synaptic activity and integration

Question 1

synapse

Answer 1

point where a nerve ending meets the next cell in line which could be neuron, gland cell, muscle cell or few others

Question 2

presynaptic neuron

Answer 2

signal arrives through nerve which then releases a neurotransmitter

Question 3

postsynaptic neuron

Answer 3

responds to neurotransmitter

Question 4

electrical synapses

Answer 4

where adjacent cells are joined by gap junctions and ions diffuse directly from one cell into the next
- quick transmission
- can’t integrate info and make decisions

Question 5

chemical synapses

Answer 5

neurons communicate by neurotransmitters
- can integrate info and make decisions
- site of learning and memory
- target of many perception drugs
- action site of addictive drugs

Question 6

synaptic cleft

Answer 6

gap between 2 cells where neurons meet each other
~20 nm wide

Question 7

cell-adhesion molecules (CAMs)

Answer 7

proteins in neuron membrane
- reaches into synaptic cleft and link tot other cells CAMs
- prevents neurons from falling apart and holds them in proper alignment

Question 8

acetylcholine

Answer 8

neurotransmitter, formed by acetic acid and choline
- excited skeletal muscle, inhibits cardiac muscle and has effects on smooth muscle and glands

Question 9

amino acids

Answer 9

glutamate, aspartate, glycine, GABA

Question 10

monoamines

Answer 10

synthesized from amino acids by removing -COOH group and retain -NH2 group

Question 11

neuropeptides

Answer 11

chains of 2-40 amino acids
- stored in secretory glands (larger than normal)

Question 12

purines

Answer 12

include adenosine and ATP

Question 13

gases

Answer 13

specifically nitric oxide and carbon monoxide
- inorganic exceptions tot usual neurotransmitter
- synthesized as needed rather than stored
- diffused in/out of axon terminal

Question 14

excitatory cholinergic synapse

Answer 14

employs acetylcholine as its neurotransmitter which excited some postsynaptic cells and inhibits others

Question 15

GABA-ergic synapses

Answer 15

employ I-aminobutyric acid (GABA)
- work by same mechanism as ACh by binding to ion channels and cause immediate changes in membrane potential
- GABA receptor is a chloride channel

Question 16

adrenergic synapse

Answer 16

employs norepinephrine
- acts through second messengers such as cAMP
- receptor is transmembrane protein associated w/ a G-protein on inner face of membrane

Question 17

cessation of signal steps

Answer 17

1. achieved by cessation of signals which stops synaptic transmission
2. neurotransmitter degration, reuptake and diffusion

Question 18

neurotransmitter degration

Answer 18

breaks it down to fragments that have no effect on postsynaptic cell

Question 19

reuptake

Answer 19

broken down parts are reabsorbed by transport proteins
- monoamine oxidase: reabsorbs and breaks down amino acid and monoamine transmitters

Question 20

diffusion

Answer 20

products diffuse away from synapse into nearby ECF

Question 21

neuromodulators

Answer 21

chemical signals w/ long-term effects on entire groups of neurons
- adjust activity by… increasing release oof neurotransmitter, adjusting sensitivity of neurons, altering rate of reuptake and breakdown

Question 22

neural integration

Answer 22

ability of neurons to process, store and recall information and make decisions

Question 23

excitatory postsynaptic potential (EPSP)

Answer 23

voltage change in direction of depolarization and makes a neuron more likely to fire
- usually result from Na+ flowing into cell
- produced by glutamates and aspartate

Question 24

inhibitory postsynaptic potential (IPSP)

Answer 24

when neurotransmitter hyper polarizes the postsynaptic cell making it more negative and less likely to fire
- caused by Cl- to flow in or to let K+ diffuse from cell
- produced by glycine and GABA

Question 25

summation

Answer 25

process of adding up postsynaptic potentials and responding to their net effect, occurs in trigger zone

Question 26

temporal summation

Answer 26

when a single synapse generates EPSP so quick that each one is generated before previous one fades

Question 27

spatial summation

Answer 27

when EPSP from several synapses add up to threshold at the axon hillock

Question 28

presynaptic inhibition

Answer 28

opposite of facilitation
- when one presynaptic neuron suppresses another one
- to reduce/halt unwanted synaptic transmission

Question 29

neural coding

Answer 29

when nervous system converts information to a meaningful pattern of action potentials

Question 30

labeled live code

Answer 30

most important mechanism for transmitting qualitative info
- based on fact that each nerve fiber to the brain leads from a receptor that specifically recognizes a particular stimulus

Question 31

recruitment

Answer 31

brings additional neurons into play as stimulus becomes stronger

Question 32

neural pools

Answer 32

larger ensembles which may consist of thousands of interneurons concerned w/ a particular body function

Question 33

neural circuit

Answer 33

pathway among neurons in a pathway

Question 34

diverging circuit

Answer 34

individual neuron transmits signals to multiple downstream neurons or one neural pool may transmit output to multiple downstream pools

Question 35

converging circuit

Answer 35

opposite of diverging circuit
- funneled to fewer and fewer intermediate/output pathways

Question 36

reverberating circuit

Answer 36

neurons stimulate each other in a linear sequence from input to output neurons but some neurons late in path send axon collaterals back to earlier neurons

Question 37

parallel after-discharge

Answer 37

input neuron diverges to stimulate several chains of neurons which eventually reconverge to one/few output neurons