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APHY 102 Exam 2a
Cardiovascular System - The Heart
| Question | Answer |
|---|---|
| what is the anatomy of the heart? | approximately the size of your first, located at the superior surface of the diaphragm, left of the midline, anterior to the vertebral column and posterior to the sternum |
| what is the pericardium? | double-walled sac around the heart composed of a superficial fibrous pericardium and a deep two-layer serous pericardium; the parietal layer and the visceral layer separated by the fluid filled pericardial cavity |
| the epicardium name is misleading because epi commonly means "on top of" - what is the other name for the epicardium? | the visceral layer of the pericardium, and it is deep to the parietal layer |
| what does the pericardium do? | protects and anchors the heart, prevents overfilling of the heart with blood, allows for the heart to work in a relatively friction-free environment |
| what allows the heart to work in a relatively friction-free environment? | the pericardium |
| true or false, the epicardium is part of the heart wall | true |
| what are the 4 parts of the heart wall from superficial to deep? | epicardium, myocardium, fibrous skeleton, endocardium |
| what is the epicardium of the heart wall? | visceral layer of the serous pericardium |
| what is the myocardium of the heart wall? | cardiac muscle layer forming the bulk of the heart |
| what is the fibrous skeleton of the heart wall? | crisscrossing, interlacing layer of connective tissue |
| what is the endocardium of the heart wall? | endothelial layer of the inner myocardial surface |
| which vessels return blood to the heart and are they veins or arteries? | veins, including superior and inferior venae cavae, and right and left pulmonary veins |
| between the venae cavae and pulmonary veins, which carry oxygenated/deoxygenated blood to the heart? | venae cavae are carrying deoxygenated blood; right and left pulmonary veins oxygenated |
| which vessels carry blood away from the heart? | pulmonary trunk, which splits into right and left pulmonary arteries, conveys blood from heart direct to lungs; ascending aorta leads to the aortic arch which has 3 branches |
| (starred) what are the 3 branches of the aortic arch? | brachiocephalic TRUNK, left common carotid, and left subclavian arteries |
| (starred) which vessels supply/drain the heart to itself? | arteries: left and right coronary (in atrioventricular groove/sulcus), marginal, circumflex, and anterior+posterior interventricular arteries; veins include small cardiac, anterior cardiac, middle cardiac vein, great cardiac vein, coronary sinus |
| is the coronary sinus an artery or a vein? | vein |
| what are the meaty/muscular struts of the heart? | trabeculae carneae |
| what structures help heart valves from going backwards? | papillary muscles and chordae tendiniae |
| which are the receiving chambers of the heart? | atria |
| what structure protrudes from each atrium? | auricle |
| trabeculae carneae muscles are to the ventricles, as _____ are to the atria? | pectinate muscles |
| the papillary muscles are attached to which valves, SA or AV? | AV valves |
| where does the blood in the right atrium come from? | superior/inferior venae cavae and coronary sinus |
| where does the blood in the left atrium come from? | pulmonary veins |
| which is more serious of a condition, ventricular afibrillation or atrial afibrillation? | ventricular afib, because you need the ventricles more importantly to work properly |
| which are the discharging chambers of the heart? | ventricles |
| the right ventricle pumps blood into where? | the pulmonary trunk |
| the left ventricle pumps blood into where? | the aorta |
| which ventricle is much thicker than the other? why? | left ventricle is thicker to push blood through farther |
| what is the pathway of blood through the heart and lungs? | venae cavae to RA to right AV valve to RV, RV to P valve to pulmonary trunk and pulmonary arteries to lungs, lungs to PV to LA, LA to left AV valve (bicuspid/mitral) to LV, LV to aortic valve to ascending aorta, aorta to systemic circulation |
| what is the other technical name for bicuspid/mitral valve? | left atrioventricular (AV) valve |
| what is coronary circulation? | the functional blood supply to the heart muscle itself |
| what are collateral routes? | safety features of the heart. even if the heart is 80% occluded at the major vessels, collateral routes ensure blood delivery to the heart |
| what is anastomosis? | junction of vessels, aka the connection between two tubular structures, such as blood vessels, intestines, or ureters. significant in the heart between the circumflex artery and anterior interventricular artery as protection against heart attacks (MI) |
| true or false, the first pair of branches off the ascending aorta are for the coronary arteries | true, but this is for ascending aorta only. the aorta proper has its first branch as the brachiocephalic trunk, et cetera. |
| what is the function of heart valves? | ensuring one-way/unidirectional flow through the heart |
| which valves lie between the atria and ventricles? | atrioventricular (AV) valves |
| (starred) what are the alternate names for the AV valves? | right AV valve = tricuspid valve; left AV valve is the bicuspid or mitral valve |
| AV valves prevent backflow into ____ when ventricles contract | atria |
| what structure(s) anchor AV valves to papillary muscles in the ventricles? | chordae tendineae |
| where is the aortic semilunar valve? | between the left ventricle and the aorta |
| where is the pulmonary semilunar valve? | between the right ventricle and pulmonary trunk |
| what do semilunar valves prevent? | backflow of blood into the ventricles |
| how many cusps do semilunar valves have? | 3 each |
| what forces AV valves to open? | blood returning to the heart and filling atria |
| true or false, as ventricles fill, AV valve flaps hang limply into ventricles | true |
| what causes AV valves to close? | when ventricles contract and atrioventricular valve cusps have blood forced against them |
| what prevents valve vlaps from everting intro atria? | when papillary muscles contract and chordae tendineae tighten |
| what forces semilunar valves open? | blood from ventricles contracting |
| as ventricles relax and intraventricular pressure falls, blood flows back from arteries, forcing what to close? | semilunar valves |
| what is the word for when heart muscle behaves as a functional unit working together? | it behaves as a functional syncytium |
| what are the histological characteristics of cardiac muscle? | striated, short, fat, branched and interconnected |
| what acts as both tendon and insertion point for the heart muscle? | the connective tissue endomysium |
| what part do intercalated discs play in the cardiac muscle? | they anchor cardiac cells together and allow free passage of ions(!) |
| what stimulates the heart? | nerves, but it is self-excitable (automaticity - beats even if nerves are cut, although not correctly) |
| how long is the absolute refractory period of the heart? | 250 ms (relatively long) - about a quarter of a second (versus 1 ms for a neuron) |
| true or false, cardiac muscle contraction is similar to skeletal muscle contraction | true |
| what are the cells of the heart's intrinsic conduction system? | autorhythmic (MYOGENIC - muscle-generated potentials) cells |
| what are 3 characteristics of myogenic cells? | initiate action potentials (immediately depolarize after repolarization), have unstable resting potentials calls pacemaker potentials (sitting at -70mv), use calcium influx rather than sodium for rising phase of the AP |
| which node generates impulses about 75 times per minute? | sinoatrial node (SA) |
| how many impulses does the sinoatrial (SA) node generate per minute and what is the reason for this number? | 75 times a minute, would be 100 but the vagal/parasympathetic system puts a brake on it |
| what delay happens to allow the ventricles to fill with blood? | the atrioventricular (AV) node delays the impulse about 0.1 second to allow the ventricles to fill with blood |
| what structure carries the heart impulse from atria to ventricles? | atrioventricular (AV) bundle aka bundle of His |
| true or false, the AV bundle splits | true, it splits into two pathways in the interventricular septum (right and left bundle branches) |
| where does the AV bundle split? | the interventricular septum |
| from where to where do bundle branches carry the heart excitation impulse? | bundle branches carry the impulse from the AV bundle toward the apex (bottom) of the heart |
| what actually carries the heart impulse to the heart apex (and ventricular walls)? | Purkinje fibers |
| what are ectopic foci? | ectopic foci are abnormal, excitable clusters of cells outside the sinoatrial (SA) node that generate independent electrical impulses, leading to premature beats or arrhythmias. ectopic means wrong place |
| when are ectopic foci likely to occur? | likely to occur when the heart's primary pacemaker (SA node) is suppressed, damaged, or when cardiac tissues are stressed, causing electrical instability |
| what is nodal rhythm? | nodal rhythm (or junctional rhythm) is an arrhythmia where impulses originate from the atrioventricular (AV) node instead of the sinus node (because this failed), like after a heart attack (MI). AV is wrongly running the show here |
| what is intrinsic ventricular rhythym? | when the ventricles beat too slow to sustain life, at about 20-40 bpm (bradycardic) |
| what parts of heart excitation correspond to which parts of the ECG's PQRS complex? | P wave: depolarization of SA node; QRS complex: ventricular depolarization (and technically atrial repolarization, but this is masked by the larger QRS complex); T wave: ventricular repolarization |
| regarding extrinsic innervation of the heart, the heart is stimulated and inhibited by what centers? | stimulated by the cardioacceleratory center, inhibited by the parasympathetic cardioinhibitory center (vagal braking) |
| an abnormal ECG shows some P waves not making it through the AV node. what condition is this? | second-degree heart block |
| an abnormal ECG shows some P waves missing. what condition is this? | junctional rhythm where SA node is not functioning at all |
| an abnormal ECG shows extremely irregular up-and-down tracings. what might this mean? | ventricular fibrillation - no coordinated pumping action - ventricles are just vibrating/fibrillating |
| the "lub dub" or "lub dup" sounds are associated with what? | closing of heart valves, S1 and S2 |
| describe what happens with the S1 heart sound | first sound (S1) occurs as AV valves close and signifies beginning of systole |
| describe what happens with the S2 heart sound | second sound (S2) occurs when SL valves close at the beginning of ventricular diastole |
| describe what happens with the third heart sound | third sound (S3), if present, is called a gallop and is due to blood passively "dripping" into the empty ventricle; rarely heard in people over 30 |
| what is systole? | contraction of heart muscle (can apply to atrial or ventricular) |
| what is diastole? | relaxation of heart muscle (can apply to atrial or ventricular) |
| what is cardiac cycle? | refers to all events associated with blood flow through the heart, including systole and diastole. phases include ventricular filling, ventricular systole, isovolumetric relaxation |
| what happens during mid-to-late diastole? | when both chambers are relaxed, ventricular filling happens: heart BP is low as blood enters atria and flows into ventricles, AV valves are open, then atrial systole occurs |
| what happens during ventricular systole? | atria relax, rising ventricular pressure results in closing of AV valves; isovolumetric contraction phase (no valves open); ventricular ejection phase opens semilunar valves |
| what happens during early diastole? | isovolumetric relaxation where ventricles relax and backflow of blood in aorta and pulmonary trunk closes semilunar valves |
| what is the dicrotic notch? | phenomenon of brief rise in aortic pressure caused by backflow of blood rebounding off semilunar valves |
| what is CO? | cardiac output, the amount of blood pumped by each ventricle in 1 minute; CO is the produce of HR (heart rate in BPM) and SV (stroke volume in amount per beat) |
| what is cardiac reserve? | the difference between resting and maximal CO (cardiac output) |
| what is a positive/negative chronotropic factor? | positive/negative chronotropic factors increase/decrease HEART RATE such as SNS and PSNS respectively |
| which nervous system regulates the heart rate? | autonomic |
| which specific nervous system is activated by stress, anxiety, excitement, or exercise? | SNS - sympathetic nervous system |
| which nervous system opposes the SNS? | PSNS - parasympathetic nervous system |
| which nervous system is mediated by acetylcholine? | parasympathetic nervous system |
| which nervous system dominates the autonomic stimulation, slowing heart rate and causing vagal tone? | parasympathetic nervous system |
| which valve has 2 cusps? | left atrioventricular valve, aka bicuspid valve, aka mitral valve |
| which heart valves have no chordae tendineae? | semilunar valves (pulmonary and aortic) |
| what cells use calcium rather than sodium for the rising phase of their action potentials? | heart cells / cardiac cells |
| which node in the heart beats at about 75 BPM? | sinoatrial node (pacemaker) - atrial systole |
| which node in the heart beats at about 40 BPM? | atrioventricular node - the electrical gateway to the ventricle (like customs when traveling) |
| what is the other name for the atrioventricular bundle? | bundle of His |
| is sinus rhythm a good thing? | yes, you would hope to hear it after the heart is shocked by a defibrillator |
| what is the formula for cardiac output? | CO = HR x SV |
| what is the formula for cardiac reserve? | maximal CO - resting CO |
| what is the formula for stroke volume? | EDV - ESV |
| what is EDV? | amount of blood collected in a ventricle during diastole |
| what is ESV? | amount of blood remaining in a ventricle after contraction |
Created by:
elianayu
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