Chapter 18: Heart Flashcards
Heart
is a double pump that pushes blood through 2 circuits; right side of heart pumps blood through pulmonary circuit (heart to lungs to heart); left side of heart pumps blood through the systemic circuit (heart to body to heart)
Size, Location, and Orientation of the Heart
size- clinched fist and less than one pound; location- medistinum; orientation- apex angled to the left
What is the heart enclosed by?
pericardium (double walled sac)
Fibrous Pericardium
outermost; tough layer of dense CT; anchors heart to surrounding tissues; prevents it from overfilling with blood
Serous Pericardium
thin, double layered serous membrane deep to the fibrous pericardium; includes parietal pericardium and visceral pericardium
Parietal Pericardium
lines inner part of fibrous pericardium
Visceral Pericaridum
aka epicardium; forms outer laer of heart wall
What is pericarditis?
inflammation/swelling of the pericardium and can lead to cardiac tamponade (heart cant pump sufficient amt and must drain fluid to help)
What are the wall layers of the heart?
3; epicardium; myocardium; endocardium
Epicardium
visceral pericadium; outermost layer
Myocardium
bundles of cardiac muscle containing a network of collagen and elastic fibers
Endocardium
endothelial layer that lones heart chambers and is continuous with blood vessel endothelium
What are some of the external structures used to identify the chambers of the heart?
coronary sulcus; anterior interventricular sulcus
Interatria Septum
separates atria and contains a shallow depression (fossa ovalis- this is the depression that is left when the foramen ovale closes in the infant
What are the three veins that the right atria receive from?
superior vena cava; inferior vena cava; coronary sinus (on posterior side)
What are the four veins that the left atria receives from?
2 left pulmonary veins and two right pulmonary veins
Ventricles
Inferior receiving chambers; 2; thicker walls than atria; separated by interventricular septum; internally have papillary muscles and trabeculae carnae; right ventricle pumps into pulmonary trunk; left ventricle pumps into aorta
Heart Valves
flaps of endocardium reinforced with connective tissue; 2 atrioventricular valves; 2 semilunar valves; prevents backflow; ensures one way flow of blood thru heart; open and close in response to pressure changes
Tricuspid Valve
AV valve; between right atrium and right ventricle; has three flaps
Biscuspid Valve
AV valve; between left atrium and left ventricle; 2 flaps; aka mitral valve
What happens when AV valves are open?
1) blood returning to the heart fills atria, pressing against the ACV valves; the increased pressure forces AV valves to open; 2) as ventricles fill AV valve flaps have limply into ventricles; 3) atria contract forcing additional blood into ventricles
What happens when AV valves are closed?
1) ventricles contract, forcing blood against AV valve cusps; 2) AV valves close; 3) papillary muscles contract and chordae tendineae tighten, preventing valve flaps from everting into atria
Pulmonary Valve
SL valves; between right ventricle and pulmonary trunk; has 3 pocket like cusps
Aortic Valve
between left ventricle and aorta; has three pocket like cusps; SL valve