Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

A&P 1 > Fundamentals of NS and Neurophysiology > Flashcards

Fundamentals of NS and Neurophysiology Flashcards

Oct 14

1
Q

Supporting Cells of PNS and function
Supporting Cells of CNS and function

A

Schwann Cell: PNS/ myelinates axons of axons in PNS
Satellite Cell: CNS/myelinates cell body (soma) of neurons in PNS

Astrocytes: CNS/ Maintain chemical balance of brain
Microglia: CNS/ Phagocytic, remove foreign micro-orgs and dead tiss.
Ependymal: CNS/ Line epith of brain ventricles and cavities
Oligodendrocytes: CNS/ myelinate axons in CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a neuron?

A

Excitable Nerve cell that transmit elec signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

3 main parts of a neuron and their functions

A
  1. Dendrite: receptive area/ receives graded potential from axon terminal of another neuron
  2. Cell Body/Soma: Bio synthetic part of the neuron. Contains the nucleus which makes proteins
  3. Axon: Transmits elec signal (action potentials) from cell body to another cell. Has the mylelin sheath
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Myelin Sheath: About and function

A

increases conduction rate of impulses/protects & insulates axons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Electrical Disequilibrium: definition

A

The difference in concentration/charge on either side of the cell membrane by separation of ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Graded Potential: Definition and function

A

Local change in membrane potential that varies w/ the intensity of the stimulus. The more intense the stim, the further the current flows

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Action Potential: Definition and function

A

All or nothing (yes or no) signal that travels along the axon and triggers release of neurotransmitters at the axon terminal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Propagation of an action potential

A

A positive feedback loop

As voltage gated Na+ channels open, ICF depolarizes which opens more voltage gated Na+ gates, which further depolarizes cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Conduction Velocities of Axons
A. Axon Diameter: what does it do re: conduction velocity?
B. Myelin Sheath: what does it do re: conduction velocity?

A

A. The larger the diameter of the axon, the faster conduction is. The larger the axon diameter the lesser the resistance to elec current

Myelin Sheath: insulates fibers, faster signal conduction, prevents leakage of charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Nerve Fibers: What are the 3 groups and what are the function and conduction rates of each

A

Group A Fibers: Large diameter/ Girthly myelinated/ conduct rates: 15- 150 meters p/ second (fastest)

Group B: Intermediate diameter/ lightly myelinated/ conduction rates: 3-15 meters p/sec (second fastest)

Group C: Small unmyelinated. conduction rate 1 meter p/ sec (slowest)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
  1. How are Neurons grouped functionally? What are the 3 types?
A

According to the direction the impulse travels in relation to the CNS.

The three types are:
1) Sensory/Afferent Neurons
2) Motor/Efferent Neurons
3) Interneurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe each of the 3 Functional type of Neurons and their functions

A
  1. Sensory Afferent Neurons: Axons travel toward CNS. Carry impulses toward CNS. Cell bodies located outside CNS (in ganglia). Unipolar
  2. Motor Efferent Neurons: Axons travel away from CNS. Carry impulses to effectors. Cell bodies located in CNS ( in grey matter). Multipolar
  3. Interneurons: Located between sensory and efferent neurons and are confined to CNS. Function is integrate information
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Synapse: definition

A

Junction site where neurons communicate/ exchange information.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Presynaptic Neuron vs Post synaptic neuron

A

Presynaptic: the neuron that is sending the info to the other

Postsynaptic: the neuron that is receiving the info from the previous neuron. Graded potentials happen here.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Axodendritic Synapse

A

Synapses between axon ending of 1 neuron and dendrites of another.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Axosomatic Synapse

A

Synapse between axon ending of 1 neuron and cell body (soma) of another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

General vs Special Senses of Sensory Division

A

General Senses: touch, pressure, proprioception, temperature, anything sensed by visceral organs

Special Senses: taste, smell, senses that req special organs (eye, ears)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Axon Hillock: Location and function

A

Located at end of cell body on neuron.
Function: decides whether action potential will or will not fire. -55 mV threshold required)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Electrical DIsequilibrium

A

Cells separate ions creating different concentrations on either side of the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Ion Concentration on each side of membrane
(ICF vs ECF) for Na+, K+, Cl-

A

Na+: in ECF: 140 mM
in ICF: 14mM
(Na+ wants to move from outside cell to inside of cell/ high to low concentration

K+: in ECF: 4 mM
in ICF 140 mM
(K+ wants to move from inside to outside cell/ high to low concentration)

Cl-: in ECF: 110 mM
in ICF: 7 mM

Cl-wants to move from outside to inside the cell (high to low concentration)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Resting Membrane Potential

A

Potential difference across the membrane. It is -70mV.
It represents a source of potential stored energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Concentration Differences of Ions across the membrane are a result of what 3 factor?

A
  1. Electrical Attraction by FIXED ANIONS (neg chg proteins inside the cell) that cannot cross the cross membrane
  2. Resting membrane is more permeable to K+ than to Na+. K+ able to leak out of of cell into ECF
  3. Active Transport by Na+/K+ ATPase Pump: Actively pumps 3 Na+ out while also pumping 2 K- back in to cell. Requires energy ea time used
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Na+/K+ ATPase Pump: function

A

To maintain resting membrane potential of -70mV & to actively pump 3 Na+ out of cell and actively pump 2 K+ back into cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Nerve: Definition

A

A bundle of Axons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Action potential. What is happening when membrane potential is at -70 mV?
1. Resting Membrane Potential 2. No gated channels are open 4. Membrane Polarized
26
Absolute Refractory Period
Ensures each AP is a separate all or nothing event. Na+ inactivation gates closed. Channels can't respond to new stimulus
27
What happens when membrane potential is at -55mV?
1. AP threshold reached, Axon hillock initiates AP. 2. Na+ channels open 3. Na+ inactivation gates close 1 mS after Na+ channel opens 3. Depolarization/ inside of membrane less negative 5. Absolute Refractory Period: happening during depolarization to repolarization on either side
28
What happens at +30mV?
1. Peak Depolarization/ Action potential max output 2. K+ channels open (+20mV to +30) K+ leaves cell 3.Na+activation gates close 4. Membrane starts to repolarize as k+ leaves cell
29
What happens at less than -70mV?
1. K+ channels close around -90mV 2. Hyperpolarization of cell membrane 3. Inside of membrane is more negative (lower than -70mV) 4. Membrane is at Relative Refractory Period
30
Chemically Gated Channels
open and close when exposed to the correct neurotransmitter Example: Ligand gated channels
31
Voltage Gated Channels
open & close when voltage threshold is crossed These are the most common
32
Mechanically Gated Channels
open when a membrane is deformed/physically stretched to open
33
What is an Ion
A charged molecule
34
Relative Charge Scale
RMP measured by assigned ECF value of zero, then measuring the difference between the 2 sides of the membrane
35
How can non charged molecules/ ions move across a membrane?
Only with a concentration gradient or active transport
36
How do molecules/ions without a concentration gradient and with passive transport move across the membrane?
Because ions are charged and can be either attracted or repelled across the membrane
37
How come ions cannot reach equilibrium even though a typical cell is permeable to K+?
Because the chemical gradient favors K+ leaking from the cell and the Electrical gradient favors attracting K+ in the cell.
38
Relative Refractory Period
Na+ activation gates closed/closing but Na+ inactivation gates are open. A strong enough stimulation can re-open activation gates & depolarize membrane & produce a 2nd AP
39
Polarization
membrane is at rest (-70mV). no gated channels open. ICF more negatively charged than ECF.
40
Depolarization
Membrane potential moves higher than -70 mV to ward zero or higher Inside of membrane becomes LESS negative
41
Hyperpolarization
Membrane potential moves even lower than -70mV. Inside of membrane become MORE negatively charged
42
When do Na+ activation gates open
@ -55mV
43
When do Na+ inactivation gates close?
Shortly after +30mV
44
When do K+ activation gates open?
@+30+mV
45
Stimulus Strengh
Intensity is coded in frequency of AP (how often they happen) and not the intensity
46
Chemical Synapses: Function and about
Allow for release and reception of neurotransmitters Consist of axon terminal, synaptic cleft, and a receptor region opening ion channels on post synaptic membrane can have either excitatory or inhibitory effect on post synaptic neuron. Binding of neuro -T either drives them toward threshold or away fromn
47
Chemical Synapses: Step 1:
AP opens Ca2+ channels in the axon terminal
48
Chemical Synapse Step 2:
Ca2+ enters membrane and initiates V-Snare/T-Snare protein DOCKING
49
Chemical Synapse Step 3:
V-Snare/ T-Snare interaction allows vesicle FUSION to membrane. Vesicles contain neurotransmitters.
50
Step 4: Chemical Synapse
Fusion results in NEUROTRANSMITTER RELEASE into synapse via EXOCYTOSIS. Complexes move away from each other and create pores in axonal membrane
51
Step 5: Chemical Synapse
Released Neuro T's cross synapse and bind w/ postsynaptic receptor channels
52
Step 6: Chemical Synapse
Ion channels open on post synaptic membrane (as result of Neuro T's binding to receptors)
53
Electrical Synapses: Function and location
Function: Synchronize activity of all interconnected neurons Allow direct rapid communication between adjacent cells through gap junctions. They are faster than chemical synapses Location: Found in embryo, cardiac and smooth muscle and brain
54
Chemical Synapse can be either____or____?
Can be either excitatory or inhibitory Excitatory: opens Na+ channels, drives toward threshold (depolarization) Inhibitory: opens K+ or Cl-, drives away from threshold (hyperpolarization)
55
Structural Classification of Neurons (3)
1. Unipolar: 1 long axon w/ cell body attached via stalk. most commonly are sensory(afferent) neurons. 2. Bipolar: cell body in middle and 2 long processes extended from ea end of soma. Only found in special sensory receptors (retinas, olfactory bulb) 3. Multipolar: (most common) many dendrites & only 1 axon that extend from soma. Mostly are motor (efferent) neurons and interneurons.
56
What are the 3 ways Neurotransmitters are terminated?
1. Degraded by the receptor terminal 2. Are re-sequestered back into the presynaptic terminal 3. Diffuse away from the synapse and broken down/destroyed by glial cells
57
Excitatory Synapses
1. Neuro-T binds to CHEMICALLY GATED channels & pushes them open. These are Chemically gated channels, (NOT voltage gated channels!). 2. Open gates/allow Ion diffusion (Na+ in & K+ out) simultaneously (more Na+ in than K+ out) 3. Na+ follow electrochemical gradient. K+ follows chemical gradient 3. Results in local depolarization cell from the above activity. This is called Excitatory Post Synaptic Potentials aka "EPSP". 4. These graded potentials vary in amplitude depending on amt of N. T. that binds. If the EPSP's reaching the hillock are strong enough to reach threshold, then an AP will result
58
What is an EPSP?
Excitatory Post Synaptic Potential It is the local depolarization of membrane from charged Ions entering membrane as result of an excitatory synapse. It is a graded potential
59
How will an EPSP result in an AP?
EPSP's vary in amplitude (strength) depending on the amt of NT that binds. If the EPSP's that reach the Hillock are strong enough they will trigger an AP.
59
What gradient does Na+ follow and what gradient does K+ follow?
Na+ follows an electrochemical gradient K+ follow a chemical gradient
60
Inhibitory Synapse (Function & how it happens)
Function: Reduces RMP potential resulting in hyperpolarization. How: when inhibitory N.T.'s bind & open K+ and Cl- channels, Cl- enters resulting in hyperpolarization of membrane. IPSP: Inhibitory Post synaptic potential: the resulting hyperpolarization of the post synaptic membrane from opened K+ and Cl- channels Na+ channels are not affected
61
How are EPSP's and IPSP's generated at the post synaptic receptors?
By either a DIRECT CHEMICAL GATES or an INDIRECT CHEMICAL GATES
62
DIRECT EFFECTS
Direct Effects: when a N.T. directly opens a channel. Ex: Acetylcholine Results in rapid, short acting synaptic potentials
63
INDIRECT EFFECTS
Indirect Effects: Depend on a 2nd messenger (G-protein or enzyme) to either open a channel or change metabolic activity inside cell. Ex of G-Protein: Norepinephrine (opens channel) Ex of Enzyme: Nitric Oxide Results in slow, long term effect on synaptic potential
64
Summation
1 single EPSP cannot induce an AP but they can summate/ add up (multiple EPSP's) enough impulses to trigger at Hillock - That is summation
65
What are the 2 types of summation?
Temporal Summation: Multiple impulses travel down a (1) presynaptic neuron (1 terminal) in rapid order and add up (summate) Spatial Summation: impulses from large # of terminals stimulate post synaptic membrane.
66
Synaptic Potentiation Hint: "Potent"
The repeated use of a synapse enhances the ability of postsynaptic excitation, producing larger post synaptic potentials (repetition of the stroke = a "Potent" blast )
67
Presynaptic Inhibition Hint: "Pre-mature...moms knocking the door"
When another neuron inhibits excitatory release via axoaxonic synapse, it leads to decreased amount of NT release.

A&P 1 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions