Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

KNES 259 - Anatomy and Physiology > Neurophysiology > Flashcards

Neurophysiology Flashcards

1
Q

what does neural communication refer to?

A
  • nerve and muscle are excitable tissues
  • they can undergo rapid changes in membrane potentials, which is critical to the function of the neurons and muscles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Anatomy of a Neuron

A
  • A typical neuron is composed of:
  • dendritic region
  • a cell body
  • axon hillock
  • an axon
  • axon terminals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Parts of the Neuron: cell body

A
  • houses nucleus and organelles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Parts of the Neuron: Dendrites

A
  • increases surface area for receiving signals
  • sends signal towards cell body
  • this is the neurons input zone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Parts of the Neuron: Axon

A
  • Nerve “fiber”
  • conducts impulses (AP’s) away from the cell body
  • the axon hillock is where the axon meets cell body and is the neurons trigger zone
  • Axon terminals are the sight of synapse with other neurons or effector organs so they release chemical messengers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Kinesins

A
  • carry nutrients, enzymes, organelles away from cell body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Dyneins

A
  • carries recycled vesicles, chemical messengers back towards cell body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Microtubule

A
  • railway that the kinesins and dynein’s use
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Membrane potential

A
  • the plasma membrane of all living cells has a membrane potential (polarized electrically)
  • separation of opposite charges across plasma membrane
  • occurs due to differences in concentration and permeability of key ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

movement of ions depends on

A
  • permeability
  • electrical gradient
  • concentration gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Nernst Equation

A
  • describes equilibrium potential for an ion
  • Eion = (61/z)log (Co/Ci)
  • Co – outside concentration
  • CI - inside concentration
  • Z – valence of the ion (Na / K are +1)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

E Na

A
  • If only Na+ were allowed to move, equilibrium would be reached at +60mV
  • both electrical and concentration gradients encourage the inward movement of Na+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

E K

A
  • if only K+ were allowed to move, equilibrium would be reaches at -89mV
  • this is due to opposing electrical and concentration gradients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Resting membrane potential for Neurons

A
  • both Na+ and K+ gates are closed
  • The potential is maintained by 4 things
    1. impermeable membrane
    2. Na+/K+ ATPase pump
    3. Increased permeability to K+ (it leaks out)
    4. anions inside of the membrane
  • resting membrane potential is around -70mV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the different membrane states of a neuron

A
  • polarization: state when the membrane potential is a value other than 0mV
  • depolarization: membrane becomes less polarized than at rest
  • repolarization: membrane returns to resting potential after a depolarization
  • hyperpolarization: membrane becomes more polarized than at rest
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Graded Potentials

A
  • serve as short-distance signals
  • initiated by mechanical, chemical, and electrical stimulus
  • usually initiated in dendrites
  • they are local and die away quickly
  • can be added together together to become larger in amplitude (summate)
  • amplitude of a graded potential depends on the stimulus strength (vary in size)
  • can be excitatory or inhibitory
  • no refractory period
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Action Potentials

A
  • brief, rapid, large (100mV) changes in membrane potential
  • They don not decrease in strength as they travel from their site of initiation
  • Na+ gates require time to reset
  • ion changes produce the 4 phases of action potential
  • when GP’s reach threshold (-55mV)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Stages of Action Potential

A
  • reaching threshold triggers Na+ gates to open - depolarization (+30mV)
  • Na+ gates close as K+ gates open with causes K+ to rush out - repolarization
  • K+ gates are too slow to close - hyperpolarization (-80mV)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Action potential characteristics

A
  • All or none principle
  • refractory periods
  • self propagating
  • uni-directional movement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the two types of propogation

A
  1. contiguous conduction
    - conduction in unmyelinated fibers
    - AP spreads along every portion of membrane
  2. saltatory conduction
    - rapid conduction in myelinated fibers
    - impulse jumps over sections of the fiber covered with insulating myelin
    - 50x faster
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Regeneration of Nerve Fibers

A
  • Depends on the location
  • Schwann cells of PNS guide the regeneration of cut axons
  • fibers in CNS myelinated by oligodendrocytes do not have regenerative ability (inhibit regeneration)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Myelin

A
  • fatty insulator (primarily composed of lipids)
  • formed by oligodendrocytes in CNS
  • formed by Schwann cells in PNS
  • leaves exposed nodes of Ranvier
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is a synapse

A
  • junction between two neurons
  • this is the primary way that neurons interact with eachother
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Convergence and Divergence

A
  • Convergence: many neurons input into one
  • Divergence: one neuron synapses with many
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

presynaptic neuron

A
  • conducts action potential towards synapse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

synaptic knob

A
  • contains synaptic vesicles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

synaptic vesicles

A
  • stores neurotransmitter (carry signals across
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Postsynaptic neuron

A
  • neuron whose action potentials are propagated away from the synapse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

synaptic cleft

A
  • space between the presynaptic and postsynaptic neurons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what occurs at a synapse

A
  • AP arrives at terminal end
  • voltage gated Ca2+ open
  • Ca2+ moves into knob
  • triggers release of neurotransmitter (NT)
  • NT migrates across synapse
  • NT binds to receptor site to open ion gates and trigger graded potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How are NT released?

A
  • calcium binds to synaptotagmin
  • stimulates SNARE proteins (ensnare vesicles)
  • causes NT release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Post Syaptic membrane

A
  • activates ionotropic receptors (actual ion channels)
  • otherwise activates metabotropic receptors (2nd messenger activation of the channel)
33
Q

How long is the synaptic delay?

A

0.2-0.5 msec

34
Q

What are the two types of synapses

A
  1. Excitatory synapses - effect Na+ or ion gates
  2. Inhibitory synapses - effect K+ or Cl- gates
35
Q

What does the size of post-synaptic potential depend on?

A
  • calcium levels (fatigue)
  • NT levels
  • Desensitization/hypersensitization
  • presynaptic inhibition or facilitation
35
Q

What is spatial summation

A
  • summation of many EPSPs occur at different locations on the dendrites at the same time
  • the impulses can combine to reach threshold
36
Q

What is temporal summation

A
  • summation of many EPSPs occur at the same location over a short period of time
37
Q

How do EPSP and IPSPs interact

A
  • some neurons have up to 200,000 terminals
  • the means that it can have inhibitory and excitatory transmission cancelling each other out
38
Q

Presynaptic facilitation/inhibition

A
  • Neuron A releases neurotransmitter that can either increase or decrease the release from neuron B
  • Ex. Opiates
39
Q

Common types of neurotransmitters

A
  • NT vary from synapse to synapse
  • same NT is always released at a particular synapse and quickly removed from synaptic cleft
  • Acetylcholine
    *dopamine/serotonin
  • Norepinephrine/epinephrine
  • Histamine
  • Glutamate
  • Gamma-aminobutyric acid (GABA)
40
Q

what are neuropeptides?

A
  • large molecules consisting of 2-40 AA
  • substance P (pain)
  • enkephalins/endorphins
  • dynorphins
  • hypothalamic releasing and inhibiting hormones
  • angiotensin II
  • cholecystokinin
41
Q

Acetylcholine (Ach)

A
  • cholinergic receptors
  • parasympathetic system/muscle
  • muscarinic vs nicotinic receptors (agonists)
  • broken down by acetylcholinesterase and recycles
  • sarin inhibits this enzyme
42
Q

Catecholamines

A
  • epinephrine/norepinephrine
  • affect consciousness, mood, attention
    *BP, HR
  • Adrenergic/noradrenergic receptors
    *broken down by monoamine oxidase or MAO
    *MAO inhibitors increase epi levels in synapse
43
Q

Seratonin

A
  • from tryptophan - modulates slow onset
  • excitatory on muscle control
  • inhibitory on sensory mediation
  • mood, anxiety, wakefulness
  • block reuptake with paxil (antidepressant) as well as LSD
44
Q

What is the impact of drugs around the synapse

A
  • altering the synthesis, axon transport, storage or release of a NT
  • modifying neurotransmitter interaction with the postsynaptic receptor
  • influencing neurotransmitter reuptake or destruction
  • replacing a deficient NT with a substitute transmitter
45
Q

Categories of drug interactions

A
  • Agonists: mimic NT when they bind
  • Antagonists: bind but do not activate, so they block site
46
Q

What are two examples of drugs that alter synaptic transmission

A
  • cocaine: blocks reuptake of NT dopamine at presynaptic terminals
  • Strychnine: competes with inhibitory NT glycine at postsynaptic receptor site
47
Q

What are two examples of bacterial toxins that alter synaptic transmittion

A
  • tetanus toxin: prevents release of inhibitory NT GABA, affecting skeletal muscles
  • destroys SNARE proteins
  • Botulism: interferes with SNARE proteins for excitatory NT which causes muscle paralysis
48
Q

Batrachotoxin

A
  • poison dart frogs
  • causes the nerves to reach threshold easier (more likely to get AP)
  • can lower threshold by 30-50mV
  • can fire at resting membrane potential in some cases
  • neurons cannot depolarize
  • causes: initial muscle spasms (including the diaphragm), eventual depletion of Ach stores which then block the stimulation of muscles
49
Q

Black Mamba Snake Toxin - Dendrotoxin K

A
  • inhibits K+ gates
  • prevents AP repolarization, meaning AP is prolonged and neuron releases more NT
  • causes: muscle spasms and tremors, then convulsions, eventually die of respiratory failure or cardiac arrest
50
Q

Increasing Extracellular K+

A
  • KCl injection
  • concentration gradient of K+ across the cell membrane is reduced
  • less K+ flows out of the cell through the “leak” channels
  • Intracellular concentration rises
  • membrane potential closer to threshold
  • In the brain it is likely to produce seizures
  • astrocytes usually absorb excess potassium from extracellular space via potassium channels in their membranes
51
Q

Curare

A
  • south and central america
  • is the paralyzing poison used on arrows
  • competes with Ach at nicotinic Ach receptors
  • inhibits action of Ach at neuromuscular junction
  • causes muscle weakness/paralysis
  • eventual death by asphyxiation (paralysis of diaphragm)
52
Q

Tetrodotoxin (TTX) - Poison from Puffer Fish

A
  • also in newts, octopus, sea stars
  • ingestion, inhalation, injection
  • inhibits voltage sensitive Na+ gates
  • no depolarization possible
  • loss of sensation, paralysis of voluntary muscles
53
Q

Box Jellyfish Toxin

A
  • Sea wasp - enough toxin to kill 60 people
  • cells become porous
  • Allows potassium leakage
  • Hyperkalemia
  • lose K+ gradient for neural cells
  • cardiovascular collapse and death within 2-5 mins
54
Q

General Anaesthetic - Sevoflurane

A
  • affects K+ leak channels that help maintain the resting membrane potential
  • this will hyperpolarize the membrane making it harder to reach threshold
  • inhalation anaesthetics prefered to tager neurons in the brainstem that control consciousness and respiration)
55
Q

Lidocaine - Local anaesthetic

A
  • Aka xylocaine
  • blocks voltage-sensitive Na+ channels in sensory neurons (no AP)
  • also block in cardiac motor neurons
56
Q

DDT - in insects

A
  • acts to open Na+ gates
  • over-firing
  • spasms and death
  • overuse in humans
  • stimulates estrogens
  • cancer causing
  • neural degradation
57
Q

what are afferent neurons

A
  • ascending
  • dendrites in periphery
  • terminal end in CNS
58
Q

what are efferent neurons

A
  • descending
  • dendrites in CNS
  • terminal ends in periphery
  • only autonomic nerves have synapses outside the CNS
59
Q

what are interneurons

A
  • all in CNS
  • make up 99% of all neurons
  • very small
60
Q

Glial cells

A
  • make up 90% of CNS cells and 1/2 of the volume
  • these are support cells that help with physical and metabolic functions for CNS
  • there are astrocytes, microglia, ependymal cells and oligodendrocytes
61
Q

what are microglia

A
  • immune cells
  • protect CNS from pathogens
62
Q

Neuroglia - Astrocytes

A
  • holds neurons in place
  • general maintenance of space
  • helps form blood-brain barrier
63
Q

Myelin

A
  • increases conduction velocity
  • secreted by schwann cells in PNS
  • secreted by oligodendrocytes in CNS
64
Q

Ependymal Cells

A
  • ciliated epithelial membrane lining ventricles
  • secrete cerebrospinal fluid
  • shock absorption
  • nutrients
  • CSF made in choroid plexus
  • flows through ventricles into arachnoid space before being absorbed into arachnoid villi
65
Q

Brain Waves

A
  • Alpha: lower frequency, relaxed state
  • Beta: higher frequency, alert and concentrating
  • Theta: light sleep
  • Delta: deep sleep
66
Q

Brain during sleep

A
  • alternates between non REM and REM sleep
  • stage 1 through 4, back to 1 and then REM sleep
67
Q

Sleep patterns

A
  • Non REM sleep (4 stages): rest and repair, theta and delta waves
  • REM sleep is a dream state, where problem solving and reverse learning occur.
68
Q

What are the speech association areas

A
  • Broca’s area (speech)
  • Wernicke’s area (speech comprehension)
  • Dyslexia is the poor connection between visual and language ares
69
Q

Limbic system

A
  • emotion, learning, and memory
  • hippocampus (learning and memory)
  • inputs to hypothalamus
  • short term memory has limited capacity, temporary neural trace but fast retrival
  • long term has a huge capacity with permanent neural trace but a slower retrieval
70
Q

Transfer from STM to LTM

A
  • relates to past events and memories
  • emotional response related to memory
  • repetition
  • sleep
  • exercise and diet
71
Q

Habituation and sesnsitiation

A
  • Habituation: decreased response to repeated in different stimuli causes decreased calcium at synapse
  • Sensitization: increased response to mild stimuli, causes more calcium to be released at syapse (emotional response included)
72
Q

Spinal cord

A
  • neuronal link between brain and PNS
  • integrating center for spinal reflexes
  • sensory input via the dorsal root
  • motor output via the ventral root
73
Q

Matter in the spinal cord

A
  • Gray matter: Unmyelinated nerve cell bodies
  • White matter: Myelinated axons that contain very few cell bodies
74
Q

Spinal reflexes

A
  • faster when brain is not involved
  • often monosynaptic
  • brain receives impulse as an afterthought
75
Q

Skeletal muscle reflexes

A
  • proprioceptors
  • golgi tendon organ and muscle spindle
  • located in muscle, joints, and ligaments
  • Alpha motor neurons carry input to muscle
76
Q

Stretch reflex

A
  • stretch of receptor sends AP’s up sensory neuron
  • this increases the firing or motor neuron to have a reflex contraction
77
Q
A
78
Q
A

KNES 259 - Anatomy and Physiology (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions