Week 7: Terms; Circulation and Tissue Perfusion Flashcards
Define Blood Pressure
the pressure of the blood on the walls of the arteries, dependent on the energy of the heart action, elasticity of the arterial walls, and volume and viscosity of the blood.
Define edema
an abnormal accumulation of fluid in the interstitial (or intercellular) tissue leading to swelling of the subcutaneous tissues.
Define embolism
the sudden blocking of an artery by a clot or foreign material which has been brought to its site of lodgment by transport through the blood.
Define embolus
from the text = a detached intravascular solid, liquid, or gaseous mass that is carried by the blood from its point of origin to a distant site, where it often causes tissue dysfunction or infarction.
Define extracellular
fluid found outside of the cells; can be further divided into intravascular compartment (the plasma inside blood and lymph vessels) and interstitial compartment (in the matrix of tissues between vessels and cells); extracellular fluid (ECF).
Define hemorrhage
bleeding; the escape of blood from the vessels.
Define hydrostatic pressure
pressure exerted by fluids
Define infarction
the formation of an infarct; a localized area of ischemic necrosis produced by occlusion of the arterial supply or the venous drainage of the part.
Define intercellular/interstitial
fluid found between cells. (both extracellular).
Define intracellular
fluid found within cells; intracellular fluid (ICF).
Define ischemia
deficiency of blood in a part, usually due to functional constriction or actual obstruction of a blood vessel.
Define oncotic pressure
the osmotic pressure due to the presence of colloids in solution; oncotic and osmotic pressure often used interchangeably
Define osmotic pressure
the attraction of fluid back into capillaries by the presence of large molecules that cannot diffuse out.
Define shock
a profound hemodynamic disturbance characterized by failure of the circulatory system to maintain adequate perfusion of and blood supply to vital organs.
Define thrombosis
the formation or presence of a thrombus.
Define thrombus
an aggregation of blood factors, primarily platelets and fibrin with entrapment of cellular elements, frequently causing vascular obstruction at the point of its formation.
Define angina pectoris
refers to the chest pain felt when the myocardium (heart muscle) receives an inadequate blood supply.
Define aneurysm
an abnormal outpouching of an artery, a vein, or the heart formed because of a weakening of the vessel wall.
Define arrtythmia
abnormal heart rhythm
Define atheromatous plaque
the characteristic lesion of atherosclerosis which consists of a ‘fibrous cap’ of connective tissue, and a necrotic core (the ‘atheroma’); also known as a ‘fibrofatty plaque’ or just plain ‘plaque’.
Define atherosclerosis
a disease of large and medium-sized arteries. It is characterized by the formation of fibrofatty deposits in the intimal layer of arteries called ‘atherosclerotic plaques’.
Define chronic ischemic heart disease
refers to the condition in which patients with severe coronary atherosclerosis suffer the symptoms of ischemic heart disease repeatedly and chronically, often due to multiple severe narrowings in their coronary arteries.
Define claudication
causes limping; e.g., intermittent claudication - pain, tension and/or weakness in the legs on walking which may intensify and result in limping, relieved by rest, seen in severe atherosclerotic disease.
Define congestive heart failure (CHF)
refers to the consequences of cardiac failure, in particular, pulmonary edema (hence ‘congestive’ failure), and the failure to perfuse the systemic circulation.
Define dysrhythmia
an abnormal rhythm; cardiac dysrhythmias refer to disturbances in the electrical rhythm of the heart.
Define fatty streak
the precursor lesion to an atheromatous plaque.
Define hypertension
elevated blood pressure; according to Canadian guidelines, hypertension is defined as having a systolic pressure consistently greater than 140mm Hg and/or a diastolic pressure consistently greater than 90mm Hg.
Define infarction
a localized area of ischemic necrosis produced by blockage of the arterial supply or its venous drainage.
Define ischemic heart disease
occurs when decreased blood flow results in an inadequate supply of oxygen to the heart muscle (myocardium).
Define myocardial infarction
an infarction occurring within cardiac muscle and is commonly referred to as a ‘heart attack’.
Define occlusion
the act of closure or state of being closed; an obstruction or a closing off; occlusive, pertaining to or affecting occlusion.
Define pericarditis
inflammation of the surface of the heart (pericardium).
Define subendocardial
involvement of only the inner half of the heart wall.
Define sudden cardiac death
death due to cardiac causes, occurring within six hours after the onset of symptoms (oftentimes a sudden collapse with only a brief period of symptoms or none at all).
Define tamponade
accumulation of fluid (commonly blood) on the external surface of the heart, but within the pericardium causing compression of the heart.
Define transmural
involvement of the full thickness of the heart wall.
Define ventricular rupture
a tear that occurs in the infarcted region of the heart following a myocardial infarction.
The circulatory system has which two functional components?
- the blood vascular system
- the lymphatic system
Describe the blood vascular system
composed of a muscular pump (heart) connected to vessels that either deliver blood to organs and tissues (via arteries) or returns blood to the heart (via veins) to complete the circuit
Describe the lymphatic system
a passive drainage system for returning excess extravascular fluid to the blood vascular system
Describe normal fluid balance conditions in the body
-As blood passes through capillary beds, proteins in the plasma are retained within the vasculature
-Little net movement of water and electrolytes into the tissues
-60% of a person’s body weight is water:
40% intracellular
15% interstitial
5% plasma
Normal fluid balance can be disturbed by which pathologic conditions?
ones that alter endothelial function, increase vascular hydrostatic pressure, or decrease plasma protein content
What is the result of disrupted fluid balance?
Result is the accumulation of fluid in tissues due to net movement of water into extravascular spaces – edema
Define hemostasis
the process of blood clotting that prevents excessive bleeding after blood-vessel damage
Inadequate hemostasis may result in what?
hemorrhage (bleeding; which can compromise regional tissue perfusion and, if massive and rapid, may lead to hypotension, shock, and death)
Normal fluid control mechanism depends on which 3 factors?
-Starling’s Law
-Local factors
-Systemic factors
what are the local factors that normal fluid control mechanism depend on?
-Lymphatic obstruction
-Vascular permeability
what are the systemic factors that normal fluid control mechanism depend on?
-Cardiovascular function
-Overall fluid balance
-Salt retention
Define Starling’s Law
movement of fluid between vessels and tissue is governed by the balance between 4 forces.
What are the 4 forces (pressure’s) of Starling’s Law?
- Hydrostatic pressure – pressure within vessel pushing fluid out
- Interstitial Fluid Pressure – pressure outside of vessel pushing fluid in
- Plasma osmotic pressure – pulling fluid in
- Interstitial fluid osmotic pressure – pulling fluid out
When will edema occur?
- when there is an increase in intravascular hydrostatic pressure
- a fall in colloid osmotic pressure
- lymphatic obstruction
- sodium retention
What are the two classifications of edema?
- Localized edema
- Generalized edema
A thrombus consists of what?
- Platelets
- Fibrin
- Red blood cells
- White blood cells
What are the possible outcomes (prognosis) of thrombosis?
- The thrombus can dissolve or be lyzed by fibrinolytic activity
- Can increase in size and obstruct vessels
- Can breakdown and form emboli
- Can become organized and may recanalize
What are the causes of thrombosis?
the primary abnormalities that lead to intravascular thrombosis are 1. Endothelial injury, 2. Stasis or turbulent blood flow, and 3. Hypercoagulability of the blood (the so-called “Virchow triad).
What is the difference between a thrombus and an embolus?
a thrombus - a mass formed within (the heart or) a blood vessel and
an embolus - a mass that travels through the circulation and becomes lodged in a blood vessel
