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Ch 18 Biology 116
Ch 18 Learning Outcomes
| Question | Answer |
|---|---|
| Describe the location and the position of the heart. | Near the anterior chest wall, directly behind the sternum. |
| Compare the base of the heart with the apex. | Base- at superior border. Apex- located on the inferior aspect of the heart. |
| Name the four chambers of the heart. | Left atrium and ventricle, Right atrium and ventricle. |
| Compare the volume of blood each circuit receives from the contraction of ventricles. | Each receives same volume of blood from contraction of ventricles. |
| Define mediastinum. | Mass of two pleural cavities that contains the heart, along with the great vessels, thymus, esophagus, and trachea. |
| Describe the heart’s location in the body. | Surrounded by pericardium in the anterior mediastinum, deep to the sternum and superior to the diaphragm. |
| Why can cardiac tamponade be a life-threatening condition? | Because of accumulating fluid within the pericardial cavity that restricts heart movement. |
| From superficial to deep, name the layers of the heart wall. | Pericardium, myocardium, and endocardium. |
| Describe the tissue layers of the pericardium. | Parietal and visceral layers. |
| Why is it important that cardiac tissue contain many mitochondria and capillaries? | Cardiac tissue is metabolically active and dependent on mitochondria for ATP and local capillaries for obtaining oxygen and nutrients. |
| The anterior view of the heart is dominated by which chambers? The posterior? | Right atrium and right ventricle. |
| Which structures collect blood from the myocardium and into which heart chamber does this blood flow? | Coronary veins. |
| Name and describe the shallow depressions and grooves found on the heart’s external surface? | Anterior interventricular sulcus marks b/w right and left ventricles. Coronary sulcus marks b/w atria and ventricles. |
| Describe the areas of the heart supplied by the right and left coronary arteries? | Right coronary artery- right atrium and both ventricles and the conducting system of the heart. Left coronary artery- left ventricle and left atrium and interventricular septum. |
| List the arteries and veins of the heart. | Arteries: left coronary artery, anterior interventricular artery, right coronary artery, marginal arteries... Veins: great cardiac vein, anterior cardiac veins, posterior vein of left ventricle... |
| Describe what happens to blood flow in elastic rebound. | Blood in the aorta is pushed into the systemic circuit & some forced back toward the left ventricle and into coronary arteries. |
| Why is the left ventricle more muscular than the right ventricle? | The left ventricle must generate enough force to propel blood throughout the body in the systemic circuit. |
| Damage to the semilunar valve on the right side of the heart would affect blood flow to which vessel? | Pulmonary trunk. |
| Define cardiac regurgitation. | Abnormal backflow of blood into the atria when the ventricles contract. |
| Describe the structural and functional roles of the cardiac skeleton. | Structurally- stabilizes positions of the heart valves and muscle cells. Functionally- isolates the atrial & ventricular myocardia. |
| What do semilunar valves prevent? | Backflow of blood into the ventricles. |
| Compare arteriosclerosis and atherosclerosis. | Arteriosclerosis- any thickening & toughening of arterial walls. Artherosclerosis- changes in the endothelial lining & formation of fatty deposits in the tunica media. |
| What is coronary ischemia? | Condition in which blood supply of the coronary arteries is reduced. |
| Describe the purpose of a stent. | Prop open the natural blood vessel, creating a channel to restore blood flow. |
| Define cardiac cycle. | The period between the start of one heartbeat and the beginning of the next. |
| Give the alternate terms for heart contraction and relaxation. | Contraction- systole Relaxation- diastole |
| Compare the duration of atrial and ventricular systole at a representative heart rate of 75bpm. | Atrial systole- 100 msec Ventricular- 270 msec |
| List the phases of the cardiac cycle. | Atrial and ventricular systole and diastole. |
| What are the two phases of ventricular systole? | Isovolumetric contraction and ventricular ejection. |
| Is the heart always pumping blood when pressure in the left ventricle is rising? Explain. | No. When pressure is rising in left ventricle, the heart is contracting but blood is not leaving the heart. |
| Why does tetany not occur in cardiac muscles? | Long refractory period that continues under relaxation. |
| List the three stages of an action potential in a cardiac muscle cell. | Rapid depolarization, plateau, and repolarization. |
| Describe slow calcium channels and the significance of their activity. | Open slowly and remain open for a relatively long period. |
| Define autorhythmicity. | The ability of cardiac muscle tissue to contract without neural or hormonal stimulation. |
| If the cells of the SA node failed to function, how would the heart rate be affected? | Heart would continue to beat but very slowly; AV node would act as a pacemaker. |
| Why is it important for impulses from the atria to be delayed at the AV node before they pass into the ventricles? | Overall, the pumping action of the heart would be less efficient. |
| Define electrocardiogram. | Recording of the electrical activities of the heart over time. |
| List the important features of the ECG and indicate what each represents. | P wave, QRS complex, and the T wave. |
| Why is ventricular fibrillation fatal? | The ventricles merely quiver and do not pump blood into the systemic circulation. |
| Compare bradycardia and tachycardia. | Brady- 60 beats per minute Tachy- above 100 beats per minute |
| Describe the sites and actions of the cardioinhibitory and cardio acceleratory centers. | The cardioacceleratory center in the medulla oblongata activates sympathetic neurons to increase heart rate... |
| Caffeine has effects on conducting cells and contractile cells similar to NE. What effect would drinking large amounts of caffeine have on the heart rate? | Heart rate would increase. |
| Define end-diastolic volume (EDV) and end systolic volume (ESV). | EDV- Amount of blood a ventricle contains at the end of diastole before a contraction begins. ESV- Amount of blood at the end of ventricular systole. |
| What effect would an increase in venous return have on stroke volume? | Increase of stroke volume. |
| What affect would an increase in sympathetic stimulation of the heart have on the end-systolic volume (ESV)? | Lower ESV. |
| Define heart failure. | A condition in which the heart can no longer meet the oxygen and nutrient demands of peripheral tissues. |
| Compute the stroke volume of the ESV is 40ml and EDV is 125ml. | 125-40 = 85 mL. |
Created by:
caylisrosson
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