Microcirculation describes the movement of blood through small vessels responsible for replenishing organ tissue with oxygen and nutrients while at the same time removing carbon dioxide and other waste products (Berne & Levy, 2001). Hormones involves in signalling are also move through capillaries (Levick, 2010). This process is accomplished by a network of blood vessels (figure 1) such as arterioles which carry oxygenated blood from the heart to the capillaries where solute exchange occurs (Berne & Levy, 2001). Removal of carbon dioxide is facilitated by venules. The majority of solute exchange occurs in the capillaries; however, some occurs in the venules. In order to allow for efficient exchange of solute in the capillaries, the arterioles contract which controls blood flow, however as a result of Vasomotion (i.e. constant change in muscle tone), the blood flow in capillaries fluctuates. Vasomotion is an intrinsic property of the vascular smooth muscle, and therefore isn’t influence by external input. Capillaries also play a role in the immune system, as white blood cells (FU & Liu, 2012) are able to pass though the wall or pores to get to infection tissue. (Levick, 2010)
Figure 1: Structure of microcirculation network (Bailey, n.d.)
Capillaries are adapted for bidirectional exchange as they consist of a single layer of endothelial cells (Berne & Levy, 2001), interrupted by pores which allow for transport of larger solutes. Furthermore, organ tissues are surrounded by a large density of capillary vessels which increases surface area for exchange and decreases distance of diffusion. Together these characteristics speed up exchange time. Capillary density varies in different areas of the body. Areas such as the heart and ske...
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...rovascular transport and tumor cell adhesion in the microcirculation. Annals of Biomedical Engineering, 40(11), pp. 2442-2455.
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Margination and adhesion to the endothelium, in which accumulation of leukocytes occurs along the endothelial wall for adhesion. Afterward, these adhesions cause the separation of endothelial cells, allowing the leukocytes to extend and Transmigrate through the vessel walls. Followed by the response of chemical mediators(chemotaxis) that influence cell migration via an energy directed process which triggers the activation of Phagocytosis, in which monocytes, neutrophils, and tissue macrophages are activated to engulf and degrade cellular debris and
Marieb, E. N., & Hoehn, K. (2013). Human anatomy & physiology (9th ed.). Boston, MA: Pearson.
The smallest arteries are called arterioles and they play a vital role in microcirculation. Microcirculation deals with the circulation of blood from arterioles to capillaries to venules the smallest veins. The liver, spleen and bone marrow contain vessel structures called sinusoids instead of capillaries. In these structures blood flows from arterioles to sinusoids to venules.
Marieb, E. N., (2006). Essentials of human anatomy and physiology. San Francisco, CA: Benjamin Cummings.
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Huether, S.E. & McCance, K.L. (2008). Understanding pathophysiology (4th ed.). St. Philadelphia, PA: Mosby Elsevier
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...
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...
They arise in the interstitial spaces of organs and tissues and they then join with the large veins just before they enter the vena cava of the heart. These lymphatic vessels tend to run parallel with the veins which allows filtration to occur. The vessels are non- muscular and contain valves which stop the fluid from going back. (Hastie, 2012).
The heart serves as a powerful function in the human body through two main jobs. It pumps oxygen-rich blood throughout the body and “blood vessels called coronary arteries that carry oxygenated blood straight into the heart muscle” (Katzenstein and Pinã, 2). There are four chambers and valves inside the heart that “help regulate the flow of blood as it travels through the heart’s chambers and out to the lungs and body” (Katzenstein Pinã, 2). Within the heart there is the upper chamber known as the atrium (atria) and the lower chamber known as the ventricles. “The atrium receive blood from the lu...
Marieb, E.N., Hoehn, K. 2013. Human Anatomy and Physiology. 9th edition. Pearson Education Inc. ISPN-13: 978-0-321-74326-8.
7. Vander A.J, Sherman J and Luciano D.S (2004) Human Physiology: The Mechanisms of Body Function, 9th edition, McGraw-Hill, New York- Accessed 22/11/2013.
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
walls of the veins are permeable to H2O at this point, starving the rest of the
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