chapter 4&5 - chemical signaling

Question 1

Galvani

Answer 1

1800s

dead frog legs relexed to electrical impulses

Question 2

Inventor of the first EEG

Answer 2

Berger

(Electroencephalogram) is a non-invasive test that measures and records the electrical activity of the brain.

Question 3

Microelectrodes

Answer 3

measure a neurons electrical activity

delivers an ele ctrical current toi a single neuron (SQUID NEURON)

Question 4

Concentration gradient vs. Electrical gradient

Answer 4

ions flow in direction until positive and negatice are equal everywhere

inc diffuses until equally distributed

Question 5

what is resting potentail

Answer 5

-70mV (K+ contribites to this the most)

Question 6

at rest, are sodium channels open or closed

Answer 6

closed

Question 7

at rest, are potassium leak channels open or closed

Answer 7

open

Question 8

how does a Na+/K+ channel work

Answer 8

3 Na+ out
2 K+ in

helps in repolarization

Question 9

what is hyperpolarization and what causes it

Answer 9

hyperpolarization is the dip below resting potentail after an action potential.

caused by EFFLUX (leaving) of K+ making outside more positve

Question 10

EFFLUX

Answer 10

exiting the side its on

Question 11

INFLUX

Answer 11

moving in/to a side

Question 12

What ion is invloved in Depolarization

Answer 12

INFLUX of Na+

Question 13

what is Saltatory conduction

Answer 13

the axon can be wrapped in mylen which carries the impulse to the nodes of Ranvier where that section of the axon depolarizes and contiues the signal down the axon

schwan PNS
oligodendricyte CNS

Question 14

what causes the AP to only move in one direction

Answer 14

the inactivated voltage gated Na+ channels cannot open again until the voltage reaches membrane potential

Question 15

EPSP

Answer 15

Excitaroy Postsynaptic Potential

Depolarizes

Influx of positive ions (e.g., Na⁺)

Question 16

IPSP

Answer 16

Inhibitory Postsynaptic Potential

Hyperpolarizes

Influx of negative ions (e.g., Cl⁻) or efflux of positive ions (e.g., K⁺)

Question 17

Temporal and Spatial Summation

Answer 17

ESPS on their own may not be able to single handedly depolarize a cell past threshold….

but several of them at the same time can add up to depolaize the cell enough to trigger an AP (thresh = -55mV

Inhibitory (IPSP’s) may cancel out some ESPS’s

Question 18

Deep Brain Stimulation

Answer 18

electrode is implated deep into the brain to stimulated areas with low-Voltage areas

used to help with parkinsons, epilepsy and more

(VIDEO WE WATCHED) - he was awake during implant

Question 19

what was the first NT found

Answer 19

Ach

found by OTTO (1921)

Question 20

OTTO’s vagus nerve experiment

Answer 20

stimulated vagus nerve and showed how it efected heart rate in FROGS

**the liquid it was in was used to stimulate a second heart. Showing that a chemical substance was being used to do this (Ach)

Question 21

critera for identifying neurotransmitters

Answer 21

1. chemical must be in neuron
2. chemical produces response in target cell
3. there must be a mechanizm to remove the neurotransmitter after use

(must work if the NT is placed on synapse by scientists)

Question 22

Gap Junction in synapse

Answer 22

electrical synapse

found between glial cells and neurons (mostly in cardiac muscles heart)

gap junctions are a pore that allows electrical signals to flow to the next neuron. (can close sometimes)

theres no delay to make contractions in smooth muscle

Question 23

how is neurotransmitter released?

Answer 23

calcium enters and causes the vessicles to fuse with the membrane to be exocytosed

Question 24

what are the 2 types of receptors in a chemical synapse?

Answer 24

Inonotropic and Metabotropic

Inon - ligand gated (instant)
opens a channel

Meta - send 2nd messengers to open channels like a G-protien to open some channels (longer time)

Question 25

How is the NT removed from the synapse?

Answer 25

1. diffusion
2. enzymes break them down
3. reuptake
4. astrocyte reuptake
5. autoreception ( inhibit further neurotransmitter release)

Question 26

what are some plastic changes that can happen to a neuron?

Answer 26

1. increased axonal transport
2. increased vesicles
3. increase size of terminal
4. change in size of cleft

Question 27

The Cholinergic System

Answer 27

Ach

• attention medication (learning/memory)
• allows you to wake up from sleep
• Ach mostly in PNS allows you to move

Question 28

The Noradrenergic System

Answer 28

Norepinephrine (NE)

• kickstarts the Sympathetic nervous system in tandem with Ach
• (autonomic) Smypathetic = NE + Ach
• (autonomic) Parasymathetic = Ach

Question 29

The Dopaminergic System

Answer 29

Dopamine (DA)

Two main pathways:

• Nigrostriatal pathway
  - substantia Nigra
• Mesolimbic pathway
  - nucleus accumbens

high amounts of dopamine are common in schizophrenia

Question 30

The Serotonergic System

Answer 30

Serotonin (5-HT)

• involved in mood and emotion
• involved in schizophrenia
• involved in appetite and digestion

Question 31

Amino Acid transmitters

Answer 31

GABA
- inhibits neurotransmitters

Glutamate
- excitatory neurotrasmitter

Question 32

Neuroinflamatory response

Answer 32

microglia and astrocytes protect brain from pathogens

GABA and Glutamate modulate these responses

if too much glutamate is released, Astrocytes reuptake the glutamate to control it

Question 33

what is a neurodegenerative disease

Answer 33

its when microglia and astrocytes switch from being neuroprotective to neurotoxic.

Question 34

What is an example of a neuropeptide neurotransmitter?

Answer 34

opioids = bodies natural pain killers

Question 35

How do psychoactive drugs work?
2 examples

Answer 35

agonist or antagonist at the synapse

Question 36

Psychoactive drug action example: Ach

Answer 36

Ach –>
- choline rich diet (agonist)
- black widow (agonist)
- Nicotine (agonist)
- physostigmine/organophophates (agonist)

• Botulin toxin (antagonist)
• Curare (antagonist)

Question 37

Psychoactive drug action example: 5-HT (serotonin)

Answer 37

5-HT –>
- MAO (agonist)
- Selective reuptake (agonist)