M1 Lec 2

Question 1

what does it mean for a neuron to be quiescent

Answer 1

it cant be replaced by the post miotic cells

Question 2

what glial cells are found in the CNS (brain + spinal cord)?

Answer 2

astrocytes and oligodendrocytes (make myelanation)

Question 3

what glial cells are found in the PNS?

Answer 3

Schwann cells

Question 4

what do microglia do

Answer 4

immune cell - react to inflammation of nerves

Question 5

what is the myelination? actions?

Answer 5

insheathment of the axon within neurons
* insulate axon
* increase conduction velocity

Question 6

what are the 4 functional regions where a signal is generated

Answer 6

1. input
2. integrative
3. conductive
4. output

Question 7

where does a neuroendocrine cell project to

Answer 7

it passes signal onto capillary

Question 8

what is the flow of signals in a neuron

Answer 8

dendrites —> cell body —> axon —> axon terminal —> synapse

Question 9

what are the 2 forms of electrochemical communication

Answer 9

1. electrical signals - changes in membrane voltage
2. chemical signals - release of neurotransmitters

Question 10

what is the cell membrane
* 3 components of the membrane?

Answer 10

it is a lipid bilayer that acts as a filter and barrier for the cell. It is highly selective filter for ions
1. phospholipid bilayer
2. proteins
3. active na/k pumps

Question 11

what is the phospholipid bilayer made up of

Answer 11

hydrophilic head (facing outward to solution) and hydrophobic tails (sandwhiched by the two heads)

Question 12

electrical concepts: whats v, i, r

Answer 12

voltage (diff in electrical potential)
current (flow of electrical charge)
resistance (opposition of flow)

Question 13

what are ions

Answer 13

charged atoms or molecules

Question 14

k and na concentrations in and out of cell?

Answer 14

• k+ high inside cell
• na+ high outside cell

Question 15

what is capacitance? how does the membrane act as a capacitor?

Answer 15

• the ability to store electrical charge
• the membrane stores charge via the separation of ions across the bilayer (has unequal ion distribution - neg inside pos outside cell)

Question 16

the membrane acts as a resistor to the flow of ions. How do ions get around this?

Answer 16

they have ion channels and provide pathways for ions to cross the membrane which reduces resistance (open/leaky channels + gated channels)

Question 17

what formula do you use to measure the difference in voltage across the membrane

Answer 17

Vm = V in - V out

Question 18

what is the concentration gradient

Answer 18

differences in ion concentration across the membrane
* move from high to low conc

Question 19

electrical gradients

Answer 19

differences in electrical potential across the membrane

Question 20

electrochemical gradient

Answer 20

combined influence of concentration and electrical gradients on ion movement
* ex: elec gradient attracts K+ in, conc gradient pulls K+ out of cell

Question 21

permeability of cell at rest

Answer 21

• most permeable to K+ bc of leaky channels
• few open Na+ channels bc limited

Question 22

what is donnan equilibrium

Answer 22

overall distribution of diffusible ions is uneven, but electrical and chemical forces are balanced

Question 23

What is the equation for chemical force?

Answer 23

Question 24

What is the equation for electrical force?

Answer 24

Question 25

what is the nernst equation and when is it used

Answer 25

used to calculate equilibrium potential for single ions (where elctrical and chemical forces are balanced)

Question 26

how do neurons communicate

Answer 26

through electrochemical signaling