Disorders of Body Fluids and Blood Flow

fluid pressure

- physical/mechanical pressure exerted on one object by another

hydrostatic pressure

- pressure exerted by, or existing within, a liquid at rest with respect to adjacent bodies

hydrodynamic pressure

- pressure created by the motion of a liquid relative to adjacent bodies (ex. blood pressure)

osmosis

- the flow of water across a semipermeable membrane from an area of high-water concentration to an area of lower water concentration

how much water and solids does our body have

- 45% solids

- 55% fluid

on the arterial end

- we have a greater hydrodynamic pressure than osmotic pressure

- this leads to a net outflow of fluid

on the venous end

- we have a greater osmotic pressure than hydrodynamic pressure

- leads to a net inflow of fluid

- keeps the system balanced

edema

an abnormal accumulation of fluid in tissue of body cavity

exudate

- inflammatory edema

- high protein content

- due to local damage

- increase vascular permeability due to inflammation, allows the protein to leak through the capillary walls

transudate

- non inflammatory edema

- low protein content

- due to systemic condition

- increased capillary fluid pressure, or decrease in plasma osmotic pressure

edema of increased fluid pressure

- increased fluid pressure leads to local or regional edema

- varicose veins: increased hydrostatic pressure in legs, leading to edema

edema of low plasma osmotic pressure

- albumin: made by the liver, determinant of plasma osmotic pressure

- cirrhosis: leads to low albumin synthesis, leading to edema

edema of salt and water retention

- heart failure: most common cause of salt and water retention

- decrease in cardiac output which leads to decrease in hydrodynamic pressure

- RAAS system

- increase Na+ and H20+ retention, decrease in osmotic pressure

- can also have pulmonary congestion

electrolytes

- salts

- chemical compounds that separate into ions when dissolved in water

- cations: positively charged

- anions: negatively charged

roles of electrolytes

- maintain the electric potential of the cell membrane

- propagate nerve signals

- enable muscle cell contraction

- solutes (important in the movement of fluids by osmosis)

hyponatremia

- decrease in plasma sodium

- due to excessive loss from sweating or vomiting and diarrhea

- impairs nerve impulses, has osmotic effects leading to muscle cramps

hypernatremia

- increase plasma sodium

- due to water depletion (dehydration), congestive heart failure

- thirst, fatigue

hypokalemia

- decreased plasma potassium

- due to diarrhea, low dietary potassium w/ alcoholism or eating disorders

- arrhythmias, disrupted muscle contraction, muscle cramps, sensory nerve malfunction

hyperkalemia

- increased plasma potassium in blood

- due to renal failure

- impairs nerve signal transmission and skeletal muscle contraction

calcium

- calcium balance is modulated by parathyroid hormone

- vitamin D is important in calcium metabolism

hypocalcemia

- decrease blood calcium due to low PTH (after surgical removal)

- vitamin D deficiency

- no symptoms in most cases

- muscle cramps in severe cases

hypercalcemia

- increased blood calcium due to increase blood PTH

- decrease neuromuscular activity

- weakness, fatigue

acid

- a compound that releases hydrogen ions when dissolved in water

- lower the pH (7 = neutral,

base

- a compound that decreases the number of free hydrogen ions, usually by releasing OH- ions

acidosis

- abnormally low blood pH (normal is btwn 7.35 & 7.45)

alkalosis

- abnormally high blood pH

CO2

- volatile acid (weak)

- in normal, increased CO2 production, we increase respiratory exhalation of CO2

- if lung function is impaired, increased CO2 accumulation leads to respiratory acidosis (headache, confusion, drowsiness, life threatening)

- during hyperventilation, decrease CO2, leads to respiratory alkalosis (dizziness, light headedness, paresthesia)

fixed acids

- amino acids, ketones

- intense exercise, release of H+ = metabolic acidosis (headache, confusion, drowsiness)

- repeated vomiting, ingestion of large amounts of base (too much antacid compounds) = metabolic alkalosis (dizziness, light headedness, paresthesia)

hyperemia

- an increase volume of blood in an affected part of the body

- a process associated with inflammation or with increase metabolic activity

- arteries dilate

- area turns read with oxygenated blood (erythmea)

congestion

- an increase volume of blood in an affected part of the body

- a process associated with impaired venous outflow

- turns dark red with poorly oxygenated blood

hemostasis

- the composite activity of blood vessel endothelium, platelets, and plasma coagulation factors (clotting factors)

- keep blood in a fluid, clot-free state

- form a clot to stop bleeding at the site of vascular injury

hemorrhage

- the escape of blood from a blood vessel

- petechiae: the smallest hemorrhages, often visible

- purpura: a hemorrhage

thrombosis

- the process of a blood clot (thrombus) forming in a blood vessel

embolism

- a sudden obstruction of an artery, typically by an embolus (a clot of blood or an air bubble that becomes stuck in a vessel)

pulmonary thromboembolism

- thrombus forms in the deep veins of the legs or pelvis, breaks off as a fragment, goes into the lungs

Systemic thromboembolism

- heart attack, thrombi in the inner wall of damaged left ventricular muscle travel to the lower extremity, sometimes the brain

air embolism

- air bubbles into the bloodstream during surgery

- scuba driver, if going to the surface too suddenly, gas bubbles can be formed

ishchemia

- a lack of oxygen supply to tissue

infarct

- an area of ischemic necrosis

white infarcts

- (bloodless infarcts)

- form when arterial obstruction occurs in dense, solid tissue (kidney, heart, or liver)

red infarcts

- (hemorrhagic infarcts)

- bloody venous or arterial obstruction occurs in loose, spongey tissue (lungs or liver)