Synapatic Transmission

Question 1

Two different types of receptors

Answer 1

Metabotrophic, ionotrophic

Question 2

Gap junctions consist of

Answer 2

Hexagonal array of proteins (connexion) forming clusters of channels. Each is about 1-2nm in diameter. Open or closed regulated by ionic concentrations. Very fast.

Question 3

Organs that contain electrical synpases

Answer 3

Pancreas, heart muscle, smooth muscle

Question 4

Chemical synapse cleft nm

Answer 4

20-50 nm wide

Question 5

Presynaptic synapse contains

Answer 5

Synaptic vesicles, secretory granules, mitcohondria and active zone

Question 6

Postsynaptic synapse contains

Answer 6

Receptors which conner the intercellular signal to an intracellular signal

Question 7

Neurotransmitter criteria

Answer 7

Must be made in the nerve (enzymatic components or precursors present)
Stimulation results in a postsynaptic response
Can be mimicked by exogenous application of neurotransmitter
Mechanism to terminate actions

Question 8

Ca2+ role in synapse

Answer 8

Ca2+ must bind with synaptic vesicles and direct them to the terminal so they can fuse and release their chemical into the synapse

Question 9

Purpose of dendritic cells

Answer 9

Communicating with other neurons

Question 10

3 types of glia in CNS

Answer 10

1. Microglia- white blood cells
2. Astrocyte- Star shaped cell that helps form the blood-brain barrier, recycles transmitters, communicates with the ventricles (AKA helps move ions, o2 or Co2 away or to neurons)
3. Oligodendrocytes- produce myeline sheathes
4. Ependymal cells- Creates barriers between compartments

Question 11

Difference between schwann cells and oligodendrocytes

Answer 11

1 schwann cell at a time wraps around the axon

Oligodendrocytes wraps around a lot axons (communicating with a lot of different neurons. More efficient)

Question 12

Synthesis of neurotransmitters

Answer 12

Primarily in the nerve terminal.
Stored in vesicles involves ATP.

Quantal release

Question 13

Dendritic spines

Answer 13

All different sizes of spines that cover the dendritic arms. They are composed of microfilaments.
Dynamic- can come and go based on use of portions of the brain.

Question 14

Different shapes of dendritic spine

Answer 14

Can indicate the health of the brain or diseases of the brain. ex: down syndrome, Fragile X syndrome

Question 15

2 examples in the autistic spectrum

Answer 15

Anglemans syndrome and fragile X syndrome

Question 16

Activity in the brain determines the type of ____ and what they look like

Answer 16

Dendritic spines

Question 17

Immature spine shape

Answer 17

Thin, stringy. Brain hasn’t matured appropriately

Question 18

Mature spine shape

Answer 18

Wider, mushroom. Brain has matured.

Question 19

Release of neurotransmitter

Answer 19

Ca2+ binds to synaptotagmin

Question 20

Snare

Answer 20

Molecules on the synaptic vesicle that hold the vesicle down to the pre synaptic area and binds it so it can’t move

Question 21

Synaptobrevin II, SNAP 25 and Syntaxin

Answer 21

Cause the vesicle to be pulled down to the terminal. Allows fusion and a pore opens.

Question 22

The release of a neurotransmitter

Answer 22

ATP-ADP causes the pore to close and separation of the vesicle from the AZ ??

Actions depend on the receptor and strength of the signal

Question 23

Recycling of the vesicle

Answer 23

Cytoskeleton grabs the vesicle after it released it’s contents and pulls it back into the axon terminal.

Question 24

How to remove neurotransmitter from the synpase

Answer 24

1. Diffusion causes neurotransmitter to move down concentration gradient and away from synapse.
2. Enzymatic degradation by acetylcholinesterase.
3. Uptake by neurons or glia cells, which are neurotransmitter transporters.

Question 25

Prozac

Answer 25

Serotonin reuptake inhibitor

Question 26

PNS glial cells (2)

Answer 26

Schwann cells produce myelin sheathes

Satellite cells support cell bodies

Question 27

Retina Glia

Answer 27

1. astrocytes, but only in the inner retina around the larger blood vessels.
2. Main glia- muller cells. Important in retinal development
3. Microglia

Question 28

Summation types

Answer 28

Adding of the graded potentials

Temporal- Summation of effect of neurotransmitters released from 2 or more firings of the same end bulb in rapid succession onto a second neuron.
Spacial- Summation of effects of neurotransmitters released from several end bulbs onto one neuron.

Question 29

The more neurotransmitter released the greater the change in ___

Answer 29

Potential o the postsynaptic cell

Question 30

Neuronal circuits

Answer 30

Diverging - single cell activates a lot of cells
Converging - One cell is stimulated by many others
Reverberating- Impulses from later cells repeatedly stimulate early cells in the circuit.
Parallel after discharge- single cell stimulates a group of cells that all stimulate a common postsynaptic cell

Question 31

Myasthenia gravis

Answer 31

Autoimmune disease that results in the decline of muscle strength. Body produces antibodies against the acetylcholine receptor, which is (N-ionotropic/nicotine) neostigmine.

Optometrists may be the first to notice the disease due to pt complaining of double vision (diplopia)- one muscle may be weaker than the other. (ptosis)

Question 32

MS

Answer 32

Autoimmune disease results in loss of transmission. Body produces antibodies against MBP found in myelinated neurons.
Attacks Myelin basic protein, typically seen in a peripheral nerve first.

Question 33

How do drugs modify synaptic transmission?

Answer 33

They can interfere or stimulate normal processes in the neuron involved in neurotransmitter synthesis, storage, and release and in receptor activation.

Question 34

How does the tetanus toxin affect synaptic mechanisms?

Answer 34

Prevents vesicle fusion with the membrane, inhibiting neurotransmitter release and causes increased muscle contraction.

Question 35

How does the bacilli toxin (botulism) affect synaptic mechanisms?

Answer 35

Interferes with actions of SNARE proteins at excitatory synapses that activate muscles. Characterized by muscle paralysis.

Low doses are used for botox injections. Used to rent wrinkles, severe sweating, and more.

Question 36

EPSP

Answer 36

A depolarizing postsynaptic potential. Results from the opening of ligand-gated Na+ channels. The postsynaptic cell is more likely to reach threshold.

Question 37

ISPS

Answer 37

Inhibitory postsynaptic potential. Results from the opening of a ligand gated Cl- or K+ channels. It causes the post synaptic ell to become more negative or hyper polarized. The postsynaptic cell is less likely to reach threshold.