The Cardiovascular SystemThe Heart Chapter 15
Describe the location of the heart and the structure and functions of the pericardium. Figure 15.1
Question 1 ď Ż
Your heart is found in the thoracic cavity with 2/3 of its mass lying to the left of the bodyâ€™s midline.
Question 2 ď Ż
The apex of the heart is formed by the left ventricle and it rests on the diaphragm.
Question 3 ď Ż
The major blood vessels enter and exit from the base of the heart.
Figure 15.2, Question 4 ď Ż
Explain cardiac tamponade. ď Ž
Because the pericardium cannot stretch, fluid builds up and compresses the heart
Objective 2 ď Ż
Describe the layers of the heart wall and the chambers of the heart
Name the three layers of the heart wall.
Epicardium (external) Myocardium (middle) Endocardium (inner)
Name the four chambers of the heart
Left atrium Right atrium Left ventricle Right ventricle
Question 7 ď Ż
Objective 4 ď Ż
Describe the structure and functions of the valves of the heart.
Question 8 ď Ż
The atrioventricular (AV) valves on the right side are also known as the tricuspid valve.
Question 9 ď Ż
What is the purpose of the chordae tendineae? ď Ž
To prevent the valves from pushing up into the atria.
Figure 15.4 ď Ż
Question 10- The AV valves on the left side are known as the bicuspid or mitral valve.
Question 11 ď Ż
Define valvular heart disease. ď Ž
Any condition in which one or more of the heart valves operate improperly.
What happens if regurgitation continues?
This leads to congestive heart failure The heart can no longer pump enough to supply the oxygen demands of the body
Objective 5, Figure 15.5 ď Ż
Explain how blood flows through the heart.
Objective 6 ď Ż
Describe the clinical importance of the blood supply of the heart.
Name the two coronary arteries and the name of the one vein. Left and right coronary arteries The vein is the coronary sinus
Question 14. Define the following:
Ischemia Angina pectoris Myocardial infarction infarction
Ischemia- local anemia due to obstruction of blood vessels. Angina Pectoris- ischemia of the myocardium, this causes chest pain. Myocardial infarction- a heart attack. Infarction- Death of an area of tissue because of interrupted blood supply. (A blood clot in the coronary arteries could cause this)
Objective 7 ď Ż
Explain how each heartbeat is initiated and maintained.
Question 15, Figure 15.6, p. 359
List the five steps for the conduction system of the heart
SA Node Action potential AV Node AV Bundle Right and left bundle to branches Purkinje fibers
List five triggers of ectopic activity (ectopic pacemaker).
Caffeine Nicotine Electrolyte imbalances Hypoxia Toxic reactions to drugs
Objective 8 ď Ż
Describe the meaning and diagnostic value of an electrocardiogram, ECG.
Objective 9 ď Ż
Describe the phases of the cardiac cycle.
Systole-contraction (PQRS) Diastole- phase of relaxation (T wave)
List the three stages of the cardiac cycle.
Atrial systole Ventricular systole Relaxation period
P wave- atria depolarize, atria contract QRS Complexventricles depolarize, ventricles contract T waveventricles repolarize
What causes heart sounds? Explain lubb and dupp.
Turbulence in blood flow created by closure of the valves causes heart sounds. Lubb- AV valves close, ventricles contract Dupp- seimlunar valves close
Explain mitral stenosis and mitral valve prolapse (MVP).
Mitral stenosis- narrowing of the mitral valve by scar formation or congenital defect. MVP- a portion of the mitral valve is pushed too far and the cusps do not close properly. About 10% of healthy people have this.
Objective 10 ď Ż
Define cardiac output, explain how it is calculated and describe how it is regulated.
How do you calculate cardiac output?
Stroke volume X beats per minute
Question 23 ď Ż
What is normal stroke volume for a resting adult? ď Ž
What is the normal heart rate in beats per minute?
75 bpm 5.25L/min
Name the three factors that regulate stroke volume and ensure that the left and right ventricles pump equal volumes of blood.
The degree of stretch in the heart before it contracts. The forcefulness of individual ventricular muscle fibers. The pressure required to eject blood from the ventricles.
Explain congestive heart failure (CHF).
The heart is a failing pump. More and more blood is left in the ventricles at the end of each cycle. The heart stretches.
Name the four causes of CHF.
Coronary artery disease Long term high blood pressure Myocardial infarctions Valve disorders
Omit Question 28.
Explain how hormones and ions regulate the heart rate.
Epinephrine and norepinephrine enhance the heart’s pumping effectiveness, increase heart rate and contraction force. Thyroid hormones increase heart rate High K+ or Na+ decrease the heart rate and contraction force.
Objective 11 ď Ż
Explain the relationship between exercise and the heart.
Question 31 ď Ż
To benefit the heart aerobic exercise must be for at least 20 minutes. How many times a week? 3-5
Question 32 ď Ż
What does sustained exercise do to benefit the cardiovascular system? ď Ž
Increases the oxygen demand
Question 33A ď Ż
A. Explain coronary artery disease. ď Ž
Atherosclerotic plaques in the coronary arteries reduce the blood flow to the myocardium.
What are the risk factors?
High cholesterol High blood pressure Smoking Obesity Diabetes Type A Personality Sedentary lifestyle
What are the treatment options?
Moderate exercise Reduce fat in the diet Drugs: nitroglycerine, beta blockers, cholesterol lowering, clot dissolving Surgical and nonsurgical procedures to increase blood supply to the heart
Define atherosclerosis and its causes.
Large to medium-sized lesions High LDL levels Prolonged high blood pressure Carbon monoxide in cigarette smoke Cytomegalovirus (Herpes virus) Diabetes mellitus
Explain the following congenital defects. Patent ductus arteriosus Interventricular septal defect Valvular stenosis Tetralogy of Fallot
Question 35 ď Ż
Patent ductus arteriosus- the ductus arteriosus between the aorta and pulmonary trunk remains open. Interventricular septal defectincomplete closure of the interventricular septum
Valvular stenosis- narrowing of one of the valves Tetralogy of Fallot- there are four defects
Interventricular septum defect An aorta from both ventricles instead of just the left Narrowed pulmonary semilunar valve Enlarged right ventricle
Define arrhythmia and name eight causes Arrhythmia- an irregularity in heart rhythm
Caffeine Nicotine Alcohol Anxiety Drugs Hyperthyroidism Potassium deficiency Heart disease
Question 37 ď Ż
One serious arrhythmia is called heart block (AV block)
Question 38 ď Ż a.
Define the following: Atrial flutter- rapid atrial contractions, atrial rhythm averages 240-360 bpm. Atrial fibrillation- an uncoordinated contraction of atrial muscles. They quiver individually instead of contract together.
Question 38 c. Ventricular fibrillation- haphazard, asynchronous ventricular muscle contractions. Circulatory failure and death occur.
Match the following J. 39. Sudden cardiac death- the unexpected cessation of circulation and breathing due to heart disease. A. 40. Cardiac angiography- A cardiac catheter is used to inject a radiopaque dye, clot dissolving drugs or tissue plasminogen activator (t-PA)
41. Cor pulmonale (CP)- Right ventricular hypertrophy caused by hypertension (high blood pressure). G. 42. Incompetent valve- any valve that does not close properly and permits backflow of blood. D. 43. Cardiomegaly- Heart enlargement E.
B. 44. Cardiac arrest- A clinical term meaning cessation of an effective heartbeat. The heart may be completely stopped or in ventricular fibrillation. I. 45. Paroxysmal tachycardia- A period of rapid heartbeats that begins and ends suddenly.
C. 46. Cardiac catheterization1.
Procedure to visualize the heartâ€™s coronary arteries, chambers, valves and great vessels. The flow of blood and oxygen can be measured
F. 47. Cardiac resuscitation- The artificial establishment of normal or near normal respiration and circulation. Follow the ABCâ€™s. Airway, Breathing and Circulation. H. 48. Palpitation- A fluttering of the heart or abnormal rate or rhythm of the heart.