Flashcards in BIOL 0800 Reading- Chapter 12 Deck (263)
What are the two components of blood?
Formed elements and plasma
What is hematocrit?
The percentage of blood volume that is erythrocytes
At any given moment, what percentage of blood volume is in the capillaries?
Only about 5%, even though that's the percentage that's doing most of the work
What is the pulmonary circuit?
Blood pumped from right ventricle to lungs to left atrium into systemic circulation
What is the systemic circuit?
Blood pumped from the left atrium to the organs/tissues to the right atrium
What is the aorta?
Where the blood leaves the left ventricle to go to systemic circulation
What is microcirculation?
Arterioles, capillaries, and venules
What is the inferior vena cava? And superior?
Brings all the veins together to bring the blood back to right atrium from below the heart; superior brings back all the blood from above the heart
What is the pulmonary trunk?
Brings blood from the right ventricle to the lungs via two pulmonary arteries (one to each lung)
What is the pulmonary vein?
Brings blood back from the lungs to the left atrium
What pattern does the branching of the capillaries create, and why?
Delivers blood to peripheral organs and tissues in parallel so that each only receives a fraction of the bloodflow
How does circulation to the liver and anterior pituitary gland differ from regular circulation?
Blood passes through two capillary beds in series connected by veins before returning to the heart (called a portal system)
What is a portal system?
When blood passes through two capillary beds in series, connected by veins, before returning to the heart
What is the equation relating flow rate, hydrostatic pressure, and resistance?
F = deltaP/R
What is the equation for resistance?
(8Lviscosity)/(pi*r^4) = R
How are blood viscosity and hematocrit related?
Increase in hematocrit increases blood viscosity
How does flow change if the radius of the blood vessel is halved?
Decreases by 16x, since R = 16x
What are the pericardium, epicardium, and myocardium?
The fibrous sac enclosing the heart; the inner layer of the pericardium; the wall of the heart
What is the difference between the left and right AV valves?
LAB RAT: left is bicuspid, right is tricuspid
How do pressure differences interact with AV valves?
If atrial pressure is greater, valve opens; If ventricular pressure is higher during contraction, valve is forced shut
What is the pulmonary valve?
From the right ventricle to the pulmonary trunk
What is the aortic valve?
From the left ventricle to the aorta
What are the two semilunar valves?
From the ventricles to their respective vessels
What is the conducting system of the heart?
The cells that don't contract but control normal heart excitation; in electrical contact with cardiac muscle cells via gap junctions
How do sympathetic postganglionic fibers interact with the heart?
Innervate the entire heart: release epi/norepi to beta-adrenergic receptors in atria and ventricles
How do parasympathetic fibers interact with the heart?
Innervate only the atria: release acetylcholine to muscarinic receptors on the atria
Where does initial depolarization of the myocardium begin?
SA node: conducting system cells near the right atrium near the entrance of the superior vena cava
Where is the SA node?
Near the right atrium by the entrance of the superior vena cava
Describe the path of depolarization triggered by the SA node.
Travels to atria (contract at virtually the same time); then to AV node at base of right atrium, which propagates to the ventricle slowly; then down the interventricular septum through the bundle of His; then to Purkinje fibers, which depolarizes both ventricles from the apex up, squeezing blood out