U5 Lecture 34

Question 1

what are the two cell types in neuronal tissue

Answer 1

nerve cells (neurons) and glial cells (neuroglia)

Question 2

what do nerve cells (neurons) do

Answer 2

involved in the generation and interpretation of electrical signals

Question 3

what do glial cells (neuroglia) do

Answer 3

support neuronal cell activity

Question 4

what do dendrites do

Answer 4

collect information

Question 5

what does the cell body do

Answer 5

process information

Question 6

what do axons do

Answer 6

propogate info

Question 7

what do synapses do

Answer 7

transmit info

Question 8

what are the two ‘parts’ to bioelectricity

Answer 8

• resting membrane potential

- action potential

Question 9

what does resting membrane potential depend on

Answer 9

• transmembrane ion gradients (Na+ and K+)

- membrane permeability to those ions

Question 10

what happens in ion gradients

Answer 10

Na, K-ATPase develops and maintains steady-state ion gradients for ALL cells

Question 11

what happens extracellularly in resting membrane potential

Answer 11

1. pumping creates ionic gradient for K+
2. K+ leaks out down its concentration gradient so that the inside of the cells becomes more negative
3. now two kinds of forces pull/push on K+ (chemical and electrical)

Question 12

what are the two opposing forces in resting membrane potential

Answer 12

1. chemical force (K+ gradient) tends to push K+ out

2. developed electrical force (inside negative) tends to pull K+ in

Question 13

In a typical cell what two things are nearly in balance

Answer 13

chemical and electrical forces for K+

Question 14

What does it mean when chemical and electrical forces for K+ are in balance

Answer 14

outwardly-directed K+ gradient results in an inside negative electrical potential

Question 15

what is the electrical potential difference (PD) measure in

Answer 15

volts

-typically -50 to -100 millivolts

Question 16

What is a characteristic of all cells at rest

Answer 16

K+ dominated inside negative membrane potential

Question 17

what two ions are typically inside the cell in resting membrane potential

Answer 17

phosphate ion and potassium ion

Question 18

what two ions are outside of the cell in resting membrane potential

Answer 18

chloride ion and sodium ion

Question 19

what happens to the membrane during rest

Answer 19

it is polarized

Question 20

what do changes in membrane permeability produce

Answer 20

large changes in the membrane potential

Question 21

what does the regulation of channel mediated ion permeability allow

Answer 21

cells to generate electrical signals

Question 22

what are the keys to manipulation of membrane potential

Answer 22

1. maintain(stable) Na+ and K+ gradients (Na/K ATPase)

2. vary the activity of specific ion channels

Question 23

what are the three ‘important’ things to remember about ion channels

Answer 23

1. integral membrane proteins
2. channels can be open or closed
3. some channels are routinely open
4. some channels have their open states regulated

Question 24

what are the 3 types of channels that are regulated

Answer 24

1. chemically (ligand) gated channels
2. mechanically gated channels
3. voltage gated channels

Question 25

what happens in chemically (ligand) gated channels

Answer 25

they open when a signal molecule binds to the channel protein ( example ACh)

Question 26

what happens in mechanically gated channels

Answer 26

they open when membrane gets stretched

Question 27

what happens during voltage gated channels

Answer 27

they open when the membrane potential gets less negative or depolarized