The Effects of Solutes in Osmosis and Diffusion on Red Blood Cells - Research Proposal Example

Running Head: Solutes The Effects of Solutes in Osmosis and Diffusion on Red Blood Cells For cells to be able to perform their specific functions, they should thrive in an environment with optimum conditions. Exposure of cells to different conditions will lead to changes which could be fatal for the organism. This study has been conducted to know the effects of varying solute concentrations on the red blood cells and the effect of temperature on diffusion. To do this, different solutes and blood samples were put in test tubes and were observed under the microscope. Crenation was observed in cells put in hypertonic solution, while lyses were observed in cells put in hypotonic solution. Cells put in isotonic solution showed no change in morphology. These results are the bases for infusing intravenous fluids to patients by health care professionals. The effect of temperature was determined by placing potassium permanganate in a beaker of water and subjected to different temperatures. A significant increase in the rate of diffusion was observed in the sample subjected to 60 degrees centigrade than those subjected to lower temperatures. INTRODUCTION The human body is made up of different organ systems which work together in maintaining an environment that is most beneficial to the organism. These systems have several mechanisms all aimed at regulating the different bodily processes. The plasma membrane plays a very important role in protecting the cell as it regulates the substances that go in and out of the cell. This ensures that the substances that go inside the cells are vital for cell functions and that harmful substances are discarded. This study has been conducted to demonstrate diffusion and osmosis, to define hypertonic, hypotonic and isotonic solutions, to measure packed cell volume and investigate how erythrocytes react to the different solute concentrations. METHODOLOGY To determine the effect of different solute concentrations on red blood cell, blood samples were mixed with the different solutes in properly labeled test tubes. The turbidity of the solution was then determined by placing the test tubes against a printed page of a book. To support the observations on the test tubes, samples were also collected from the tubes using pasteur pipettes and were put in glass slides and were viewed under the microscope with the magnification of 10x40. The results were then tabulated and recorded on table 1. The packed cell volume of the blood samples were also determined by taking 15ml of blood samples by using capillary tubes. The unfilled end of the tubes were then sealed with cristaseal. The capillary tubes were placed into the centrifuge with the sealed ends toward the outside and were spun for 10 minutes. The packed cell volume was then measured and recorded with the use of the microhaematocrit reader. To demonstrate the effect of temperature on diffusion, potassium permanganate crystals were mixed with water in a beaker and were placed at different temperatures. Changes in the solutions were observed every ten minutes and were recorded on table 2. RESULTS AND DISCUSSION The human body is made up of approximately 100 trillion cells,25 trillion of which are red blood cells. Cells are made up of organelles that have specific functions for cell metabolism, respiration and regulation. The intracellular fluid, or the fluid inside the cells, is made up primarily of potassium, magnesium and phosphate ions, while the extra cellular fluid, or the fluid outside the cell membrane is made up of sodium, chloride and bicarbonate and other nutrients needed by the cell like oxygen, glucose, fatty acids and amino acids (Guyton, 1992). In order for cell functions to proceed properly, and thus keep the organism well and healthy, the different organ systems of the body must work together to maintain a stable internal environment despite the many changes that occur in the external environment, or a state which is referred to as homeostasis. Homeostasis in cells is made possible by the regulatory function of the plasma membrane, a semi-permeable membrane made up of a lipid bilayer and proteins that surrounds the cell. The selective permeability of the plasma membrane allows the transport of molecules essential for cell functions into the cell and the inhibition of harmful substances from being taken up by the cell. There are two types of transport processes : the passive transport process and the active trasport process. The passive transport process does not require energy for molecules to traverse the membrane. It utilizes the kinetic energy of molecules as they bump in all directions as a result of differences in concentration, pressure or electrical charges, which then lead to a net movement in one direction. These differences are referred to as a gradient, and the movement of molecules from an area of higher to lower concentration is referred to as moving down a concentration, pressure or electrical gradient. Guyton (1992) differentiated diffusion (also called “passive transport”) from active transport by defining diffusion as a “random molecular movement of substances molecule by molecule either through intermolecular spaces in the membrane or in combination with a carrier protein” (p.32), and active transport as “the movement of ions or other substances across the membrane in combination with a carrier protein but additionally against an energy gradient,… a process that requires an additional source of energy besides kinetic energy to cause the movement” (p.33). Diffusion in cells is further subdivided into two types: simple and facilitated diffusion. In simple diffusion, molecules move from one side of the cell membrane to the other without the aid of carrier proteins. Osmosis is a special form of diffusion in which water molecules move from an area of higher concentration to an area of lower concentration across a differentially permeable membrane ( Gottfried, 1994). Facilitated diffusion,on the other hand, is the movement of substances across a semipermeable membrane through the different transport proteins along the concentration gradient. Solutions can be either hypertonic, hypotonic or isotonic. A solution is said to be hypertonic if it has a solute concentration that is higher than that of another solution. It is hypotonic if its solute concentration is lower than that of another solution, and isotonic if both solutions have the same solute concentrations. Marieb (2003) described blood as the river of life that surges within us. It makes up about 8% of the human body and is the only tissue in our body that is fluid, making it an efficient means to transport oxygen and other vital nutrients to the different organs. Hematopoiesis, the process by which blood cells are formed takes place in the red bone marrow, also known as the myeloid tissue. It is found primarily on the flat bones of the skull, pelvis, ribs, sternum,and proximal epiphysis of the humerus and femur (Marieb, 2004). Blood is made up of plasma, the liquid portion, and the formed elements which make up 45% of the blood (Gottfried, 1994). The formed elements are the erythrocytes, leukocytes, and platelets. Erythrocytes, or red blood cells (RBC) contain the oxygen-carrying molecule hemoglobin. They are shaped like flattened discs that have a depression in the center. They do not have nuclei and can’t synthesize proteins, making them unable to repair themselves and thus live a short life span. Leukocytes, or white blood cells (WBC) function as the body’s defense against harmful microorganisms and foreign bodies invading the body. Platelets play a significant role in blood coagulation. To demonstrate the effect of solute concentration on cells, this study made use of blood samples immersed in different solutions. The results are as follows: Table 1 The effect of different solute concentrations on red blood cell Test tube # 1 2 3 4 5 6 Solute 0.9% NaCl 10% NaCl Distilled water 20% Glucose Detergent water Type of solution Isotonic hypertonic hypotonic hypertonic hypertonic hypotonic Observation Poor clarity Poor clarity; moving quickly then settled and motionless Can see print but not clearly Cannot see print No clarity Quite clear; Clear with dark spots 10X40 No change in cell shape Shape of the cell changed Cells lysed Crenation occured agglutination Cells lysed PCV 42% 41% 40% 42% 43% 43% Mean PCV : 42% Cells need to live in an environment that is optimum for their growth. Subjecting cells to different conditions will cause changes which could ultimately lead to cell death. This is the reason why health care profesionals should take strict precaution when administering intravenous fluid to patients under their care. Isotonic solutions such as Ringer’s lactate, 5% dextrose, and 0.9% saline have the same solute and water concentrations as cells do (Marieb, 2003). This is the reason that the RBCs observed in test tube 1 (0.9% NaCl solution) have exhibited no visible change in shape, because the solute concentrations inside and outside the cell are equal. When cells are put in a hypertonic solution, the tendency is for the water molecules inside the cell to move out to a region where there is a lower water concentration, thereby causing the cells to shrink, or crenate, as observed in test tubes 2 and 4. Hypertonic solutions are at times given to patients with edema, a condition characterized by too much fluid retention which causes the patient’s hands and feet to swell. Administering hypertonic solutions help draw excessive water out of the cells and into the bloodstream for the kidneys to eliminate (Marieb, 2003). When cells are subjected to a hypotonic solution, that is a solution with lesser solute concentration and therefore greater water content,water molecules rush into the cell until the cell takes on a globular shape and finally burst or lyse,as what happened to cells in test tubes #3 and 6. Distilled water is the best example of a hypotonic solution as it contains no solutes at all. Hypotonic solutions are sometimes given to patients who suffer from dehydration. Drinking hypotonic drinks such as colas, tea and sports drinks after a bout of loose bowels will rehydrate the body and put the cells back in shape, making the patient feel better and normal again (Marieb, 2003). Detergents are soap substitutes that form water-soluble products (Robinson, 1988). When put in a test tube with RBCs, it caused agglutination or clumping together of the cells. This may be attributed to the antibodies’ ability to detect foreign bodies which causes them to bind to RBCs and cause agglutination. Packed cell volume, or hematocrit is the percentage of red blood cells in the blood as determined by centrifuging blood in a “hematocrit tube” until the cells become packed tightly in the bottom of the tube (Guyton, 1992). Normal hematocrit value for males is 42 and 38 for females. A drop in hematocrit to as low as 10 is indicative of anemia while an excessive production of RBCs, although rare, will result to polycythemia. Table 2. The effect of temperature on diffusion Time elapsed A/60c B/46c C/1c cold D/room temperature 20c 55 bubbles No change No change Full diffusion 45 No change No change No change Part diffusion 35 No change No change A partial diffusion 25 No change No change No change No change 15 No change No change No change No change 0-5 1 minute fully disbursed Disbursed No change No change Temperature plays an important role in diffusion as it speeds up the diffusion process by increasing the kinetic energy of molecules, thereby increasing pressure which leads to a faster diffusing activity. This is exemplified by the results of this experiment. The sample that was placed in a higher temperature resulted to a higher rate of diffusion. It took only 1 minute for the potassium manganate to fully disperse at 60 degrees centigrade, while the one placed at room temperature took 55 minutes before it got completely dispersed in the solution. REFERENCES Gottfried, S. (1994). Human biology. USA: Mosby. Guyton, A. (1992). Human physiology and mechanisms of disease. USA: W.B. Saunders. Marieb, E. (2003). Essentials of human anatomy and physiology, 7th ed. California: Pearson Education. Robinson, H. (1988). College chemistry with qualitative analysis, 8th ed. USA: D. C. Heath and Company. Read More