Circulatory System: Review Questions Flashcards
1.1 Review Question: Describe the path that a red blood cell takes through the circulatory system from the right side of the heart returning to the right side of the heart. Hypothesize what is happening to the amount of oxygen carried within that cell.
right side of the heart to pulmonary trunk to pulmonary arteries to pulmonary arterioles to pulmonary capillaries to pulmonary venules to pulmonary veins to left side of heart to aorta to systemic arteries to systemic arterioles to systemic capillaries to systemic venules to systemic veins to vena cava to right side of heart
Oxygen is picked up in the pulmonary capillaries and remains high in the blood until it is delivered to tissues by the systemic capillaries. Oxygen levels in the blood are lower in the systemic veins and right side of the heart, then increase again when blood flows back through the lungs.
1.2 Review Question: What are the three determinants of resistance to flow, and which is varied physiologically to alter blood flow?
- viscosity of blood
- length of a blood vessel
- radius of the blood vessel
Because resistance varies as the 4th power of radius, a small increase in radius causes a large decrease in resistance thereby increasing flow, and a small decrease in radius causes a large increase in resistance, thereby decreasing flow. Because radius can change very quickly, it is by far the most important physiological determinant of resistance. However, changes in viscosity do occur slowly and can have major long-term effects on resistance and thus blood flow.
