Membrane potentials

Question 1

What is resting membrane potential

Answer 1

unequal distribution of ions in and out of cell

Question 2

What makes membrane potential larger

Answer 2

greater separation of charges across membrane > larger the potential

Question 3

Which side of membrane is more negative

Answer 3

ICF more negative than ECF

Question 4

Typical resting MP of cells

Answer 4

Skeletal muscle = -90mV
Cardiac muscle = - 90mV
Spinal motor neurons = -70mV
Gland epithelia = -50mV

Question 5

What causes the resting membrane potential

Answer 5

• concentration gradient
• electrical gradient
• permeability for ions

Question 6

Membran v Action Potential

Answer 6

Every cell has membrane potential > excitable tissue can change their membrane potential (action potentials)

Question 7

What can trigger a membrane potential change

Answer 7

• stimulus
• change in voltage
• chemical messenger
• spontaneous

Question 8

Steps of each action potential

Answer 8

• Na+ channels open and potential depolarises rapidly
• at same time K+ channels open but take time
• threshold (-50mV) is reached for AP to start
• once peak reached > K+ start working and cell starts repolarising and ends up dipping below resting (hyper)
• then back to normal