10.02 Hemodynamic disorders, thrombosis and shock Flashcards
microcirculation
60% of body weight is water: 2/3 intracellular, 1/3 interstitial, <5% blood plasma
microcirculation: circulation beyond capillary caused by hydrostatic and osmotic pressures
at the arterial end, water and small molecules are drawn into tissue due to hydrostatic pressure (BP)
at the venous end, water and small molecules are drawn out of tissue into blood due to high [albumin] in blood (osmotic pressure)
edema
excessive fluid in interstitial tissue spaces.
ankle edema is most common for walking people
can be collected in the body cavities: hydro-thorax, -pericardium, -peritoneum (ascites)
ascites: GI track has low BP b/c of portal and more susceptible to edema
anasarca
severe and generalized edema from heart to feet.
pathophysiological mechanism
increased capillary pressure or decreased osmotic pressure
lymphatic obstruction impairing fluid drainage
sodium retention, and obligagtory associated water
albumin
albumin
liver failure: not enough albumin synthesis
protein-poor diet or starvation
kidney failure: if albumin is filtered out (it shouldn’t)
kidney and edema
if albumin is filtered out.
if incoming BP is low
- juxtaglomerular apparatus senses BP going into the glomerulus. if too low, it interprets as too little fluid and releases renin which acts on adrenaln gland to try to increase BP and fluid intake
- if problem is not fluid amount but pump failure or too much fluid absorption elsewhere, increased fluid intake worsens the problem
stasis dermatitis
lack of tissue perfusion leads to tissue response
response is to generate new blood vessels but vascular endoth is not semi-permeable
amont of blood moving through tissue increases, but no increase in perfusion
when tissue is damaged, it cannot be repaired
DOES NOT CAUSE EDEMA
pathological response to bacterial infection
normally, when body is infected, endoth become more permeable to allow WBCs to pass through
this response fails if the heart fails or if all vessels in the body become permeable at the same time (casued by IgE: increases vascular permeability).
leads to cardiogenic shock or anaphylactic shock
shock
definition, casues, signs and consequences
- def: poor systemic perfusion
- caused by endotoxins (bacteria), herat failure or hemorrhage
- signs: weak and rapid pulse, greatly reduced BP, rapid and shallow breathing, cold and clammy skin (except when caused by endotoxin > warm and flushed).
- common in nursing homes b/c residents lay down all day >> low BP and even lower BP in GI track >>> necrosis in GI
- when in shock, body goes into fight-or-flight and blood goes to brain and muscles not other internal organs (same when surgery).
decubitus ulcers
pressure sores: granulation of tissue which prevents normal healing process
heart function laws
Starling’s law: more blood in herat, more blood pumped out
Law of La Place: bigger the heart, more force it needs to pump
when BP is low, body assumes Starling’s law and tries to increase fluid but if it’s under La Place’s law, more fluid means more force needed and heart eventually fails
when heart works harder, it build muscles on the outside >> heart gets bigger >> more force needed >> harder it has to work
heart infartion
apoxia leading to tissue death
damaged part is replaced by fibrous tissue and it can rupture
blood can fill up peritoneum cavity and build pressure until heart can’t pump anymore
thrombosis
a clot formed inside the heart (risk factors: previous infartion or atrial fibrillosis)
it circulates (thrombi embolus) then gets stuck somewhere
deep vein thrombosis (DVT): formed in lower extremities and stuck in pulmonary arteries
embolus
- fat
- air
- amniotic fluid
- fat: when long bones break, fatty BM come in contact with blood and form a clot.
- air: sudden change in pressure (plane, scuba diving)
- amniotic fluid: very coagulative
