BRS Physio Flashcards
Characteristics of simple diffusion
Not carrier mediated
down an electrochemical gradient
Passive
Facilitated diffusion
down electrochemical gradient
passive no metabolic energy
Carrier mediated
Example: Glucose transport
Primary Active Transport
agasint electrochemical gradient
needs ATP and is active
carrier mediated
Example: Na-K-ATPas
Voltate gated channels
Opened or close by changes in membrane potential
Example: Na/K
Ligand gated channels
Open or close by hormones, second messengers or neurotransmitters
Example: Nicotinic receptor
At rest the membrane potential is far more permeable to
K over Na
Depolarization
Makes the membrane potential less negative
Hyperpolarization
Makes the membrane potential more negative
Inward current
Flow of positive current into the cell and depolarizes the membrane
Outward current
Flow of positive current outside of the cell, hyperpolarizes the membrane
What happens during the upstroke of the action potential? And what drug can block this?
Depolarization casues rapid openeing of the activation gates of the Na channels. Lidocaine
What two steps happen during depolarization
inactivation gates close of NA
K+ gates slowly open
During what condition does acommodation happen? And what is the result in the body?
hyperkalemia and muscle weakness
What two things increase conductance?
Increased fiber size
Myelination
In chemical synapses which ion enters the presynaptic terminal causing neurotransmitter release
Ca
At the neuromuscular junction what neurotransmiter is released from the presynaptic terminal? What about the post?
Pre: AcH
Post: Nicotinic
What catalyzes the formation of ACH from CoA and choline?
Choline acetyltransferase
What does Botulinum toxin do?
Blocks release of ACh from presynaptic terminals causing a total blockade
What does Neostigmine do?
Inhibits acetylcholinesterase which prolonges and enhances action of AcH at muscle end plate.
Examples of excitatory postsynaptic potentials and waht do they do?
Depolzarie cell by opening Na and K, include AcH, norepinephrine, epinephrine, dopamine, glutamate and serotonin.
Examples of inhibatory postsynaptic potentials and what they do?
hyperpolarize , open Cl- channels, GABA, glycine
Noreepinephrine
Primary transmiter from postganglionic sympathetic neurons, binds with alpha or beta receptors, removed by MAO
Epinephrine
Synthesized from NE by the action of phenylethanolamine in the adrenal medulla
Dopamine
Midbrain neurons, inhibits prolatin sectrtion
Serotonin
High concetrations in brain stem from tryptophan and is converted to melatonin in the pineal gland
Histamine
From hypothalamus
Glutamate
most prevalant excitatory neurotransmisiter
GABA/ Glycine
Inhibatory neurotransmiter
Nitric Oxide
short acting inhibatory neurotransmitter in GI. blood vessels and central nervous system.