The erythrocyte membrane has many functions, the first of which is to serve as an impenetrable fluid barrier which separates the inside contents of the cell from the plasma. The membrane allows it to transport O2 and CO2 by maximizing the ratio of surface area to volume with its biconcave disc shape. The membrane is also strong and is constantly going through shape and metabolic changes and has a tensile or lateral strength that is greater than that of steal. The membrane is also more elastic than a comparative latex membrane, this strength and elasticity allows for deformability (Solberg, 2013). The red blood cell membrane is roughly 5 micrometers thick. The cell membrane also allows the cell to be flexible, or having deformability, which allows the cell to adjust to small vessels in the microvasculature while allowing the cell to maintain a constant surface area to volume ratio (Stoeme-Martin, Lotspeich-Steininger, & Koepke, 1998). Some of the microvasculature is so small that it has a smaller diameter than the erythrocyte, so the erythrocyte membrane allows for it to change shape (rapid elongation and folding) to squeeze through these vessels and then “reform” into its original shape once through these vessels. If the cell was spherical in shape, there would be a loss of surface area which would cause an increased uptake of cations and water, which would cause the cell to lyse.
The unique composition and structure of the red blood cell membrane allows the cell to selectively pass nutrients and ions into and out of the cell. The lipids and proteins located on opposite sides of the membrane are different, an arrangement that is termed asymmetric, and allows for the selective passage of molecules into and out of the cell ...
... middle of paper ...
...ts duty of delivering oxygen to the tissues and returning the carbon dioxide from the tissues to the lungs. The red blood cell does this by circulating through the body’s network of veins, capillary networks and arteries. The erythrocyte membrane functions to allow the cell to squeeze, deform and reform through these networks while maintaining pressure and concentration differences and contributes to the overall metabolic homeostasis of the body. The red blood cell unique composition contributes to all of the membranes major functions, which again allows the red blood cell to survive and perform its duty.
References
Solberg, B. (Composer). (2013). The Erythrocyte Part 2: Structure and Components. Grand Forks, North Dakota, USA.
Stoeme-Martin, E., Lotspeich-Steininger, C. A., & Koepke, J. A. (1998). Clinical Hematology. Philadelphia: Lippincott.
In this experiment, we determined the isotonic and hemolytic molar concentrations of non-penetrating moles for sheep red blood cells and measured the absorbance levels from each concentration. The results concluded that as the concentration increased the absorbance reading increased as well. A higher absorbance signifies higher amounts of intact RBCs. The isotonic molar concentration for NaCl and glucose is 0.3 M. The hemolysis molar concentration for NaCl and glucose is 0.05 M. Adding red blood cells to an isotonic solution, there will be no isotonic pressure and no net movement. The isotonic solution leaves the red blood cells intact. RBC contain hemoglobin which absorbs light, hemoglobin falls to the bottom of the tube and no light is absorbed. Determining the isotonic concentration of NaCl and glucose by finding the lowest molar concentration. In contrast to isotonic molar concentration, hemolysis can be determined by finding the
Dialysis tubing is made from regenerated cellulose or cellophane, and is used in clinical circumstances to ensure that molecule have a filtered flow, and that larger solute molecules do not enter the dialysis tubing (Alberts, 2002). Like a cell membrane, dialysis tubing has a semi-permeable membrane, which allows small molecule to permeate through the membrane. Thus, the dialysis tubing mimics the diffusion and osmosis processes of the cell membrane (Alberts, 2002). Although the dialysis tubing has a semi-permeable membrane, which mimics a cell, its structure is different. The me...
The circulatory system and respiratory system share a highly important relationship that is crucial to maintaining the life of an organism. In order for bodily processes to be performed, energy to be created, and homeostasis to be maintained, the exchange of oxygen from the external environment to the intracellular environment is performed by the relationship of these two systems. Starting at the heart, deoxygenated/carbon-dioxide (CO2)-rich blood is moved in through the superior and inferior vena cava into the right atrium, then into the right ventricle when the heart is relaxed. As the heart contracts, the deoxygenated blood is pumped through the pulmonary arteries to capillaries in the lungs. As the organism breathes and intakes oxygenated air, oxygen is exchanged with CO2 in the blood at the capillaries. As the organism breathes out, it expels the CO2 into the external environment. For the blood in the capillaries, it is then moved into pulmonary veins and make
oxygen out of the blood and uses it in the body's cells. The cells use
Red blood cells deliver the oxygen to the muscles and organs of the body.
Homeostasis is essential to the cell’s survival. The cell membrane is responsible for homeostasis. The membrane has a selective permeability which means what moves in and out of the cell is regulated. Amino acids, sugars, oxygen, sodium, and potassium are examples of substances that enter the cell. Waste products and carbon dioxide are removed from the cell.
The Circulatory System is a transportation and cooling system for the body. The Red Blood Cells act like billions of little mail men carrying all kinds of things that are needed by the cells, also RBC's carry oxygen and nutrients to the cells. All cells in the body require oxygen to remain alive. Also there is another kind of cells called white blood cells moving in the system. Why blood cells protect from bacteria and other things that are harmful. The Circulatory system contains vein arteries, veins are used to carry blood to the heart and arteries to carry the blood away. The blood inside veins is where most of the oxygen and nutrients are and is called deoxygenated and the color of the blood is dark red. However, blood in the arteries are also full of oxygen but is a bright red. The main components of the circulatory system are the heart, blood, and blood vessels.
The direction of osmosis depends on the relative concentration of the solutes on the two sides. In osmosis, water can travel in three different ways. If the molecules outside the cell are lower than the concentration in the cytosol, the solution is said to be hypotonic to the cytosol, in this process, water diffuses into the cell until equilibrium is established. If the molecules outside the cell are higher than the concentration in the cytosol, the solution is said to be hypertonic to the cytosol, in this process, water diffuses out of the cell until equilibrium exists. If the molecules outside and inside the cell are equal, the solution is said to be isotonic to the cytosol, in this process, water diffuses into and out of the cell at equal rates, causing no net movement of water. In osmosis the cell is selectively permeable, meaning that it only allows certain substances to be transferred into and out of the cell. In osmosis, the proteins only on the surface are called peripheral proteins, which form carbohydrate chains whose purpose is used like antennae for communication. Embedded in the peripheral proteins are integral
“The plasma membrane is the edge of life, the boundary that separates the living cell from its nonliving surroundings. The plasma membrane is a remarkable film, so thin that you would have to stack 8,000 of these membranes to equal the thickness of the page you are reading. Yet the plasma membrane can regulate the traffic of chemicals into and out of the cell. The key to how a membrane works is its structure” (Simon, 02/2012, p. 60).
Mauritz J, Esposito A, Ginsburg H, Kaminski C, Tiffert T, Lew V. The Homeostasis of Plasmodium falciparum-Infected Red Blood Cells. 2009; 5 (4): e1000339. Available from: http://www.ploscompbiol.org/article/info%3Adoi%2F10.1371%2Fjournal.pcbi.1000339 [Accessed 24 Mar 2014].
On a cellular level, Mrs. Jones’ cells are dehydrated due to osmotic pressure changes related to her high blood glucose. Cells dehydrate when poor cellular diffusion of glucose causes increased concentrations of glucose outside of the cell and lesser concentrations inside of the cell. Diffusion refers to the movement of particles from one gradient to another. In simple diffusion there is a stabilization of unequal of particles on either side of a permeable membrane through which the particles move freely to equalize the particles on both sides. The more complex facilitated diffusion is a passive transport of large particles from a high concentration of particles to a lower concentration of particles with the aid of a transport protein (Porth, 2011). The cellular membranes in our bodies are semipermeable allowing for smaller molecules to flow freely from the intracellular to extracellular space. The glucose molecule, however; is too large to diffuse through the cellul...
A three-dimensional structure of hemoglobin is determined by X-ray crystallography showed hemoglobin is made up of four polypeptide chains, each of those chains has a very similar three-dimensional structure to the single polypeptide chain in myoglobin. The major type of hemoglobin found in adults (HbA) is made up of two different polypeptide chains: the alpha-chain that consists of 141 amino acids residues, and the beta-chain of 146 residues. Each chain, like that in myoglobin consist of eight alpha-helices and each contains a heme prosthetic group. Therefore, hemoglobin can bind four molecules of oxygen. The four polypeptide chains, two alpha and teo beta, are packed tightly together in a tetrahedral array to form an overall spherically shaped molecule that is held together by multiple noncovalent interactions.
Red blood cells are carriers of oxygen. A percentage of these cells contain hemoglobin, which has the capacity to combine with iron. It's the iron-hemoglobin molecular structure that helps carry oxygen-rich blood from the lungs to your tissues and in return, delivers carbon dioxide back to the lungs to be expelled. A CBC with Differential that shows low red blood cell levels can indicate anemia. RBCs comprise about 40% of total blood volume; the RBC count is the number of red blood cells per cubic millimeter of blood (Rauen, 2012). Normal red blood cells values vary a...
π is equal to the osmotic pressure, V is equal to the cell volume and B is the intracellular solids (Hall). Ponder’s R value is the ratio of intracellular solvent volume to the water in its environment; R=(Vi -b)/W. These two equations are related because Ponder’s R value is a measure of how much of an osmometer a cell is while the van’t Hoff relation shows what the osmotic pressure is, both inside and outside the cell. Overall cell membrane permeability can be measured by Ponder’s R value while the osmotic pressure differentials between the external environment and the internal environment are seen with the van’t Hoff relation (Hall). Cells evolved to become great osmometers, but not perfect osmometers, in order to provide a way for solutes to move along permeable membranes. The van’t Hoff relation permits organisms to live in environments of varying osmolarity because regulating solute concentration within a cell can increase or decrease the cell’s affinity for osmosis (Darnell et al). Ponder’s R value, on the other hand, shows how a cell can never become a perfect osmometer. If a cell could become a perfect osmometer, it could cause cell lysis or shrinkage of the cell (Hall). The avoidance of perfect osmometry can be seen within the human erythrocyte as a small portion of cell water will not take part in an osmotic exchange due to tonicity within its
Red Blood Cells contain hemoglobin molecules to help bind to oxygen to bring to other tissues. Without this function, cells would not be able to go through the process of cellular respiration and can only survive a short time. Red Blood Cells are also able to carry bicarbonate as a waste product and carry a variety of hormones to communicate between organs.