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
Capillaries are very small; in fact, capillaries are the tiniest of all blood vessels. They form the connection between veins and arterioles in the circulatory system. However, capillaries tend to be found everywhere. Unlike veins and arteries, the capillaries main function is not transporting blood. They allow the movement of substances, mainly gases Oxygen and Carbon Dioxide into and out of the capillary. Capillaries have very thin walls that are only one cell thick, which allows substances (such as oxygen) to diffuse through the wall effortlessly. They are also incredibly narrow; so narrow, that blood cells move through it one at a time. As arteries divide into arterioles and continue to diminish in size as they near muscle, they become capillaries. Here, the capillaries form a mesh like structure (capillary bed), forming a network throughout the muscle. This allows a fast and efficient transfer of oxygen-carrying red blood cells to the site where they are needed. With the combined structure of the thin walls and a large surface area, capillaries allow diffusion of oxygen and carbon dioxide with ease. This is ideal for the respiratory system which is in charge of oxidizing the blood
According to Virtual Medical Centre (2014) the primary function of the blood is to act as a transport, to give the body protection and to help regulate. The blood dissolves gases such as oxygen and carbon dioxide. The blood also transports vital nutrients throughout the body, such as micro-nutrients, fatty acids and amino acids. The flow of the blood helps to regulate the body’s temperature. Also the blood removes wastes material of metabolism. Blood cells (white and red cells) are carried through the body to help with the body’s natural defense, blood clotting and the carry anti-bodies.
Erythropoietin is a glycoprotein that is produced primarily in the kidneys in adults and, to a lesser extent, in the liver. It behaves like a hormone, regulating the level of erythropoiesis, and keeping the RBC count within a narrow range
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.
Blood serves as the body transport system; blood carries oxygen to the lungs and cells throughout the body. It takes carbon dioxide or toxins from out the body. The components of the blood fight off different diseases by recognizing engulfing microorganisms and molecules from overseas that doctors found in the blood. The other components support the transports through the kidneys, hormones in the body, and the digestive system to help pass the nutrients through the body.
Tortora, G., & Derrickson, B. (2012). The cardiovascular system: The blood. In B. Roesch (Ed.),
“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).
VanPutte, Cinnamon L., Jennifer L. Regan, and Andrew F. Russo. "Chapter 11: Blood."Seeley's Essentials of Anatomy & Physiology. New York: McGraw-Hill, 2013. N. pag. Print.
Erythrocytes, or what are commonly known as red blood cells (RBC) within our bodies are constantly being faced with a changing environment. Tonicity is referred to as the concentration of solutes, permeable and nonpermeable, as well as the concentration of water both influencing the water that will come and goe through the RBC, and the surrounding fluid of the RBC (Sherwood, 2013). Osmosis on the other hand is known as the movement of water from an area of low concentration to an area of high concentration and this will happen across a cell’s membrane until it reaches a state where it is isotonic.
In life, it is critical to understand what substances can permeate the cell membrane. This is important because the substances that are able to permeate the cell membrane can be necessary for the cell to function. Likewise, it is important to have a semi-permeable membrane in the cell due to the fact that it can help guard against harmful items that want to enter the cell. In addition, it is critical to understand how water moves through the cell through osmosis because if solute concentration is unregulated, net osmosis can occur outside or inside the cell, causing issues such as plasmolysis and cytolysis. The plasma membrane of a cell can be modeled various ways, but dialysis tubing is especially helpful to model what substances will diffuse or be transported out of a cell membrane. The experiment seeks to expose what substances would be permeable to the cell membrane through the use of dialysis tubing, starch, glucose, salt, and various solute indicators. However, before analyzing which of the solutes (starch, glucose, and salt) is likely to pass through the membrane, it is critical to understand how the dialysis tubing compares to the cell membrane.
Red blood cells with normal hemoglobin (HbA) move easily through the bloodstream, delivering oxygen to all of the cells of the body. Normal red blood cells are shaped like doughnuts with the centers partially scooped out and are soft and flexible.
Cellular membranes are complex mixtures of proteins and lipids. Cell membranes are composed of a phospholipid bilayer, consists of two leaflets of phospholipid molecules and their fatty acid chain form the hydrophobic interior of the membrane bilayer; and proteins that span the bilayer and/or interact with the lipids on either side of the two leaflets. Transmembrane proteins are the type of membrane proteins which span the entire length of the cell membrane. They are embedded between the phospholipids and provides a channel through which molecules and ions can pass into the cell. They enable communication between cells by interacting with chemical messengers. Membrane proteins were classified into two comprehensive categories- integral and
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.