Neuronal Action Potential PDF

11/6/24 PHARMACOLOGY maker 4 PHYSIOLOGY REVIEW 5 A & P Review Answer The cell membrane is a ________________ bilayer...

11/6/24 PHARMACOLOGY maker 4 PHYSIOLOGY REVIEW 5 A & P Review Answer The cell membrane is a ________________ bilayer penstein we The cell membrane is mostly impermeable to ________ – soluble substances such as ions and glucose Yeti µ Structurally, ion channels, receptors and enzymes are ________________ Oxygen and carbon dioxide move through cell membranes via this mechanism. amusion The sodium-potassium ATPase (pump) moves __(how many?)__ Na ions 3Pmmouijati.in t.IE __(in/out)__ and ___(how many?)___ K ions __(in/out)__ Ion channels transport charged ions across cell membranes causing actpornigt iEcI conduction of electrical signals, known as ____________ _____________ The endoplasmic reticulum makes proteins, lipids and metabolizes carbohydrates. The sarcoplasmic reticulum in the muscle stores and releases what important 2nd messenger? 6 2  11/6/24 THE ACTION POTENTIAL Deponanremain resit a ssw.es s 7 NEURONAL ACTION POTENTIAL 70 Resting membrane potential (slightly polarized) at -70 mV ICF relatively ________________ Negative compared to ECF sodunpotasionremiqe.is 8 30 NEURONAL ACTION POTENTIAL propagate the along membrane Stimulus (e.g., change in nearby membrane potential) initiates process Threshold at –55mV when Na+ voltage-gated channels open ________________________________ mail.EEriani neses Te egm b eeso 9 3  11/6/24 30 NEURONAL ACTION POTENTIAL Membrane potential at +30mV, time-bound Na+ channels close = inactivation K+ voltage-gated channels open as delayed response to original stimulus hiii in I ________________________________ 10 iE a Heparisation NEURONAL ACTION POTENTIAL Na+/K+ ATPase active K+ channels are slow to close transport of ions i iE _______________________________ RESTING MEMBRANE POTENTIAL mails 11 ACTION POTENTIAL ABNORMALITIES Calcium inexmanntense potential Hypocalcemia – prevents Na+ channels from closing between APsLacion ○ Sustained __________________________________ muscer deporisation (repetitive fire; e.g., tetany) Hypercalcemia – decreases cell membrane permeability to Na ○ Decreased excitability of membrane ithadtocrestactionpotential Reprovisationisagents 12 4  11/6/24 ACTION POTENTIAL ABNORMALITIES Potassium Hypokalemia – more negative RMP potential resinmansion iiiIi ○ _____________________________________, decreased membrane excitability (e.g., skeletal muscle weakness) man examsmanner Sodium Sodium channel blockade, prevents threshold potential for AP generation (e.g., decreased contractility, altered cardiac conduction) netd ens Pairst.in theseIntentitit Iii the 13 THE SYNAPSE AP from pre-synaptic membrane to post-synaptic membrane across cleft Pre-synaptic membrane viii Vesicles with neurotransmitter Reuptake pump c an aaaa.in cnn.mn Voltage-gated ca channels Receives afferent action potential https://www.dana.org/article/qa-neurotransmission-the-synapse/ 14 THE SYNAPSE i Post-synaptic membrane I I i NT binds receptors Efferent action potential iiii.it iiiiiiii Receptors & structural proteins maintain synaptic homeostasis = postsynaptic density andit manume pag.zeaests.mn https://www.dana.org/article/qa-neurotransmission-the-synapse/ 15 5  11/6/24 THE SYNAPSE presomizmanson posiS.EE 16 THE SYNAPSE Modulation Change in synaptic function Synaptic signaling, membrane potentials influence depolarization & stimulus response Delay 0.3 - 0.5 ms → NT release, diffusion, binding, ion flow barista not Fatigue to s ame cause Repetitive stimulation of excitatory synapses Reduced post-synaptic responseemanedepoisae.atepaorisaons May also be related to depletion of NT stores comes 17 THE SYNAPSE Post-Tetanic Facilitation Repetitive stimulation of presynaptic terminal Short rest period Synapse _____________________________________ go quasarepeness more than normal to subsequent stimulation ingens tore L cat 18 6  11/6/24 THE SYNAPSE Neuronal Responsiveness Changes in pH ○ Alkalosis - increased excitability ○ Acidosis - decreases __________________________________ excitability Changes in PaO2 ○ Hypoxia - decreased excitability 19 RECEPTOR PHARMACOLOGY 20 CELL MEMBRANE LIPID BILAYER 21 7