Vessel Variety
This class of arteries, including the aorta, expands during systole and recoils during diastole to keep blood flowing.
What are Conducting (or Elastic/Large) arteries?
These are the most common capillaries, where endothelial cells are held together by tight junctions, allowing only small solutes like glucose to pass.
What are Continuous capillaries?
This is the force that blood exerts against a vessel wall, typically measured at the brachial artery.
What is blood pressure?
These sensors, located in the carotid sinuses, monitor blood pressure and initiate a negative feedback loop to slow the heart if BP rises.
What are Baroreceptors?
This "Silent Killer" can lead to heart failure by increasing afterload and making the myocardium work harder until it becomes inefficient.
What is Hypertension?
These small "resistance" arteries are the most significant point of control over peripheral resistance and blood flow.
What are Arterioles?
Found in the kidneys and small intestine, these capillaries have "filtration pores" to allow for rapid absorption or filtration.
What are Fenestrated capillaries?
This measurement is calculated as the difference between systolic and diastolic pressure.
What is pulse pressure?
This potent hormone is a powerful vasoconstrictor; its production is often blocked by "inhibitor" drugs to treat hypertension.
What is Angiotensin II?
This condition involves a weak point in an artery forming a bulging sac that may rupture; atherosclerosis is its most common cause.
What is an Aneurysm?
This anatomical "shortcut" allows blood to bypass a capillary bed entirely and flow directly from a metarteriole to a venule.
What is a Thoroughfare Channel (or Metarteriole)?
These irregular, blood-filled spaces in the liver and bone marrow have wide gaps that allow large proteins and whole blood cells to enter circulation.
What are Sinusoids?
Calculating this "Average" pressure is vital because it most influences the risk level for edema, fainting, and kidney failure.
What is Mean Arterial Pressure (MAP)?
This hormone, secreted by the heart, is the "antagonist" to aldosterone—it increases salt excretion to lower blood volume and pressure.
What are Natriuretic Peptides?
This pathological accumulation of excess fluid in a tissue can be caused by kidney failure, histamine release, or lymphatic obstruction.
What is Edema?
These vessels are known as "capacitance vessels" because they are thin-walled, flaccid, and hold about 64% of the body’s blood at rest.
What are Veins?
This term describes the 15% of filtered fluid that is NOT reabsorbed by the capillaries and must be picked up by the lymphatic system.
What is Lymph (or Lymphatic drainage)?
Chronic resting blood pressure higher than this specific numerical value is clinically defined as Hypertension.
What is 130/80 mm Hg?
This reflex is an automatic response to a drop in perfusion to the brain, triggered by the medulla oblongata to restore blood flow.
What is the Medullary Ischemic Reflex?
These result from the failure of venous valves, often caused by long periods of standing, which allows blood to pool and distend the vessels.
What are Varicose Veins?
These specialized veins, such as those in the brain or heart, have thin walls, large lumens, and no smooth muscle, making them incapable of vasoconstriction.
What are Venous Sinuses?
These contractile cells wrap around capillaries and can regulate blood flow or differentiate into new vessel cells for repair.
What are Pericytes?
According to the principles of hemodynamics, flow is proportional to this power of a vessel's radius.
What is the Fourth Power?
This local control phenomenon occurs when blood supply is cut off and then restored, causing flow to surge above normal levels.
What is Reactive Hyperemia?
In this type of circulatory route, blood flows through two consecutive capillary networks (like between the intestines and liver) before returning to the heart.
What is a Portal System?