23 terms

Chapter 18 Cardiovascular System

Orientation of Heart
Base of heart=superior
Fibrous Pericardium
outermost covering, dense CT, protects, achors, prevents overfilling
Serous Pericardium
deep to fibrous pericardium
parietal=lines internal surface of fibrous pericardium
visceral=epicardium=covers external surface fo heart
same as visceral epicardium
outermost layter, simple squamous epithelium and loose areolar CT
bulk of heart; cardiac muscle
arranged in spiral bundles, causes a wringing effect when heart contracts
innermost layer
simple squamous epithelium
lines heart chambers, continues with blood vessels to become endothelium
Seperation from Atrium from Ventricle
Externally: Coronary Sulcus seperates each atrium from its ventricle
Internally: Atrioventricle (AV) vavle
Seperates ventricles from blood vessels
Semilunar valves (SV)
Pulmonary Circuit
Right side pump.
right side of heart->lungs->left side of heart
Systemic Circuit
left side of heart->body->right side of heart
Respiratory Membrane
the pulmonary capillaries surround the alveoli and includes a basement membrane
-blood in capillaries becomes oxygenated as it passes by alveoli
-O2 from alveoli into caps.
-CO2 diffuses from caps into aveoli
simple squamous epithelium
Pathway of Blood
Right Atrium > Tricupsid Valve > Right Ventricle > Pulmonary Semilunar Valve > Pulmonary Trunk > L and R Pulmonary arteries > Pulmonary Capillaries (lungs) > Pulmonary Veins (oxygenated) > Left Atrium > Bicuspid valve > Left Ventricle > Aortic Semilunar Valve > Aorta > Systemic Ciculation > RA
Heart Valves
Atrioventricular (AV): tricuspid and bicuspid seperates atrium from ventricle
semilunar (SL): pulmonary (R) and aortic (L) sperate ventricle from blood vessel
AV Vavles
Open when ventricles are relaxed and filling with blood
Closed when ventricles contract to prevent backflow
Chordae Tendineae
Anchor the cusps of the AV valve to papillary muscles
SL Valves
Closed as ventricles filling with blood (relaxed)
Open as ventricles contract to allow ejection of blood
Coronary Circulation
heart requires 5% of the blood supply to nourish itself
coronary arteries and cardiac veins
saphenous vein from leg and cut into grafts-connect from the aorta to the coronary arteries to bypass the blockage
Coronary Arteries
Right and left coronary arteries arise from base of aorta
encircle heart in coronary sulci
anastomoses: junctions of vessels allow collateral routes for blood flow in case of blockage.
blockage may require bypass surgery
Cardiac Veins
Join to form the coronary sinus which drains deoxygenated blood into the RA
Cardiac Muscles
cells are highly interdependent
gap junctions at intercalated discs
short, fat branched cells
gap junctions-ions pass
desmosomes-keep cells from separating as muscle contracts
Contractile Cells
99% of heart cells
contract, carry out pumping action
Autorhythmic cells
1%, don't contract
fire action potentials that spread thru heart via gap junctions
localized along intrinsic conduction system that coordinates contraction of heart chambers
Cardiac Intrinsic Conduction System
Sinoatrial (SA) node pacemaker-initiates pulse > atrioventricular AV node > atrioventricular bundle > connects atria to ventricles > bundle branches (septum) > Purkinje Fibers (depolarize contractile cells for ventricles)