Neurons w3

Question 1

multiple sclerosis

Answer 1

autoimmune disease to attack own myelin - protective sheath:
- poor coordination

Question 2

importance of synapses

Answer 2

• to impose breaks in neutrons to reduce neural system overload

Question 3

Acetylcholine (ACh)

Answer 3

mobility issues, memory impairment- influences muscle activity &memory - Alzheimers: underproduction of ACh

Question 4

Neuro-modulators

Answer 4

brains own opioids - opium like chemicals

biggest group: endorphins

Question 5

endorphines

Answer 5

• inhibit pain transmission

- increase pleasure

Question 6

3 types of neurones

Answer 6

sensory neurones
motor neurones
inter-neurones

Question 7

sensory neurones

Answer 7

imput from sense organs to spinal cord & brain

Question 8

motor neurones

Answer 8

output from brain & spinal cord to muscles & organs

Question 9

inter-neurones

Answer 9

connective/ associative functions relays info between neurones.

Question 10

withdrawal reflex

Answer 10

subcontious act - bypasses brain, only through spinal chord - brain after. noxious stimulus - sensory neurones- excitatory info- interneurones- spinal chord-

Question 11

autonomic nervous system

Answer 11

sympathetic:
parasympathetic:
Homeostasis:

Question 12

Action Potential (nerve impulse)

Answer 12

1) Resting state inside axon: -70mv, Na, K channels closed
2) Pressure/ sensory imput disturbs membrane: -55mv - threshold voltage, triggers Na channels to open, Na+ diffuses in, more +ve charge inside than out, +30mv (Depolarisation)
3) Impulse passes, K+ channels open to go out, inside -ve voltage (depolarisation)
4) Some K+ channels rain open, more -ve charge than resting (hyperpolarisation)
5) in “refractory period”sodium-potassium pumps return 2 K+ to inside, 3 Na+ returned to outside = back to resting potential -70mv

Question 13

Facilitated diffusion

Answer 13

passive unless agains conc. grad.
used by
Carrier Proteins: change shape to allow certain large or polarised ions/molecules to move across membrane
will only move molecules against conc. grad. when ATP present, slow transportation rate

Channel proteins: stay same shape, can close or open in response to certain stimuli, cannot move molecules against conc. grad., faster transportation rate

Question 14

neuron components

Answer 14

soma: cell body

Axon: conducts electrical impulses away from the cell body to other neurons, muscles, or glands

Dendrites: specialized receiving units that collect messages from neighboring neurons and send them on to the cell body

Question 15

psych resting potential:

Answer 15

• Neuron is separated from surrounding fluid by a cell membrane; substances pass through ion channels
• Inner ions are more negatively charged than outer ions, resulting in a net negative charge for the resting neuron (polarization)

Question 16

psych Action potential:

Answer 16

• Positive sodium ions enter the neuron, causing brief depolarization
• It begins at one end of the axon & moves down along it

Question 17

absolute refractory period

Answer 17

• happens at each point along axon after action potential passed
• During this period the membrane is not excitable & cannot discharge another impulse.

Question 18

Graded Potentials:

Answer 18

changes in the negative resting potential that do not reach the action potential threshold

Question 19

neurotransmitter stages:

Answer 19

1) synthesis
2) storage
3) release
4) Binding
5) deactivation

Question 20

neurotransmiter synthesis

Answer 20

the transmitter molecules are formed

Question 21

1 - storage

Answer 21

transmitter molecules are stored in synaptic vesicles (in axon terminals)

Question 22

2- release

Answer 22

action potential causes transmitter molecules to move from synaptic vesicles across the gap

Question 23

3- Binding

Answer 23

transmitter molecules bind themselves to receptor sites embedded in the receiving neuron’s cell membrane

Question 24

4- neurotransmitter deactivation

Answer 24

occurs in two ways:

• Transmitter can be broken down by other chemicals
• Reuptake: transmitter molecules are taken back into the presynaptic axon terminals