Heart chp 25 Flashcards
Cardiovascular System
Circulatory system = heart and blood vessels
Heart
muscle, fxn = pump blood thru vessels of CV system, cardiac striated muscles, chambers (2 atria, 2 ventricles)
Atria lie post to ventricles (horizontal blood flow)
In thorax, btw lungs, resting on diaphragm
Structures that protect the heart
Ant - sternum
Laterally - ribs, ICM, lungs
Post - thoracic vertebrae
Pericardium - tough connective (fibroserous) tissue sac
Pericardium
outer layer blends w central tendon of diaphragm inf.
sup/post - fibrous layer blends w major vessels (VC, aorta, pulm trunk)
Myocardium - cardiac muscle
Endocardium - inner epithelial lining of chambers
Three surfaces
Sternocostal - adjacent to sternum and costal cartilages
Diaphragmatic - adjacent to diaphragm
Pulmonary - adjacent to medial surface of left lung
Apex
rounded projection, points inf and left, 6 CC
Base
where great vessels attach
Auricles (earlike appendage)
lateral surface of both atria, allow for increased capacity
Crista Terminalis
vertical muscular ridge, post wall of RA
Musculi Pectinati
from crista terminalis, ridge-like extensions
Found only in RA, and right and left auricles
RA venous openings
Superior and Inferior Vena Caval opening, (valve of IVC = nonfunctional), opening of coronary sinus (ant/sup to IVC)
Interatrial septum
btw right/left atrium,
fossa ovalis, limbus fossa ovalis
Foramen Ovale
foramen present in the fetal stages of development btw RA/LA, closes at birth, then called fossa ovalis
Tricuspid Valve (Right Atrioventricular)
Guards right atrioventricular opening, from RA to RV, closes during contraction of ventricles, preventing backflow
Atrioventricular valves composed of:
Cusps - flaps of connective tissue
Chordae tendineae - connective tissue cords, attach to lower surface of cusps
Papillary muscle - internal folds of ventricular muscle, chordae tendineae attach (a type of trabecular carneae)
Trabecula Carneae
irregular ridge like projections of muscle
papillary muscle and moderator band (septomarginal trabecular)
Moderator Band (Septomarginal Trabecula)
attaches to interventricular septum and ant papillary muscle
contains the right branch of atrioventricular bundle
Semilunar Valve
3 flaps or cusps
nodule - thickening of fibrous tissue at free edge of cusp, fills small gap when closed
Lunula - narrow thin crescent area extending from each side of nodule
Sinuses - spaces btw cusps and wall of vessels
Pulmonary Circulation
RV → pulmonary semilunar valve → pulmonary trunk → Rt and left pulmonary arteries → Rt and left lungs → oxygenated blood returns via FOUR pulmonary veins (2 from rt lung, 2 from left) → LA
LA
Musculi pectinati in left auricle only
4 opening of pulmonary veins and left atrioventricular valve
Bicuspid Valve (Mitral valve)
Has 2 cusps, chordae tendineae, and papillary muscles
LV
has trabecula carneae
very thick ventricle wall
performs more work and is larger
Aortic Semilunar Valve
3 cusps, nodules, and lunulae
aortic sinuses - origins of right and left coronary arteries
SA node
pacemaker, jxn of SVC and RA
impulse initiated in SA node, spreads thru atrial muscle to both atria, causing them both to contract, reaches atrioventricular node
