Cardiovascular System Flashcards
What is the cardiovascular system?
-The requirement for a circulatory system is a consequence of increasing size and complexity of multicellular organisms
-Provides a concentration gradient from the blood to cells for nutrients and in the opposite direction for waste
What is the primary and secondary roles of the circulatory system?
What are the 3 types of transport in the circulatory system?
What are the two serial circuits that stem from the heart?
Pulmonary circuit:
-Lungs
-Pulmonary capillaries
Systemic circuit:
-Systemic arterioles, capillaries and venules
-In all organs and tissues except the lungs
Explain vasculature in the cardiovascular system
Explain the transport of blood through the heart and major blood vessels
How does blood flow through the cardiovascular system?
What is the source of pressure in the cardiovascular system?
Explain how pressure gradients influence fluid flow
What opposes flow and how can you predict it?
How does vessel radius influence blood flow?
How does vessel length and liquid viscosity influence blood flow?
How does velocity of flow differ from flow rate?
What is the pericardium?
Describe Atrioventricular valves (AV)
Describe Semilunar valves
Explain the cardiac conduction system
What is atrial conduction?
Four special conducting bundles:
-Backman’s bundle: conducts action potentials from the SA pacemaker into the left atrium causing contraction
-Anterior, middle and posterior internodal pathways: conduct the action potential from the SA node to the AV node, depolarizing right atrial muscle along the way
what is ventricular conduction?
-Layer of connective tissue prevents conduction directly from atria to ventricle
-Conduction slows down through the AV node to allow blood from atria to empty into ventricles
-Depolarization proceeds through the septum to the apex (bundle of His followed by bundle branches)
-Then spreads up the walls of the ventricles from apex to base (Purkinje fibres)
Sa node > Internodal pathways > AV node > Bundle of His > Bundle branches > Purkinje fibres
How do ventricles contract?
-muscles have a spiral arrangement that ensures blood is squeezed upward from the apex of the heart
What is a complete conduction block?
-Happens if electrical activity cannot be transgerred from the atria to the ventricles
-Caused by a damage in conduction pathway
Eg. Block at the bundle of His results in a complete dissociation between the atria and ventricles
-The SA node continues to be pacemaker for the atria, but electrical activity does not make it to the ventricles so the purkinje fibers take over as the pacemaker for the ventricles
-Requires an artificial pacemaker
What is an electrocardiogram (ECG, EKG) and its function?
-Represents the summed electrical activity of all cells in the heart recorded from the surface of the body (NaCl-based ECF are good conductors of electricity)
-Provide information on heart rate and rhythm, conduction velocity and even condition of tissues in the heart
-If electrical activity of the heart is moving toward the positive electrode of the lead then an upward deflection is recorded
-If electrical activity is moving away from positive electrode, it is recorded as downward deflection
-Electrical activity moving perpendicular to the axis of the electrodes causes no deflection (baseline)
What are arrhythmias?
-Electrical problems during the generation or conduction of APs through the heart and can appear as elongated semgments or intervals, altered, missing or additional waves
What are premature ventricular contractions?
-Purkinje fibres randomly kcik in as pacemaker, can be due to insufficient oxygen to myocardium, excessive Ca2+, hypokalemia, medications, exercise, high levels of adrenaline
-Perceived as skipped beat or palpatation