MCAT BIO CH. 9 PART 1 Flashcards
What is perfusion?
The flow of blood through a tissue
What is ischemic?
Inadequate blood flow resulting in tissue damage due to shortage of oxygen and nutrients and buildup of metabolic waste
What is hypoxia tissue?
Adequate circulation is present but the supply of oxygen is reduced
What is the difference between ischemia and hypoxia?
Waste build up in ischemia but removed in hypoxia
What is the difference between arteries and veins?
Arteries: Carry blood away from the heart at high pressure
Veins: Carry blood back toward the heart at low pressure
What do arteries branch into?
Arterioles; lower blood pressure
What do the arterioles lead to?
Capillaries
What important component do arterioles have in their walls and what does that allow?
Smooth muscle in their walls that can act as a control valve to restrict or increase the flow of blood into the capillaries of tissues
What important component do capillaries have in their walls and what does that allow?
Thin walls made of a single layer of cells; designed to allow the exchange of material between the blood and tissues
Where does blood go after it passes through capillaries?
Venules, small veins that lead into veins back to the heart
What do veins lack in their walls?
Lack a muscular wall
The inner lining of all blood vessels is formed by what?
A thin layer of endothelial cells
What are the four most important roles of endothelial cells?
- Vasodilation/constriction
- Inflammation
- Angiogenesis
- Thrombosis
What substances regulate vessel diameter?
Nitric oxide and endothelia
What is the important of vaso control?
Maintaining blood pressure, tissue oxygenation and thermoregulation
What does the release of inflammatory chemicals stimulate endothelial cells to do?
Increase there expression of adhesion molecules
What does the increase of adhesion molecules by endothelial cells allow?
Molecules allow white blood cells to adhere to the endothelial cells and enter the injured tissue
What is angiogenesis?
Formation of new blood vessels
What do angiogenesis growth factors stimulate?
Endothelial cells to break from an existing vessel and proliferate in surrounding tissues, creating new vessels
What does angiogenesis allow based on supply?
Increase supplies oxygen and nutrients to help sustain cell division and growth
What is thrombosis?
Blood clotting
How do endothelial cells prevent blood clots?
Secrete substances that inhibit the coagulation cascade
Which side of the heat has the pulmonary circulation? What about the systemic circulation?
Right side; left side
What is an exception to the rule of blood passing through only one set of capillaries before returning to the heart?
Portal systems