BIOL 0800 Reading- Chapter 12 Flashcards Preview

Physiology > BIOL 0800 Reading- Chapter 12 > Flashcards

Flashcards in BIOL 0800 Reading- Chapter 12 Deck (263)
Loading flashcards...

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


What is the AV node?

Located at base of right atrium; depolarized after atrial contraction; propagates the action potential slowly, allowing the atria to finish contracting before the ventricles contract