Brainscape's Knowledge GenomeTM

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


See full index

PSYC 211 > Chapter 2: COMMUNICATION BETWEEN NEURONS > Flashcards

Chapter 2: COMMUNICATION BETWEEN NEURONS Flashcards

1
Q

What does the lock and key theory state?

A

Neurotransmitter molecules fit the binding sites of receptors like a key fits in a lock. Neurotransmitter binding conveys the neural message to the postsynaptic cell.

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

What are the two sides of the synapses?

A
  • presynaptic cell (axon terminal of a neuron)
  • postsynaptic cell (dendrite or soma)
  • they are separated by a synaptic cleft.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Under what form is the synaptic transmission? (electrical or chemical)

A
  • presynaptic: electrical to chemical (electrical impulse travel down the axon, then neurotransmitter release in extracellular fluid at the synaptic cleft)
  • postsynaptic: electrical
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does synaptic transmission dysfunction lead to ?

A

It leads to mental disorders

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

What are the general characteristics of synaptic transmission?

A
  • mostly chemical (what happens between presynaptic and postsynaptic)
  • synaptic cleft: filled with a matrix of fibrous extracellular protein
  • presynaptic: usually axon terminal
  • postsynaptic: contains neurotransmitter receptors.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What different synaptic arrangements are there and what are they based upon?

A
  • axodendritic, axospinuous, axosomatic, axoaxonic, dendrodendritic
  • based upon which part of neurons is postsynaptic to the axon terminal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the different steps of chemical synaptic transmission?

A
  • Neurotransmitter synthesis
  • Load neurotransmitter into synaptic vesicles
  • Vesicles fuse to presynaptic terminal
  • Neurotransmitter spills into synaptic cleft
  • Binds to postsynaptic receptors
  • Biochemical/electrical response elicited in postsynaptic cell
  • Removal of neurotransmitter from synaptic cleft
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the presynaptic terminal contain?

A
  • small spheres: synaptic vesicles, 50nm, store NT.

- larger vesicles: secretory granules, contains soluble protein, also called dense-core vesicles.

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

What is the site of NT release called?

A

-active zone: synaptic vesicles clustered in cytoplasm adjacent to active zone

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

How are NT released by vesicles?

A

-Released when synaptic vesicles fuse with membrane and break open, spilling contents into the synaptic cleft

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

How is NT release triggered?

A
  • Arrival of AP
  • Depolarization of terminal membrane causes voltage gated calcium channels to open
  • Elevation in Ca+ triggers to be released
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is NT released via exocytosis?

A
  • Basically what was explained earlier when vesicles fuse with membrane.
  • Process in which intracellular vesicle moves to plasma membrane and fuse at the active zone.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does exocytosis exactly happen?

A
  • Rapid: 0.2 msec of Ca+ influx
  • Ca+ enter at active zone (where voltage gates are located)
  • synaptic vesicles ready and waiting
  • calcium modifies snare proteins to initiate exocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is docking?

A

A molecular modeling technique that is used to predict how a protein (enzyme) interacts with small molecules (ligands).

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

What happens once binding occurs?

A
  • the postsynaptic receptors open neurotransmitter-dependent ion channels (also called ligand-gated ion channels), which allow the passage of specific ions in and out of the cell
  • NT open ion channels by at least 2 methods, direct and indirect.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the direct method in which NT open ion channels?

A

-ionotropic receptor: When a NT-dependent ion channel is equipped with it’s own binding site, a molecule of the appropriate NT attaches to it, and the ion channel opens.

17
Q

What is the indirect method of opening ion channels?

A
  • Metabotropic receptors are located close to G-proteins.
    1. Molecule of NT binds to metabotropic receptor
    2. Receptor activates G-protein
    3. G-protein activates enzyme that stimulates the production of chemical second-messenger.
    4. Second-messengers (molecules) travel through cytoplasm, attach themselves to ion channel and cause them to open.
18
Q

What are the characteristics of the direct and indirect methods?

A
  • Direct: transmitter-gated, fast, Amines and AAs.

- Indirect: G-protein-coupled, slower long-lasting and diverse actions, n type of NT can bind.

19
Q

What determines the nature of the postsynaptic potential at a particular synapse? (EPSP or IPSP)

A

-determined by the particular type of ion channel the NT open.

20
Q

What are the 4 major types of NT-dependent ion channels found in the post-synaptic membrane?

A
  • sodium (Na+)
  • potassium (K+)
  • chloride (Cl-)
  • Calcium (Ca2+)
21
Q

What is an EPSP? (Excitatory Postsynaptic Potential)

A

-Excitatory depolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button.

22
Q

What is an example of EPSP?

A
  • NT-dependent Sodium channel is the most important source of EPSP.
  • When sodium channels open, diffusion and electrostatic push Na+ in.
  • Causes depolarization
23
Q

What is IPSP? (Inhibitory Postsynapatic Potential)

A

An inhibitory hyperpolarization of the postsynaptic membrane of a synapse caused by the liberation of a NT by the terminal button.

24
Q

What is an example of IPSP?

A
  • Sodium-potassium transporters maintain a small surplus of K+ inside the cell.
  • If K+ channels open, these positive ions will leave the cell, so inside of cell will become more negative: hyperpolarization.
25
Q

What happens when inhibitory nt open chloride channels?

A
  • If the membrane is at resting potential: nothing happens because diffusion and electrostatic balance the chloride ion.
  • If membrane has already been depolarized by excitatory synapses located nearby, opening chloride channels will allow Cl- to enter. So these negative ions will bring resting potential back. Helps neutralize EPSP
26
Q

What happens when Ca+ channels open?

A
  • Same as sodium: depolarizes the membrane, producing EPSP.
  • But also does more like trigger migration of vesicles in presynaptic and release of NT, and activating special enzymes in postsynaptic.
27
Q

How are postsynaptic potentials terminated with reuptake?

A
  • extremely rapid removal of a TN from synaptic cleft by terminal button
  • After Nt relaesed into synapses, presynaptic uses special transporter molecules to return NT into presynaptic.
28
Q

How are postsynaptic potentials terminated by enzymatic deactivation?

A
  • accomplished by an enzyme that destroys the molecules of the NT
  • Ex: acetylcholinesterase (AChE) deactivates acetylcholine.
  • This prevents desensitization.
29
Q

What are called the interaction of the effects of excitatory and inhibitory synapses?

A
  • neural integration
  • more excitatory=more rate of firing=depolarization
  • more inhibitory=less rate of firing=hyperpolarization=bring membrane potential away from threshold
  • IPSP cancel effects of EPSP
30
Q

What is EPSP summation and what are the two types?

A
  • addition of different EPSPs to produce depolarization
  • spatial summation: adding EPSPs generated spontaneously at different synapses in same dendrite.
  • temporal summation: adding EPSPs generated at the same synapse in rapid succession
31
Q

What are autoreceptors?

A

-Some neurons possess receptors (autoreceptors) that respond to the nt that they themselves release.

32
Q

What do autoreceptors do when stimulated by a molecule of the nt?

A
  • They regulate internal processes, like the synthesis and release of the nt.
  • Mostly inhibitory activity
  • Decreases the rate of synthesis and release of nt.
33
Q

What do axoaxonic synapses do?

A
  • They alter the amount of nt released by postsynaptic axon.

- They can produce presynaptic inhibition or presynaptic facilitation.

34
Q

What are neuromodulators?

A
  • chemicals released by neurons that travel farther and are dispersed more widely than are nt.
  • Most are peptides (chains of amino acids)
  • secreted and larger amounts and travel longer distances.
35
Q

What do neuromodulators affect ?

A

General behavior states such as vigilance, fearfulness, and sensitivity to pain.

36
Q

What are hormones and what do they affect?

A
  • secreted by cells of endocrine glands, or cells located in various organs.
  • cells that secrete hormones release them into the extracellular fluid.
  • hormones distributed to the body through the bloodstream
37
Q

What are target cells?

A
  • cells that contain receptors for a particular hormone

- many neurons are target cells and hormones can affect their behavior.

PSYC 211 (45 decks)

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