EXSC 224 Exam #3CH18What are the two circuits in the cardiovascular system?a. Pulmonary and Systemic What are the characteristics of the pulmonary circuit?a. Low pressured, carries deoxygenated blood to the lungsWhat are the characteristics of the systemic circuit?a. High pressured, carries oxygenated blood to the organs and tissues, the carries deoxygenated blood back to the pulmonary circuit What is pulmonary edema?a. high blood pressure in the pulmonary circuitWhat is the right semilunar valve? Left?a. pulmonary semilunar; Aortic Semilunar Name the left AV valve. Right?a. bicuspid = left; tricuspid= right Which of the ventricles is stronger and what circuit does it pump to?a. the left ventricle pumps to the systemic circuitDescribe the blood flow through the pulmonary circuit. a. Superior/inferior vena cavae  right atriumtricuspid valveRight ventriclepulmonary semilunar valve pulmonary arterylungsDescribe the blood flow through the systemic circuit. a. pulmonary veinsleft atriumbicuspid valveleft ventricleaortic semilunar valve aortabodyWhat is the cardiac skeleton?a. dense connective tissue that holds the valves in place and separates the atria and the ventricles What are the chordae tendineae?a. the structures anchored tricuspid and bicuspid valves and connected to the papillary musclesDescribe the atrioventricular valves opening process.a. Blood retuning to the heart and fills the atria, building pressure on the AV valves, until they’re forced open b. the opening AV vales cause the ventricles to begin fillingc. atria contract, forcing additional blood into the ventricles Describe the atrioventricular valves closing process. a. ventricles contact, forcing blood against the AV valvesb. the AV valves are forced closedc. papillary muscle contract and chordae tendineae tighten, prevents valves from opening into the ventricles What is the pericardium? a. the serous membrane that surrounds the heart; decreases friction that occurs when the heart expandsWhat is the myocardium?a. cardiac muscle layerWhat is the endocardium?a. Connective tissue layer that lines atria, ventricles and valves. Composed of dense irregular connective tissue, separates myocardium from the blood. How does the heart get its blood supply?a. the arterial coronary circulation provides oxygenated blood to the myocardium; the venous coronary circulation carries deoxygenated blood from the arterial coronary circuitto the coronary sinus and empties into the right atrium What happens in a coronary artery bypass graft (CABG)a. a vein is taken from the leg and grafted into the coronary vessels under where a narrowing or clot occurs to provide and correct proper blood flow Describe balloon angioplasty. a. a stent is inserted and is opened and closed consciously to break up plaque buildup in the blood vessels; patients are more likely to have a heart attack in the 24 hours afterDescribe a coronary stent. a. a mesh like stent is inserted into a blood vessel with plaque buildup that remains in the artery for life. Again greater risk of heart attack for first 24 hours after.What are the striations in cardiac muscle?a. SarcomeresHow do myocytes communicate with each other?a. gap junctionsCompare and Contrast cardiac and skeletal muscle. a. cardiac muscle contains myocytes, cardiac muscle is branched and connected by gap junctions, no neuromuscular junctions, they’re auto-mitotic What is Cardiac Output (Q)?a. Q (L/min) = heart rate (contraction/mins) X stroke volume (mL/contraction)- Average output: 5L/minWhat are the two types of heart beat regulation? a. Intrinsic and Extrinsic Describe the Intrinsic method of heartbeat regulationa. Automaticity: the heart initiates its own contractions (Spontaneous depolarization)b. SA Node: “pace maker” tissues around the superior vena cava and right atrium spontaneously depolarizes at 100 bpm c. AV Node: between right atrium and ventricle, back up plain if the SA node doesn’t work; depolarizes @70 bpm d. Bundle Branches/ Perkinjie fibers: distributes pulse from AV node to the vetricles ; depolarizes @ 50bpm, plan c if both the SA and AV nodes don’t worke. Cardiomyocytes: slowest to depolarize @ 30 BMPDescribe Ventricular myocyte - Phase 0a. membrane depolarization; opening of fast Na+ channelsDescribe Ventricular myocyte - Phase 1a. brief phase; absolute refractory period; closure of fast Na+ channels and opening of K+channelsDescribe Ventricular myocyte - Phase 2a. plateau; prolonged absolute refractory period; closure of K+ channels and opening of Ca2+ entry through Leaky type Ca2+ channels. Keeps ventricle depolarized (holds contraction)Describe Ventricular myocyte - Phase 3a. repolarization; closure of Ca2+ channels and reopening of K+ channelsDescribe Ventricular myocyte - Phase 4a. re-establish Na+/K+ gradients; pump 3 Na+ for every 2 K+What is the duration of a cardiac muscle action potential?a. 300 milliseconds Why can’t the SA node establish a resting membrane potential?a. leaky (slow) sodium channels Sympathetic NS controlsa. cardio acceleratoryParasympathetic NS controlsa. cardio inhibitoryWhat is Stoke Volume and how is it determined? a. the amount of blood pumped by the ventricles upon systole (Contraction)SV = End Diastolic Volume (EDV) – End Systolic Volume (ESV)Regulated by Preload, Contractility and Afterload. Describe Preload.a. the degree to which heart muscle is stretched during diastole (Filling)- relies on rate of venous return. Higher return = higher preload - remember the length tension relationship; @ rest sarcomeres in cardiac myofibers are below their optimal length, meaning less cross bridges are able to form. Higher preloads increase the amount of stretching of the sarcomeres and increase the number of cross bridges formed, meaning a higher EDV, stroke volume and cardiac output.Describe Contractility. a. contractile strength achieved by a given muscle *Contractility is independent of SV or EDV*- Higher contractility = higher volume of blood pumped by the heart and a low ESV- relies on the Calcium concentration in the cytosol “ionotropic effect”, effected by sympathetic activity. Sympathetic neurons release the neurotransmitter Norepinephrine, NE causes activation of the cyclic amp second messenger system; allowing the openingof Ca channels on the plasma membrane and on the SR , allowing greater levels of Ca into the cytosol to bind to troponin C and allow for better cross bridge formation =