By I. Angir. Lynchburg College.

It is • The lower third of the oesophagus is a site of porto-systemic venous considered in four parts: anastomosis generic crestor 10 mg fast delivery. The sphinc- • The pyloric sphincter controls the release of stomach contents into ter of Oddi guards this common opening order 10mg crestor. The sphincter is composed of a thickened layer of circu- pancreatic duct (of Santorini) opens into the duodenum a small lar smooth muscle which acts as an anatomical purchase crestor 5 mg on line, as well as physiolo- distance above the papilla 20mg crestor. The junction of the pylorus and duodenum can be seen • Third part (10 cm)athis part is crossed anteriorly by the root of externally as a constriction with an overlying veinathe prepyloric vein the mesentery and superior mesenteric vessels buy crestor 20mg mastercard. The cardiac sphincter acts to prevent reflux of peritoneal fold stretching from the junction to the right crus of stomach contents into the oesophagus. The discrete anatomical sphincter at the cardia; however, multiple factors terminal part of the inferior mesenteric vein lies adjacent to the contribute towards its mechanism. The superior artery arises from the coeliac axis compression of the short segment of intra-abdominal oesophagus by in- and the inferior from the superior mesenteric artery. The body are denervated thus not compromising the motor supply to the coeliac branch of the posterior vagus passes to the coeliac ganglion stomach and hence bypassing the need for a drainage procedure (e. A large internal surface area throughout the towards the right iliac region on the posterior abdominal wall. The small and ileal branches arise which divide and re-anastomose within the intestine is suspended from the posterior abdominal wall by its mesen- mesentery to produce arcades. End-artery vessels arise from the tery which contains the superior mesenteric vessels, lymphatics and auto- arcades to supply the gut wall. The origin of the mesentery measures approximately 15 sists of few arcades and little terminal branching whereas the vessels to cm and passes from the duodenojejunal flexure to the right sacro-iliac the ileum form numerous arcades and much terminal branching of end- joint. No sharp distinction occurs between the jejunum and ileum; however, certain characteristics help distinguish between them: Small bowel obstruction (Fig. Loops of jejunum tend to occupy the umbilical region adhesions and herniae are the most frequent causes. In the pelvic position the appendix may be close to the ovary in the female Longitudinal muscle Circular muscle Rectum Levator ani Obturator internus Fat of ischiorectal fossa Sphincter Deep Submucosa ani Superficial Sphincter ani internus externus Subcutaneous Pudendal canal Adductor muscles Inferior rectal vesels and nerve Fig. It commences in front of ascending, transverse, descending and sigmoid colon have similar the 3rd sacral vertebra as a continuation of the sigmoid colon and fol- characteristic features. The teniae coli fan out over the rec- course from the base of the appendix (and form a useful way of locating tum to form anterior and posterior bands. These sacculations are visible • Peritoneum covers the upper two-thirds of the rectum anteriorly but not only at operation but also radiographically. In the female it is reflected forwards onto ray, the colon, which appears radiotranslucent because of the gas within, the uterus forming the recto-uterine pouch (pouch of Douglas). They are adherent to the posterior The anorectal junction is slung by the puborectalis component of lev- abdominal wall and covered only anteriorly by peritoneum. This is the site where the The appendix varies enormously in length but in adults it is approxim- proctodeum (ectoderm) meets endoderm. The base of the appendix arises from the postero- tion is reflected by the following characteristics of the anal canal: medial aspect of the caecum; however, the lie of the appendix itself is • The epithelium of the upper half of the anal canal is columnar. In most cases the appendix lies in the retrocaecal posi- trast the epithelium of the lower half of the anal canal is squamous. The appendix has the follow- mucosa of the upper canal is thrown into vertical columns (of Mor- ing characteristic features: gagni). The only blood supply to the appendix, the appendicular artery (a • The blood supply to the upper anal canal (see Fig. In superior rectal artery (derived from the inferior mesenteric artery) cases of appendicitis the appendicular artery ultimately thromboses. The lower anal canal is sensitive to pain as it is sup- • The bloodless fold of Treves (ileocaecal fold) is the name given to a plied by somatic innervation (inferior rectal nerve). Most surgeons still opt to invaginate the appendix stump as a precau- tionary measure against slippage of the stump ligature. The lower gastrointestinal tract 43 18 The liver, gall-bladder and biliary tree Opening in central tendon of diaphragm Hepatic vein Liver Spleen Portal vein Splenic vein Inferior mesenteric vein Superior mesenteric vein Fig. The transmission of blood from the portal system to the inferior vena cava is via the liver lobules (fig. The extensive length of gut that is surface is related to the diaphragm and its lower border follows the con- drained by the portal vein explains the predisposition for intestinal tour of the right costal margin. These are separated antero-superiorly by the falciform ligament The gall-bladder lies adherent to the undersurface of the liver in the and postero-inferiorly by fissures for the ligamentum venosum and liga- transpyloric plane (p.

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During the process purchase crestor 10mg mastercard, the plasma membrane invaginates into tiny pockets buy 5 mg crestor otc, which draw fuids from the surroundings into the cell buy cheap crestor 5mg on-line. Finally purchase 20 mg crestor with visa, these pockets pinch off and are known as pinosomes or phagosomes cheap 20mg crestor overnight delivery, which fuse with lysosomes and liberate their contents into the cell cytosol. Vesicles containing secretory materials fuse with the plasma membrane and discharge their contents into the exterior. Table 1 Similarities and differences between facilitated diffusion and active transport Facilitated Diffusion Active Transport 1. Needs a carrier protein and they are Needs a carrier protein and they are named as transporters or channels. Solutes are transported from high Solutes are transported from low concentrations to low concentrations concentrations to high concentrations 6. The co-effcient of viscosity of a liquid is defned as the force in dynes required to maintain the streamline fow of one fuid layer of unit area over another layer of equal area separated from one another by 1 cm at a rate of 1cm/sec. If a small sphere of radius ‘r’ and density ‘r’ falls vertically through a liquid with the density ‘r’at a steady velocity ‘u’, inspite of the acceleration due to gravity (g), the co-effcient of viscosity and density are related as follows. The lubricating property of the synovial fuid is achieved mainly by the viscous nature of the mucopolysaccharides present in the synovial fuid. But a surface molecule (b) suffers a much greater intermolecular 7 attraction towards the interior of the liquid than towards the vapour phase, because fewer molecules are present in the vapour phase. Surface tension (¡) is defned as the force acting perpendicularly inwards on the surface layer of a liquid to pull its surface molecules towards the interior of the liquid mass. Density - Macloed’s equation relates surface tension to the density of the liquid (r) and that of its vapour (r’). As the temperature of the liquid increases, the surface tension decreases and becomes zero at the critical temperature. Solutes - Solutes that enter the liquid raise the surface tension of the solvent, while solutes that concentrate on the surface lower the surface tension. Emulsifcation of fats by bile salts - Bile salts lower the surface tension of the fat droplets in the duodenum, which aids in digestion and absorption of lipids. Surface tension of plasma: The surface tension of plasma is 70 dynes/cm, which is slightly lower than that of water. Hay’s test for bile salts - The principle of surface tension is used to check the presence of bile salts in urine. When fne sulphur powder is sprinkled on urine containing bile salts ( as in jaundice), it sinks due to the surface tension lowering effect of bile salts. Dipalmitoyl lecithin is a surfactant that is secreted by the lung alveoli, which reduces the surface tension and prevents the collapse of lung alveoli during expiration. Osmosis is a colligative property of solution that depends on the number of molecules or ions of the solute in the solutions. A solution having lower or higher osmotic pressure with respect to the other is called as hypo-osmotic or hyperosmotic solutions respectively. The osmotic pressure exhibited by these impermeable solutes is called as the tonicity of the solution. A solution having lower or higher tonicities with respect to the other is called as hypotonic or hypertonic solutions respectively. The ability of the membrane to withstand hypotonic solution depends upon the integrity of the membrane. Certain genetic disorders like sickle cell anemia and defciency of vitamin E makes the erythrocyte membrane more fragile. Osmotic pressure of blood is largely due to its mineral ions such as sodium, potassium, chloride, calcium and protein. The osmotic pressure exerted by proteins is of considerable biological signifcance owing to the impermeability of the plasma membrane to the colloidal particles. The net difference in the hydrostatic pressure and osmotic pressure is responsible for the fltration of water at the arterial end of the capillary and the reabsorption of the same at the venous end. The renal excretion of water is regulated partly by the osmotic pressure exerted by the colloids in the blood plasma.

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Usually discount crestor 10mg on line, the name of the tissue crestor 20 mg on-line, organ and the region which develops infammation is suffxed with ‘itis’ for example conjunctivitis cheap crestor 10 mg with visa, gastritis and pharyngitis respectively crestor 5mg low cost. The infammatory response helps to mobilize the nonspecifc defense forces to the tissue space where pathogen is present 5mg crestor. The damaged cells release chemical mediators such as histamine from the mast cells, which dilate the near by blood vessels. They get activated due to the tissue damage and this process leads to “walling off” the area and this helps to prevent spreading of the infectious material. It attaches to the target and releases a lethal burst of chemicals called as perforins that penetrate the cell wall. Interferon Interferons are proteins produced by body cells when they are invaded by viruses, is released into the bloodstream or intercellular fuid, in order to induce healthy cells to manufacture an enzyme that block viral replication. The complement system is the part of innate immune system plays an important defense against microorganisms, especially gram-negative bacteria. The complement system consists of a set of over twenty serum proteins which are getting activated as follows. The pathways include the classic pathway (C1qrs, C2, C4), the alternative pathway (C3, factor B, properdin) and these two pathways converge at the component C3. Generally, they take part in differentiating self and non self antigens and the presentation of processed foreign antigen to activate the T cells. It has the special ability to keep memory of frst time exposure of an antigen (primary immune response) and mounts better response when there is second time exposure of same antigen (secondary immune response). Natural (Due to natural entry of pathogen) Actively acquired Artificial (Due to artificially introduced antigen like immunization process) Natural (Baby receives the antibody synthesized by the Passively mother through mother’s milk acquired Artificial (Antibodies are introduced artificially) 150 10. Though the classifcation separates the cell mediated and humoral immunity with different cell types they do interact to bring an effective immune response. Specifc T-cells are stimulated to produce lymphokines that are responsible for the antigen-induced B-cells proliferation and differentiation. Through a process of clonal selection specifc B-cells are stimulated, the activated B-cell frst develops into a B-lymphoblast, becoming much larger and shedding all surface immunoglobulin. This terminal differentiation stage is responsible for production of primarily IgM antibody during the primary immune response. Upon subsequent encounter with antigen, these cells respond very quickly to produce large amounts of IgG, IgA or IgE antibody, generating the better secondary immune response. These stages are, of course, initiated upon encounter with antigen and activation by T-helper cell to secrete lymphokines. When high doses of antibody interact with the entire antigen’s epitopes thereby inhibits interactions with B-cell receptors. T cells are initially formed in the bone marrow and get its maturation and differentiation in the thymus gland. T cells are associated with certain types of allergic reactions called Delayed hypersensitivity and also in transplanted organ rejection. Suppressor (T ) cells appear S to regulate the immune response once the antibody formation reached the adequate levels. In addition, these proinfammatory cytokines activate the immune system, mobilizing neutrophils from bone marrow, causing dendritic cells to migrate to lymph nodes, and also initiating changes in adipocyte and muscle metabolism and also responsible for inducing fever. Antigens can be defned as a substance that can combine specifcally to the components of immune response such as lymphocytes and antibodies. An immunogen is any substance that has the ability to evoke B or T or both B and T mediated immune reactions. Whole antigen cannot combine with the antibody as antibodies are formed against specifc regions on the surface of an antigen called antigenic determinant or epitopes. Most antigens are proteins, nucleoproteins, lipoproteins, 153 glycoproteins, or large polysaccharides with a molecular weight greater than 10,000. However the low-molecular-weight substance that can combine with an antibody but cannot induce the formation of antibodies are called as haptens. However the following factors can also infuence it, 1) The antigenic response which is indicated by the quantum of antibody formed in response to antigenic stimulation varies depending on the dosage of antigen administered, route of administration and use of adjuvant etc. Because of this the virus which has the very low molecular weight proteins escapes the immune response. Recruit other cells and molecule to destroy the pathogen (effectors function or Biological activity) 154 Fig.

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