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Echocardiography
DMSI 135
| Term | Definition |
|---|---|
| How long does it take your heart to move your entire blood supply? | 26 seconds |
| What is the only property of the cardiac cell? | Intrinsic |
| What is automaticity? | The ability to initiate an electric impulse. |
| What does the long refractory period ensure? | The long factory ensures the depolarization wave will stop once it has crossed the heart. |
| What is excitability? | The ability of a cardiac cell to respond to an electrical impulse. |
| What is conductivity? | The ability of the cells to conduct the impulse to adjacent cells. High speed conduction. |
| What is contractility? | The ability of a cardiac cell to shorten and cause muscle contraction as a response to electrical stimuli. |
| _____ is high within the cell and low outside of the cell/resting state | Potassium |
| ____ is high outside of the cell and low within the cell/resting state | Sodium |
| What causes action potentials? | The movement of ions across the membrane |
| What is an action potential and what is it based on. | The action potential is a representation of the changes in voltage of a single cardiac cell. This action potential is based on the purkinji fibers. |
| What is potential? | Potential is the potential energy or capacity used to drive ions across the cellular membrane. |
| What is membrane potential? | The difference in electrical charge between the inside and the outside of a cell. |
| What happens during resting membrane potential? | The cell is not producing an action potential. |
| What does action potential result in? | Ventricular contraction |
| Cardiac cells at rest a.k.a. the resting state are_____ meaning____ | Polarized, no electrical activity |
| The inside of the cell is more_____ while the outside of the cell is more____. What is this imbalance across the cell membrane called? | Negatively charged, positive. Resting potential. |
| List all of the action potential phases in order. | Phase 0 – depolarization, phase 1 – brief polarization, phase 2 excitation – contraction coupling (ventricular contraction) phase 3 – early repolarization (squeezed empty) phase 4 resting membrane potential |
| True or false – cardiac cells can lose their internal negativity. | True – cardiac cells can lose their internal negativity during depolarization. |
| What is the fundamental electrical event of the heart? | Depolarization |
| True or false – depolarization is not propagated from cell to cell | False – depolarization is propagated from cell to cell, producing a wave of depolarization that can be transmitted across the entire heart. |
| What happens during repolarization? | The cardiac cells restore their resting polarity through membrane pumps which reverse the flow of ions. |
| True or false. – Action potential is produced during resting membrane potential. | False – NO ACTION POTENTIAL IS PRODUCED IN THE STATE |
| When does the absolute refractory period occur? | Phases 1 – 3 but mainly between 2–3 |
| What happens during action potential phase 0 | Rapid depolarization. The membrane potential shifts into positive voltage range. This phase is central to rapid propagation of the cardiac impulse. Rapid sodium influx. |
| What happens during action potential phase one | Rapid polarization. This phase sets the potential for the next phase of action potential. Potassium exists the cell. |
| What happens during action potential phase 2? | Plateau phase; phase 2 is the longest phase, it is unique among excitable cells and marks the phase of calcium entry into the cell. Calcium activates contraction. |
| What happens during action potential Phase 3 | Rapid repolarization that restores the membrane potential to its resting value. Squeezed empty. |
| What happens during action potential phase 4 | Resting membrane potential. sodium and calcium channels close. The action potential results in ventricular contraction.. |
| Ions move across the membrane during___this causes___. | Depolarization, muscle contraction. |
| How does depolarization and contraction occur? | As a wave across the heart muscle. |
| What is repolarization and what does it cause? | Repolarization is when the ions return to resting state and become more negative inside the cell. This causes muscle relaxation. |
| What signals the heart to contract? | Electrical pulses traveling down through the heart. |
| True or false – the atrium must contract before the ventricles | True |
| Ventricles must contract ___ to ___ | Apex to base |
| What is the SA node known as and where is it located? | The pacemaker of the heart, border of the SVC and RA |
| What is the intrinsic rate of the SA node? | 60–100 BPM |
| Which node generate an impulse that traverses the atrial fibers to produce the atrial contraction? | SA node |
| How do the atria communicate with each other? | The Bachman‘s bundle |
| What is the rate of the atrial ventricular node and where is it located? | 40 to 60 BPM. Located in the floor of the RA. |
| How does the AV node receive the signal from the SA node? | Internodal tracts |
| The AV node is know as ___. And ensures ___ | The gateway to the ventricles . Ensures that the atrial contraction is complete before the ventricular contraction. |
| True or false- the Sa and AV node only respond to sympathetic responses. | False- the nodes respond to both sympathetic and parasympathetic responses |
| Where is the bundle of His located and where does it receive its impulse from? | The interventricular septum. From the AV node and transfers it to the Apex. |
| How many branches does the bundle of His divide into? | 3. one right branch and two left branches. |
| What develops from bundle branches and spread through the ventricles | Purkinje fibers |
| True or false ventricle stimulation will cause depolarization of the cells | True |
| How does a contraction occur? | Endocardium to epicardium and base to Apex, wringing motion |
| What are the components of the conduction system? | SA node > AV node> bundle of his> right and left bundle branches>purkinje fibers |
| What is systolic function? | The ability of the heart to eject blood from the heart |
| What are the two cycles of cardiac function? | Systolic and diastolic function |
| List examples of heart disease that can cause a reduction in the systolic function | HTN, CHF, cardiomyopathy, ischemia from blockage |
| What is diastolic function? | The ability of the ventricles to relax and fill |
| What are the four main things cardiac function depend on and which is more important | 1 how well ventricular wall thickens 2 how well the walls contract and how well all segments work in this motion 3 the size of the chambers 4 most important -ventricular end diastolic pressure |
| What is wall thickening and wall motion referred to as | Contractility |
| What does the function of wall, thickening and wall motion indicate? | How well the coronary arteries are supplying each segment, allowing for good motion |
| Walls should thicken and contract in___ thin and relax in____ | Systole. Diastole |
| If the wall does not thicken or construct properly it’s considered____ | WMA wall motion abnormalities |
| Hyperkinetic | Excessive wall motion |
| Hypokinetic | Decreased wall motion |
| Akinetic | No movement or thickening of the myocardium |
| Dyskinetic | Movement away from the center of the cavity; maybe an indication of MI-paradoxical movement |
| What could akinetic indicate? | MI or hibernation |
| What is hibernation? | Ischemic segment that is akinetic, but not infracted. It is a reversible condition. |
| What happens if a wall becomes ischemic | There will be diastolic dysfunction because of the lack of relaxation and decreased diastolic function |
| When can walls become dyskinetic? | When the walls do not compensate for increased pressure |
| The size of the chamber can Indicate_____ | Cardiac function, good, and bad |
| What corresponds to the degree of fiber stretch in the muscles of the ventricular walls | Left ventricular end diastolic pressure and right ventricular end diastolic pressure |
| True or false the extent the fiber stretch will depend on the amount of blood in the ventricle | True |
| The greater the amount of blood in the ventricle = | The greater force needed to eject blood from the ventricle |
| What is a normal heart rate? | 60 to 100 BPM |
| What is stroke volume? | The volume of blood ejected out of of the heart within EACH BEAT |
| What is a normal stroke volume? | 70 - 100 ml |
| What does stroke volume depend on? | LVEDV |
| The greater the LVEDV and heart rate the greater the___ | Stroke volume |
| What is cardiac output? | The combination of the stroke volume and heart rate |
| Cardiac output is the volume pumped out of the LV in___ | One minute |
| What is a normal cardiac output? | 4–8 liters/minute |
| What is the formula for cardiac output? | SV x HR |
| What is the cardiac index? | The cardiac output adjusted for the body surface area |
| What is blood pressure? | The pressure within the arteries |
| For blood pressure the top number is ___and the bottom number is___ | Systole. Diastole. |
| What is the normal blood pressure? | 100– 140/60– 90 |
| What is preload? | The volume of blood exerted in the ventricle at end diastole |
| What is afterload? | The pressure that has to be overcome for the ventricles to eject blood from the heart |
| What is cardiac reserve? | The heart’s ability to push its normal cardiac output above normal limits |
| What law is associated with length tension relationship? | Frank Starling law |
| What does Frank Starling law pertain to? | The degree of stretch in cardiac muscle (pathology dependent) |
| What means greater force of contraction and leads to an increased cardiac output? | Increase stretch of cardiac muscle |
| True or false, the more blood that goes into the ventricle during diastole or preload, the less force of contraction needed to eject the blood | False the more blood that goes into the ventricle during diastole or preload, the greater of the force of the contraction needed to eject blood |
| What is the Frank Starling relationship? | An intrinsic property of myocardium by which increased length results in enhance performance during the next contraction. |
| Why is Frank Starling law very important in cardiac function | Increased venous return, and the corresponding increase in EDV result in greater stroke volume during the next beat, the ventricles can then accommodate increased venous return with a more vigorous contraction that ejects a greater amount of blood |
| A normal heart rate = | Good ventricular filling |
| What causes a decrease volume of blood entering the heart and what does it lead to? | Extremely rapid heart rate; causes the heart to beat less forcefully |
| True or false the longer the interval between heartbeats the greater, the contraction needed to eject the blood | True |
| What is an interval? | The time between beats |
| What happens during a regurgitation? | The chamber receives blood from two directions |
| What is a result of an increased preload volume? | Dilation of the heart chambers |
| What is preload increased by? | Any state of fluid overload, which increases the load to be moved |
| What are examples of pressure loads that increase afterload and what is a result of a increased afterload? | Aortic stenosis, idiopathic hypertrophic subaortic stenosis, pulmonic stenosis, HTN, pulmonary HTN. Increased afterload will result in hypertrophy.. |
| What is afterload also known as? | Systemic vascular resistance, or SVR (the amount of resistance, the heart must overcome to open the aortic valve and push blood volume out into systemic circulation |
| Inotropic is the___ | Contractility of the heart muscle or the force of contraction |
| Chronotropic is the_____ | Rate of contraction or the heart rate |
Created by:
Lindseybeck1023
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