Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

NEUR 321 > Midterm 2 > Flashcards

Midterm 2 Flashcards

(77 cards)

Start Studying
1
Q

Luigi Galvani

A

Observed that a frog leg twitched during an electrical storm. He concluded that the NS used electricity to communicate and he was partially correct

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

Otto Loewi

A

First evidence of chemical communication involvement in neurocommunication
- Stimulated the vagas nerve (slows rate of heart contractions. He found that another heart in the same solution also had a reduced rate of contraction even though its vagus nerve was not directly stimulated.
- He concluded that there must be a chemical release in the first heart that was affecting the other heart
- NEEDS BOTH ELECTRICAL AND CHEMICAL COMMUNICATION
chemical - ACh

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

What are the only excitable cells types?

A

neurons and muscle cells

these are the only cells with voltage gated sodium ion channels

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

What factors can lead to a graded potential occurring ?

A

Chemical (NT receptors)
Mechanical (stretch receptors)

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

What is the strength of the stimulus coded by?

A

The number/frequency of action potentials

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

Hodgkin-Huxley Model

A

Described the ionic basis of the AP - considered the most important achievement in cellular neurophysiology.
Mathematical + biophysical model of the AP
- the textbook model
- used squid axons

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

Graded potentials

A

Are variable with magnitude and duration which depends on strength and duration of the triggering event
Spread passively (no channel opening outside the point of origin, decreminating with distance from point of initiation
Travel over short distance

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

Channels during Resting

A

Na+ voltage activated gate is closed, Na+ inactivation gate is open. Channel is closed but not inactivated

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

Channels during depolarization.

A

Na+ flows into the cell because both the Na+ voltage activated gate and inactivation gate are open.

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

Channels during repolarization

A

Na+ voltage activated gate is open but the inactivation gate is closed and thus Na+ no longer flows into the cell.
K+ voltage gate is open and K+ moves out of the cell
Absolute refractory period

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

Channels during hyperpolarization

A

Na+ voltage activate gate is closed, the Na+ inactivation gate is open. No Na+ flows. K+ voltage activated gate is open.

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

Relative refractory period

A

Due to the K+ activation gate still being open and letting K+ out. The neuron needs more of a depolarizing stimulus to reach threshold for an AP to be generated during this period

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

How to speed up the nerve impulse?

A

Make the ions bigger in diameter or prevent ions from the leaving the axon by covering much of it with myelin

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

Group C fibres

A

Carry sensory information. They are unmyelinated, small diameter, and thus slow conducting
Include postganglionic fibres in the ANS and nerve fibres at the dorsal roots.

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

How do neurons generally make signals from distant synapses on dendrites for meaningful?

A

Larger PSP generated as distant synapses
signal boosters - VG Ca2+ channels - allow Ca2+ in to further encourage the cell to reach threshold

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

Where is an action potential initiated in neuron?

A

In the axon hillock - dense area of ion channels. There are no ion channels in the soma

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

How do touch sensory receptors work?

A

There is a dendrite wrapped around hairs. Displacement of hairs open stretch-activated channels in the dendrites membrane. When the channels open they allow an influx of Na+ ions sufficient to depolarize the dendrite to its threshold level

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

What is a renshaw loop ?

A

The axon collaterals of motor neurons will synapse with a renshaw cell (interneuron) . which then innervates the motor neurons
Indirect inhibition through renshaw interneuron controls motor neurons

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

Electrical synapse

A

Direct cytosolic (electrical conducting) bridges between cells (Na+ flows through)
Very fast but not very plastic (not a lot of modulation going on.
Not common in the mammalian brainy,
although invertebrates have many. Heart has many.

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

Chemical synapse

A

Not as fast as electrical synapse but very plastic (in the number of receptors, amount of NT, etc)

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

How many classical NTs are there versus neuropeptides?

A

7 diff classical NT’s
100 diff chemicals that are neuropeptides

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

How does the release of NT from the presynaptic neuron occur?

A

AP arrives at the axon terminal –> depolarization from the sodium influx activates voltage gated calcium channels – leads to calcium influx. Increase in intracellular calcium triggers the vesicles to fuse with the presynaptic neuron membrane – get exocytosis of NT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When more action potentials occur - what happens at the synapse?

A

Get MORE calcium influx which means MORE NT is released

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

Why can magnesium chloride be used as an anaesthetic?

A

When applied to body, it will be influxed into the cell instead of calcium – don’t get fusion of the NT vesicles with the membrane - don’t get exocytosed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Ionotropic receptor?
Ligand gated ion channel Faster than metabotropic
26
Metabotropic receptor?
GPCR The receptor type and ligand bind ultimately determines what effect the NT will have on the cell Slower than ionotropic
27
Neurotransmitter
Chemical messenger used by neurons A NT must be made or present in the cell that is releasing it. The released chemical must be capable of producing an effect on its target (
28
Neurotransmitter
Chemical messenger used by neurons A NT must be made or present in the cell that is releasing it. The released chemical must be capable of producing an effect on its target (so the target MUST have receptors) Effect of the chemical must be able to be mimicked by the exogenous application of the same or similar substance (response mimicked) There should be a mechanism to remove or inactivate the NT when its work is done
29
Neuropeptide
Peptides that do not act directly as NTs but rather increase or decrease the action of an NT Synthesized in the cell body of a neuron Act usually as neuromodulators >100 have been identified Often co-localized with classical NTs and act as neuromodulators
30
Dale's Exclusion Principle
States that although different NT's can be produced at different synapses within the brain, idvl neurons are capable of releasing only one classical NT A couple rare exceptions - co-release of GABA-glycine, Ach - glutamate, dopamine-glutamate
31
How is NT cleared from the synapse?
receptor desensitization elimination of active NT from the cleft - diffusion of NT away from the synapse - inactivation of NT by enzymatic degradation - remove of the NT by glia-uptake or re-uptake mechanisms
32
Desensitization of ionotropic receptor
Typical in the Nicotinic Acetylcholine receptor NT is released but it might not activate the receptor anymore May bind but the receptor will not be activated/opened up. Won't let ions through. temporary
33
Homologous Desensitization of metabotropic receptor?
Activated receptor gets phosphorylated ----able to become endocytosized -- receptor is removed from the membrane
34
Heterologous desensitization of metabotropic receptor?
Desensitization occurs as a result of phosphorylation of one type of receptor as a result of kinases by another. Receptor becomes less responsive
35
How is acetylcholine made?
Made from dietary choline and acetyl CoA by choline acetyl transferase (ChAT). Then degraded by acetyl cholinesterase into acetate and choline Acetylcholine is the NT released at the neuromuscular junction
36
What receptors does acetylcholine bind to?
Ligand gated ion channels - nicotinic receptor GPCR - muscarinic receptor
37
Where is acetyl choline produced in the brain?
Basal forebrain and brainstem Projeccts to hippocampus, amygdala, cerebral cortex (find ACh receptors here)
38
Acetylcholine and disease
Involved in learning and memory Decline associated with Alzheimers disease - specifically in the hippocampus there is not enough release of ACh
39
Monoamines
Include catecholamines (dopamine, NE, E), indolamines (serotonin, melatonin), and imidazoleamines (histamine)
40
Dopamine
Made from tyrosine Produced in 3 systems mesolimbic, mesocortical, mesostriatal Component of the reward pathway - makes you feel good Associated with Schizophrenia (excessive dopamine release)
41
Mesolimbic and Mesocortical pathways
Dopamine production From the ventral tegmental area -projects to the nucleus acumbens, amygdala, hippocampus, and cortex Schizophrenia - excessive dopamine produced here is associated with Schizophrenia
42
Mesostriatal pathway
Dopamine release From the substantia nigra (basal ganglia) - projects to striatum (caudate and putamen) Loss associated with Parkinson's Disease (not enough dopamine release) Providing L-Dopa to these patients may help!
43
Receptors for Dopamine?
5 receptors, all GPCR!
44
Pathway to create Dopamine
Tyrosine--tyrosine hydroxylase--> L-Dopa--> DOPA decarboxylase --> Dopamine
45
Norepinephrine
Made from dopamine Dopamine --> dopamine b-hydroxylase --> NE Post ganglionic neuron in the sympathetic NS If you have Parkinson's you may not have enough NE either because NE is derived from dopamine
46
Where is NE synthesized in the brain?
Locus coeruleus, lateral tegmental area, dorsal medullary group Projects widely (cortex, cerebellum, hippocampus, etc)
47
Action of NE?
Modulates physiological states: - mood (anti-depressant target) - ADHD (attention) - sleep/wake - sexual behaviour - arousal - stress reactions - cognitive functions Can bind to alpha1,2 or beta 1,2 receptors
48
Serotonin
5-HT - 5hydroxytrypotomine Made from tryptophan Produced by Raphne nuclei and projects widely in the brain Has 7 classes of receptors (13-15 in total) 1 ligand gated channel - all others are GPCR
49
What does serotonin regulate?
sleep, mood, anxiety
50
Histamine
Made from the amino acid histidine Made in the tuberomammillary nucleus of the hypothalamus Plays a key role in arousal Used for allergies - anti-histamines (first generation allergy meds made people drowsy because they were able to cross the BBB and mind to receptors in the brain) - second generation anti-histamines are not able to cross the BBB and therefore don't cause drowsiness
51
Histamine receptors
Has 5 receptors. 4 in the brain 3 GPCR and one Cl- LG ion channel Projects widely - cerebellum, brainstem, cortex
52
Amino acid transmitters
Most common class of NT in the CNS
52
Amino acid transmitters
Most common class of NT in the CNS - include glutamate, aspartate, GABA, and glycine
53
Glutamate
classical NT Amino acid transmitter there are 4 types of glutamate receptors (IGPCR) Involved in learning and memory after a stroke - can get cell death due to overactivation - too much glutamate excitatory
54
GABA
amino acid transmitter inhibitory 3 types of GABA receptors (1 LG, 2 GPCR)
55
Opioid peptides
Enkaphalines and endorphins. Natural pain killers. Endogenous morphines. Bind to opioid receptors
56
Pituitary peptides
Oxytocin, vasopressin
57
Endocannabinoids
endogenous molecules that bind to cannabinoid receptors They are synthesized as needed and act as retrograde messengers (released from the post-synaptic cell - bind to CB1 and CB2 receptors on the presynpatic cell Play a role in memory, appetite, pain, anxiety Most common receptors are CB1 and CB2 (GPCR) CB1 is activated by THC
58
Retrograde messenger
Molecule released from the post-synaptic neuron that binds to the pre-synaptic neuron ex. cannabinoids, nitric oxide
59
Purines
transmitter molecule ex. adenosine - involved in sleep production. Caffeine prevents the binding of adenosine from its receptor
60
Gases as transmitter molecules
ie nitric oxide - a retrograde messenger (Post- pre) that enhances the pre-synaptic release of glutamate. Involved in memory Also important for smooth muscle relaxation Zinc can also act as a transmitter as an ion
61
Habituation
The overtime decreased response to steady or repeated stimuli NS is interested in change rather than constant stimuli Stimuli still there but you don't perceive them - why? With repeated stimulation, the Ca2+ VG channels in the presynaptic terminal desensitizes. Normally with AP incoming it triggers Ca2+ channel to open causes influx of Ca2+ causing vesicle fusion to the membrane. With VG Ca2+ channel desensitized - get less Ca2+ influx and therefore less NT release into the synapse. DECREASED RESPONSE
62
Sensitization
Exhibiting greater responses based on experience. ie horror movie scare build up In sensitization - Ca2+ has a larger effect - get more NT released from the synapse - larger response. In the slug, the increase in Ca2+ was mediated by an interneuron receiving a sensory signal - causes it to relase serotonin which then reduces K+ efflux - prolonging AP in the sensory neuron (where the calcium is) Shorter than habituation
63
Filopodia
branches of dendrites - formed that are constantly looked for new connections - become spines if the connection is meaningful
64
What is the effect of long-term habituation on synapses?
Decrease in synapses
65
What is the effect of long term sensitization on synapses?
Increase in synapses
66
Glutaminergic synapses
Very involved in learning and memory Can involve ionotropic (LG ion channels) or metabotropic (GPCR) receptors
67
Ionotropic glutaminergic receptors
AMPA, NMDA
68
NMDA receptors
ionotropic glutamate receptor Agonists: glutamate and NMDA Willow allow Na+, Ca2+ in and K+ out of cell. HAS A MAGNESIUM BLOCK THAT MUST BE REMOVED BEFORE IONS ARE ABLE TO PASS HIGH CALCIUM PERMEABILITY
69
AMPA receptors
ionotropic glutaminergic receptor Agonists: glutamate, AMPA Will allow Na+ and a bit of Ca2+ in and then let K+ out. NO MAGNESIUM BLOCK LOW CALCIUM PERMEABILITY
70
Binding of glutamate in NMDA and AMPA receptors
Glutamate binds to both receptors on the postsynaptic neuron but initially only Na+ flows in (and K+ out) through the AMPA receptor as the magnesium block is blocking the NDMA receptor. This Na+ influx depolarizes the post-synaptic area, causes the release of the Magnesium block. This opens up the NDMA receptor and as such, both Na+ and Ca2+ are able to flow in. Calcium then activates enzymes - leads to second messenger system activation - this can lead to retrograde signal regeneration calcium-calmodulin (dependent kinase)
71
What causes the magnesium block to be removed on the NMDA receptor?
The depolarization caused by the influx of Na+ ions caused by the opening of the AMPA channel
72
How does calcium calmodulin protein kinase enhance excitability?
It mobilizes new AMPA receptors (more receptors) It makes existing AMPA receptors more responsive (increasing their conductance) - POSITIVE FEEDBACK LOOP
73
CREB
Ca2+ can activate cAMP responsive binding protein (CREB) which is a TF that binds DNA and promotes gene expression -- lead to protein synthesis = ie. new receptors (long term plasticity)
74
cAMP and CREB
important for memory formation
75
Drug
A chemical substance of known structure, other than a nutrient or an essential dietary nutrient, that when administered to a living organism, produces a biological effect
76
Medicine
A chemical preparation, which usually but not necessarily, contains one or more drugs, administed from the intention of producing a therapeutic effect. Contains substances besides the drug that make them more conveniant to take Medicine contains the drug

NEUR 321 (6 decks)

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