Lecture 15 Flashcards
For fluid define it
what controls it
what occurs for normal fluid
what occurs for excess fluid
Fluid
its the movement of water & low molecular weight solutes is controlled by hydrostatic pressure and plasma colloid osmotic pressure
normal fluid movement into the interstitial at the arteriolar end of microcirculation and then goes tot he venular vasculature
if there is excess fluid it goes to the lymphatics, retting to the blood stream via the thoracic duct
For oedema define it and discuss the 2 types
Oedema= abnormal accumulation of interstitial fluid or fluid in the body cavities 2 types transudate -low protein -few cells -clear fluid mainly watery and electrolytes Exudate -high protein -many cells -opaque, viscous fluid
For oedema
discuss its location
define anasarca and oedema in various serous cavities
Oedema can be generalised or localised
anasarca; severe generalised oedema producing swelling of sc tissue
oedema in various serous cavities; hydrothoraxic- fluid in the pleural cavity
What causes oedema
causes of oedema
- increased vascular permeability
- increased 4 hydrostatic pressure
- decreased 4 osmotic pressure
- decreased lymphatic drainage
For increased vascular permeability who causes it and what does it cause
increased vascular permeability
related to injury, inflammatory or immunological stimuli
stimulus results in release pf chemical mediators ->endothelial contraction & widening of inter endothelial gaps allow the fluid to flow out
What causes an increased hydrostatic pressure
increased hydrostatic pressure due to impaired venous outflow due to obstructive thrombosis portal hypertension congestive heart failure -Na & H2O retention
What causes a decreased osmotic pressure and what does this result in
Decreased osmotic pressure
due to excess loss or reduced synthesis of plasma which causes
-reduce colloid pressure
-net movement of fluid into tissues
-secondary aldosteronism-> secondary Na and fluid retention (increase amount of Na and H2O because Na bring H2O in with it which will increase the blood volume)
causes a protein loss maybe due to
-Nephrotic syndrome; leaky glomerular capillary way -> loos of albumin->generalised oedema
-GIt disease
-parasitism
-reduced albumin synthesis secondary to liver disease or decreases protein consumption from malnutrition
For decreased lymphatic drainage what does it cause
Decrease lymphatic drainage
- lymphatic obstruction (tumour)
- inflammation within lymphatic system
- swelling of surrounding tissue -> compression
- fribrosis
- thrombus formation
Explain the 2 types of altered perfusion
the type of process
level of oxygen
charactertics
altered perfusion (blood flow) -hyeraemia active process oxygenated blood vasodilation increased blood flow erythema -congestion- blood can't get out of the venous system passive process which causes the pooling of the blood deoxygenated blood reduced outflow cyanosis tissue turns blue from the lack of O2
What is decreased tissue perfusion and what cause it
Decreased tissue perfusion (reduced blood supply to tissue)
due to; obstruction of blood vessel, congestion or decreased cardiac output
List the types of decreased tissue perfusion
-Ischaemia; perfusion is not enough to meet metabolic demands eg. lack of O2, nutrients et.c
-Infarction; local area of ischaemia that undergoes coagulator necrosis
can be
arterial (loss of incoming blood supply to downstream tissue and causes coagulative necrosis)
or venous (loss of venous return, coagulative necrosis and tissue upstream is affected)
-torsion (section of the gut with twisted blood vessels so the blood can get in but can’t get out cause veins are thin)
-obstruction
List and explain the different types of shock
Shock;
- hypovolaemic shock; reducing circulating blood volume eg. haemorrhage
- cardiogenic shock; failure of heart to pump blood eg. cardiomyopathy
- Hypotensive shock decreased peripheral vascular resistance, anaphylactic, neurogenic and septic shock e.g allergies
What are the 4 main pathophysiological causes of oedema formation
4 main pathophysiological causes of oedema formation
- increased vascular permeability
- increased IV hydrostatic pressure
- Decreased IV osmotic pressure
- decreased lymphatic drainage
What’s the difference between a transudate and exudate?
Transudate; low protein few cells clear fluid (watery and electrolytes) Exudate: high protein many cells opaque fluid
Define shock as it relates to fluid distribution in the body
shock; a circulatory dyshomeostasis (breakdown of a homeostasis system) with loss of circulating blood volume, reduced cardiac output, inappropriate peripheral vascular resistance its due to; loss of circulating blood volume reduced cardiac output decreased vascular resistance
