Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Histo > Basic Neuronal Synapse > Flashcards

Basic Neuronal Synapse Flashcards

(49 cards)

Start Studying
1
Q

General Nerve Classification

A

Nerve fibers classified by the size of the fiber

Includes motor and sensory neurons

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

A-fibers

A

medium to large nerve fiber; myelinated

Aa, Ab, Agamma, Adelta–largest to smallest

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

C-fibers

A

small fiber, unmyelinated

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

Sensory Nerve Classification

A

Organized from largest to smallest

Ia : Muscle spindle primary ending (muscle stretch)
Ib: Golgi tendon organ: (muscle tension)

II: Muscle spindle secondary ending
III: Small, myelinated: (crude touch, sharp p!)
IV: Unmyelinated C-fibers: (dull, aching pain and temp)

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

Motor Neurons: (largest to smallest)

A

Alpha motor neuron
Gamma motor neuron
C-motor neuron

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

Alpha Motor Neuron

A

Extrafusal muscle fibers (skeletal muscle fibers)

Muscle fiber contraction

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

Gamma Motor Neuron

A

Intrafusal muscle fibers (muscle spindle)

Generate muscle response to sensory input from muscle spindles; control muscle spindle length

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

C-motor neuron

A

Autonomic nervous system fibers to smooth muscle

sympathetic and parasympathetic

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

Factors affecting NCV

A 
Membrane myelination
Neuron fiber diameter
Temperature 
Cold – decreases NCV
Heat – increases NCV
Pharmacological agents: most decrease NCV
Pathological processes: decrease NCV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Neuronal Synapses

A

Synapses are where neurons communicate with other neurons
axon terminal of one neuron that is adjacent to the dendrites of another neuron
consists of pre-synaptic neuron and post-synaptic neuron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Pre-synaptic neuron

A

releases neurotransmitter chemicals from the axon terminal

NTs bind to post-synaptic neuron and cause a change in MB permeability

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

Components of synapse

A

axon terminal
synaptic vesicles
synaptic cleft
post-synaptic receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Axon terminal

A

pre-synaptic neuron

Contains numerous synaptic vesicles and mitochondria

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

Synaptic vesicles

A

Contain neurotransmitters

Vesicles fuse with pre-synaptic membrane for exocytosis of contents

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

Synaptic cleft

A

Space between neurons that is maintained by reversible binding between membrane proteins of synaptic cells

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

Post-synaptic receptors

A

Protein receptors on membrane of post-synaptic neuron

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

Synaptic Sites: Axodendritic

A

Axon to dendrites and spines (most common type)

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

Synaptic Sites: Axosomatic

A

Axon to cell body synapse

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

Synaptic Sites: Axoaxonic

A

Axon to axon synapse

Most often occur at the initial segment or at the axon terminal of post-synaptic neuron

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

Synaptic Sites: Dendrodendritic

Study These Flashcards
A

Dendrite to dendrite synapse

Occur infrequently and are typically reciprocal connections (synaptic communication in both directions)

21
Q

Chemical Synapse

Study These Flashcards
A

Release of neurotransmitter (NT) molecules into synaptic cleft

NT is released from the pre-synaptic terminal

NT binds to specialized receptors on the post-synaptic membrane

Each type of neurotransmitter has specific receptors on the post-synaptic membrane

Different NTs and their respective receptors have different effects on the post-synaptic cell

22
Q

Electrical Synapse

Study These Flashcards
A

Synapse that consists of gap junctions between adjacent cells

Gap junctions allow free passage of ions:

Any polarity change in one cell is easily passed to the adjacent cell

Allows synchronization of polarity changes among numerous adjacent cells
Abundant in connections between smooth muscle and cardiac muscle cells
Also contained within mammalian CNS

The easy transmission of changes in membrane potential between cells is important in contraction of:

Myocardium, smooth muscle of GI tract, and glandular epithelium

These synapses allow for coordinated contraction of smooth and cardiac muscle tissue

23
Q

Electrical Synapses components:

Study These Flashcards
A

Gap Jxn
fast transmission
common in smooth and cardiac muscle

24
Q

Chemical Transmission of AP

Study These Flashcards
A
  1. AP reaches the pre-synaptic terminal
  2. Change in membrane potential opens voltage-gated Ca 2+ channels to allow Ca 2+ to flow into the terminal
  3. Ca 2+ interacts with vesicles to cause vesicle fusion and exocytosis of neurotransmitter
  4. Neurotransmitter binds to receptor site on post-synaptic membrane
  5. Receptor is activated and creates channel opening in post-synaptic membrane
25
Synaptic Transmission: Post Synaptic processing of NT
Neurotransmitter degradation/removal must occur to clear the cleft for new signal transmission NTs bind receptor, cause action and are released from receptor Diffusion – molecule unbinds from receptor and simply “floats” away from cleft Re-uptake - pre-synaptic terminal removes neurotransmitter and recycles it Enzymes – chemically degrade neurotransmitters
26
Post-synaptic Response: potentials
Receptor-activated channels open to allow ion influx into post-synaptic cell Amount of transmitter released (and bound) determines how many of these receptors/channels will be activated Ion flux results in local potential change called: Post-Synaptic Potential or graded potentials Post-synaptic potentials are short-lived (milliseconds) changes in membrane potential
27
Excitatory Post-Synaptic Potential (EPSP)
Influx of Na+ and Ca 2+ results in local depolarization--moves closer to threshold
28
Inhibitory Post-Synaptic Potential (IPSP)
Influx of Cl- results in local hyper-polarization | further away from threshold
29
Neuronal Intergration
The post-synaptic membrane contains thousands of transmitter-gated channels that create EPSPs or IPSPs Post-synaptic neurons compute (integrate) numerous EPSPs and IPSPs = (summation) Integration/summation occurs in order to determine whether the overall set of stimuli creates enough depolarization to reach threshold for the post-synaptic neuron Excitation of post-synaptic neuron requires numerous EPSPs to provide enough polarity change to reach action potential threshold
30
Spatial summation
Summation of all the EPSPs that are occurring simultaneously on neuron
31
Temporal summation
Summation of EPSPs at the same synapse when they occur in rapid succession Within 3-15 milliseconds of each other
32
Divergence
Process by which a signal from a single neuron is transmitted to a large number of post-synaptic neurons Allows amplification of a signal from one neuron to many neurons
33
Convergence
Process by which multiple signals from different neurons excite a single post-synaptic neuron Allows summation of input of several neurons
34
Presynaptic Fxn
Functions of the pre-synaptic terminal can be affected by axoaxonal synapses it receives Axoaxonal synapses alter NT release from axon terminal
35
Presynaptic inhibition
Axoaxonal synapse causes anion (Cl-) channel opening | Reduces the positive charge of the presynaptic cell, and reduces the amount of NT released
36
Presynaptic Facilitation
Axoaxonal synapse slows K+ channel opening of pre-synaptic neuron Prolongs depolarization and increases NT release
37
Characteristics of Neurotransmitters
Chemicals contained in vesicles in the pre-synaptic terminal Released into synaptic cleft as mode of transmission of signals between neurons Neurotransmitters are either excitatory or inhibitory Most cells produce only one neurotransmitter Most receptors bind only one particular NT Some NTs can bind to more than one receptor As a rule, no 2 NTs bind the same receptor but the same NT may bind to many different receptors- each different receptor that a NT binds to is called a receptor subtype receptors often named by their agonists
38
Acetylcholine: Neurotransmitter
Excitatory NT Major NT of the ANS and the neuromuscular junction Utilizes nicotinic receptors at the neuromuscular junction Utilizes muscarinic receptors at several areas of CNS and in the heart PNS (parasympathetics system)
39
Receptor Blockade
Curare: blocks nicotinic receptors (creates paralysis) Atropine: blocks muscarinic receptors (increase heart rate) BoTox: blocks nicotinic receptors (creates paralysis)
40
Glutamate: NT
Major excitatory neurotransmitter of CNS Utilizes three different receptors with variable locations within the CNS AMPA, NMDA, Kainate Released in large quantities in cerebral injury and/or pathology Excess excitation can have deleterious effects on neurons and CNS function: Epilepsy Cerebrovascular accident (CVA) Seizures
41
GABA: NT
Major inhibitory neurotransmitter of CNS Utilizes GABAa and GABAb receptors A receptors: open Cl- channels B receptors: use intracellular messenger to affect gene transcription and ultimately neuron function Important in long-term memory/learning Barbituates and benzodiazepenes (anti-anxiety, anti-depressants) Bind to GABAa receptor and lengthen duration of channel opening when GABA is bound
42
Catecholamines: NT
Dopamine, serotonin, norepinephrine, epinephrine
43
Dopamine
Inhibitory NT with receptors throughout CNS Involved with motor function, memory, mood and emotions Important function of maintaining smooth, controlled movements Lack of dopamine leads to Parkinson’s disease Excess dopamine associated with schizophrenia
44
Serotonin (5-HT)
(5-hydroxytryptamine) | Inhibitory NT associated with mood (euphoria), emotion, sleep
45
LSD
Agonist of serotonin (binds serotonin receptor
46
Prozac
Inhibits reuptake of serotonin; allows it to be longer acting at synapses
47
Tryptophan
Molecular precursor to serotonin
48
Norepinephrine
noradrenaline
49
Epinephrine (adrenaline)
Major NTs of the autonomic nervous system Both have excitatory and inhibitory functions Function of these NTs is dependent on which receptor type they bind Use adrenergic receptors: Alpha 1 and alpha 2 receptors Beta 1 and beta 2 receptors

Histo (12 decks)

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