biological electricity Flashcards
(12 cards)
whats excitable tissue for
it allows an individual animal to respond more rapidly to its changing environment and maintain homeostasis
what is electricty
this is the medium that evoltuion has chosen to convey the information rapidly around the body via the nervous system
examples of excitable tissue
-nervous system
-the heart
-smooth muscle
what do nerve cells do?
they generate electricity
they generate a potential difference across the membrane
in ancient times what did the greeks consider the mind in terms of
“animal spirits” within the fluid cavities of the brain
rene descartes
established the brain as the set of the mind but hypothesised upon mechanisms involving fluids within nerves as the force
who suggested nerve force might be electricty
isaac newton and stephen hales
why are biological materials very poor conductors
-their cable properties are bad and passive electrical resistance can only spread by a few mm before they are dissipated by the resistance
what have excitable tissues developed to overcome physical deficiencies
they’ve developed action potentials
what is another characteristic of biological electricity
-it has very low voltage
-the potential difference across a neuronal membrane is approx 70 millivolts
why are resting potentials essential
they are essential for excitable cells to generate action potentials
where do resting potentials derive from
-the work of the sodium potassium pump
-the selectively permeable membrane
-largely negatively chrhed proteins within the cell
