Synaptic Transmission

Question 0

Brain only understands…

Answer 0

Electrical signals

Question 1

Membrane polarity

Answer 1

Separation of positive and negative charges
Na ions concentrated on the outside
K ions concentrated on the inside

Question 2

Signals

Answer 2

Chemical to Electrical to Mechanical

Question 3

Neuromuscular Junction

Answer 3

Always excitatory
Acetylcholine
Always stimulates muscular contraction

Question 4

Synapse mediated by gap junctions

Answer 4

Electrical synapse

Gap junctions: formed by connexons/connexins

Question 5

Purpose of Schwann cell

Answer 5

Production of myelin sheath

Question 6

Cochlear connexins

Answer 6

Maintainin the fluid in the cochlea

Question 7

Chemical synapse

Answer 7

There is a space called synaptic cleft

Bind to postsynaptic receptor

Question 8

Ca ions

Answer 8

Essential for synaptic transmission

Question 9

Neurotransmitter

Answer 9

If excitatory, binds with postsynaptic and opens the channel for the entry of Na ions

Question 10

Blockage of Ca channels

Answer 10

Blockage of release of neurotransmitters
Will not open Na channels in postsynaptic terminal
(e.g. Pain will not be felt)

Question 11

Direct transmitter : Ionotropic

Fast transmission dahil diretso na!

Answer 11

Indirect transmitter : Metabotropic
Slow transmission and modulation
Utilizes secondary messenger

Question 12

Most common synapses

Answer 12

Axosomatic synapses
Axodendritic synapses

vs

Axo-axonic synapse

Question 13

Inhibitory neurotransmitter binding to receptor

What happens?

Answer 13

Opens K and Cl channels
More negative
Hyperpolarized! (Not depolarized)
Signal will stop there

Question 14

Voltage threshold for action potential to go to the next neuron
Must be reached

Answer 14

10-20 mV

Question 15

Types of inhibitory inputs

Answer 15

Presynaptic inhibition - impt in pain

Postsynaptic inhibition

Question 16

Temporal summation

Answer 16

Repetitive stimulation from one neuron can generate an action potential
Reach 15-20 mV

Question 17

Presynaptic facilitation

Answer 17

Used in rehabilitation

Question 18

With repetitive stimulation of the hippocampus..

Answer 18

Longterm potentiation

Impt in memory and learning!!!

Question 19

Are EPSPs and IPSPs graded?

Answer 19

Yes! Summation of stimulation to generate action potential

Question 20

Neurotransmitters

Excitatory or inhibitory?

Answer 20

Acetylcholine
In muscles, excitatory
In the heart (pacemaker), inhibitory (HOW?) —> bec. increase in Ca leads to inhibition and slowing of the heart

Biogenic amines BOTH
Glutamate Excitatory
GABA inhibitory (CNS, brain, spinal cord)
Glycine BOTH but highly inhibitory (excitatory, impt in the spinal cord, stimulates the NMDA receptor)
Opiates BOTH

Question 21

Learn by heart and minds!!!

Second-messenger systems

Answer 21

Diff. systems

cAMP: norepinephrine
Phosphonolsitol: Ach
Archidonic: Histamine

Question 22

Ach

Answer 22

Impt in control of movement, cognition, autonomic control

Deficiency in Ach esterase: Alzheimers

Binds with nicotinic receptor (ionotropic, in NMJ, bind with Na channels, less in autonomic)

Question 23

Epinephrine (correlate: effect on asthma, allergies, breathing!!!)
Beta receptors - abundant in the lungs than in the heart

Answer 23

Noradrenaline

Alpha receptors - greater in the heart than the lungs

Question 24

Dopamine receptors

Answer 24

D1 and D2 - striatum (smooth movement ~ Parkinsons disease); movement disorders
D3 - D5 - effect on the mood

Most D receptors are metabotropic

Synthesized in amygdala, arcuate nucleus

Question 25

Serotonin

Answer 25

In the CNS, actions are different from peripheral serotonin

Found in limbic system
Inhibition (anti-serotonergic) : anti- depressant

Question 26

Glutamate receptors

Answer 26

Ionotropic
NMDA (Na, Ca, K)- for this to open, sufficient voltage (comes from the opening of non-NMDA), ligand glutamate, glycine ~ related to vetsin! (MSG)
AMPA (Na, Ca)

Metabotropic

Excitatory transmission: glutamate binds to non NMDA

Question 27

Bad side of NMDA (Pathological)

Answer 27

More Ca ions to enter the cell —> cell death

Excess stimulation may be detrimental

Question 28

Opiate receptors

Answer 28

Mu High K conductance
Kappa Low Ca conductance
Delta Pure analgesic