Fluids and Electrolytes
Acid-Base Balance
Physiology of Perfusion
Shock
Hypovolemia
100
What is turgor?
Normal tension in a cell; the resistance of the skin to deformation.
100
What is a normal pH range?
7.35-7.45
100
What are the major functions of perfusion?
O2 transport and waste removal
100
What is shock/hypoperfusion?
Inadequate perfusion of the body tissues, resulting in an inadequate supply of O2 and nutrients to the body tissues.
100
What is ischemia?
A blockage in the delivery of oxygenated blood to the cells
200
What do isotonic, hypertonic, and hypotonic mean?
Isotonic: equal in concentration of solute molecules Hypertonic: having a greater concentration of solute molecules Hypotonic: having a lesser concentration of solute molecules
200
What is carbonic anhydrase?
An enzyme that causes carbonic acid to be converted into CO2 and water very rapidly.
200
What are three ways that waste is excreted
Exhalation, urine, and feces.
200
What is the container of the cardiovascular system?
Blood vessels
200
How does the body initially compensate for blood loss?
As blood volume decreases, the preload drops, the stroke volume drops, causing a drop in systolic BP, reducing the pressure, reducing the ability to send blood through the capillary beds. Baroreceptors detect a dec in BP, and send a signal to the brain. The SVR is increased, and hormones inc heart rate, causing the BP to return to normal. If blood loss stops, the body replaces the lost blood
300
Name and describe the 4 compartments that water is distributed into.
Intracellular fluid (75%): the fluid inside the body cells Extracellular fluid (25%): the fluid found outside the body cells -Interstitial fluid (17.5%): the fluid found in body tissues, outside the cells and the vascular system -Intravascular fluid (7.5%): the fluid within the circulatory system; blood plasma
300
Describe respiratory acidosis and alkalosis.
Acidosis: acidity caused by abnormal retention of CO2 resulting from impaired ventilation. -dec breathing -> inc CO2 -> inc H2CO3 -> inc H+ -> dec pH Alkalosis: alkalinity caused by excessive elimination of CO2 resulting from increased respirations. -inc breathing -> dec CO2 -> dec H2CO3 -> dec H+ -> inc pH
300
Two factors that regulate blood flow through the vessels
Peripheral (Systemic) vascular resistance [resistance to blood flow], and pressure within the system.
300
What are three mechanisms that cause shock?
Fluid loss Profound vasodilation Cardiac failure
300
What is cellular ischemia and how does it work?
If blood loss continues, the venous system constricts to maintain preload, and SVR increases to maintain the systolic BP, while the diastolic increases, narrowing the pulse pressure. Blood is shunted from noncritical organs, which then use anaerobic metabolism, causing CO2 and lactic acid to accumulate. HR also slowly increases. Blood loss inc, more and more cells deprived of O2, more waste accumulates. Bloodstream becomes acidic and chemoreceptors stimulate an inc in depth and rate or respirations.
400
Name three factors that can cause dehydration.
-GI losses from prolonged vomiting, diarrhea, or malabsorption disorders -Increased insensible loss: loss of H2O through normal mechanisms that is difficult to detect or measure -Increased sweating can result in significant fluid loss -Internal losses of fluid into various body fluid compartments -Plasma losses from burns, surgical drains and fistulas, and open wounds
400
Describe metabolic acidosis and alkalosis.
Acidosis: acidity caused by an increase in acid often because of inc production of acids during metabolism or from causes such as vomiting, diarrhea, diabetes, or medication. Alkalosis: alkalinity caused by an increase in plasma bicarbonate resulting from causes including diuresis, vomiting, or ingestion of too much sodium bicarbonate
400
What are precapillary and postcapillary sphincters and how do they work?
Precapillary: sphincter at the origin of the capillary (btwn the arteriole and capillary). Responds to local tissue conditions and opens as more arterial blood is needed Postcapillary: sphincter at the end of the capillary (btwn the capillary and the venule). Opens when blood is to be emptied into the venous system.
400
How can you tell when someone goes from compensated to decompensated shock?
Entry into decompensated shock is indicated by a precipitous drop in systolic BP, and a decreased mental status
400
What is capillary stagnation and how does it work?
Blood loss continues, sympathetic stimulation and reduced perfusion to the kidneys, pancreas, and liver cause release of hormones. SVR reduces blood flow to more tissues. Circulation only limited to critical organs; inc in anaerobic metabolism. Buildup of lactic acid and CO2 relaxes precapillary sphincters, but postcapillary remain closed. Capillary beds engorge and fluid is lost. Capillary and cell membranes break down, red blood cells clump together and form coagulated cells.
500
Describe active transport and facilitated diffusion.
Active transport: movement of a substance through a cell membrane against the osmotic gradient (from an area of lesser concentration to an area of higher concentration) Facilitated diffusion: diffusion of a substance such as glucose through a cell membrane that requires the assistance of a "helper" or carrier protein
500
What are the 3 major mechanisms to remove H+ ions from the body and how do they work?
1. Bicarbonate buffer system: H+ + HCO3- <-> H2CO3 Inc acid -> inc carbonic acid dec acid -> dec carbonic acid Synthesis or elimination of excess carbonic acid: H+ + HCO3- <-> H2CO3 <-> H2O + CO2 inc H+ = inc CO2 2. Respiration: inc breathing -> dec CO2 -> dec H2CO3 -> dec H+ -> inc pH ; inc breathing = inc elimination of CO2 Dec breathing -> inc CO2 -> inc H2CO3 -> inc H+ -> dec pH 3. Kidney Function: can regulate pH by altering theconcentration of bicarbonate ion (HCO3-) and H+ in the blood. inc elimination of HCO3- and retention of H+ = lowered pH retention of HCO3- and excretion of H+ = inc pH
500
What is the Fick Principle?
The movement and utilization of O2 by the body depends on: adequate concentration of inspired O2, appropriate movement of O2 across the alveolar/capillary membrane into the arterial bloodstream, adequate number of red blood cells to carry the O2, proper tissue perfusion, and efficient off-loading of O2 at the tissue level.
500
Name and describe the three stages of shock.
Compensated: hemodynamic insult to the body in which the body responds effectively. Initial stage of shock in which the body progressively compensates for continuing blood loss. Decompensated: continuing hemodynamic insult to the body in which the compensatory mechanisms break down Begins when the body's compensatory mechanism can no longer maintain preload. Irreversible: Final stages of shock in which organs and cells are so damaged that recovery is impossible. Transition is difficult to identify in the field.
500
What is capillary washout and how does it work?
Building acidosis causes the postcapillary sphincters to relax and those byproducts, potassium, and the coagulated red blood cells are dumped into the venous circulation. Causes metabolic acidosis, and releases emboli. Cardiac output drops toward 0, cellular perfusion drops toward 0, PVR drops, BP drops and the body moves toward death
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