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33 Cards in this Set
- Front
- Back
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why is the heart considered a double pump?
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it propels blood through the lungs (pulmondary circulation) and the rest of the body (systemic circulation) simultaneously
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how much blood does the heart pump per day?
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at rest ~1800 gallons through 60,000 miles of blood vessels
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general description of heart
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hollow cone-shaped organ, weighs only 10 ounces, 4 chambers
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location of heart
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rests in muscular diaphragm separating thoracic and abdominal cavities; sits in thoracic space called mediastinum
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where is the apex?
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2/3 of heart lies to the left of the midline (apex) formed by LV in deep 5th intercostal space
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where is base?
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superiod and posterior in the mediastimun and is formed mostly by LA
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describe the pericardium
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triple-layered bad that surrounds and protects heart; it's held in the mediastinum but has freedom to contract
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describe the fibrous pericardium
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tough, inelastic, fibrous connective tissue attached to great vessels of heart, diaphragm, and roots to lungs;
anchors the heart, prevents over-stretching and protects |
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describe serous pericardium
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thinner and more delicate membrane that forms double layer around heart
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describe parietal layer of serous pericardium
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outer portion fused to inside surface of fibrous pericardium
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describe visceral layer of pericardium
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inner layer aka epicardium or the outer wall of heart itself; adheres tightly to heart muscle (myocardium)
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describe pericardial cavity
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between parietal and visceral layers is small space; contains pericardial fluid for lubrication to reduce friction as heart moves
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describe epicardium
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wall of heart itself; outermost layer of serous pericardium; thin transparent membrane with slippery texture
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describe myocardium
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middle layer, cardiac muscle cells, responsible for pumping action of heart; muscle fibers are involuntary, striated, branched swirling diagonally around heart in interlacing bundles forming atria and ventricles
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describe intercalated discs
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cardiac muscle cell contacts neighboring cells by transverse thickenings of sarcolemma; within that are gap junctions that electrically couple the cells so they work as unit (functional syncytium)
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define cardiac skeleton
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dense fibrous conn tissue separating atria and ventricles; fibrous tissues uncouples electrical activity of atria and ventricles so they can work independently
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define endocardium
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innermost layer, simple squamous epithelium overlying thin conn tissue; becomes continuous with endothelium of blood vessels
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describe heart chambers
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4 compartments that receive circulating blood; R/L atria with an auricle that increases the volume of the atrium during exercise; also R/L ventricles
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define coronary sulcus/interventricular sulci
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chambers delineated by a series of grooves in which coronary arteries and veins lie
coronary slcus separate atria from ventricles anterior/posterior interventricular sulci separate two ventricles front and back |
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what is the role of cardiac skeleton?
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separates ventricles from atria so they can work separately
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define interatrial septum
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chambers are separated by muscular walls (septa); interatrial septum separates atria---contains fossa ovalis, remnant of foramen ovale (allowed blood to flow from RA to LA
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describe interventricular septum
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separates ventricles and is divided into two portions; superior membranouis and inferior muscular IVS
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describe atrial wall thickness
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myocardium is thin because it only moves blood into ventricles; only small pressure is needed
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describe ventricular wall thickness
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myocardium thicker because it moves blood to lungs or rest of body; LV is thickest bc generates large amount of pressure
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superior vena cava brings blood from where
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most of upper body to heart (head, neck, upper extremity, thorax)
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inferior vena cava brings blood from where
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all parts of body inferior to diaphragm
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blood from coronary sinus
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receives blood frm coronary veins draining the heart itself and delivers to RA
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blood flow through heart
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body, RA, TCV, RV, PSLV, PA, Lungs, LA, BV, LV, ASLV, Aorta, body
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what are heart valves?
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connective tissue of the cardiac skeleton convered with endocardium to prevent backflow of blood; open and close with pressure changes
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two types of heart valves?
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atrioventricular, semilunar
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describe AV valves
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TV/BV; triangle shaped
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what are chordae tendinae
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tendinous cords on conn tissue; anchor down valves inside ventricle wall by attaching to papillary muscles
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coronary circulation
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two coronary arteries are responsible for total blood flow to myocardium
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