Chapter 18 - Circulatory Flashcards
Systemic circuit
Transports oxygenated blood and nutrients to all organs and tissues, ultimately returning deoxygenated blood to right atrium
Left ventricle –> right atrium
Trunks
Several large arteries connected and branching from one another
Aorta
Large elastic artery extending from left ventricle of the heart
Superior and inferior vena cava
Two large veins that all the vessels of systemic venous system merge into.
Dual venous drainage
Important for controlling body temperature. Hot weather - venous blood flows through superficial veins, cold weather - blood is routed to deep veins.
Arteriosclerosis
A thickening and toughening of arterial walls. Account for half of all deaths in U.S.
Atherosclerosis
Formation of lipid deposits in the arterial tunica media associated with damage to the endothelial lining.
High bp
High blood cholesterol
Smoking
Balloon angioplasty
Tip of a catheter contains an inflatable balloon. Once in position the balloon is inflated, pressing plaque against the vessel walls.
Coronary artery disease CAD
Areas of complete or partial blockage of coronary circulation.
Coronary ischemia
Reduced circulatory supply.
Thrombus
Blood clot
Stent
Fine wire-mesh tube that is inserted into a vessel following an angioplasty.
Cardiac cycle
Period between the start of one heartbeat and the beginning of the next. A complete round of systole and diastole.
Systole
Contraction - chamber contracts and pushes blood into an adjacent chamber or into an arterial trunk.
Diastole
Relaxation - chamber fills with blood an prepares for the next contraction.
Isovolumetric contraction
Ventricular contraction pushes the AV valves closed, but does not create enough pressure to open the semilunar valves.
First phase of ventricular systole
Ventricular ejection
Ventricular pressure rises and exceeds pressure in arteries, semilunar valves open and blood is forced out of the ventricles.
Second phase of ventricular systole
Pre potential or pacemaker potential
Gradual spontaneous depolarization of the sa and AV nodes.
Slowing rate of spontaneous depolarization
Acetylcholine released by parasympathetic neurons opens chemically gated K+ channels, slowing rate of spontaneous depolarization.
Speeding rate of spontaneous depolarization
Norepinephrine released by sympathetic neurons binds to beta-1 receptors, leading to the opening of ion channels
Cardiac centers
In the medulla oblongata, contain autonomic headquarters for cardiac control.
Cardioinhibatory center - parasympathetic neurons
Cardioacceleratory center - sympathetic neurons
Sympathetic innervation
Via postganglionic fibers within cardiac nerves
Parasympathetic innervation
Via vagus nerve and synapses with ganglion cells in cardiac plexus.
P wave
Depolarization of atria
P-R interval
Time from beginning of p wave to beginning of QRS complex. Too long of a time can indicate damage to conducting pathways or AV node
QRS complex
Depolarization of ventricles.
Q-T interval
Beginning of q wave to end of t wave. Indicates time for ventricles t undergo a cycle of depolarization and repolorization. Can be lengthened by electrolyte disturbances, medications, conduction problems, ischemia, or myocardial damage.
Pulmonary circuit
Composed of arteries and veins that transport blood between the heart and lungs.
Begins at right ventricle, ends at left atrium
