Please describe & explain the main parts of the pacemaker and action potential observed in the SA node. Millivolts +20 O -60 Why does this action potential look different than that of a neuron in the nervous system? During what portion of this action potential is there contraction of the myocardiocyte? Voltage gated ca+ channels Compare the electrical activity above with the action potential observed in the average cardiomyocyte (below). +20 Millivolts 0 -20 -40 -60 he channels na -80 -100 pacemaker potentials CHCN channels Time- Nat in сад+ in (slow) K+ out 0 50 100 150 200 250 300 350 400 Milliseconds

Please describe & explain the main parts of the pacemaker and action potential observed in the SA node. Millivolts +20 O -60 Why does this action potential look different than that of a neuron in the nervous system? During what portion of this action potential is there contraction of the myocardiocyte? Voltage gated ca+ channels Compare the electrical activity above with the action potential observed in the average cardiomyocyte (below). +20 Millivolts 0 -20 -40 -60 he channels na -80 -100 pacemaker potentials CHCN channels Time- Nat in сад+ in (slow) K+ out 0 50 100 150 200 250 300 350 400 Milliseconds

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Can you help with number 1 and 2 This is not and will not be graded
Caffeine lowers the heart rate by increasing rates of depolarization at the SA node True False Nicotine raises the heart rate because it stimulates the activity of the sympathetic neurons in medulla oblongata True False The Frank-Starling Law of the Heart states that the force of heart contraction is directly proportional to the initial length of the muscle fiber, within optimal limits of length True False If the sarcomeres stretched beyond the optimal length, the force of contraction would go down, but that can potentially happen only during open heart surgery when the heart is not constrained by the pericardium, lungs, ribs and diaphragm. True False It is the Na+ channel-driven spontaneous depolarization that is affected by sympathetic and parasympathetic inputs to speed up or slow down the firing rate of the SA node and other conductive cells. True False
Antiarrhythmic drugs are used to correct an irregular heartbeat. Give 2 examples each of class 1-1V drugs that act at positions 0-4 of the myocardial action potential sequence. Do not give brand names, use generic names.
A person eats a plan that is an agonist to adrenergic receptors on contractile myocardial cells. Which of the following is NOT likely to happen if the adrenergic receptors on this persons conctractile myocardial cells get blocked. Contractile myocardial cells will depolarize more slowly slower uptake od Ca2+ by Ca2+ ATPase from sarcomeres less Ca2+ released from sarcoplasmic reticula following action potentials voltage gated Ca2+ channels get held open longer
Other than heart rate what are two other variables that increase with exercise and why do they increase? Possibly variables include systolic BP, Diastolic BP, MAP, R-T interval, etc.
Can you help with number 6 and 7 This is not and will not be graded
Please help me answer questions 12 and 13
Hyperglycemia associated with diabetes promotes a prothrombotic state by affecting a number of different steps in the clotting pathway. Which of the following would result in more rather than less clotting? Check all that apply. The correct answers reflect the effect of hyperglycemia on the clotting pathway! less conversion of plasminogen to plasmin 7 000000000 abnormally low number of platelets platelets more sensitive to thromboxane A2 elevated conversion of plasminogen to plasmin platelets less sensitive to thromboxane A2 low sensitivity to NO and PGI2 increased prothrombin in the blood increased amount of fibrinogen in the blood less prothrombin in the blood abnormally high number of platelets less fibrinogen in the blood high sensitivity to NO and PGI2
please identify one feature (resting membrane potential, the voltage at a particular point of the action potential, the types of ions moving through voltage-gated channels...) of a neuronal action potential or skeletal muscle sarcomere contraction, and relate it to the action potential or contraction of an SA node cardiocyte or a non-SA node cardiocyte ("regular" cardiocyte). Identify whether this feature is similar to the cardiocyte or different.
When given an image of a cardiac contractile cell, such as the one below, describe the steps that occur during excitation-contraction coupling (the "before step 1" step show with the squiggly red arrow below), contraction (steps 1-6 below) AND relaxation (steps 7-10 belowl). Be sure to fully describe the role of Ca¹² ATPase and Na+Ca+2 exchanger (NCX) in steps 9 and 101 ECF ICF SR Ca2+ RyR Cat sparks Ca signal Contraction Ca channel T-tubule 2 K ATP ATP 3 Na Ca²+ Sarcoplasmic reticulum Cat stores (SR) 3 Nat Ca NCX Relaxation Ca2+ Actin Myosin