,Ca2+,Cl-
Passive transport
Selective permeability
Can be gated
20
Q
What are 3 qualities of ion pumps
A
Na+/K+,Ca2+
Active transport
Require energy as ATP
21
Q
What are the two forces acting on non gated potassium ion channels
A
Electrical gradient attract potassium into the cell
Concentration gradient attract potassium outside of the cell
22
Q
What are two forces acting on the non gated sodium channel
A
Electrical gradient attract sodium into the cell
Concentration gradient attract sodium out of the cell
23
Q
What is the ratio between sodium and potassium
A
3 sodium out
2 potassium in
24
Q
What is the difference in electrical potential between inside and outside of membrane and what is the goal
A
Energy source
Goal is to reach equilibrium
25
How are neurotransmitters cleared from the synaptic cleft (3 points)
Active reuptake
Diffusion
Enzyme degradation
26
What triggers vesicles to release neurotransmitters in the synaptic cleft
Action potential
27
What is the term for passing the signal from one cell to the next via chemical signalling
Synaptic transmission
28
What binds to receptors on postsynaptic cells and what results from it
Neurotransmitters
Causes ion channels to open on postsynaptic cell (1-3 milliseconds)
29
What are 7 CNS neurotransmitters
Glutamate (primary excitatory neurotransmitter)
GABA (primary inhibitory neurotransmitter)
Acetylcholine
Dopamine
Serotonin
Norepinephrine
Histamine
30
What are gap junctions
Direct electrical and chemical conduction
Law plasticity
No amplification
Fast process
31
What are two classes of postsynaptic receptors
Ionotropic
Metabotropic
32
3 qualities of ionotropic receptors
Ligand-gated ion channels
Brief, strong and fast response
Che neurotransmitter can have multiple types of receptors
33
2 qualities of metabotropic receptors
Uses a series of processes to trigger change in ion flow
Slower, sustained response
34
Which PSP depolarize the cell
Excitatory postsynaptic potential (epsp)
35
Which PSP hyperpolarizes the cell
Inhibitory postsynaptic potential (ipsp)
36
4 qualities of electronic conduction
Passive
Fast
Exponentially attenuating
Travel short distances
37
How do PSPs travel from the dendrites to the axon hillock
Electronic conduction
38
When do action potentials fire?
If the sum exceeds a threshold potential
39
What kind of summation involve PSPs from different synapses
Spatial summation
40
What kind of summation involves PSPs from the same synapse
Temporal summation
41
Why do self-regenerating propagation travel in only one direction?
Na+ ion channels need to reset during absolute refractory period
42
What nervous system(s) are neurons present in?
Central nervous system (CNS)Peripheral Nervous System (PNS)
43
What is the primary function of a neuron?
Information processing and transmittal
Receive information via dendritesIntegrate information via the axon hillockConduct information along axonOutput information via axon terminal and synapse
44
What are the major components of a neuron?
DendritesAxon hillockAxonSynapse
45
What is the function of the axon hillock?
Information processing
46
What is the major function of an axon?
Input conduction
47
What is the primary function of the axon terminal?
Terminal butons (output zone)
48
What is the difference in electrical potential across membranes?
More positive ions outside of neuronsMore negative ions inside of neurons
49
What is the resting membrane potential? (Numeric value)
-70 millivolts
50
Describe ion channels? (4 points)
Na+, K+, Ca2+, Cl-Passive transportSelective permeabilityCan be gated
51
Describe ion pumps? (3 points)
Na+/K+, Ca2+Active transportRequire energy (ATP)
52
Describe K+ ions in non gated ion channels (4 points)
High concentration of K+ inside the cellLow concentration of K+ outside the cellTwo forces acting on K+ (Electrical gradient attract K+ into cell. Concentration gradient attract K+ outside of cell. Nernst equation is used to calculate equilibrium of each ion.)
53
Describe Na+ in non gated ion channels (2 points)
High concentration on Na+ inside and outside the cellTwo forces acting on Na+ (Electrical gradient attract Na+ into cell. Concentration gradient attract Na+ outside of cell.)
54
How many Na+ and K+ enter/exit the cell while maintaining resting potential?
Pushes out 3 Na+ out of cellK+ into cellResults in greater Na+ outside and greater K+ inside the cell (higher resting potential)
55
Define energy source
Difference in electrical potential between inside and outside of membrane
56
What does resting membrane potential involve? (Regarding ion flow)
Involves passive and active ion flow that balance out ionic charge
57
What are the synaptic vesicles? (3 types)
SynapseExocytosisEndocytosis
58
What is synaptic transmission?
Passing signal from one cell to the next via chemical signalling (neurotransmitters)1-3 milliseconds
59
What do action potential do in synaptic transmission?
Triggers vesicles to release neurotransmitters in synaptic cleft
60
What do neurotransmitters do in synaptic transmission?
Bind to receptors on post-synaptic cellCause ion channels to open on post-synaptic cell
61
Describe gap junctions AKA electrical synapse (4 points)
Direct electrical and chemical conductionFastLow plasticityNo amplification
62
How are neurotransmitters cleared from the synaptic cleft? (3 points)
Active reuptakeDiffusionEnzyme degradation
63
What are two major CNS neurotransmitters?
Glutamate (primary excitatory neurotransmitter)GABA (primary inhibitory neurotransmitter)
64
What are 4 characteristics of neurotransmitters?
Synthesized by and localized within presynaptic neurons, and stored in the terminal boutonReleased by presynaptic neurons when action potentials occurPostsynaptic neurons contain receptors specific to itA mechanism exists to remove it after release
65
What are two types of post-synaptic receptors?
IonotropicMetabotropic
66
Describe ionotropic receptors (3 points)
Ligand-gated ion channelsBrief, strong and fast responseOn neurotransmitter can have multiple types of receptors
67
Describe metabotropic receptors (2 points)
Uses series of processes to trigger change in ion flowSlower, sustained response
68
What 2 effects can neurotransmitters and their receptors have?
Excitatory effect: excitatory post-synaptic potential (EPSP)Inhibitory effect: inhibitory post-synaptic potential (IPSP)
69
What do EPSPs do to the cell?
Depolarizes cell
70
What do IPSPs do to the cell?
Hyperpolarizes cell
71
What 4 things do PSPs at the trigger zone depend on?
Strength of PSP at synapseTimecourse of PSP at synapseDistance from the synapseTime since the action potential
72
What are 2 types of summation?
Spatial summation: PSPs from different synapses (ie. different locations in space)sum together Temporal summation: PSPs from the same synapse (ie. different points in time) sum together
73
When do action potentials fire?
When the sum exceeds a threshold potential
74
Describe an action potential (4 points)
Rapid depolarization and repolarizationOccurs at threshold potential (~55mV)All or none (constant amplitude and constant timecourse)Refractory period (~5ms)
75
Define the voltage gate
When the membrane potential goes up to the threshold, the gate opens and starts allowing ions through
76
What happens at threshold in action potential?
Voltage-gated Na+ channels open, and positive Na+ ions flow into cellAs depolarization continues, even more voltage-gated Na+ channels open, increasing depolarization
77
Describe saltatory conduction (5 points)
AP jumps from node of Ranvier to the nextOccur in myelinated axonsRelatively fastSelf-regenerating Travel long distance
78
What are the 5 main functions of glial cells?
Support neurons physicallySupply neurons with nutrients and oxygenInsulate neurons from each other Protect neurons from pathogens and clean out dead neuronsModulate/regulate neural activity
79
What are the 4 types of neuroglia in the CNS?
Ependymal cellsOligodendrocytesAstrocytesMicroglia
80
What are the 2 types of neuroglia PNS?
Satellite cellsSchwann cells
81
What are 4 functions of Astrocytes (CNS) and Satellite cells (PNS)?
Structural support for neuronsHelp create the blood-brain barrier (BBB)Provide nutrients to neuronsModulate neural activity through reuptake of neurotransmitters and regulation of ion concentration
82
What are the functions of Oligodendrocytes (CNS) and Schwann cells (PNS)?
Wrap axons in myelin to insulate them and speed conduction of action potentials
83
What is the function of Ependymal cells (CNS)?
Help produce and circulate cerebrospinal fluid (CSF)
84
What is the function of Microglia (CNS)?
“Brains clean up crew”Devour and digest cellular debris (phagocytosis) in CNS
85
What are the 3 planes of section?
Horizontal transverse axialCoronal frontalSagittal (midsagittal)
86
How do you identify the horizontal/transverse/axial portion of the brain?
Shape typically more oval/ elongated in natureBilateral symmetry
87
How do you identify the coronal/frontal portion of the brain?
Rounder shapeBilateral symmetry
88
How do you identify the sagittal portion of the brain?
NOT bilateral symmetry
89
What are the 2 divisions of the peripheral nervous system? What are their functions?
Somatic: Voluntary control of actionSomatosensory: from skin to brain Motor: from brain to musclesAutonomic:Sympathetic and parasympathetic: regulation of involuntary functions (heart, gut, glands, etc)
90
What are the 2 types of neurons in the somatic nervous system (SNS)?
Afferent sensory neuronsEfferent motor neurons
91
What are the functions of afferent sensory neurons? (3 points)
Receives inputSensory cell body is in Dorsal Root ganglionDamage to pathway= motor impairments
92
What are the functions of efferent motor neurons? (3 points)
Send outputCell body in spinal cord but is part of PNSDamage to pathway= motor impairments
93
Where is the autonomic nervous system? What is its function?
Part of the peripheral nervous system that regulates internal (visceral) processes
94
What types of neurons are present in both the parasympathetic and the sympathetic systems? (2 types)
Visceral afferent sensory neurons: receive information from our organsVisceral efferent motor neurons: send information to our organs
95
Describe the sympathetic system of ANS (5 points)
“Fight or flight” and quick responseIncreases blood flow to skeletal musclesIncreases heart rateInhibits digestionDilates pupils for far vision
96
Describe the parasympathetic system of ANS (4 points)
“Rest and digest”, “feed and breed”, and calmnessIncreases blood flow to gutFacilitates digestionConstricts pupils for near vision
97
What are the 3 components for protection in the CNS?
Meninges: coveringCerebrospinal fluid (CNS): cushioningVentricles: fluid filled spaces
98
What are the components of the meninges? And their functions? (3 types)
Dura mater: thick, tough membraneArachnoid mater: thin fibrous membrane with trabeculae extending through the subarachnoid space to the pia mater. Contains the subarachnoid space: filled with CSFPia mater: delicate membrane that follows the cortical surface
99
What is the function of ventricles?
Choroid plexus: produce and maintain cerebrospinal fluid
100
Describe Cerebrospinal fluid (CSF)? And its functions?
Produced in choroid plexusesCirculates in ventricular system (blockages causes hydrocephalus)
Functions:Mechanical shock absorberChemical stabilityClearing of waste
101
What are the major developmental divisions of brain? (3 sections)
Forebrain: diencephalon, telencaephalon Midbrain: mesencephalonHindbrain: metencephalon, myelencephalon
102
What are the components of the telencephalon? (3 points)
Cerebral cortexHippocampusBasal ganglia
103
What are the components of the diencephalon? (2 points)
HypothalamusThalamus
104
What are the components of the mesencephalon? (3 points)
Superior colliculus Inferior colliculusMotor nuclei
105
What are the components of the metencephalon? (2 points)
PonsCerebellum
106
What is a component of the myelencephalon?
Medulla
107
What are the 3 components of the brainstem?
MidbrainPonsMedulla
108
Describe cranial nerves (2 points)
Brainstem organized similarly to the spinal cordCranial nerves containing afferent (sensory) and efferent (motor) signals
109
What is the pons responsible for? (3 points)
BalanceTasteSwallowing
110
What is the medulla responsible for? (3 points)
BreathingHeart rateBlood pressure
111
What is the midbrain responsible for? (3 points)
Inferior colliculi: audition (hearing)Superior colliculi: vision and eye movementsSubstantia nigra: dopamine, reward learning, addiction, movement, etc
112
What are the subcortical structures of the brain? (6 points)
Cerebral cortexHippocampusBasal gangliaHypothalamusThalamusCerebellum
113
What is the cerebellum responsible for? (4 points)
Motor controlCoordinationPostureEquilibrium
114
What is the hypothalamus responsible for? (5 points)
Hormone releaseBody temperatureHungerThirstSleep
115
What is the thalamus responsible for? (3 points)
Sensory-motor hub and relay:Lateral geniculate nucleus: visual relayMedial geniculate nucleus: auditory relay
116
What is the subcategories of the striatum in basal ganglia? (2 points)
Caudate: voluntary movement and goal-directed actionPutamen: motor skills and reinforcement learning
117
What is the subcategory of the basal ganglia responsible for regulation of voluntary movement?
The globus pallidus
118
What is the subcategory of the basal ganglia responsible for aversion, motivation, pleasure, reward?
The nucleus accumbens
119
What is the amygdala responsible for?
Emotion: fear episodic long-term memory
120
What is the hippocampus responsible for? (2 points)
Episodic long-term memorySpatial navigation
121
What are the 4 components/lobes of the cerebral cortex?
Frontal lobeParietal lobeOccipital lobeTemporal lobe
122
What are commissures?
Connections between hemispheres
123
What gray matter? White matter? Ventricle?
Gray matter: cortical surface cell bodiesWhite matter: myelinated axonsVentricles: cerebro-spinal fluid (CSF)
124
What are the broadman areas? (4 points)
Classified regions based on cytoarchitecture (thickness of cell layers)Identified 52 areasStructural classification (functional differences)Widely used to refer to areas of interest
