Module 8 ML-3 Flashcards
Three types of cardiac muscle cells
pacemaker
conducting
contractile
Pacemaker
a small fraction of cardiac muscle cells that have automaticity (automatically generates an AP); SA node determines the heart rate
SA node APs/min
100/120
AV node APs/min
60-80 APs/min
Conducting cells
30-50 APs/min
Conducting cells
all cardiac muscle cells are conducting cells because they all conduct APs, a small amount are specialized to rapdily spread the electrical stimulus to the chambers
What are the conducting cells
Bundle of His, right and left bundle branches and Purkinje fibers
Contractile Cells
99% of cardiac muslce cells whose activity allows blood to be pumped out of the heart
Coronary arteries
the first branches off the aorta and their openings rae behind aortic valve cusps
What provides oxygen and nutrients to the heart muscle cells?
coronary capillaries
What returns blood back to the right atrium
coronary veins
How many miles of blood vessels are in your body
60,000-100,000
What is the ultimate function of the circulatory system
ensure adequate blood flow through capillaries of various organs
What is the path of blood
-right ventircle
-pulomnary valve (SL)
-pulomonary trunk
-pulmonary arteries
-pulmonary arterioles
-capillaries of lungs
-pulomary venules
-pulmonary veins
-left atrium
-left AV valve
-let ventricle
-Aortic valve (SL
-Aorta
-arteries
arterioles
-capillaries
-venules
-veins
-venae cavaw
-right atrium
-right AV valve
Vasoconstriction
small redius, high resistance, low flow
Vasodilation
big radius, low resistance, high flow
Atria
chambers through which blood flows from veins to ventricles
-receive blood from veins
-contraction addes to ventricular filling but not essential
Ventricles
chambers whose contractions produce the pressures that drive blood through the pulmonary and systemic vascular systems and back to the heart
arteries
-low resistance tubes conducting blood flow to organs
Arterioles
major sites of resistance to flow, regulate the pattern of blood flow distribution to the various organs
Capillaries
major site of exchange
Venules
sites of migration of leukocytes from the blood into tissues
Veins
low resistance high capacity vessels carrying blood back to the heart
What is the purpose of heart valves
to promote one way direction of blood flow
