Module 3: Lecture 1 Flashcards
what separates the intra and extra cellular fluid?
the plasma membrane
- restricts the flow of molecules (bilipid membrane, not just anything can cross it)
is a water molecule able to cross a bilipid membrane?
no
are ions water soluble?
yes
do ions have attractive forces?
yes between them
what would the ions in the extracellular and intracellular fluid do if there was not a membrane?
they would just mix
what is the membrane potential?
the restriction of ions in the membrane and the difference of charges in the ICF and ECF due to the difference of ions between them
- preventing ions from freely diffusing into their lower concentration space
what does saying “the membrane has been polarized” mean?
there is a separation of charge across the membrane
ex. -4 inside the cell and +6 inside the cell gives us a difference of 10
what is the fundamental basis for cellular communication in nervous and muscle tissues?
when we allow ions to somehow mix and traverse across the membrane
- the separation of charge that allows your nervous system to communicate
the plasma membranes of all living cells are polarized _________.
electrically
- separates charge to form a ‘membrane potential’
what are the key factors regarding membrane potential?
- it is defined by the separation of charge
- difference in the relative number/concentration of cations and anions in the ICF and ECF (dictates the degree or magnitude of the membrane potential)
- difference in permeability of key ions
- therefore: ion movement (membrane potential) is influenced by both ion concentration and membrane permeability
- membrane potential is measured as volt or millivolt
what is the basis of cellular communication?
- restricting the movement of ions st rest because of the cell membrane
- when we allow the charges to mix, we can use the mixing to perform work
what is the fundamental basis that allows your nervous system to communicate?
- separation of charge of the cell/plasma membrane
what is membrane potential measured by?
Volt or millivolt (mV)
the movement of ions across a membrane are determined by?
- concentration gradient (high to low)
- electrical gradient (opposites attract, similar charges repulse)
- combined effects = the electrochemical gradient
whether the ion moves across the membrane or not depends on?
whether the membrane is permeable to that ion
- cell membranes are very restrictive to the flow of ions across it
what makes a membrane have a ‘potential’?
when there is an unequal distribution of electrical forces
- hence, a membrane potential has been generated
- exists because of an unequal + and - on both sides
in biological cells, there are many ions in the ICF and ECF, but there is a greater concentration of ions located?
in a thin layer along the outer and inner surface of a cell membrane
is the membrane itself charged?
no