Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Ch 17 Heart Function
Function of the Heart
| Question | Answer |
|---|---|
| Contraction of the myocardium | Systole |
| Relaxation of the myocardium after diastole | Diastole |
| Cardiac cycle represent the: | Events that occur in the heart during one heartbeat (0.8 sec for a heart rate of 70 bpm) |
| Atrial systole def. | Atria contract pumping blood into ventricles |
| Ventricular systole def. | Ventricles contract pumping blood into pulmonary trunk and aorta |
| Diastole def. | Heart relaxes allowing blood to fill chambers |
| The ANS can affect heart activity in several ways 1.) | Alter the rate at which the cardiac impulse is fired |
| The ANS can affect heart activity in several ways 2.) | Change the speed at which it travels through the heart |
| The ANS can affect heart activity in several ways 3.) | Increase the force of myocardial contraction |
| Sympathetic stimulation of the heart results in increased: | SA node activity -> increased HR, transmission of impulse through His system, force of myocardial contraction |
| Potential clinical results of excessive sympathetic stimulation of heart | Racing heart due to "fight or flight" response, circulatory shock; heart hailure, Tachydysrhythmias |
| Function of sympathomimetic drugs: | Mimic effects of SNS |
| Function of sympatholytic drugs: | Inhibit effects of SNS |
| What happens to SA node activity as a result of parasympathetic stimulation of the heart? | Decreased SA node activity -> Decreased HR, which has an inhibiting effecton SA node to achieve 'normal' heart rate Decreased transmission of impulse to AV node |
| Another name for parasympathetic stimulation of the heart | Vagal stimulation |
| Results of vagal heart stimulation | Bradycardia, Bradydysrhythmia |
| Bradycardia def. | Caused by excessive vagal discharge to the point where the heart beats below 60 bpm |
| Bradydysrhythmia def. | Abnormal heart rhythm with a rate of less than 60 bpm |
| Function of vagomimetic drugs | Mimic effects of PSNS |
| Function of vagolytic drugs | Inhibit effects of PSNS |
| Def. of cardiac output | The amount of blood pumped by each ventricle in 1 minute (usually about 5L per minute) |
| Cardiac Output = | Heart Rate x Stroke Volume |
| Heart rate def. | Number of times heart beats in one minute |
| Stroke volume def. | Amount of blood pumped by ventricle in each heart beat |
| Normal heart rate | 60-100 bpm |
| Average heart rate | 72 bpm |
| Average resting stroke volume | 60-80 mL per beat |
| Ventricles normally only pump approximately ____________ of blood | 67% |
| Starling's Law of the Heart | The greater the stretch of the myocardial fibers the greater the force of contraction (i.e. the more blood in the ventricle the more forceful the contraction, the greater the stroke volume) |
| Positive Inotropic Effect def. | Stimulation of heart by sympathetic NS |
| End Diastolic Volume (EDV) def. | Amount of blood in ventricle at the end of resting phase (AKA Preload) |
| Ejection Fraction def. | The % of blood pumped from ventricle following contraction (typically 67%) |
| Afterload def. | Resistance to blood flow from the ventricles (ex. semilunar valve stenosis, hypertension) |
| Inotropic Effect def. | A change in myocardial contraction not related to stretch of myocardium |
| Positive Inotropic Effect def. | Increases the force of myocardial contraction |
| Negative Inotropic Effect def. | Decreases the force of myocardial contraction |
| Chronotropic Effect def. | A change in HR (Pos or Neg Chronotropic Effect) |
| Dromotropic Effect def. | Change in speed of the transmission of the cardiac impulse (positive and negative dromotropic effect) |
| Left heart failure happens when the left: | Ventricle fails to pump blood into aorta. Usually due to MI or chronic hypertension |
| Backward left heart failure blood backs up where? | Pulmonary circulation |
| Pulmonary Edema happens as a result of | Backward left heart failure. Fluid builds up in the lungs |
| Symptoms of Pulmonary Edema | Dyspnea, cyanosis, cough, orthopnea, tachycardia |
| Treatment for Pulmonary Edema | Nitroglycerin, oxygen, morphine, upright posture, diuretic |
| Forward left heart failure - what happens? | Systemic circulation does not effectively receive oxygenated blood and increased sympathetic stimulation |
| In right heart failure, the right: | Ventricle fails to pump blood into pulmonary arteries |
| Right heart failure is usually due to: | Left-sided heart failure or chronic lung disease |
| During right heart heart failure especially chronic lung disease what happens to blood flow? | Blood backs up into venous system. Results in jugular vein distension, hepatomegaly, splenomegaly, digestive symptoms. Pitting edema. |
Created by:
CBaney
Popular Anatomy sets