Lecture 6: Organ Failure Flashcards
___are blind ended capillaries that dump into the venous system
Lymphatics
Lymphatics are ___ pressured, valves, and dependent on forces like ___ contraction to maintain flow
Low pressure, muscle contraction
Do lymphatic vessels have small or large gaps
Large
What percent of the body weight is fluid
60%
What percent of fluid body weight is intracellular, extracellular (plasma and interstitial)
Intracellular: 40%
Extracellular: 20%- 4% plasma and 16% interstititum
What is the extracellular matrix composed of
Structural (collagen type 1, elastin), adhesive (fibronectin, laminin), and absorptive (glycsaminoglycans, proteoglycans)
What 4 things control fluid movement
- Hormones
- Receptors
- Osmotic and hydrostatic forces
- Integrity of vascular system
What hormones control fluid movement
RAAS: vasoconstriction and water retention
Atrial natriuretic peptide: promote renal sodium and water extraction and vasodilation
What receptors control fluid movements
- Osmoreceptors in hypothalamus
- Baroreceptors in blood vessels
What is shock: circulatory failure
Systemic hypoperfusion due to macro and/or micro-circulatory failures
What is the outcome of shock: circulatory failure
Hypotension—> impaired tissue perfusion—> cellular hypoxia—> anaerobic metabolism—> cellular degeneration—> cell death
Describe the steps that occur when the body tries to compensate during hypovolemia shock
- Hypovolemia shock
- Initial compensation: increase HR, perfuse vital organs
- Metabolism shifts to glycolysis
- Progressive morphological deterioration of cells—> swelling, necrosis
What are the two forms of macro circulatory failure
- Cardiogenic
- Hypovolemia
What is cardiogenic macro circulatory failure and some examples
Failure of heart to adequately pump blood due to MI, ventricular tachycardia, fibrillation, arrhythmias, HCM, DCM, cardiac output obstruction (pulmonary embolism, aortic stenosis), and pericardial tamponade
What is hypovolemic macro circulatory failure and some examples
Reduced circulation of blood volume by massive blood loss or fluid (vomiting, diarrhea, burns_, leading to decreased vascular perfusion and tissue hypoperfusion
What happened here
Pericardial sac markedly expanded—> cardiogenic shock-macro circulatory failure
What cardiac abnormality can result from compression of the heart cause by fluid collecting in sac surrounding the heart
Cardiac tamponade
What happened
Cardiogenic shock-macro circulatory failure—> aortic rupture and cardiac tamponade
What this and what happened?
Hemangiosarcoma at right auricle, resulting in pericardial sac expanded—> increase pressure on right auricle—> rupture—> cardiac tamponade
What are the types of shock due to microcirculatory failure
- Blood maldistribution: decreased peripheral vascular resistance and polling of blood in peripheral tissue
What are some examples of blood maldistribution
Anaphylactic shock- type I, IgE hypersensitivity
Septic shock- endotoxemia
Neurogenic shock-
What is the most common type of septic shock
Endotoxemia
Describe the pathogenesis of anaphylactic shock
- Exposure of insect, plant, drug or vaccine
- IgE mediated mast cells granulation
- Histamine and other mediators
- Systemic vasodilation and increased vascular permeability
- Blood hypotension
- Tissue hypoperfusion
What is the major cause of septic shock endotoxemia
Gram negative bacilli but can be gram positive