1-neurons and action potentials and all that yucky stuff

Question 1

glial cells (glia)

Answer 1

• outnumber neurons 10:1, traditionally thought to play a supportive role to neurons
  
  • physically and metabolically
• provide scaffolding on which the nervous system is built
• help neurons line up closely with each other to allow neuronal communication
• insulation for neurons
• transport nutrients and waste products
• mediate immune responses

Question 2

neurons

Answer 2

• interconnected information processors that are essential for all of the tasks of the nervous system

Question 3

Dendrites

Answer 3

receives information and transport it to the cell body

• recieve neurotransmitters and report to nucleus with an excitatory or inhibitory charge
  
  • create action potential!!

Question 4

neuronal membrane:

Answer 4

acts as a boundary that controls what substances enter and leave the neuron.

keeps extracellular and intracellular fluid separate

Question 5

cell body (soma)

Answer 5

core of the neuron which maintains the cell and ensures it is working effectively, collects and processes information

Question 6

axon

Answer 6

transmits information form one part of the neutron to the other

Question 7

Node of Ranvier

Answer 7

gaps in the myelin sheath which facilitates a more efficient and quick conduction of action potentials.

Question 8

Oligodendrocytes

Answer 8

• one type of glial cell. The role of these cells is to support neurons in the brain.
  
  • Oligodendrocytes specifically maintain the myelin sheath in the central nervous system.

Question 9

myelin sheath

Answer 9

helps info travel down axon faster, surrounds the neuron in layers of its proteins and fat, made of glial cells

Question 10

Axon/terminal buttons

Answer 10

Send the signal to the next neutron. The terminal buttons contain synaptic vesicles that are packed with neurotransmitters.

Question 11

synapse

Answer 11

gap between two neurons

Question 12

resting potential:

Answer 12

• the state of readiness of the neuron membrane between signals

-70 millivolts

Question 13

state of the cell during the resting state?

Answer 13

• in resting state, sodium (Na+) is higher concentrations outside the cell, so it will tend to move into the cell once gates are open
• potassium (K+) is more concentrated inside the cell and will tend to move out of the cell once gates are open
• inside of the cell is negatively charged compared to the outside!!

Question 14

threshold of exitation

Answer 14

• 50 millivolts

Question 15

Vesicles

Answer 15

filled with neurotransmitters, releases neurotransmitters into the synapse

Question 16

gates

Answer 16

pick up neurotransmitters, NT are the key to the gate!

Question 17

electrochemical event

Answer 17

neuronal communication

Question 18

all-or-none phenomenon

Answer 18

either you have not enough signal, or enough and BOOM ACTION POTENTIAL

Question 19

action potential!! process!!

Answer 19

• neuron recieves signal at dendrites!! state changes abruptly!!
• gates open on the neuronal membrane
  
  • allows NA+ ions, propelled by both charge and concentration differences to move into the cell
  • internal charge of the cell becomes more positive!!
• if charge reaches a certain level (threshold of excitation) action potential begins!!
  
  • -55 mv
• at the peak! sodium gates close and potassium gates open
  
  • it pumps out not only the potassium ions but the sodium as well
• positively charged potassium ions leave, the cell begins repolarization
• first, it hyperpolarizes, becoming slightly more negative than the resting potential
• then it levels off, getting the potassium back in, returning to the resting potential
• moves like a wave—some of the sodium ions that enter the cell diffuse to the next section of the axon
  
  • raising the charge past the threshold of excitation and triggering a new influx of sodium ions
• moves all the way down the axon to the terminal buttons

Question 20

How neurotransmitters are transmitted across a synapse

Answer 20

• once NT are released into the synapse, they travel across the small space and bind with corresponding receptors on the dendrite of an adjacent neuron

Question 21

receptors

Answer 21

proteins on the cell surface where NT attach, vary in shape, different shapes matching different neurotransmitters

    - NT and receptor have a **lock-and-key** relationship!!
        - specific NT fit specific receptors like  how a key fits a lock

Question 22

Once the neurotransmitters are delivered?

Answer 22

• excess NT in the synpase drift away, broken down into inactive fragments
• reabsorbed in a process known as reuptake
  • NT being pumped back into the neuron that released it, in order to clear the synapse
    
    • clearing the synapse provides a clear “on” and “off”
    • regulates the production of NT

Question 23

EXCITATORY

Answer 23

neurotransmitters that INCREASE the positive charge!!

• dopamine—mood/sleep/learning
• norepinephrine—fight/flight, concentration
• glutamate—memory/learning
• acetylcholine—muscle/memory

Question 24

INHIBITORY

Answer 24

neurotransmitters that DECREASE positive charge!!

• serotonin—mood/sleep
• GABA—sleep/anxiety
• Endorphins—pain/pleasure

Question 25

acetylcholine

Answer 25

involved in muscle action, memory

potential effect on behaviour: increase arousal, enhanced cognition

Question 26

beta-endorphin

Answer 26

involved in pain, pleasure

potential effect on behaviour: decreased anxiety, decreased tension

Question 27

dopamine

Answer 27

involved in mood, sleep, learning,

potential effect on behaviour: increased pleasure, suppressed appetitie

Question 28

Gamma-aminobutyric acid

Answer 28

involved in brain function, sleep

potential effect on behaviour: decreased anxiety, decreased tension

Question 29

glutamate

Answer 29

involved in memory, learning

potential effect on behaviour: increased learning, enhanced memory

Question 30

norepinphrine

Answer 30

involved in heart, intestines, alertness

potential effect on behaviour: increased arousal, suppressed appetitite

Question 31

serotonin

Answer 31

involved in mood, sleep

potential effect on behaviour: modulated mood, suppressed appetitie

Question 32

agonist

Answer 32

INCREASES the function of an NT by mimicking and NT at the receptor site

Question 33

antagonist

Answer 33

DECREASE OR INHIBIT the function of a neurotransmitter

Question 34

reuptake inhibitors

Answer 34

• prevent unused NT from being transported back to the neuron
• leaves more NT in the synapse for a longer time, increasing its effects