Neurons

Question 1

What is the morphological division?

Answer 1

CNS and PNS

Question 2

What is cephalisation?

Answer 2

the formation of central ganglia and brains in one end of the animal body

Question 3

What is the dorsal chord?

Answer 3

in the vertebrate line of the animal kingdom

Question 4

What is the ventral chord?

Answer 4

In the invertebrate line

Question 5

What are the main functions of the nervous system?

Answer 5

TO monitor and regulate inner organs, release chemical messengers

Question 6

Is the neural membrane polarised?

Answer 6

yes

Question 7

Where are ion channels distributed?

Answer 7

along the neural membrane

Question 8

Ion’s distribution and properties enable the neruon to…

Answer 8

generate tiny localised bioelectric currents.

Question 9

What do all neurons have?

Answer 9

Input zone,
integration zone,
conduction zone,
output zone

Question 10

What is the input zone?

Answer 10

soma, dendrites

Question 11

What is the integration zone?

Answer 11

between soma and axon

Question 12

what is the conduction zone?

Answer 12

axon

Question 13

what is the output zone?

Answer 13

axon terminals

Question 14

Neuronal membrane is selectively what?

Answer 14

permeable

Question 15

Most channels are made from ___ proteins that assemble themselves to produce a central _____

Answer 15

4

pore

Question 16

Ion channels have a selectivity filter that only allows…

Answer 16

ions of a particular charge and size to pass through

Question 17

What does the semi-permeable membrane allow

Answer 17

diffusion whilst the passage is open. When ion channels in the neural membrane open, ions can diffuse.

When ion channels are closed, ions can diffuse inside the cell and along the membrane but not beyond the membrane and out of the cell.

Question 18

Ion distribution differs inside and outside of the cell which forms an

Answer 18

electrochemical gradient

Question 19

What are the three classes of ion channels

Answer 19

Gated ion channels, ion pumps, lead channels

Question 20

What do gated ion channels do?

Answer 20

remain closed until activation for a very brief period of time, either by electrical signals (voltage-gated) or by drugs or messenger molecules (ligand-gated).

Question 21

What are voltage-gated?

Answer 21

electrical signals

Question 22

What are ligand-gated

Answer 22

messenger molecules

Question 23

WHat do ion pumps do?

Answer 23

actively transport ions in and out of the neuron

Question 24

What do leak channels allow

Answer 24

a specific ion type to freely diffuse (e.g. they are always open and let K+ through but not Na+)

Question 25

What do ion pumps help do?

Answer 25

restore and maintain the difference in ion concentrations inside and outside the neuron

Question 26

What are the most importatn pumps in ion pumps

Answer 26

Sodium-potassium and calcium

Question 27

What is intracellular recordings?

Answer 27

Microelectrodes are placed inside

Question 28

What are extracellular recordings?

Answer 28

Microelectrodes are placed outside

Question 29

How do we measure neural currents?

Answer 29

Voltage (V) – difference in potential, measured in volts Strength of current (I) – electrostatic force moving charge per second, measured in amperes Resistance (R) – difficulty of passing a current along a conductor Multimeter – instrument to measure voltage, current, resistance

Question 30

What is Ohm's law?

Answer 30

V = I x R

Question 31

How thick are squids axons

Answer 31

1mm

Question 32

How much bigger are squids axons than mammalian?

Answer 32

100-1000x bigger

Question 33

What is resting potential?

Answer 33

Membrane potential of a nerve cell at rest

Question 34

What is neural signal?

Answer 34

Change of resting potentail to more negative or positive potntial

Question 35

WHat is hyperpolarisation?

Answer 35

a more negative membrane potential than the resting potential

Question 36

What is depolarisation?

Answer 36

a more positive membrane potential than the resting potential

Question 37

where do graded potentials occur?

Answer 37

in dendrites

Question 38

What is action potential (spike)

Answer 38

- An all-or-nothing response when the depolarisation increases above a neuron-specific threshold (action potentials never occur during hyperpolarisation)