lec 5

Question 1

synapses 3 parts

Answer 1

1. axon terminal of pre-synaptic neuron
2. synaptic cleft (space between cells)
3. membrane of post-synaptic cell

Question 2

convergence

Answer 2

-many synapsis’ come to one post synaptic cell

Question 3

divergence

Answer 3

-one pre synaptic cell going to many post synaptic cells

Question 4

electrical synapses

Answer 4

• -pre synaptic and postsynaptic cells are joined by gap junctions
• local currents from arriving action potentials can flow directly across junction

Question 5

chemical synapse

Answer 5

• synaptic cleft
• vesicles located at axon terminal that contain neurotransmitters

Question 6

chemical synapse events that occur

Answer 6

1. Once we hit a threshold, Ca2+ comes into cell causing vesicles to come to end of axon terminal
2. vesicles release neurotransmitters which attach to receptors of ligand gated channels
3. leads to change in membrane potential in post synaptic cell

Question 7

binding of neurotransmitters

-ionotropic receptors

Answer 7

• neurotransmitters bind to receptors on the plasma membrane of postsynaptic cell
• if activated receptors themselves are ion channels = Ionotropic receptors

Question 8

binding of neurotransmitters

-metabotropic receptors

Answer 8

-have messengers that activates receptors that indirectly influence ion channels by signal transduction through G proteins. this opens ligand gated channels

Question 9

synaptotagmin and SNAREs

Answer 9

1. Ca2+ binds to synaptotagmin
2. triggers a change in the shape of SNARE proteins
3. leads to exocytosis (release of neurotransmitters) by fusion to the membrane

Question 10

synaptic activation

Answer 10

• ONE WAY
• neurotransmitters are removed from synaptic cleft once activate post synaptic potential

Question 11

How neurotransmitters are removed from synaptic cleft *

Answer 11

1. transported to presynaptic neuron for reuse (reuptake)
2. transported to nearby glial cells for degration
3. diffuse away from the receptor cell
4. transformed into inactive substance

Question 12

EPSP

excitatory post synaptic potential

Answer 12

• graded potential on post synaptic membrane that results in depolarization
• Na+ into and K+ out of the cell

- one synapse not enough to do a action potential

-want neurons firing at same time or being close together so action potential occurs

Question 13

IPSP

Inhibitory Post synaptic potential

Answer 13

-graded potential on post-synaptic membrane that results in hyperpolarization

-Cl- into and K+ out of the cell

Question 14

synaptic integration

Spacial summation

Answer 14

• spatial summation of post-synaptic potentials
• adding simultaneous graded potentials
• potentials originate at different sites on cell body

Question 15

temporal summation

Answer 15

-input signals arrive from the same presynaptic cell at different times

Question 16

acetylcholine (ACh)

Answer 16

• major neurotransmitter in PNS
• activates receptors on postsynaptic membrane
• cholinergic neurons release ACh
• Acetylcholinesterase rapidly destroys ACh

Question 17

Two types of ACh receptors

Answer 17

1.Nicotinic receptor

-ionotropic receptor

2. Muscarinic receptor (M&M)
   - metabotropic receptor

Question 18

glutamate

Answer 18

-most common excitatory amino acid neurotransmitter

AMPA

-ionotropic receptor

-opens ligated ion channels, lets in sodium to cell to depolarize

NMDA

-Ionotropic receptor

-has magnesium ion on it needs high voltage to let ion come off and let calcium in, only comes off when its depolarized

Question 19

GABA

Answer 19

• inhibitory neurotransmitter in the brain
• when GABA binds to GABA receptor, there is an increase CL- flux into the cell
• Hyperpolarization occurs so no action potential is occuring

Question 20

Agonist

Answer 20

substance that activate receptor (mimics neurotransmitter)

Question 21

antagonists

Answer 21

substances that inhibit receptor

Question 22

neurotransmitters and receptors

ACh

glutamate

GABA

Answer 22

CHOLINERGIC

GLUTAMATERGIC

GABA-ERGIC