Circulation And Tissue Perfusion And Cardiac And Vascular Health Flashcards
What is the structure of the Heart?
- 4 chambers: 2 atria, 2 ventricles
- 4 valves
- Coronary arteries
What is the function of the heart?
- pulmonary (right) circulation
- systemic (left) circulation
What is Pulmonary Circulation?
- right ventricle pumping venous blood to the lungs to get oxygenated
- low pressure
What is Systemic Circulation?
- left ventricle pumping oxygenated blood out to organs of the body
- high pressure
Why is the Left Ventricles wall much thicker in comparison to the right?
Because it is required to pump blood throughout the body under higher pressure
What are the two functions of the Circulatory System?
- blood vascular system
- lymphatic system
What is the Blood Vascular System?
Composed of 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
What is the Lymphatic System?
a passive drainage system for returning excess extravascular fluid to the blood vascular system
How can normal fluid balance be disturbed?
by pathologic conditions that alter:
- endothelial function
- increase vascular hydrostatic pressure
- decrease plasma protein content
What is the result of altered fluid balance? (Overhydration)
accumulation of fluid in tissues due to net movement of water into extravascular spaces - edema
What is Hemostasis?
the process of blood clotting that prevents excessive bleeding after blood-vessel damage
What does inadequate Hemostasis result in? (4)
- hemorrhage
- hypotension
- shock
- possibly death
What can Thrombosis or Embolism cause?
Obstruction of blood vessels, potentially causing ischemic cell death
What does derangements in fluid balance or blood supply cause? (6)
- edema
- thrombosis
- embolism
- ischemia
- infarction
- altered perfusion
What is Ischemia?
inadequate blood supply to an area of tissue
What are the causes of Ischemia? (2)
- decreased blood supply: inadequate cardiac output
- obstruction of blood vessels
What is Infarction?
Tissue death if ischemia is severe and complete
- results in coagulative necrosis
What are the types of Infarcts?
- white
- red
What is White Infarct?
- pale infarct
- in organs with single blood supply: heart, kidney, spleen
- Arterial occlusion/insufficiency
What is Red Infarct?
- hemorrhagic infarct
- in organs with dual (collateral) blood supply: liver, lung, intestine
- Venous occlusion/insufficiency
What can be done to treat plaque build up?
- medications
- angioplasty
- Bypass surgery
What is Coronary Artery Bypass Surgery?
When a vein is grafted to the diseased coronary artery to provide a “bypass” or “detour” around the narrowed segment
What is PCI?
Percutaneous Coronary Intervention
What is Acute Coronary Thrombosis?
- when the build up of plaque in the coronary arteries rupture, causing occlusion (blockage of the blood supply)
- causes acute myocardial infraction
What is Acute Myocardial Infraction?
when a narrowed coronary artery becomes acutely occluded by a thrombus which usually forms in the lumen overlying a chronic plaque
What is the treatment for Acute Coronary Thrombosis?
timely administration of thrombolytic drugs can “dissolve” the thrombus and restore blood flow, preventing or limiting infarction
What is a Thrombosis?
formation of a mass (clotted blood - an aggregation of coagulated blood) within the heart or blood vessels; adherent to the vascular endothelium
What does a Thrombus consist of? (4)
- platelets
- Fibrin
- red blood cells
- white blood cells
What are the causes of Thrombosis?
- Endothelial Injury
- Stasis or turbulent blood flow
- hypercoagulability of the blood
What are the causes of Endothelial Injury?
- physical injury
- inflammation
- endothelial activation/alteration
What are the causes of changes of blood flow?
- turbulence
- stasis (slow circulation): lack of activity, decreased cardiac output, increased blood viscosity
What are the causes of changes in blood composition?
- increase in platelets
- hypercoagulability
What is Hypercoagulability?
abnormally high tendency of blood to clot
What causes Hypercoagulability?
- genetic abnormalities
- acquired conditions (prolonged bed rest)
What is the outcome for Thrombosis? (4)
- 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 most commonly affected vessels of a Thrombosis? (5)
- coronary artery (myocardial infraction)
- cerebral artery (stroke)
- mesenteric arteries (intestinal infarction)
- renal arteries (kidney infarction)
- arteries of the leg (gangrene)
What is an Embolism?
Occlusion of a blood vessel by a mass (embolus) transported to the site through the blood stream (may be solid, liquid, or gas)
What are the different types of Embolisms?
- thromboembolus
- gas (air)
- fat
- tumour
- others: foreign body
What are Thromboembolus? (4)
- formed by a thrombus
- most common type of emboli
- range in size from microscopic to those which are large enough to occlude major arteries
- may occur in either arteries or veins
What does an Embolism do?
Lodges in vessels too small to permit further passage, resulting in partial or complete vascular occlusion
Where do majority of pulmonary emboli form?
deep veins of the legs
What is the most common source of arterial emboli?
the heart
What is Shock?
a state in which diminished cardiac output or reduced effective circulating blood volume impairs tissue perfusion and leads to cellular hypoxia
What causes Shock?
- decreased blood volume
- decreased cardiac output
- redistribution of blood
What are the types of Shock? (5)
- Hypovolemic
- Cardiogenic
- Septic
- Anaphylactic
- Neurogenic
What is Hypovolemic Shock?
Inadequate blood or plasma volume
- hemorrhage
- fluid loss
What is Cardiogenic Shock?
Failure of myocardial pump resulting from intrinsic myocardial damage, extrinsic pressure, or obstruction of outflow
What is Septic Shock?
Outpouring of inflammatory mediators from innate and adaptive immune cells that produce arterial vasodilation, vascular leakage, and venous blood pooling
ex. Overwhelming microbial infections
What is Anaphylactic Shock?
Systemic vasodilation and increased vascular permeability that is triggered by an immunoglobulin E mediated hypersensitivity reaction
What is Neurogenic Shock?
Loss of function of the sympathetic nervous system (resulting in loss of regulation of heart rate, blood pressure, temperature)
What is the effect of Shock?
Hypoxic or anoxic cell injury
What is Primary Hypertension?
- vast majority of cases
- genetic and environmental etiologies
- treatable not curable
What is Secondary Hypertension?
- uncommon
- Possible causes: Endocrine, Drugs/medication, kidney disease, tumours
- may be curable if cause can be eliminated
What is Hypertension Related Hyaline Atherosclerosis?
It is a type of arteriolosclerosis, which refers to thickening of the arteriolar wall and is part of the ageing process
What are complications of Hypertension Related Hyaline Arteriolosclerosis? (2)
- intraparenchymal brain hemorrhage
- Chronic renal failure
What does Hypertension result in? (2)
- Increased workload of the Left Ventricular
- Hypertrophy
What is Left Ventricular Hypertrophy?
Due to increased workload due to chronic hypertension, and to meet this demand, the LV’s wall increases in thickness and overall heart mass increases, causing increased demand on coronary blood flow
What is a Hemmorhage?
a discharge or escape of blood from the blood vessels into the surrounding tissues or to the exterior of the body or into a body cavity
What are the causes of a Hemorrhage? (6)
- trauma to large blood vessels due to surgical procedures or fracture
- weakened artery
- infections
- invasive tumours
- hypertension
- hemorrhagic diatheses
What is a Hematoma?
accumulation of blood within the soft tissues
What is a Petechiae?
pinpoint hemorrhages, usually in the skin; mainly involving skin, mucous membranes and serosal surfaces
What is Purpura?
Diffuse, superficial hemorrhages in the skin, 3-5mm
What is Ecchymosis?
a larger superficial hemorrhage; what we call a bruise
What is a Hemothorax?
Collection of blood in the pleural cavities due to trauma or rupture of aorta
What is a Hemopericardium?
Collection of blood in the pericardial cavity around the heart due to rupture of heart or the aorta
What is a Hemoperitoneum?
Collection of blood in the abdominal cavity due to rupture of an aortic aneurysm or trauma to liver, spleen, or aorta
What is a Hemarthrosis?
Collection of blood in the joints
What is Edema?
Abnormal accumulation of fluid in the interstitial/intercellular tissue, leading to swelling of the subcutaneous tissues
What does normal fluid control mechanism depends on? (3)
- starling’s law
- local factors: lymphatic obstruction, vascular permeability
- systemic factors: cardiovascular function, overall fluid balance, salt retention
What is Starling’s Law?
movement of fluid between vessels and tissue is governed by the balance between 4 forces
When will Edema occur? (4)
- an increase in intravascular hydrostatic pressure
- a fall in colloid osmotic pressure/oncotic pressure of plasma
- lymphatic obstruction
- Sodium retention
What is Lymphatic Obstruction?
accumulation of intersitital fluid due insufficient reabsorption and deficient removal proteins
What does Lymphatic Obstruction result from?
a localized obstruction caused by an inflammatory or neoplastic condition
What is Sodium retention?
causes both increase in hydrostatic pressure and reduced vascular osmotic pressure
What are the two types of Edema?
- localized
- Generalized
What is Localized Edema? (2)
Occurs due to:
- increased hydrostatic pressure due to local vascular obstruction
- Lymphatic obstruction: compression by tumor or inflammation (local)
What is Generalized Edema?
Occurs due to:
1) increased hydrostatic pressure
2) decreased oncotic pressure:
3) sodium retention
What is Hydrostatic Edema?
If the hydrostatic pressure at the venous end of the capillary system is elevated, reabsorption is decreased
What is Oncotic Edema?
when there is a decrease in oncotic pressure, an increase in hydrostatic pressure, an increase in capillary permeability, or a combination of these factors.
What is Inflammatory and Traumatic Edema?
Edema that results if the vascular bed becomes leaky following injury to the endothelium
What is Lymphedema?
Lymphatic obstruction causing edema
What is Atherosclerosis?
Build up of plaque in the arteries
What is the process of Atherosclerosis?
1) Chronic endothelial Injury
2) Endothelial dysfunction
3) Smooth muscle emigration from media to intima. Macrophage activation
4) Macrophages and smooth muscle cells engulf lipid
5) Smooth muscle proliferation, collagen and other ECM deposition, extracellular lipid
What are the major modifiable risk factors of Atherosclerosis? (4)
- smoking
- hypercholesterolemia
- Diabetes mellitus
- Chronic hypertension
What are the non-modifiable risk factors of Atherosclerosis?
- old age
- family history of early onset heart disease
What is the pathogenesis of Atherosclerosis?
- slow progression
- long “silent” phase
What are the complications of Atherosclerosis in the Heart?
angina pectoris/myocardial infarction
What are the complications of Atherosclerosis in the Brain?
Transient ischemic attack/stroke
What are the complications of Atherosclerosis in the Legs?
Intermittent claudication/gangrene
