Term
| What are the 3 Scientific prinicples on which dialysis is based? |
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Definition
| Osmosis, Diffusion, & Ultrafiltration. |
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Term
| What are the 3 main kidney functions that Dialysis treatments replace? |
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Definition
1. Removal of excess fluids from Blood.
2. Removal of excess waste in Blood.
3. Balancing of Electrolytes in the Bloodstream. |
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Term
| Which main function does the dialysis fail to replace? |
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Definition
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Term
| What is an endocrine function? |
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Definition
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Term
| What are the four hormones that healthy kidneys secrete into the bloodstream? |
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Definition
1. Rennin
2. Calcitriol
3. Erythropoietin
4. Thrombopoietin |
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Term
| Why is it important to understand the endocrine function of the kidney? |
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Definition
| It is neccessary to understand the full impact the kidneys have on the body. |
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Term
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Definition
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Term
Of the four hormones secreted by healthy kidneys, what is the function of:
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Definition
| Rennin regulates proper pressure. Rennin breaks down certain blood serum proteins that are responsible for arterial wall constriction. |
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Term
Of the four hormones excreted by the kidneys, what is the role of:
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Definition
| Erythropoietin regulates the transfer of oxygen and nutrients throughout the blood by increasing the production of healthy red blood cells in the bone marrow. |
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Term
Of the four hormones excreted by the kidneys, what is the primary role of:
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Definition
| TPO, or thrombopoeitin, is responsible for stimulating the production of blood platelets, which aids in the clotting response. |
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Term
Of the four hormones excreted by the kidneys, what is the function of:
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Definition
| Calcitriol is a byproduct produced by the kidneys when Vitamin D is present in the bloodstream. It is known as Vitamin D3, and it helps the body to absorb Calcium. |
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Term
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Definition
| A mixture of solvent and solute. |
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Term
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Definition
| The disolvable substance. |
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Term
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Definition
| The substance that disolves the solute. |
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Term
| Why is water considered the universal solvent? |
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Definition
| Because over time, Water can disolve or errode almost all matter. |
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Term
| Identify the components of dialysate. |
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Definition
Solvent & Solute
By which treated water contains proportioned amounts of dissolved
Salt Ions (Electrolytes) and sometimes glucose. |
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Term
Pt blood electrolyte levels can be controlled by changing what during dialysis? |
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Definition
The dialysate composition.
Adding electrolytes to the dialysate at a concentration higher than the pts blood will cause a concentration gradient, and electrolytes will enter the pt blood until an equilibrium is reached during treatment. |
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Term
| Define semipermiable membrane? |
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Definition
| A pourous barrier that only permits certain sized molecules to pass. |
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Term
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Definition
The total pourous area of the membrane, allowing for passive or active transport of molecules across the membrane.
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Term
| Diffusion utilizes which type of transport? |
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Definition
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Term
| Which molecules are usually prevented from passage through the semipermiable membrane of the dialyzer? |
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Definition
| WBC, RBC, some Viruses, and Proteins. |
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Term
| Which molecules are small enough to pass through the semipermiable membrane? |
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Definition
| Urea, Water, and Electrolytes, Bicarbonate Solution. |
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Term
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Definition
| Process by which atoms, molecules or particles move from areas of high concentration to areas of lower concentration. |
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Term
| Diffusion can occur in which states of matter? |
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Definition
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Term
| Explain how blood is a solution. |
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Definition
| Blood plasma is the solvent, and the solutes disolved by the plasma are electrolytes and other substances. Particulate matter are proteins and WBC, RBC which do not disolve, yet remain suspended in the Blood plasma. |
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Term
| Passive transport into and out of the body's cellular membranes occurs by which two processes? |
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Definition
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Term
| Which direction do solutes move across the membrane? |
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Definition
| They can move in any direction, but always move from areas of high concentration to areas of lesser concentrations. |
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Term
| Passive Solute movement naturally increases when? |
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Definition
| The concentration gradient of the solute increases. |
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Term
| Theoretically, when does diffusion stop? |
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Definition
| When there is no loger a concentration gradient. |
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Term
| How is dialysate is able to remove wastes from blood serum? |
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Definition
| By means of concentration gradients. |
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Term
| How does molecular weight influence particle movement? |
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Definition
| Larger dissolved particles diffuse slowly and with some difficulty. Smaller molecules/dissolved particles diffuse more easily and quickly. |
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Term
| What are examples of blood components that are difficult to diffuse accross the semipermiable membrane of a dializer? |
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Definition
White blood cells,
Red Blood Cells,
Albumin,
Blood Platelets,
Some Bacteria &Viruses. |
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Term
| How does temperature affect diffussion? |
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Definition
| Molecules move faster at increased temperatures, therefore warmer fluids permit faster diffussion. |
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Term
| What are the factors that affect diffusion? |
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Definition
| Temperature, molecule size, surface area, flow geometry and membrane permeability. |
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Term
| How does a dialyzer's surface area affect diffusion? |
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Definition
| Greater surface areas usually lead to more pores, and a membrane with more pores allows for faster diffussion of the smaller molecules. |
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Term
| How does the "countercurrent" flow between dialysate and blood aid diffusion? |
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Definition
| It maintains the highest concentration gradients between the blood and dialysate possible, thus promoting the rapid removal of waste matter and ease of electrolyte transfer from one side of the membrane to the other. |
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Term
| What is the main diffrence between Osmosis and Diffusion? |
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Definition
| In diffusion, solutes move. In osmosis, the solvent moves across a membrane. |
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Term
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Definition
| Osmosis is when the solvent moves across a membrane from an area of low solute concentration towards the area of higher solute concentration. |
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Term
| Define an osmotic pressure gradient. |
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Definition
| The difference in concentrations of solute within a solution on either side of a membrane. |
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Term
| When does osmosis and diffussion stop? |
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Definition
| When an equilibrium is reached on both sides of the membrane. |
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Term
| What is a natural example of hydraulic pressure that can overcome osmotic pressure? |
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Definition
Gravity.
This is one reason the dialzyer is flipped leaving the arterial side up. |
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Term
| How is ultrafiltration accomplished in the dialzyer? |
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Definition
| Additional pressure is created by gravity, as wells as high pressure gradients across the membrane. These pressure differences force high concentrations of molecules across the membrane into the dialysate faster. |
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Term
| Which type of heat transfer causes solute drag? |
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Definition
Convection.
Convection causes a solvent to drag along smaller solutes when heat is present in the solution as the solvent crosses the membrane during the process of osmosis. |
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Term
| What forces affect the movement of fluid through the tubing of the extracorporeal circuit? |
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Definition
| Resistance (pressure/constriction), flow rate (volume) and velocity (speed). |
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Term
| How is flow rate measured in dialysis? |
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Definition
| Mililiters (mL) of fluid flowing per minute (min) measured ( mL/min). |
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Term
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Definition
| The speed that a fluid flows. |
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Term
| What is the relationship between flow and resistance in a fluid system? |
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Definition
| The greater the flow, and the greater the resistance, the greater the pressure will be. |
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Term
| Name the three cell compartments in the body. |
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Definition
| Intracellular, Interstitial & Intravascular. |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| Inside the vessels or vascular system. |
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Term
| During dialysis, from which body compartment is water primarily removed? |
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Definition
| The vascular compartment. |
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Term
| What does the extracorporeal circuit consists of? |
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Definition
| The dialyzer and the tubing. |
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Term
| Identify the two restriction points in the extracorporeal circuit. |
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Definition
| The arterial needle insertion and the veneus neele insertion points. |
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Term
| Why is the arterial insertion point a sourse of resistance? |
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Definition
| Because at this restriction point, the arterial pump is pulling blood from the body faster than the source can naturally release it, causing a NEGATIVE PRESSURE (below zero). |
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Term
| Positive pressue is converted from negative pressure inside the tubing within the arterial blood pump. As this positive pressure increases in the lines where does it reaches its highest point? |
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Definition
| At the Arterial header, where blood enters the dialyzer fibers. |
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Term
| There is little resistence in the blood compartment why? |
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Definition
| Blood is following from the arterial header into the dialzyer, towards the pull of gravity, so there is little resistance. |
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Term
| Where is the lowest point of positive pressure? |
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Definition
| The veneous pressure, measured as blood leaves the blood compartment of the dialyzer. |
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Term
| How is hydraulic pressure, created by gravity is calculated? |
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Definition
| By averaging the blood entering and leaving the dialzyer fibers. |
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Term
| Explain how gravity overcomes osmotic pressure during ultrafiltration (UF). |
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Definition
The force of gravity is the true hydraulic pressure that overcomes osmotic pressure within the dializer, because it is greater in force, thus aiding in UF, by forcing fluid out of the blood,through the membrane,and into the dialysate. |
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Term
| How does dialysis affect the intracellular compartments in the body during the course of a treatment? |
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Definition
| Diffusion occurs continuously in the pts body. As cleansed blood is returned to the intravascular system, it dillutes the existing blood, and creates a new concentration gradient. As the intracellular wastes are exposed to this new concentration gradient, the wastes within the cells are drawn out and are released into the interstitial space where they are in turn deposited into the intravascular system to be processed through the extracorporeal circult where they are in turn dialyzed. |
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Term
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Definition
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Term
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Definition
Sieving Coefficent.
It is a measure of porosity. During convective transport both the size and number of holes in the dialyzer membrane will determine how porous it's membrane actually is. |
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Term
| What does SC value of 1.0 mean? |
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Definition
| This means that under ideal circumstances, 100% of a given solute (disolvable particulate matter or disolved molecules) could pass through the membrane. |
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Term
| What does a SC value of 0 .4 mean? |
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Definition
| This means that under ideal circumstances, only 40% of a given solute could pass through the membrane, and the other 60% would remain in the pts bloodstream. |
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Term
| What happens if the intracellular regions of the body have high levels of toxic solutes? |
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Definition
| Water is pulled out of the blood and into the cells causing edema. |
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Term
| How is edema treated during dialysis? |
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Definition
| Sodium is added to dialysate at a greater concentration than the blood, so it is permitted to enter the bloodstream. Once in the bloodstream, water is drawn out of the cells, in an attempt to dillute the blood sodium levels, this blood is dialyzed, and the water in it is removed. Near the end of treatment, the sodium level in the dialysate is reduced so that it is removed from the bloodstream safely. |
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Term
| How does a saline bolus help a pt with low blood pressure? |
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Definition
| Saline once in the blood system causes the fluid within the cells to be drawn out and into the bloodstream, thus increasing the blood volume and pressure on the vascular walls. Increased blood volume typically increases the blood pressure. |
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