0331 - Transmission between cells - VY Flashcards Preview

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Flashcards in 0331 - Transmission between cells - VY Deck (31):
1

What are the two types of synapses that allow communication between a neuron and another cell

Chemical and Electrical synapses

2

What is the difference between electrical and chemical synapses

Electrical synapses are allow flow of ions between 2 cell membranes via gap junctions. They are a direct link between the cytoplasm of adjacent cells. Chemical synapses allow communication between excitable cells. They occur via a complex mechanism involving neurotransmitters, Ca+, ligand receptors and enzymes

3

Where are generally neurotransmitters produced?

In the presynaptic terminal

4

Where are neurotransmitters released and what compound regulates this release

Neurotransmitters are released from their vesicles in the synaptic cleft. This release is regulated by CA + (calcium).

5

What do neurotransmitters released into the synaptic cleft bind to

Neurotransmitters released into the synaptic cleft bind to postsynaptic ligand receptors.

6

What are the 2 ways neurotransmitters can be inactivated

Re-uptake and degradation.Neurotransmitters released into the synaptic cleft can be reabsorbed into the synaptic terminal via Na dependant transport . Neurotransmitters can also be degraded in the synaptic cleft before they reach ligand receptors in the postsynaptic membrane via breakdown by enzymes

7

Explain in a few key sentences how an action potential may be generated via neurotransmitter release

Ca+ signals the release of a quart (amount of neurotransmitter in a vesicle) NT into synaptic cleft. NT binds to specific ligand receptors which cause opening of ion channels in the postsynaptic membrane. Channel activation causes depolarisation of the postsynaptic membrane which excites an action potential

8

What is a neuromuscular junction

A neuromuscular junction is a specialised synapse that connects the nervous system to the muscular system. The postsynaptic membrane has post junctional folds. NMJ is a excitatory synapes. Vesicles release Acetyl Choline as neurotransmitters.

9

Where do electrical synapses between 2 cell membranes occur

Electrical synapse occur in gap unctions

10

What is a vesicle

A small fluid filled vacuole from within a body

11

What are gap junctions

Gap junctions are specialized intercellular connections between 2 adjacent cells made of channels.

12

What proteins regulated Ca2+ release into the presynaptic cleft

Voltage gated Ca2+ channels

13

What is the role of Ca2+ in a chemical synapse?

Intracellular Ca2+ causes synaptic vesicle fusion with the presynaptic membrane. This fusion releases the contents of vesicles into the synaptic cleft

14

Where are vesicles proteins synthesized in neuron and where are they processed and sorted?

Vesicles proteins are synthesized in the rough endoplasmic reticulum and pass through the golgi apparatus network for processing

15

What is the role of the fast axonal transport microtubule system?

The fast axonal transport microtubule system

16

What is clathrin-mediated endocytosis?

Clathrin-mediated endocytosis is the re-internalization of synaptic vesicles via the presynaptic membrane

17

What are the 2 families of postsynaptic receptors?

Ionotropic receptors and metabotropic receptors.Ionotropic receptors are transmembrane proteins channels that regulate ion movement in and out of the postsynaptic membrane. A metabotropic receptor is coupled with a secondary messenger protein (G protein). Ligands activated these receptors which activate the second-messenger which initiates downstream responses

18

Where do electrical synapses between 2 cell membranes occur

Electrical synapse occur in gap unctions

19

What is a vesicle

A small fluid filled vacuole from within a body

20

What are gap junctions

Gap junctions are specialized intercellular connections between 2 adjacent cells made of channels.

21

What proteins regulated Ca2+ release into the presynaptic cleft

Voltage gated Ca2+ channels

22

What is the role of Ca2+ in a chemical synapse?

Intracellular Ca2+ causes synaptic vesicle fusion with the presynaptic membrane. This fusion releases the contents of vesicles into the synaptic cleft

23

Where are vesicles proteins synthesized in neuron and where are they processed and sorted?

Vesicles proteins are synthesized in the rough endoplasmic reticulum and pass through the golgi apparatus network for processing

24

What is the role of the fast axonal transport microtubule system?

The fast axonal transport microtubule system

25

What is clathrin-mediated endocytosis?

Clathrin-mediated endocytosis is the re-internalization of synaptic vesicles via the presynaptic membrane

26

What are the 2 families of postsynaptic receptors?

Ionotropic receptors and metabotropic receptors.Ionotropic receptors are transmembrane proteins channels that regulate ion movement in and out of the postsynaptic membrane. A metabotropic receptor is coupled with a secondary messenger protein (G protein). Ligands activated these receptors which activate the second-messenger which initiates downstream responses

27

What is an autoreceptor

An autoreceptor is typically a G-protein-coupled receptor that regulates neurotransmitter release via feedback

28

What is the action of excitatory neurotransmitters?

Excitatory neurotransmitters usually result in the influx of Na+ and K+ leading to depolarisation

29

What is the action of inhibitory neurotransmitters

Inhibitory neurotransmitters usually result in influx of Cl- leading to hyperpolarisation

30

What is the action of neuromodulatory neurotransmitters

Neuromodulatory transmitters modulate the function of surrounding cells (e.g. hormones such as serotonin or dopamine)

31

What are some ways drugs, toxins and disease can affect synaptic transmission

Signal blocking (e.g. Ca2+ channel blocking)Blocking of vesicle fusion with membrane (e.g. tetanus)AChE inhibitors (block breakdown of ACh preventing recycling of vesicles)

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