Module 7 Circulation Flashcards
Body Water Distribution
- 40% intracellular
- 15% interstitial
- 5% plasma
Lymphatic System
- Passive drainage
- Returning excess extravascular fluid to vascular system
Hemostasis
- Blood clotting
- Prevent excessive bleeding
- After blood vessel damage
Disrupted Fluid Balance
- Pathological conditions that alter endothelial function
- Increase vascular hydrostatic pressure
- Decrease plasma protein content
Inadequate Hemostasis
- Hemorrhage
- Compromise regional tissue perfusion
- Hypotension, shock, death
Derangements in Blood Supply/Fluid Balance
- Edema
- Thrombosis
- Embolism
- Ischemia & infraction
- Altered perfusion (hemorrhage/shock)
Edema
- Accumulation of fluid
- Interstitial/intercellular tissue
- Leads to swelling of subcutaneous tissues
Local Edema Factors
- Lymphatic obstruction
- Vascular permeability
Systemic Edema Factors
- Cardiovascular function
- Overall fluid balance
- Salt retention
Sterling Forces (Move Fluid Out)
- Hydrostatic pressure
- Interstitial fluid osmotic pressure
Sterling Forces (Draw Fluid In)
- Plasma osmotic pressure (colloid)
- Tissue (interstitial) fluid pressure
Edema Occurrence Conditions
- Increase in intravascular hydrostatic pressure
- Fall in colloid osmotic pressure/oncotic pressure of plasma
- Lymphatic obstruction
- Sodium retention
Localized Edema
- Increased hydrostatic pressure due to local vascular obstruction
- Lymphatic obstruction compression by tumour/inflammation
Generalized Edema
- Reflects a global disorder of fluid/electrolyte metabolism
- Increased hydrostatic pressure
- Decreased colloid osmotic pressure
- Sodium retention
Decreased Colloid Osmotic Pressure
- Loss of serum albumin proteins in renal failure
- Decreased synthesis of albumin
- Loss of serum proteins (malnutrition)
Hydrostatic Edema
- Hydrostatic pressure at venous end elevated
- Decreases reabsorption
- If lymphatic capacity exceed edema fluid accumulates
Oncotic Edema
- Decrease in osmotic pressure
- Loss of albumin
- Decreases reabsorption
- Edematous fluid accumulates
Inflammatory/Traumatic Edema
- Vascular bed ‘leaky’ following injury to endothelium
- Local or systemic
Lymphedema
- Lymphatic obstruction
- Accumulation of interstitial fluid
- Insufficient reabsorption
- Deficient removal of proteins
- Increasing osmotic pressure in interstitial space
Thrombosis
- Formation of a mass (clotted blood)
- Within heart or blood vessels
Thrombus Components
- Platelets
- Fibrin
- Red & white blood cells
Thrombosis Causes
- Endothelial injury
- Stasis/turbulent blood flow
- Hypercoagulability of blood
Endothelial Injury Causes
- Physical injury
- Inflammation
- Infectious agents
- Abnormal blood flow
- Metabolic abnormalities
Blood Flow Change Causes
- Turbulence
- Stasis (slow circulation)
- Decreased cardiac output
- Increased blood viscosity
Blood Composition Change Causes
- Increase in platelets
Hypercoagulability
- High blood clotting tendency
- Alterations in coagulation factors
- Genetic/acquired
Thrombus Prognosis
- Dissolve/lyzed by fibrinolytic activity
- Increase in size & obstruct vessels
- Breakdown & form emboli
- Organized & may recanalize
Commonly Affected Vessels
- Coronary artery (heart attack)
- Cerebral artery (stroke)
- Mesenteric arteries (intestinal infarction)
- Renal arteries (kidney infarct)
- Arteries of the leg (gangrene)
Embolism
- Occlusion of blood vessel by mass (embolus)
- Travels through circulation
- Becomes lodged in blood stream
Thromboembolus
- Most common type of emboli
- Formed from a thrombus
- Thromboemboli arise from thrombi
- Size range
- Occur in arteries or veins
Pulmonary Emboli
- Arise from deep veins of the legs
- Small
- Clinically silent
- Undergo organization over time
- Incorporated into the vascular wall
Arterial Emboli
- Heart
- Thrombi on heart walls/diseased valves
- May lodge in brain (stroke/infraction)
Cause of Ischemia
- Due to inadequate blood supply to an area to tissue
Causes of Blood Vessel Obstruction
- Thrombus
- Embolus
- Pressure
- Damage (vessel wall inflammation)