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Cardiovascular system. The term CIRCULATORY SYSTEM refers to H E A R T B L O O D V E S S E L S B L O O D The term CVS refers to HEART (4 chambered muscular pump) Arteries veins Capillaries. Cardiovascular system. 2 major divisions Pulmonary circuit Systemic circuit.
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Cardiovascular system The term CIRCULATORY SYSTEM refers to • H E A R T • B L O O D V E S S E L S • B L O O D The term CVS refers to • HEART (4 chambered muscular pump) • Arteries • veins • Capillaries
Cardiovascular system 2 major divisions • Pulmonary circuit • Systemic circuit
Functions of the Heart • Generating blood pressure • Routing blood • Heart separates pulmonary and systemic circulations • Ensuring one-way blood flow • Heart valves ensure one-way flow • Regulating blood supply • Changes in contraction rate and force match blood delivery to changing metabolic needs
Cardiovascular system PERICARDIUM a double walled sac • Parietal • Visceral (E P I C A R D I U M ) • Pericardial cavity Is space b/w PT and VS membranes 5-30 ml of pericardial fluid Lubrication
Cardiovascular system HEART WALL • E P I C A R D I U M • M Y O C A R D I U M • E N D O C A R D I U M
Cardiovascular system V A L V E S Heart needs valves that ensures a predominantly ONE-WAY flow Opening and closing is the result of pressure gradients b/w the UPSTREAM and DOWNSTREAM sides of the valve
RA ----- right AV valve ---- right ventricle ----- pulmonary valve ----- pulmonary trunk ---- pulmonary arteries to lungs pulmonary veins returning from lungs ---- LA ---- left AV valve ---- LV ---- aortic valve ---- aorta --- other systemic vessels - IVC / SVC ----- back to RA Cardiovascular system P A T H W A Y O F B L O O D
OPERATION OF HEART VALVES • Ventricular pressure greater than artery pressure • The valve is forced open • Blood is ejected
OPWERATION OF HEART VALVES • Ventricular pressure lower than arterial pressure • Arterial blood holds the valve closed
OPWERATION OF HEART VALVES • Arterial pressure greater than ventricular pressure • Valve open and blood flows through
OPWERATION OF HEART VALVES • Ventricular pressure rises above arterial pressure • The blood in the ventricle pushes the valve cusps closed
Cardiac muscle • Cardiac myocytes (cardiocytes) are shorter and thicker • Each myocyte linked to several others at its ends • The linkages are called I n t e r c a l a t e d d i s c s
Cardiac muscle an intercalated disc has • electricalgap junctions That allows each myocyte to directly stimulate its neighbors • mechanical junctions (DESMOSOMES) Keep myocytes from pulling apartwhen heart contracts
Cardiac muscle • Sarcoplasmic reticulum is less developed than sk. M • T tubules are larger and admit supplemental Calcium from ECF • It contains built-in P A C E M A K E R that rhythmically sets off a wave of electrical excitation ( A U T O R H Y T H M I C )
Cardiac muscle • Cardiac muscle doesn’t exhibit quick twitches like Sk. M • Cardiac muscle uses aerobic respiration almost exclusively • Rich in myoglobin and glycogen