Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
|
What is the primary function of the CV system?
|
The primary purpose of the CV system is transport.
|
|
|
Describe the two modes of transport used in the CV system and their source of energy.
|
1) Bulk flow - the perfusion pressure achieved by the heart.
2) Diffusion - Takes advantage of capillary surface area, decreased velocity, and oncotic pressure across membranes to transport materials |
|
|
What is meant by perfusion pressure? What is meant by transmural pressure?
|
Perfusion pressure is the difference in pressure along a vessel (input pressure - output pressure).
Transmural pressure is the difference in internal and external vessel pressure |
|
|
Understand the general layout of the circulatory system.
|
Systemic and pulmonary circulation is in series.
Circulation within the systemic or the pulmonary circulation is parallel. Central circulation is heart + pulmonic circulation. |
|
|
What is meant by cardiac output?
|
Cardiac output is the volume of blood pumped by one ventricle in one minute. CO of the left ventricle should equal CO of right ventricle (and vice versa).
|
|
|
Define systolic and diastolic pressures.
|
Systolic pressure is the peak blood pressure. Diastolic pressure is the trough blood pressure.
|
|
|
Compare the perfusion pressures for the systemic and pulmonary circulations. Explain how the same volume of blood can flow through each system every minute when their perfusion pressures are so different.
|
Perfusion pressure for systemic is much higher than pulmonary circulation (about 10x higher). This is because pulmonary blood is ~1/3 the volume of systemic and the length of the circulation (and, thus resistance to flow) is greatly reduced.
|
|
|
Understand the distribution of blood volume in the CV system.
|
75% is systemic
25% is pulmonary In systemic circulation.... 80% is in veins/venules 15% in arteries/arterioles 5% in capillaries |
|
|
Be able to trace the course of a RBC from the time it leaves the heart until it returns about one minute later. Describe the type of vessels it encounters and how they are suited to the passage of the RBC.
|
1) RBC enters RA from Vena Cava
2) RBC enters RV through R. Atrioventricular valve (tricuspid) 3) RBC is pumped out pulmonary semilunar valve blah blah blah |
|
|
Name three portal systems and understand why they are the exceptions to the rule that blood usually encounters only one capillary bed in a single pass through the systemic circulation.
|
Renal Portal - drop-off waste in kidney and allows kidney to adjust water/electrolyte balance. 1st capillary bed is not deoxygenated.
Sphlanchnic Portal - picks up stuff in the GI and enters portal vein. Then goes to liver (2nd capillary bed). Hepatic artery supplies O2 to liver. Hypothalamic Portal - picks-up hormone from hypothalamus and drops-off in pituatary |
|
|
Which vessels have the largest cross-sectional area, the slowest velocity of blood flow and the largest surface area? Why?
|
Capillaries - tons of capillaries each with small XS area add up to a large total XS area. Same goes for the SA.
Since individual capillaries have a small XS area, it slows blood flow significantly, thereby reducing velocity. |
|
|
How does polycythemia affect viscosity? What is its affect on the heart?
|
Polycythemia is abnormally high hematocrit. Increased cells in the blood. This would increase overall viscosity. Increased viscosity increases cardiac workload.
|
|
|
How does anemia affect cardiac output?
|
Anemia is a low PCV. This would reduce viscosity and reduces cardiac workload initially. However, tissue perfusion is then low and cardiac output must increase to compensate. This ultimately increases cardiac workload.
|
|
|
Understand the relative size and shape of the major constituents of blood.
|
RBC - 7.5um in biconcave discs
WBCs usually larger Fibrinogen, globulins, and lipoproteins are <15nm. |
