Shared Flashcard Set


1st and second lecture

Additional Physiology Flashcards





A) What is the order of Cardiac eletrical action

B) What are the cells involved in cardiac action

C) 2 cell types for action potentials in heart 



A) Electrical activity before contraction and relaxtion. Activated sequentially.

B) Pacemaker, conducting tissue, myocyte cells


C) 1. slow action potential. Less than one percent pacemaker with auto-rhythmicity

2. fast action potetion more than 99%. Myocytes and specialized conducting tissue


A) What are the three electrical states of cardiac Membrane potential

B) Membrane potential is determined by what?

C) Differences in ion charge [] set by?

D) What is a characteristic of ionic resting membrane potential of heart (phase 4)?


A)1. resting 2. depolarizing (systole) 3. repolarizing (diastole)

B) electrical charge inside and out and [] of the ions

C) active ion pumping and membrane permeability

D)high intracellular K+

high k+ permeability

No Na or anion permeability


A) Describe the fast action potential graph

B) Who reestablishes the ion concentration gradient?


1) phase 4 2) Phase 0- increase na permeability 3) phase 1- low na permeability. 4) phase 2- high calcium permeability and low k permeability 5) phase 3- high k permeability and low calcium permeability 6) phase 4 again.

B) Na/K atpase and Ca atpase.


A) Describe the slow action potential graph

B) what phase is missing?

C) what is effective and relative refractory period?


A) 1) phase 4- Ca++ in and Na+ out

phase 0- increase Ca++ in

phase 2- peak

phase 3- K+ out

B) phase 1

C) no depolarization possible, limited depolarization possible


A) How does epinephrine control heart rate?

B) How does norepinephrine control heart rate?

C) Describe the Cardiac Conduction System


A) Depolarizes autorhythmic cells and speeds up depolarization

B) hyperpolarizes membrane potential of autorhythmic cells and slows depolarization.

all occurs in phase 4

C) SA node to AV node via internodal pathways. Then moves down the atria where signal is slowed. Signal goes down ventricular conducting system (intraventricular septum, endocardium, epicardium) to the apex and then upward from the apex.


A) What are some common cardiac conduction problems

B) What are some causes of cardiac problems?


A) Loss of SA node pacemaking (Bradycardia)

Asystole- complete failure of pacemaker cells.

B) Drugs, hypothermia, myocardial infraction 


A) What is an electrocardiography and how is it detected.

B) What does the P wave, and QRS and T wave tell you?

C) Abnormalities of EKG lead to?

D)What are some EKG abnormalities?


A) Sum of individual routes of depolarization and repolarization that moves across the heart. electrodes can detect electrical activity.

B) atria contraction, ventricular contraction and repolarization.

C)Thickness of chambers, hypertension, changes in electrolytes.

D) atrial fibrilation, ventricular fibrilation, third-degree block.


A) What is Starling's law of the heart?

B) Outline excitation-contraction coupling of the heart


A) Stronger force (volume ejected) with greater resting length of sarcomeres. Due to Ca++ sensitivity

B) action potential comes in. 2) ca channels open. 3) ca induces ryanodine channels to open. 4) summation of ca binds to troponin. 5) relaxation occurs when ca unbinds and ca pumped back into sarcoplasmic reticulum. Ca is exchanged with Na


A) name both atrioventricular and both semilunar valves.

B) name parts of cardiac mechanical cycle


A) mitral and tricuspid. Aortic and Pulmonic valve

B) 1. late diastole 2. atrial systole 3. isovolemic ventricular contraction 4. ventricular ejection 5. isvolemic ventricular contraction


A) What are the variables of cardiac cycle?

B)Determinants of preload

C) Factors enhancing contractility?

D) factors inhibiting contractility?


A) End-diastolic pressure - end-systolic pressure = stroke volume.

B) external factors- preload and afterload

intrinsic- inotropic state

C) Treppe phenomenon and post-extrasystolic potentiation.

D) drugs and increased sympathetic tone.

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