UAB Physiology Lab Final Questions And Answers Graded A+

Motor end plates are lined with what type of receptors? - Nicotinic receptors What releases ACh in a neuromuscular junction? - Axon Terminal What breaks down ACh, ending excitation at motor end plate? - AChE (acetylcholinesterase) ________ undergoes conformational change in response to action potential, physically attached to RyR - DHP receptor Gated Ca++channel on terminal cisternae of sarcoplasmic reticulum? - RyR (ryanodine receptor) Globular protein with active binding site for myosin head. - Actin Regulatory protein that blocks myosin binding site on actin at rest - Tropomyosin Regulatory protein with binding site for Ca++, undergoes conformational change to move tropomyosin when Ca++is bound - Troponin What is known as the Rigor State during a contraction? - When ADP is released but the myosin head is still bound to Actin Elastic protein connecting Z disk to M line, helps align filaments and passively shorten stretched muscle - Titin Inelastic protein associated with thin filament, helps maintain alignment - Nebulin What detects Action Potential along the Sarcolemma? - EMGFailure to generate or maintain output - Fatigue Psycholigical, can choose to continue - Central Fatigue Physiological failure, no choice - Peripheral Fatigue Describe an Autorhythmic cell. - -Non contractile -Self Stimulating -No resting potential -Use Na+ and Ca+ to depolarize Autorhythmic cells organized into nodes and pathways - Conduction System Connections between cells (both types) in the Heart. - Intercalated Disks Why is the SA Node called the "pacemaker" - Due to the fastest rate of depolarization What type of Fibers spread signals out at the apex of the heart? - Purkinje Fibers (Conduction Pathways) In Contractile cells, Calcium acts as a what? - Messenger Time between beats, one complete cycle, usually R wave to R wave - Interbeat Interval (IBI) From start of P wave to start of Q wave, time for atrial depolarization and contraction - P-R Interval (or P-Q Interval)From end of P wave to start of Q wave (or R if Q is not easily seen), time for atrial contraction and AV node delay - P-R Segment (or P-Q Segment) From end of S wave to start of T wave - S-T Segment