CVPR 03-24-14 08-09am Overview CV Anatomy - Proenza Flashcards
The functions of the cardiovascular system
- Distributes dissolved gases & nutrients.
- Removes metabolic waste
- Contributes to systemic homeostasis by controlling temp, O2 & nutrient supply, pH, ionic composition.
- Quickly adapts to changes in conditions and metabolic demands
Three parts of the cardiovascular system
- Heart (pump)
- Blood (transportation)
- Vasculature (including lymphatic system) (pipes).
Lt vs Rt Heart Side pumps to…
Left side of heart pumps blood to system circulation. Right side pumps to pulmonary circulation.
“In Series” arrangement of circulatory system
The primary arrangement of cardiac/pulmonary circulatory system. No direct connection between right and left (septum separates sides). Output of left and right sides of heart must be closely matched.
Pulmonary circulation vs. System circulation
A. Pulmonary: low pressure, single pathway between heart and lungs (“series”).
B. Systemic: higher pressure, multiple pathways from heart to different systemic vascular beds (“parallel”).
“In Parallel” arrangement of circulatory system … where occurs
The primary arrangement of SYSTEMIC circulation.
Importance of “parallel” arrangement of systemic circulation
- Oxygenated blood visits only one organ system before returning to pulmonary circulation.
- Changes in metabolic demand or blood flow in one organ do not significantly affect other organs.
- Blood flow to different organs can be individually varied to match demand.
Changes in blood flow to different organs during rest vs exercise
- At rest, most blood is directed to brain (~14%), skeletal muscle (~15%), GI system (21%), and kidney (22%).
- During exercise, up to 80% of blood may be directed to exercising muscle.
Major exception to “in parallel” systemic circulation
Hepatic circulation — large fraction of hepatic blood supply is via intestinal circulation
Layers of the heart wall
Outside to inside:
- Epicardium
- Myocardium
- Endocardium
Epicardium defn.
Outer membrane of the heart wall; Connective tissue & fat
Myocardium defn.
Thick middle muscle layer of the heart wall
Endocardium defn.
Inner membrane of the heart wall; Made of endothelial cells, as in vessels
Pericardium defn.
Fluid-filled membranous sac enclosing entire heart — Not connected to walls of heart — Stiff & non-compliant, resists sudden distension of chambers
Layers of pericardium
Fibrous layer (outer), Parietal pericardium, [Pericardial fluid], Visceral pericardium (inner)
Pericarditis
Inflammation of the pericardium –> restricts filling of the heart
Chambers of the heart (4)
Ventricles (left and right) = the main pumping chambers; separated from each other by interventricular septum………
Atria (left and right) = small “primer” chambers to supply the ventricles with blood; thinner walled.; separated from each other by interatrial septum
Left vs. Right Ventricles
Left ventricle supplies higher pressure systemic circulation, so is bigger with thicker walls than the right ventricle. The left ventricle does more work, uses more O2 than the right.
Vessels of the Heart (4)
- Vena cavae –> inlet to rt. atrium from body
- Pulmonary artery –> outlet from rt. ventricle to lungs
- Pulmonary vein –> inlet to lt. atrium from lungs
- Aorta –> outlet from lt. ventricle to body
Vena cavae
Superior vena cava & inferior vena cava; Inlet vessels into the right atrium
Pulmonary artery
Outlet vessel from right ventricle [Arteries go Away from the heart]…odd for an artery b/c it carries DEoxygenated blood
Pulmonary vein
Inlet vessel into left atrium
Aorta
Outlet from left ventricle; Main blood supply to body; Garden-hose sized, ~1” in diameter
Valves defn.
Thin flaps (“cusps”) of fibrous tissue covered by endothelium........... *Mitral valve has two cusps (bicuspid); the others have three.
Valves of the Heart (4)
- Tricuspid valve (btwn rt atrium & rt ventricle) …….2. Pulmonic valve (btwn rt ventricle & pulmonary artery)……. 3. Mitral valve (btwn lt atrium & lt ventricle)…….4. Aortic valve (btwn left ventricle & aorta)