Lecture 10 & 11: Synapses

Question 1

What are Synapses connection

Answer 1

Between two neurons or a neuron and another cell that is specialized for the transfer of information

Question 2

Synapses is delivered from the _____ cell to the __________ cell

Answer 2

presynaptic cell to the postsynaptic cell

Question 3

What are the two main ways we classify Synapses

Answer 3

1) Functional

2) Location

Question 4

Define Electrical functionality for neurons

Answer 4

Passes directly between 2 cells, carried by the movement of ions between cells
Common in cardiac and smooth muscle
Depolarization or hyperpolarization
Fast

Question 5

How does the relationship work between synapses and intelligence

Answer 5

more synapses = more intelligent

Question 6

Define Chemical functionality for neurons

Answer 6

Specilized form of exocytosis
Electrical signals from one neuron is converted to a chemical signal to cross the synaptic cleft then is converted back to an electrical signal

Question 7

Is chemical or electrical functionality more common for neurons

Answer 7

Chemical

Question 8

Define Axodendritic synapses

Answer 8

Axon directly to dendrites (almost no reactions)

Question 9

Define Axosomatic synapses

Answer 9

Axon directly to Soma

(more of an influence

Question 10

Define Axoaxonic (initial segment)

Answer 10

Axon to either initial segment (trigger zone)

Most powerful

Question 11

If synaptic activity leads to Depolarization of the postsynaptic cell it is considered

Answer 11

EPSP

Question 12

IF ssynaptic activity leads to hyperpolarization of postsynaptic cell it is considered

Answer 12

IPSP

Question 13

True or False; The grand Sum of EPSPs and IPSPs acting on a cell will determine whether the cell will reach threshold and fire an AP

Answer 13

True

Question 14

Where must a threshold be reached to fire an AP

Answer 14

Axon Hillock

Question 15

Define Excitatory postsynaptic potential (EPSP)

Answer 15

A depolarizing synaptic potential

Question 16

Define Inhibitory postsynaptic potential

Answer 16

A hyperpolarizing synaptic potential

Question 17

Cells with GAP junctions are said to be connected by what

Answer 17

Cytoplasm

Question 18

Define Axoaxonic (pre synaptic)

Answer 18

If excitatory, depolarizes Ca+ in, causes a release of a neurotransmitter
If inhibitory- hyperpolarizes less Ca+ in, inhibits neurotransmitter

Question 19

What are norepinephrine, dopamine, histamine, serotonin examples of

Answer 19

Amines neurotransmitters

Question 20

Give an example of two novel neurotransmitters

Answer 20

Peptides and purines

Question 21

Define synaptic delay

Answer 21

Time it takes for a substance to diffuse across and cause a postsynaptic response

Question 22

What is Acetylcholine used by and causes what

Answer 22

Motor neurons to cause an excitation of skeletal muscles

Question 23

How many different receptors are there for ACh and what are they and which one is fastest

Answer 23

1) Nicotinic receptor (FAST)

2) GPCR - Muscarinic receptor (SLOW)

Question 24

Describe what happens when ACh binds to Nicotinic receptrs

Answer 24

Causes an Entry of Na+ causing a depolarization of the cell resulting in an EPSP

Question 25

Describe what happens when ACh binds to muscarinic receptor

Answer 25

Creates 2nd messenger Kinase which phosphorylates K+ leakage channels causes K+ channels to close resulting in a depolarization stopping the leakage of positive charge (EPSP)

Question 26

Where is Norepinephrine used, how many channels and types of channels, describe receptors

Answer 26

CNS All use GPCR NO ion channels Alpha and beta receptors

Question 27

Glutamate is a main _____ in the ____

Answer 27

excitatory in CNS

Question 28

What are the two types of Receptor channels for Glutamate and describe each

Answer 28

Iontoropic receptor channels a) NMDA - Allows Na+ and Ca+ to enter (some K+ leaks out) causing depolarization of the cell. Typically blocked by Mg+ ions that get ejected when cell is depolarized by binding glutamate b) AMPA - Binds glutamate causing an influx of Na+ causing a depolarization

Question 29

Describe GABA and its receptor channels

Answer 29

Main inhibitory neurotransmitter used throughout the CNS 1) GABA A - Binds ligand causing the influx of Cl-causing a hyperpolarization of the cell. IPSP 2) Metabotropic GABA B - Binds a ligand and generates 2nd messengers kinases

Question 30

Which GABA receptor is faster and why

Answer 30

GABA A is faster cause it does not need a 2nd messenger to create an effect

Question 31

What synapse is is Acetylcholine located at

Answer 31

Cholinergic

Question 32

True or False (GONNA BE A QUESTION ON EXAM) When given a 2nd messenger it is very easy to tell the effect of it

Answer 32

FALSE; Need lots of information

Question 33

True or False; Not all GPCP Will cause closure of K+ channels

Answer 33

True

Question 34

Which synaptic receptors, a receptor channel or GPCR causes a faster postsynaptic response

Answer 34

Lingand-gated ion channel because it doesn't require a 2nd messenger

Question 35

AChR receptor channels do what

Answer 35

Na+ and a little K+ Depol

Question 36

NMDA receptor channels do what

Answer 36

Na+, Ca2+, k+ Depol

Question 37

AMPA receptor channels do what

Answer 37

Na+, little K+ Depol

Question 38

GABA A receptor channels do what

Answer 38

Cl- Hyperpol

Question 39

Define Divergence and Convergence

Answer 39

Divergent pathways, one presynaptic neuron branches to affect a larger number of postsynaptic neurons Convergent pathways many presynaptic neurons provide input to influence a smaller number of postsynaptic neurons

Question 40

If two subthreshold potentials arrive at the trigger zone within a short period of time they may ____

Answer 40

Sum together and initiate an AP

Question 41

Synaptic plasticity is the ability of neurons to do what

Answer 41

change synaptic strength

Question 42

The best studied neurons that exhibit long-term potentiation in mammalian brains are located where

Answer 42

in the hippocampus

Question 43

the cell must be ____ in order to gate NMDA-R open

Answer 43

Depolarized

Question 44

Loong Term maintenance of synaptic potentiation does what 3 things

Answer 44

changes in gene expression creation of new synapses co-ordinated pre and post- synaptic effects

Question 45

LTP (long-term potentiation) is seen as what and requires what

Answer 45

A long lasting potentiation of the EPSP | Requires: NMDA and AMPA receptors