electrical properties of nuerons Flashcards
what is the basic unit for nervous system
nuerons … they generate electrical signals and communicate to other nuerons
neuron basic features
- cell body
- one side there is
- that hosts nucleus and different organelles
- dentrites= receives signals from environment or other nuerons
neuron electrical signals
travel from dendrites, across axon
then signal is relayed at axon terminal to another neuron
what happens on axon terminal
info relayed chemically thru synpatic commiucation
function of neuron
transform electrical info into chemical info
main function of plasma membrane
act as barrier , distingushes intracellular components from the extra cellular space
structure of membrane
phospholipids, contains hydrophilic head which is polar (faces the cytosol and extracellular space)
phosolipid tails
hydrophobic
face each other
provide a very hydrophobic environment that is v impermeable to lots of molecules
what can pass the membrane
- gases
- very small uncharged molecules
- very few small charged molecules
what can not pass the membrane
ions
large charged molecules
water passing through
water can pass the membrane if the driving force is very strong
types of transport across membrane
- diffusion ( only for gases) no requirement for engery
- facilitaed diffusion HIGH —-> LOW
active transport requires ATP. L—->H
facilitated diffusion applies to
molecules that are not permeable in the membrane tf they cant pass on their own
tf they need protein … channels or protein carriers
active transport
energy required to move a substance across a membrane against its concentration gradient
why does active transport need ATP
going from low conc to high conc
tf need to break energetic barrier of going against conc.
the electrochemical gradient is
combination of concentration and charge differences across the membrane
driving force for ion transport
nueronal membrane charge
negatively charged on cytoplasmic side
positively charged on extracellular side
membrane potential:
charge Q
current I
- net imbalance of number of positively charged and negatively charged particles in a given place
- flow of electrically charged particles , in body fluids these are ions eg Na+, K+ , Cl-
membrane potential:
voltage V
measure of potential difference between two points . In these points , one of them is more positive than the other .
in the context of nuerons and their membranes , electrical voltage represents the
electrical potential energy gradient.
since one side is + and other side is - , the electrical potential energy will drive charged particles to go from one side to another
electrical potential (voltage)
difference in charged between inside v outside of cell
why does interior of cell have relative negative net charge in comparison to outside of the cell
ionic composition of cytoplasm
membrane potential:
electrical gradient
-influenced by
-ions
–overall electrical charge
-positive ions would flow to areas of negative charge
membrane potential :
chemical gradient
-influenced by
-ions
- individual conc. of a particular ion
- all ions move to areas of high conc. to low
