Mechanical Events of the Heart
During this phase of the cardiac cycle, both sets of chambers are relaxed and ventricles fill passively.
late diastole
What are the five items that make up the vascular tree?
arteries, arterioles, capillaries, venules, and veins
What kind of blood vessel is made up of only endothelium?
capillaries
What percentage of cardiac cells do not initiate their own action potential?
99%
60-70% of blood lies where?
systemic veins
This is the first phase of ventricular contraction. It pushes the AV valves closed, but does not create enough pressure to open the semilunar valves.
isovolumic ventricular contraction
Arteries carry ______ away from the ______ to the tissues
blood;heart
What is the largest blood vessel in diameter and how big is is?
veins; 5.0mm
What kind of cells do not contract?
auto-rhythmic cells
The systemic arteries hold __-__% of blood
10-12
During this phase of the cardiac cycle, atrial contraction forces a small amount of additional blood into ventricles.
atrial systole
What are the smallest vessels in the body?
capillaries
The arteriole walls are made up out of what?
smooth muscle
What three ions cause the pacemaker potential?
Na+, K+, & Ca+
The pulmonary circuit holds __-__% of blood
10-12
During this phase of the cardiac cycle, blood flows from the venous side into the atrium and into the ventricles.
midventricular diastole
How do venules form?
when capillaries rejoin
Why is the pulmonary artery often depicted blue in diagrams?
pulmonary arteries are often shown as blue, but in reality they carry deoxygenated blood, which is a darker shade of red
What causes the heart to beat?
a result of action potentials that it generates itself
What percentage of blood is found in the hear?
8-11%
During this phase of the cardiac cycle, ventricular pressure rises and exceeds pressure int the arteries. The semilunar vales open and blood is ejected.
ventricular ejection
Veins are formed when ____ merge and they return ______ _____ to the heart.
venules; deoxygenated blood
Which two types of blood vessels contain endothelium, elastic tissue, smooth muscles, and fibrous tissue?
veins and arteries
What are auto-rhythmic cells responsible for?
these cells initiate action potential for the working cells
What percent of blood is found in the capillaries?
4-5%