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A&PII - Ch 18
Cardiovascular System - Heart
| Question | Answer |
|---|---|
| chambered muscular organ that pumps blood received from the veins into the arteries, thereby maintaining the flow of blood through the entire circulatory system | heart |
| medial cavity of the thorax containing the heart, great vessels, and trachea | mediastinum |
| posterior surface of heart; about 9cm wide & directed toward right shoulder | base |
| points inferiorly toward left hip | apex |
| btwn 5th & 6th ribs just below left nipple; caused by apex of beating heart contacting chest wall | apical impulse |
| contains film of serous fluid; located btwn parietal & visceral layers; slit-like | pericardial cavity |
| serous membranes lubricated by serous fluid in pericardial cavity allows the layers to __ __ past one another during heart activity; friction free environment | glide smoothly |
| inflammation of pericardium, roughens serous membranes surfaces; as beating heart rubs against its pericardial sac it creates & creaking sound | pericarditis |
| beating heart rubs against its pericardial sac it creates & creaking sound | pericardial friction rub |
| condition in which heart is compressed by fluid; "heart plug" | cardiac tamponade |
| superficial, visceral layer of serous pericardium; often infiltrates with fat | epicardium |
| layer of the heart wall composed of cardiac muscle | myocardium |
| myocardium is the layer that __ | contracts |
| in myocardium, branching cardiac muscles cells are tethered to one another by crisscrossing connective tissue fibers & arranged in __ __ | spiral/circular bundles |
| spiral/circular bundles of myocardium effectively __ all parts of heart together | link |
| connective tissue fibers that form dense network that reinforces myocardium internally; network of collagen & elastic fibers | fibrous skeleton of heart |
| fibrous skeleton of heart also __ cardiac muscle fibers | anchors |
| fibrous skeleton of heart constructs rope-like rings that provide __ __ where great vessels issues from heart & around heart valves | additional support |
| because connective tissue is not __ __ fibrous skeleton of heart limits direct spread of action potentials across heart to specific pathways | electrically excitable |
| glistening white sheet of squamous endothelium resting on thin layer of connective tissue that lines the interior of the heart | endocardium |
| on inner __ __ endocardium lines heart chambers & covers fibrous skeleton of valves | myocardial surface |
| endocardium is __ __ endothelial linings of blood vessels leaving & entering heart | continuous with |
| two superior receiving chambers of the heart | atria |
| paired, inferiorly located heart chambers that function as the major blood pumps | ventricles |
| internal partition that divides heart longitudinally; separates atria | interatrial septum |
| internal partition that divides heart; separates ventricles | interventricular septum |
| forms most of anterior surface of hear | right ventricle |
| dominates inferoposterior aspects of heart & forms heart apex | left ventricle |
| grooves visible on heart surface; indicate boundaries of 4 chambers; carry blood vessels supplying myocardium; encircles junction of atria & ventricles like crown | coronary sulcus |
| cradling anterior interventricular artery; marks anterior position of septum separating right & left ventricles | anterior interventricular sulcus |
| anterior interventricular sulcus continues to provide similar landmark on heart's posteroinferior surface | posterior interventricular sulcus |
| small, wrinkled, protruding appendages that increase atrial volume | auricles |
| right & left atria are free of distinguishing __ __ | surface features |
| anterior portion of right atrium; ridged by bundles of muscle tissue | pectinate muscles |
| posterior & anterior regions of right atrium are separated by C-shaped ridge | crista terminalis |
| left atrium is mostly smooth & pectinate muscles are | only found in auricle |
| shallow depression in interatrial septum that marks spot where foramen ovale (opening) existed in fetal heart | fossa ovalis |
| functionally, atria are __ __ for blood returning to heart from circulation | receiving chambers |
| atria are relatively small, thin-walled chambers because they need contract __ __ to push blood " downstairs" into ventricle | only minimally |
| atria contribute little to __ __ activity of heart | propulsive pumping |
| superior vena cava, inferior vena cava, & coronary sinus are veins in which | blood enters right atrium |
| returns blood from body regions superior to diaphragm | superior vena cava |
| returns blood from body areas below diaphragm | inferior vena cava |
| collects blood draining from myocardium | coronary sinus |
| enter left atrium; transport blood from lungs back to heart; best seen in posterior view | pulmonary veins |
| left atrium makes up most of | heart's base |
| make up most of the volume of heart | ventricles |
| marking internal walls of ventricular chambers; irregular ridges of muscle | trabeculae carneae |
| cone-like; play role in valve function. projection into ventricular activity | papillary muscles |
| when ventricles contract, blood is propelled out of heart & | into circulation |
| blood pumped from right ventricle; routes blood to lungs | pulmonary trunk |
| major systemic artery; arises from the left ventricle of the heart | aorta |
| left ventricle ejects blood | into the aorta |
| heart is actually two side-by-side pumps, each serving | separate blood circuit |
| blood vessels that carry blood to/from lungs; serves gas exchange | pulmonary circuit |
| blood vessels that carry functional blood supply to/from all body tissues | systemic circuit |
| right side of heart __ circuit pump | pulmonary |
| blood returning from body is __ & __ | oxygen-poor; carbon dioxide-rich |
| freshly oxygenated blood is carried by __ __ to left side of heart | pulmonary veins |
| opposite ___ ___ exist in veins & arteries of pulmonary circuit | oxygenation conditions |
| left side of heart is | systemic circuit pump |
| freshly oxygenated blood __ __ is returned to left atrium & passes into left ventricle which pumps into aorta | leaving lungs |
| blood loaded with CO2 & depleted of O2 returned through __ veins to right side of heart, where enters right atrium through superior/inferior venae cavae | systemic |
| pulmonary circuit is a short, low-pressure __ | circulation |
| systemic circuit takes long pathway through entire body & encounters about | 5x as much friction |
| walls of left ventricle are 3x as __ as those of the right | thick |
| left ventricle __ is nearly circular | cavity |
| right ventricular cavity is __ into crescent shape that partially encloses left ventricle | flattened |
| functional blood supply of the heart; shortest circulation in the body | coronary circulation |
| arise from base of aorta & encircle heart in coronary sulcus; arterial supply of coronary circulation is provided by | right & left coronary arteries |
| runs toward left side of heart & then divides into major branches | left coronary artery |
| follows anterior interventricular sulcus & supplies blood to interventricular septum & anterior walls of both ventricles | anterior interventricular artery |
| anterior interventricular artery is also known as | left anterior descending artery |
| supplies left atrium & posterior walls of left ventricle | circumflex artery |
| courses to right side of heart where it gives rise to 2 branches | right coronary artery |
| serves myocardium of lateral side of heart | right marginal artery |
| runs to heart apex & supplies posterior ventricular walls | posterior interventricular artery |
| near apex of heart posterior interventricular artery __ with anterior interventricular artery | anastomosis |
| together branches of right coronary artery supply __ atrium & nearly all __ ventricle | right; right |
| __ supply of heart varies considerably | arterial |
| there are __ __ among coronary arterial branches | many anastomoses |
| many anastomoses among coronary arterial branches provide __ __ for blood delivery to heart muscle | additional/collateral routes |
| additional/collateral routes provided by anastomoses among coronary arterial branches are not __ __ to supply adequate nutrition when coronary artery is suddenly occluded | robust enough |
| complete blockage of coronary artery branches leads to | tissue death & heart attack |
| coronary arteries provide __, __ blood flow to myocardium | intermittent; pulsating |
| coronary arteries & main branches lie in __ & send branches inward to nourish __ | epicardium; myocardium |
| coronary arteries & branches deliver blood when heart is __ but are fairly ineffective when ventricles are __ because they are compressed by contracting myocardium | relaxed; contracting |
| heart requires / of body's __ __ | blood supply |
| left ventricle receives the __ __ blood supply | most plentiful |
| after passing through capillary beds of myocardium, venous blood is collected by __ __, whose paths roughly follow those of coronary arteries | cardiac veins |
| cardiac veins join together to form enlarged vessel called __ __, which empties blood into right atrium | coronary sinus |
| coronary sinus is on __ __ of heart | posterior aspect |
| great cardiac vein, middle cardiac vein, & small cardiac vein are all | tributaries of coronary sinus |
| located in anterior interventricular sulcus; part of coronary sinus | great cardiac vein |
| located in posterior interventricular sulcus; part of coronary sinus | middle cardiac vein |
| runs along heart's right inferior margin; part of coronary sinus | small cardiac vein |
| anastomosis is connection of __ __ of a branching system to form a network | separate parts |
| severe suffocating chest pain caused by brief lack of oxygen supply to heart muscle | angina pectoris |
| condition characterized by dead tissue areas in the myocardium; caused by interruption of blood supply to the area | myocardial infarction (MI) |
| MI is commonly called | heart attack |
| because adult cardiac muscle is essentially amitotic, most areas of cell death are repaired with __ __ tissue | noncontractile scar |
| damage to __ __ in MIs, which is the systemic pump, is most serious | left ventricle |
| blood flows in __ __ from atria to ventricles & out great arteries leaving superior aspect of the heart | one direction |
| bundle of specialized fibers that conduct impulses from the AV node to the right and left ventricles | atrioventricular (AV) bundle |
| atrioventricular (AV) bundle is also called | bundle of His |
| right atrioventricular valve | tricuspid valve |
| left atrioventricular valve | mitral valve |
| tiny white collagen cords attached to each AV valve, anchoring cusps to papillary muscles | chordae tendinae |
| when heart is relaxed AV flaps __ __ into ventricular chambers below | hang limply |
| valves that prevent blood return to the ventricles after contraction; aortic and pulmonary valves | semilunar valves |
| when ventricles are contracting & interventricular pressure rises above pressure in aorta & pulmonary trunk __ __ open | SL valves |
| forces heart to repump same blood over & over because valve does not close properly * blood backflows | incompetent valve |
| valve flaps become stiff & constrict opening | valvular stenosis |
| specialized muscle of the heart; striated & contracts by sliding filament mechanism | cardiac muscle |
| cardiac muscle cells are | shirt, fat, branched, & interconnected |
| each cardiac muscle fiber contains one/at most two large, pale, centrally located __ | nuclei |
| intercellular spaces filled with loose connective tissue matrix containing numerous capillaries in cardiac muscle | endomysium |
| plasma membranes of adjacent cardiac cells interlock at dark-staining junctions called | intercalated discs |
| intercalated discs contain anchoring __ & __ __ | desmosomes; gap junctions |
| prevent adjacent cardiac cells from separating during contraction | desmosomes |
| allow ions to pass from cell to cell, transmitting current across entire heart | gap junctions |
| because cardiac cells are electrically coupled by gap junctions, myocardium behaves as a single coordinated unit called | functional syncytium |
| account for 25-35% of volume of cardiac cells & give cardiac cells high resistance to fatigue | large mitochondria |
| have Z discs, A bands, & I bands that reflect arrangement of thick (myosin) & thin (actin)filaments | sarcomeres |
| T tubules are wider & enter the cell once per sarcomere at the Z disc | system for delivering Ca2+ |
| cells of heart can initiate their own depolarization, as well as the rest of heart as well in spontaneous & rhythmic way | automaticity/autorhythmicity |
| in cardiac muscle, heart either contracts as unit or not at all because | gap junctions electrically tie all cardiac muscle cells together into single contractile unit |
| depolarization wave travels across heart from cell to cell via __ __ through gap junctions | ion passage |
| in cardiac muscles the __ __ __ lasts approximately 250 ms; this is the inexcitable period when Na+ channels are still open/inactivated | absolute refractory period |
| the long cardiac refractory period normally prevents __ __, which would stop heart's pumping action | tetanic contractions |
| about 1% of cardiac fibers are __, having special ability to depolarize spontaneously and thus pace heart | autorhythmic |
| bulk of heart muscle is composed of __ __ __ responsible for heart's pumping activity | contractile muscle fibers |
| cardiac muscle is adaptable & readily switches __ __ to use whatever nutrient supply is available, including lactic acid | metabolic pathways |
| real danger of an inadequate blood supply to myocardium is __ __ __, not of nutrient fuels | lack of O2 |
Created by:
lfrancois
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