Cardiovascular: The heart
I. Anatomy of the heart
A. Size
1.
2. Mass-
B. Location
1. Encloseda. the medial cavityb. Restsc. Lies anterior to1. Posterior tod. Lies betweene. 2/3 erds of it’s mass-
C. Dimensions
1. Base (top)2. Apex (bottom)3. Apical impulse-
D. Coverings of the heart
1. Pericardiuma. Fibrous Pericardium1.
2.
3.
b. Serous Pericardium-
1. parietal layer
2. visceral layer
a. Function1. pericardial cavity2. function to-
c. Pericarditis1. if untreated2. cardiac tamponade-
E. Layers of the heart wall- made up of three layers
1. Epicardium
a.
b. visceral layer of…
2. Myocardiuma. composedb. the layer-
3. Endocardium (inside the heart)
a. linesb. made up ofc. continuous-
F. Chambers of the Heart (4 chambers)
1. Atriaa. Two atria1. Rt Atrium- blood enters via…
- Superior vena cava- inferior vena cava- coronary sinus
2. Lt Atrium- blood enters via…
a. pulmonary veins1. left pulmonary2. right pulmonary-
2. Ventriclesa. Two ventricles1. Right ventricle2. Left ventricle-
G. Septum (divide)
1. Interatrial Septum2. Interventricular Septum-
H. Pathway of Blood
1. 2 circuits
a. Pulmonary circuitb. Systemic circuit-
2. Pulmonary Pump
a. blood returning from the bodyb. Entersc. Pumps intod. in the lungse. Returned to the heartf. left Atrium-
3. Systemic Pump
a. from left atriumb the Aortac. branches off aorta-
4. Workload
a. Rt Ventricle-
b. Lt Ventricle1. resistance2. walls3. Ventricular cavity4. Ventricular pressure-
I. Coronary Circulation (nourishment of the heart)
1. Arterial supplya. originate-
2. Left Coronary Arterya. Anterior interventricular Artery (the anterior descending Artery)
1. supplies bloodb. Circumflex Artery-
3. Right Coronary Arterya. Right Marginal Arteryb. Posterior interventricular Artery-
4. Anastemoses (join or merge)-
5. Delivery of blood by coronary arteries occursa. requires1. Left Ventricle-
6. Cardiac Veins- (receive blood)
a. collectb. empties into-
7. Blockage of Coronary Arteriesa. Angina Pectorisb. damaged tissue-
J. Heart Valves (direct flow)
1. Four valvesa. preventb. blood-
2. AV Valves (atrioventricular valves)a. Tricuspid valve1. Threeb. Mitral valve (bicuspid)2. Two
c. Chordae tendinea1. function3. Semilunar valvesa. Aortic and pulmonary(semilunar valves) function4. No valves ina. backflow-
II. Cardiac Muscle Fibers
A. Microscopic Anatomy
1. Similar2. Difference with skeletal muscle
a. short
b. fat
c. branched
d. interconnected1. desmosomes2. functional syncytiume. Large1. accounts2. gives-
f. Gap junctionsg. Refractory Period1. prevents titanic contractionsh. Autorhythmic-
B. Energy Requirements
1. Greater need for2. No3. nutrients4. oxygen starved cellsa. hindersb. increased areas of-
III. Heart Physiology
A. Electrical events: intrinsic conduction1. Intrinsic Conduction System
a.
b. Autorhythmic cells1. results in-
2. Pacemaker Potentials (prepotentials)a. Ion channels (sarcolemma)b. Results in
1.stronger action potential
2.reverses-
3. Conduction across the Heart
a. Sino Atrial node (SA node)
1. Generates impulses2. Sets3. Known as4. Producesb. Atrioventricular Node (AV Node) see Fig 18.14-
1. Extends2. To3. Connects to-
c. Bundles1.Purkinje fibersa. Highly elaborate-
d. Arrythmia1. between2. Artificial Pacemaker-
4. ANS Control of the Heart
a. Sympatheticb. Parasympatheticc. Cardiac Center1. Cardioaccelerating center
2. Cardioinhibitory center
d. innervated by the cranial nerve-
5. Electrocardiography
a. ECG (EKG)1. a composite2. not a trace of a singleb. Waves (deflections)1. P wave2. QRS wave3. T wavec. Intervals-
6. EKG Graph Segments
a. P wave1. initiated-
b. PQ intervalc. QRS1. Atrial2. 3 wave shape due tod. ST Segmente. T Wavef. Healthy heart1. size 2. Duration 3. Timing
g. Changes in wave form, duration or timing1. Large R wave2. ST segment3. Prolonged QT interval-
7. Heart Sounds
A. Made by1. first heart sound2. Pause between sounds3. Second soundB. Abnormal Heart Sounds
1. Heart murmurs2. Common in3. Defective Heart Valvesa. backflowb. Swishes1. Stenotic8. Mechanical Events: The Cardiac Cycle
A. Characterized by1. Systole2. Diastole3. Atriole4. Ventricular-
B. Counter filling and empting
1. Atrial Distole (relax)2. Ventricular Systole3. Isovolumetric contraction Phase4. Isovolumetric Relaxationa. Atria5. Starts all over again
9. Cardiac Output (CO)A. the product of1. Stroke Volume defined asCO = HR x SV
75 beats/min x 70 ml/beat = 5259 ml/min or 5.25 liters/min
B. Blood Volume
1. Entire blood supplyC. Regulation of Stroke Volume (SV)1. End Diastolic Volume (EDV)-
2. End Systolic Volume (ESV)a. ESV is determined
1. atrial2. force of contration3. Stroke Volume (SV)a. Preload1. Control of stretchb. Contractility
1. influenced by2. increaseda. in response toc. Afterload-
10. Homeostatic Imbalance of the Heart
A. Tachycardia1. Characterized by2. Leads to3. Caused byB. Bradycardia1. Characterized2. leads to3. Caused by
a.
b.
c.
C. Congestive Heart Failure (CHF)1. Coronary Atherosclerosis
a. Fat builds upb. Blocking (impeding)2. High Blood Pressure (Hypertension)3. Myocardial infarction (infarcts)a. disruptionb. depression ofc. due to4. Dilated Cardiomyopathya. stretched
b. flabby
c. myocardiumd. Causese. Heart enlarges5. Heart side failures
A. Left side failure1. Pulmonary Congestion2. due to3. Pulmonary edema-
B. Right side Failure1. Pooled fluids (Edema)C. Treatment1. Diuretics-