Cellular communication - Lecture 9: Electrical properties of the plasma membrane

studied byStudied by 0 people
0.0(0)
learn
LearnA personalized and smart learning plan
exam
Practice TestTake a test on your terms and definitions
spaced repetition
Spaced RepetitionScientifically backed study method
heart puzzle
Matching GameHow quick can you match all your cards?
flashcards
FlashcardsStudy terms and definitions

1 / 15

encourage image

There's no tags or description

Looks like no one added any tags here yet for you.

16 Terms

1

How is the plasma membrane a resistor?

  • low resistance for hydrophobic substances

  • high resistance for charged substances

New cards
2

What is the function of the Na-K pump?

  • continuously pumps sodium outside the cell and potassium inside the cell

  • this generates a concentration gradient

    • extracellular [Na+ ] is higher than intracellular [Na+ ]

    • extracellular [K+ ] is lower than intracellular [K+ ]

  • the difference between ion concentrations inside and outside the cell generates an electric potential

New cards
3

How is the electric potential measured?

Em = E[inside the cell] - E[outside the cell]

inside of the cell is always kept negative with reference to the outside

New cards
4

What happens when a positively charged molecule is allowed to pass through the membrane of the cell?

  1. initially the concentration gradient and the electrical force will be to the same direction

  2. The passage of few positive ions through the membrane creates a current that quickly changes the voltage of the cell to be positive, thus the direction of the electrical force will be flipped

New cards
5

What is the equilibrium potential?

  • the potential at which the concentration gradient is equal to the electrical force imposed by the movement of an ion across the membrane

  • each type of ion has it’s own value of equilibrium potential in the cell

  • it is calculated using the Nernst equation

New cards
6

What is the Nernst equation?

is used to calculate equilibrium potential (Ek ): Ek = RT/zF * log([ion concentration outside the cell]/[ion concentration inside of the cell])

New cards
7

Why is the resting potential of the cell always kept close to the equilibrium potential of K+ ions?

because the membrane is more permeable to K+ than other ions

New cards
8

What happens during mild hyperkalemia (high K+)?

  • abnormal heart rhythms

  • more than 7nM may cause cardiac arrest

New cards
9

What happens during hypokalaemia (low K+)?

  • muscle weakness

  • fatigue

New cards
10

How is the membrane potential calculated?

knowt flashcard image
New cards
11

What does depolarization mean?

increasing cellular membrane potential towards positive values

New cards
12

What does repolarization mean?

means bringing membrane potential back to resting state after depolarisation

New cards
13

What does hyperpolarization mean?

decreasing cellular membrane potential towards negative values

New cards
14

What stimulates ion channels?

  • voltage change

  • ligand binding

  • temperature

  • pH

  • mechanical stimulation

  • calcium

<ul><li><p>voltage change</p></li><li><p>ligand binding</p></li><li><p>temperature</p></li><li><p>pH </p></li><li><p>mechanical stimulation</p></li><li><p>calcium</p></li></ul><p></p>
New cards
15

What is the cellular phenomenon that is a cycle of depolarization followed by repolarization?

action potential

New cards
16

What are examples of the excitable cells?

  • neurons

  • skeletal myocytes

  • cardiac myocytes

  • smooth muscle cells

  • alpha cells

  • beta cells

New cards

Explore top notes

note Note
studied byStudied by 64 people
213 days ago
4.7(3)
note Note
studied byStudied by 26 people
891 days ago
5.0(1)
note Note
studied byStudied by 25 people
514 days ago
5.0(1)
note Note
studied byStudied by 4 people
688 days ago
5.0(1)
note Note
studied byStudied by 16 people
903 days ago
5.0(1)
note Note
studied byStudied by 10 people
760 days ago
5.0(1)
note Note
studied byStudied by 67 people
701 days ago
5.0(4)
note Note
studied byStudied by 44 people
758 days ago
5.0(3)

Explore top flashcards

flashcards Flashcard (92)
studied byStudied by 11 people
841 days ago
4.0(1)
flashcards Flashcard (116)
studied byStudied by 10 people
800 days ago
5.0(1)
flashcards Flashcard (43)
studied byStudied by 15 people
3 days ago
5.0(1)
flashcards Flashcard (57)
studied byStudied by 17 people
750 days ago
5.0(2)
flashcards Flashcard (40)
studied byStudied by 2 people
177 days ago
5.0(1)
flashcards Flashcard (71)
studied byStudied by 42 people
385 days ago
5.0(4)
flashcards Flashcard (82)
studied byStudied by 41 people
88 days ago
5.0(1)
flashcards Flashcard (222)
studied byStudied by 29 people
646 days ago
5.0(1)
robot