P3 - Fluids and Vascular Disorders Flashcards
vessels that have large diameter lumens, thick tunica media, and are pressure reservoirs
arteries
vessels that have narrow lumens, thick tunica media and distribute blood to greatest areas of need
arterioles
site of nutrient/waste product exchange
capillaries
types of capillaries (3 types)
- continuous
- fenestrated
- discontinuous (sinusoidal)
location and function of continuous capillaries
- brain, muscle, lung, bone
- exchange water, O2, CO2 and ion
location function of fenestrated capillaries
- renal glomeruli, intestinal villi, endocrine glands
- pores bridged by thin membrane that allows controlled transfer of small molecules and limited amount of protein
location and function of discontinuous (sinusoidal) capillaries
- liver, spleen, bone marrow, lymph nodes
- junctional complexes between endothelial cells to allow RBC, plasma proteins, and WBC
vessels that are very distensible, thin walls, and low vascular resistance
- venules
venules can store what percentage of blood volume
- 65%
features of lymphatic system
- blind ended capillaries near vascular capillaries
- large interendothelial gaps
- valves to prevent back flow
cause of activated state of endothelium
- oxidative stress
- inflammation
- infectious agents
- trauma
activated state of endothelium effects
- release of vasoactive mediators
- cytokine mediators
- activation of clotting
hydraulic (hydrostatic) pressure
- pressure in a fluid system acted on by a pump
colloidal osmotic pressure (COP) or oncotic pressure
- pressure that keeps blood in vessels
in health percentage of albumin that contributes to total COP in the plasma
- 75-80%
stariling’s law calculates
- difference between hydraulic and osmotic pressure
purposes of hydraulic/oncotic pressure gradients (2)
- constant flow between microcirculation and interstitium for exchange of nutrients and waste products
- interstitium provides fluid buffer to increase or decrease plasma volume to ensure effective circulatory function
pathogenesis of increased plasma volume (hypervolemia)
- water moves into interstitium and into cells -> due to hydraulic and osmotic gradients -> cells swell
pathogenesis of decreased plasma volume (hypovolemia)
- water leaves interstitium and cells -> cells shrink
accumulation of excess interstitial fluid
- edema
edema is due to (4 things)
- intravascular permeability
- increased hydraulic pressure
- decreased oncotic pressure (COP)
- decreased lymphatic pressure
intravascular permeability due to (7 things)
- inflammatory vasoactive substances (histamine, substance P, bradykinin, cytokines)
- infectious agents
- immune mediated mechanisms
- toxins
- metabolic
- type I hypersensitivity (histamine)
- clotting abnormalities
increased hydraulic pressure due to (2 things)
- right-sided heart failure
- left-sided heart failure
transudate fluid
- low or high protein
- low cells
exudate fluid
- high protein
- many cells
effusion fluid
- variety of effusions, biliary, chylous, neoplastic, inflammatory
