Flashcards in Lymph Deck (29):
What separates the extravascular interstitial space from the intravascular space?
semipermeable capillary endothelium
How does interstitial fluid return to circulation?
via the lymphatic system
What are the two main fxns of the lymph system?
fluid handling and immune surveillance
How do Starling forces relate to fluid handling?
cause the interchange of fluids between the intravascular and interstitial space
What are the three main determinants for filtration?
Net hydrostatic pressure, Net oncotic pressure, Capillary filtration
What is the capillary hydrostatic pressure determined by?
blood pressure and specific resistances of local arterioles and venules
What is oncotic pressure?
osmotic pressure exerted by proteins in blood plasma…tends to pull water into the circulatory system
What is capillary oncotic pressure?
osmotic pressure contributed by plasma proteins (mainly albumin
What is the interstitial oncotic pressure?
osmotic pressure contributed by osmotically active proteins in the interstitium
Why are oncotic pressures determined by proteins?
because there is no large difference of salt conc btw interstitium and plasma
what is the result of increased intravascular hydrostatic pressure?
What is the result of decreased intravascular oncotic pressure?
What causes hypoabluminemia?
low protein intake, not enough protein produced (liver failure), too much protein lost in urine (nephrotic syndrome)
When does increased capillary filtration occur?
when endothelium is damaged (burns, inflammation, toxic damage)
How does inflammation increase capillary filtration?
can disrupt tight junctions between endothelial cells resulting in swelling
What kind of toxic damage can increase capillary filtration?
What diseases can cause lymphatic obstruction?
lymphoma, metastatic cancers, surgical removal of lymph
What are platelets derived from?
What is the difference btw neutrophils and macrophages?
neutrophils can circulate whereas macrophages reside in tissues. also macrophages are matured monocytes
What is the most important fxn of neutrophils and macrophages?
What are the 3 factors that determine whether phagocytosis will occur?
How smooth is it? (rough surfaces increase likelihood of phagocytosis). Protective protein coat? (most native tissues have them, dead tissues and foreign particles are without these coats). Tagged with an antibody or marker (opsonization)? (if so, more likely to be ingested
What bacteria has a coat that is resistant to lysosomal digestion and secretes substances that resist killing effects of neutrophils/macrophages?
What are histiocytes?
macrophages in skin/sub q
What are kupferr cells?
macrophages in the liver
What diseases are patients who have asplenia more susceptible to and how should you treat them?
certain types of bacterial pathogens (such as Streptococcus pneumoniae, & Haemophilus influenzae—as these are encapsulated). vaccinate with pneumovax and H. flu
What is the walling off effect?
Fibrinogen clots act in interstitial tissues which helps to block fluid flow making it difficult for bacteria to spread
What is the left shift?
occurs when neutrophils rise rapidly
What substances are most implicated in the feedback control of macrophages/neutrophils?
TNF, IL-1, GM-CSF, G-CSF, M-CSF (colony stimulating factors)