2. Neuronal transport

Question 1

name the specialised rough ER in the cell body

Answer 1

Nissl Substance

Question 2

how long is the sciatic nerve

Answer 2

over a metre

Question 3

name neutrons specialised intermediate filament

Answer 3

neurofilament

Question 4

what is the function of microtubules

Answer 4

facilitates movement within the cell

Question 5

how are microtubules affected in Alzheimers

Answer 5

microtubule associated protein Tau is destabilised- disrupting cell transport

Question 6

what are neurofilaments involved in

Answer 6

involved in motility, structural support and axonal transport

Question 7

describe anterograde transport

Answer 7

materials are transported from the soma to the axon terminals

Question 8

what is the soma

Answer 8

the cell body

Question 9

what is anterograde transport also known as

Answer 9

orthograde transport

Question 10

describe retrograde transport

Answer 10

transport of materials from the axon terminals to the soma

Question 11

what type of materials are transported in anterograde transport

Answer 11

small vesicles, enzymes

Question 12

what type of materials are transported in retrograde transport

Answer 12

larger vesicles, nerve growth factor

Question 13

which is a faster method of neuronal transport

Answer 13

anterograde (fast= 200-400mm/day)

retrograde= 200 mm/day

Question 14

what two forces move ions across membranes

Answer 14

chemical force

electrical force

Question 15

describe chemical force

Answer 15

differences in concentration cause diffusion of molecules (high conc -> low conc)

Question 16

describe electrical force

Answer 16

movement on ions based on charge of the cell vs the extracellular environment

Question 17

what is the term to describe the combination of electrical and chemical force

Answer 17

the electrochemical driving force

Question 18

what are the three types of gated channels

Answer 18

1) ligand gated channels
2) mechanically gated channels → activated by physical force eg pressure
3) voltage-gated channels

Question 19

what are the two broad categories of ion channels

Answer 19

gated channels and open channels

Question 20

describe ion concentration under resting conditions

Answer 20

low Na+

high K+

Question 21

describe potassium movement under resting conditions

Answer 21

constant flow of K+ ions down their concentration gradient out of the neuronal via open K+ channels

Question 22

what is the purpose of the sodium potassium pump

Answer 22

prevents an equilibrium forming
pumps 3na+ OUT
2k+ IN
results in a more positive charge outside the neuronal

Question 23

what is the resting membrane potential of most cells

Answer 23

-70 mV

Question 24

describe what happens to electrochemical gradients when sodium channels open

Answer 24

1. chemical gradient drives diffusion into cell
2. electrical force pulls ions into cell (attraction)
3. NA+ enters cell
4. neuron becomes more positive → forces decrease
5. forces balance = no nett flow

Question 25

describe what happens to electrochemical gradients when potassium channels open

Answer 25

1. chemical gradient= diffusion out of cell
2. electrical force= attraction into cell
3. chemical force greater than electrical force
4. potassium leaves neuron
5. cell becomes more negative
6. chemical force driving out and electrical force driving in balance= no nett flow

Question 26

define equilibrium potential

Answer 26

the membrane potential required to counteract chemical forces acting on one ion across a membrane

Question 27

what equation calculates equilibrium potential

Answer 27

Nernst equation