Lec 09

Question 1

Synapses

Answer 1

Where neuron meets its target cell

Question 2

Synapse target cell can be

Answer 2

1- neuron to neuron
2- neuron to muscle

Question 3

Electrical synapse

Answer 3

Gap junction where current flow directly from one cell to other

Question 4

Gap junctions

Answer 4

Allow very rapid communication within network of cells

Question 5

Chemical synapses

Answer 5

Electrical signals in presynaptic cell converted to chemical signals for transmission to postsynaptic cell

Electrical—chemical—neurotransmitter—graded potential—action potential

Question 6

At synapse

Answer 6

1-AP depolarize axon terminal
2-Open voltage-gated calcium channels
3-calcium enter the cell
4-Calcium triggers exocytosis of synaptic vesicles
5-Neurotransmitters diffuses across synaptic cleft
6-neurotransmitters bind with receptors(NEUROTRANSMITTER GATED CHANNEL) on postsynaptic cell
7-Binding initiate a response in postsynaptic cells
8Response can be EPSP/IPSP

Question 7

Neurotransmitter termination

Answer 7

1- Neurotransmitters can be returned to axon terminal
2- Enzyme inactivate neurotransmitter
3- Neurotransmitters cam diffuse out of synaptic cleft

Question 8

Acetylcholine

Answer 8

Neurotransmitter for voluntary movement

Question 9

Acetylcholine breaking enzyme

Answer 9

Acetylcholinesterase

Question 10

Neurotransmitter

Answer 10

1- Chemical must be found in presynaptic neurons
2- Chemical must be released in response to presynaptic depolarization
3- Chemical must act on specific receptors on postsynaptic neurons
4- Chemical must be terminated after release
5- Chemical application to postsynaptic neuron must have same effect as when it is released by neuron

Question 11

Frequency of neurotransmitters released

Answer 11

Affected by:
1-AP firing rate (strong stimulus)

Question 12

More neurotransmitter releases

Answer 12

4-Larger in magnitude of neurotransmitters
3-More excitation
2-Higher firing rate
1-Higher intensity stimulus

Question 13

Neurotransmitter in CNS

Answer 13

Excitatory or inhibitory
The kind depends on
1- transmitter molecules
2- post synaptic receptor

Question 14

EPSP

Answer 14

Depolarization
Na ion

Question 15

IPSP

Answer 15

Hyperpolarization
Cl-/k+

Question 16

IPSP AND EPSP

Answer 16

Are graded potentials

Question 17

Neurotransmitters

Answer 17

Rapid-short acting synaptic potential

IONOTROPIC

Question 18

Ionotropic

Answer 18

Fast, mediated by receptor channels

Question 19

Neuromodulators

Answer 19

Slow synaptic potentials and long-term effects

METABOTROPIC

Question 20

Metabotropic

Answer 20

Slow response mediated by GPCR

Question 21

Divergent pathway

Answer 21

One presynaptic neuron branches to many downstream
1 primary
Some secondary
Many tertiary

Question 22

Convergent pathway

Answer 22

Many presynaptic neurons send input to smaller number of postsynaptic neurons

Many primary
Some secondary
1 tertiary

Question 23

Global presynaptic inhibition

Answer 23

Ipsp and epsp fire but summed signal is below threshold
No AP in trigger zone and any target cells

Question 24

Selective Presynaptic inhibition

Answer 24

AP generates
Inhibitory neuron fires and block specific axon terminal

Question 25

Myasthenia gravis

Answer 25

Synaptic disease
-Attack neuromuscular junction between somatic motor and skeletal muscles
-Muscle weakness
-Autoimmune decrease in acetylcholine receptors