Term
| What is the size of the heart? |
|
Definition
|
|
Term
| Where is the heart located? |
|
Definition
| Between lungs, displaced 2/3 to the left. |
|
|
Term
|
Definition
| Study of heart and associated diseases. |
|
|
Term
| What two layers make up the pericardium? |
|
Definition
| Outer fibrous layer, inner serous layer: consists of parietal layer and visceral layer which contain the pericardial cavity. |
|
|
Term
|
Definition
| Inflammation of pericardium. |
|
|
Term
| What is cardiac tamponade? |
|
Definition
| When blood or fluid gets into the pericardial cavity, life threatening. |
|
|
Term
| What this difference in pre-birth blood circulation of the heart? |
|
Definition
| Ductus arteriosus which goes from pulmonary trunk to the aorta, bypasses lungs. |
|
|
Term
|
Definition
| Small pouches on top of each atrium that increase atrial capacity. |
|
|
Term
|
Definition
| Grooves containing blood vessels and fat, separate chambers from each other. |
|
|
Term
| What are functions of the fibrous skeleton of the heart? |
|
Definition
| Surrounds valves, valve attachment, cardiac muscle insertion, prevents valve ocerstretching, electrical insulator to prevent AP spread from atria to ventricles. |
|
|
Term
| How do heart valves open/close and what is their function? |
|
Definition
| Open/close due to pressure changes, papillary muscles contract on chordae tendinae to prevent back-flow through valves. |
|
|
Term
| What are the atrioventricular valves and where are they? |
|
Definition
Tricuspid: between right atrium and ventricle
Bicuspid: between left atrium and ventricle |
|
|
Term
| What are the semilunar valves and where are they? |
|
Definition
Pulmonary: between right ventricle and pulmonary artery
Aortic: between left ventricle and aorta |
|
|
Term
| What is the path of coronary circulation and what are vessels that are a part of it? |
|
Definition
| Right and left coronary arteries branch from ascending aorta to supply blood to cardiac muscle, coronary veins go to coronary sinus which empties into right atrium |
|
|
Term
| Describe the histology of cardiac muscle. |
|
Definition
| Shorter than skeletal muscle fibers, larger diameter, branched, same sarcomere arrangement, mitochondria larger and more numerous, less sarcoplasmic reticulum, intercalated disks which function as desmosomes and gap junctions. |
|
|
Term
| What is the function of the cardiac conduction system? |
|
Definition
| Controlled systematic contraction of different parts of heart, atrial contracts first then ventricular. |
|
|
Term
| Where is the SA node found and what is its function? |
|
Definition
| Found in right atrial wall just below superior vena cava, functions as pacemaker, establishes fundamental rhythm (90-100 bpm), atria contract after action potential. |
|
|
Term
| Where is the AV node found? |
|
Definition
| Located in septum between atria, similar histology to SA node. |
|
|
Term
|
Definition
| Only electrical connection between atria and ventricles, fibrous skeleton electrically insulates atria from ventricles in rest of heart. |
|
|
Term
| What are the right and left bundle branches? |
|
Definition
| Extend through interventricular septum, impulses travel to apex of ventricles. |
|
|
Term
| What are purkinje fibers? |
|
Definition
| Large diameter, rapid conduction. |
|
|
Term
| Where does the action potential in the heart begin and what are contractile fibers? |
|
Definition
| Begins in SA node, contractile fibers cause atrial and ventricular contractions and are brough to threshold by excited neighboring cells. |
|
|
Term
| What are the 4 stages of the action potential in hearts? |
|
Definition
Depolarization: rapid, voltage-gated Na+ channels open, Na+ floods into cell, membrane potential changes from -90 to +20 mV
Plateau: Ca2+ channels open in sarcolemma and sarcoplasmic reticulum, Ca2+ levels rise in cytosol inside muscle cells, K+ channels close, cardiac muscle reamins depolarized 250x longer than skeletal
Repolarization: recovery of RMP (back to -90mV), voltage gated K+ channels open and Ca2+ channels close
Refractory period: time during which cardiac muscle cannot contract, lasts longer than contraction itself, no tetanus possible in cardiac muscle, another contraction cannot occur until relaxation underway |
|
|
Term
| What is an electrocardiogram? |
|
Definition
| Graphic representation of electrical changes in heart measured on surface of body, function to detect normal conduction pathway/enlarged heart/heart damage. |
|
|
Term
|
Definition
| Atrial depolarization, AP from SA to the atria, atria contract. |
|
|
Term
|
Definition
| Ventricular repolarization, prior to ventricular relaxation, if too low heart not getting enough O2, if too large may be too much K+ present. |
|
|
Term
| Describe the PQ interval. |
|
Definition
| Conduction time from beginning of atrial excitation to ventricular excitation, time for AP to travel through SA node/AV node/and rest of system, if long may indicate CAD or rheumatic fever. |
|
|
Term
| Describe the QRS interval. |
|
Definition
| Ventricular depolarization, AP spreads through ventricles, ventricle contraction. |
|
|
Term
| Describe the QT interval. |
|
Definition
| Beginning of ventricle depolarization to end of repolarization, too long may indicate MI damage/coronary ischemia/conduction damage. |
|
|
Term
| Describe the ST interval. |
|
Definition
| Time that ventricular fibers are fully depolarized, too long indicates MI, too short indicates heart is O2 starved. |
|
|
Term
| What is the cardiac cycle? |
|
Definition
| Events associated with one heartbeat, includes systole and diastole. |
|
|
Term
| Describe relaxation in the cardiac cycle. |
|
Definition
| At end of the heart beat, all 4 chambers relaxe, all 4 valves close, relaxation takes up half of cardiac cycle. |
|
|
Term
| Describe atrial systole in the cardiac cycle. |
|
Definition
| Atrial pressure is greater than ventricular pressure, AV valves open, takes up 1/8 of cardiac cycle. |
|
|
Term
| Describe ventricular systole in the cardiac cycle. |
|
Definition
| AV valves shut which is first heart sound, then all valves close, ventricular pressure then rises, semilunar valves then open which is ejection, then semilunar valves close which is second heart sound, ventricular systole takes up 3/8 of cardiac cycle. |
|
|
Term
|
Definition
| Listening to sounds of body's interior, heart sounds caused by blood turbulence from valve closures, lubb is AV closure and dupp is semilunar valve closure, heart murmur is sounds other than lubb dupp |
|
|
Term
| What is cardiac output and the equation for it? What is the equation for SV? |
|
Definition
| Volume of blood ejected from left or right ventricle each minute, equation is CO = HR X SV, SV is amount of blood ejected with each contraction and is equal to EDV - ESV. |
|
|
Term
|
Definition
| Ratio between max CO and CO at rest. |
|
|
Term
| What is preload and how does it relate to SV? |
|
Definition
| Degree of stretching on cardiac muscle fibers before contraction, preload is proportional to EDV, increase in preload leads to increase in SV. |
|
|
Term
| What is myocardial contractility? |
|
Definition
| Force of contraction of individual fibers, strength of heartbeat, increase in cotractility leads to increase in SV. |
|
|
Term
| What are positive inotropic agents? |
|
Definition
| Increase contractility which leads to increase in SV, epinephrine increases Ca2+ inflow into cardiac muscle cells, sympathetic stimulation of ANS. |
|
|
Term
| What are negative inotropic agents? |
|
Definition
| Decrease contractility which will decrease SV, inhibition of sympathetic ANS, anoxia (lack of O2) and acidosis (lower pH) both leade to lower force of contraction, elevated K+ extracellular levels. |
|
|
Term
| What is afterload and how does it relate to SV? |
|
Definition
| Pressure needed to overcome in ventricles to open semilunar valves, increased by hypertension and artherosclerosis, increase in afterload causes decrease in SV. |
|
|
Term
| What is congestive heart failure? |
|
Definition
| Heart fails to pump, blood remains in ventricles, increases preload, leads to overstretching of heart over long period of time which leads to less forceful contractions. |
|
|
Term
| What are congestive heart failure symptoms? |
|
Definition
| Leads to weaker contraction, can't supply O2 demands of body, pulmonary edema (if left ventricle fails), peripheral edema (if right ventricle fails) |
|
|
Term
| Describe the autonomic regulation of HR including the receptors involved. |
|
Definition
| Receptors send signals to medulla oblongata, proprioceptors indicate physical activity, baroreceptors measure BP, chemoreceptors deal with blood chemistry. |
|
|
Term
| What does sympathetic stimulation do to the heart? |
|
Definition
|
|
Term
| What does parasympathetic stimulation do to the heart? |
|
Definition
|
|
Term
| What hormones and ions are involved in the chemical regulation of HR? |
|
Definition
| Epinephrine, norepinephrine, and thyroid hormones are involved. Excess Na+ and K+ decrease contractibility, excess Ca2+ increases contractibility. |
|
|
Term
| What are 4 other factors in HR regulation? |
|
Definition
Age - HR decreases with age until too old
Gender - females faster than males
Physical fitness - bradycardia is less than 50 bpm, tachycardia is greater than 100bpm
Temperature - fever or strenuous activity increase HR, hypthermia decreases HR |
|
|
Term
| What is coronary artery disease? |
|
Definition
| #1 cause of death in US, caused when heart receives inadequate O2 due to obstructed blood vessels, symptoms include hypertension/angina/stroke/MI (heart attack) |
|
|
Term
| What are risk factors for coronary artery disease? |
|
Definition
| High blood cholesterol, high blood pressure, cigarette smoking, obesity, sedentary lifestyle, diabetes mellitus, males more likely to get this until 70 where women more likely cause of menopause. |
|
|
Term
| What are the long term effects of plasma lipids in coronary artery disease? |
|
Definition
| Plaque formation, block lumen, restrict blood flow, increased risk for thrombus. |
|
|
Term
| What is the function of lipoproteins in blood? |
|
Definition
|
|
Term
| What do low density lipoproteins do and are they good or bad? |
|
Definition
| Transport lipids from liver to arteries, bad. |
|
|
Term
| What do high density lipoproteins do and are they good or bad? |
|
Definition
| Transport excess lipids back to liver, good. |
|
|
Term
| What is the formula for total cholesterol? |
|
Definition
|
|
Term
| Above what number is total cholesterol considered a high risk? |
|
Definition
|
|
Term
| What is arteriosclerosis? |
|
Definition
| Thickening of artery walls and loss of elasticity. |
|
|
Term
|
Definition
| Excess LDLs accumulate in walls of medium/large arteries, endothelial and smooth muscle cell damage which leads to plaque formation which obstructs blood flow which attracts platelets for clotting. |
|
|
Term
| What is a coronary spasm? |
|
Definition
| Intermittent smooth muscle spasm of coronary artery, atherosclerosis which leads to MI which can lead to sudden death. |
|
|
Term
|
Definition
|
|
Term
| How is coronary artery disease diagnosed? |
|
Definition
| Stress test, echocariography which is listening through ultrasound, cardiac catheterization which will help visualize the artery, cardiac angiography which views inside vesicles/ventricles. |
|
|
Term
| What are coronary artery disease treatments? |
|
Definition
| Drugs such as nitroglycerine and beta blockers, bypass grafting, percutaneous transluminal coronary angioplasty, lase angioplasty. |
|
|
Term
| What is a myocardial ischemia? |
|
Definition
| Partial obstruction of blood flow in coronary arteries, hypoxia is reduced oxygen supply which is the result of ischemia, weakens cells without killing them, angina pectoris occurs which is chest pain. |
|
|
Term
| What is a myocardial infarction? |
|
Definition
| Also called heart attack, complete obstruction to blood flow in coronary artery, tissue death occurs, treated with clot-busting agents/heparin/PTCA/CABG. |
|
|
Term
| What are congenital heart defects? |
|
Definition
| Exist at birth, examples are: coarctation of the aorta which is extreme aortic stenosis (narrowing of blood vessel) that strains the heart and leads to high BP, patent ductus arteriosus which is embryonic connection between aorta and pulmonary trunk which normally closes at birth but fails to resulting in aortic blood flow into pulmonary trunk to lungs and overworking of both ventricles. |
|
|
Term
| What are other congenital heart defects? |
|
Definition
| Septal defects such as ASD which is an opening between right and left atria or VSD which is an opening between the right and left ventricles. |
|
|
Term
|
Definition
| Abnormal or irregular heart beat, causes include improper impulse conduction/production, chemicals such as caffeine/nicotine/alcohol, anxiety, and hyperthyroidism. |
|
|
Term
|
Definition
| AV block is most common, 1st degree block results in long PQ, 2nd degree results in dropped beats, 3rd degree results in no SA impulse through the AV node and atria and ventricles contracting independently and dizziness and convulsions. |
|
|
Term
| What is an atrial flutter? |
|
Definition
| 240-360 bpm, 2nd degree heart block accompanies this, atria contracting too fast resulting in not every beat getting through to ventricles. |
|
|
Term
| What is an atrial fibrillation? |
|
Definition
| Asynchronous atrial contractions and sometimes the atrial pumping ceases altogether, up to 300-600 bpm. |
|
|
Term
| What are ventricular premature contractions? |
|
Definition
| Ectopic region begins action potential, results in extra systoles, usually harmless. |
|
|
Term
| What is a ventricular fibrillation? |
|
Definition
| Asynchronous ventricular contraction resulting in ventricle pumping to cease, death imminent unless medical intervention, defibrillation can save victim. |
|
|
Term
|
Definition
| Image of heart and vessels using x-rays and dye. |
|
|
Term
|
Definition
| Loss of effective heartbeat, ventricular fibrillation, cardiac standstill. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| Right ventricular hypertrophy, caused by pulmonary hypertension. |
|
|
Term
|
Definition
| Awareness of strong fast irregular or galloping heartbeat, usually brief, may be caused by underlying heart-related condition. |
|
|
Term
| What is paroxysmal tachycardia? |
|
Definition
| Sudden racing of heartbeat. |
|
|
