blood pressure Flashcards
What is the relationship between wall tension and pressure in a cylinder?
Wall tension is directly proportional to pressure.
What is the relationship between wall tension and radius in a cylinder?
Wall tension is directly proportional to the radius.
How does vessel size affect wall tension?
The larger the vessel, the greater the wall tension.
What is vessel compliance?
Vessel compliance is the volume change caused by a change in pressure.
What factors can affect vessel compliance?
Age and wall pathologies can affect vessel compliance (e.g., atherosclerosis or calcification).
What is laminar flow?
Laminar flow refers to the smooth, streamlined flow of fluid where the velocity is slower at the edges.
What conditions are more likely to cause turbulent flow?
Turbulent flow is more likely to occur with increased velocity and low fluid viscosity.
What are some causes of turbulence in blood flow?
Turbulence in blood flow may be caused by vessel junctions (e.g., vessel branching), obstacles (e.g., foreign bodies), and mixing (e.g., “holes-in-the-heart”).
What are the layers of the arterial wall from outermost to innermost?
The layers of the arterial wall from outermost to innermost are adventitia, media, and intima.
What are the components of the arterial media layer?
The arterial media layer consists of the external elastic membrane, smooth muscle, and internal elastic membrane.
What is the innermost part of the arterial wall?
The innermost part of the arterial wall is the endothelium, located in the intima layer.
What is atherosclerosis?
Atherosclerosis refers to the build-up of fats, cholesterol, and other substances in and on the artery walls, forming plaques that can restrict blood flow and lead to heart attacks, strokes, and peripheral arterial disease.
What are the stages of plaque development in atherosclerosis?
The stages of plaque development in atherosclerosis are fatty streak, fibrous plaque, occlusive atherosclerotic plaque, and plaque rupture.
What can trigger a blood clot in atherosclerosis?
Plaque rupture can trigger the formation of a blood clot.
What are the components of intimal plaque in atherosclerosis?
Intimal plaque in atherosclerosis can progress from fatty streak to fibrous plaque to calcified plaque, eventually leading to plaque rupture.
What is the effect of medial thinning in atherosclerosis?
Medial thinning in atherosclerosis leads to increased compliance of the artery.
What is adventitial erosion in atherosclerosis?
Adventitial erosion refers to damage or erosion of the adventitia layer of the arterial wall in atherosclerosis.
What are some functions of the endothelium in regulating blood vessels?
The endothelium plays a role in the local control of vessel tone, local control of thrombogenicity, capillary filtration, and release of vasodilator substances such as nitric oxide and prostacyclin.
What are some endothelium functions in local vessel tone control?
The endothelium regulates local perfusion and can induce vasodilation by releasing substances like nitric oxide and prostacyclin.
What are some functions of the endothelium in the local control of thrombogenicity?
The endothelium conceals collagen and plaque constituents, secretes antithrombotic factors such as prostacyclin, and prevents excessive blood clot formation.
What are nitric oxide and prostacyclin?
Nitric oxide and prostacyclin are vasodilator substances released by the endothelium.
What does it mean for something to be thrombogenic?
Thrombogenic means that it is liable to provoke blood clotting, either through the activation of platelets, the activation of the blood clotting cascade, or both.
What is the process of myocardial infarction caused by coronary thrombosis?
The process involves plaque rupture, exposing collagen and lipid in a thin cap, “vulnerable” plaque, leading to platelet adhesion and activation of the clotting system, ultimately resulting in the occlusion of the coronary artery.
What is plaque in the context of myocardial infarction?
Plaque refers to the build-up of fats, cholesterol, and other substances in and on the artery walls, with a lipid-rich core covered by a fibrous tissue cap.
How does a thrombus form in the context of myocardial infarction?
A thrombus, or blood clot, forms when blood is exposed to collagen and lipids, activating platelets and the blood clotting pathways.
What are the stages in the ischemic cascade as ischemia severity increases over time?
The stages in the ischemic cascade are hypoperfusion, metabolic disturbance (including arrhythmia), diastolic dysfunction, systolic dysfunction (leading to acute heart failure), ECG changes, chest pain, and myocyte necrosis.
What are the consequences of decreased LV contractility?
Decreased LV contractility leads to increased left atrium/pulmonary vein pressures, which can cause pulmonary oedema, as well as increased pulmonary artery/right ventricle/right atrium pressures, which can cause peripheral oedema. It also results in increased venous return (preload) and can cause an increase in cardiac output.
How does decreased cardiac output affect fluid retention and cardiac production?
Decreased cardiac output leads to increased renin/angiotensin/aldosterone levels, which in turn cause renal sodium and water retention. This leads to increased contractility and eventually increased cardiac output.
What is another pathway by which decreased cardiac output leads to increased fluid retention and cardiac output?
Another pathway involves increased sympathetic activation, increasing renin/angiotensin/aldosterone levels and subsequent renal sodium and water retention. This, in turn, increases contractility and, eventually, cardiac output.
What is remodelling in the context of cardiovascular physiology?
Remodeling refers to chronic changes in tissue shape, size, and function in response to injury. It can occur due to pressure overload, volume overload, or myocardial damage.
What can cause pressure overload in the cardiovascular system?
Pressure overload can be caused by narrow valves or hypertension.
