Anatomy And Physiology Of The Stomach Biology Essay

The tummy is a hollow, muscular organ merely below the stop that shops the nutrient during feeding, secretes digestive juice, mixes nutrient with these juices, and propels partly digested nutrient, called bell into the duodenum of the little bowel. Its major anatomic boundaries are the lower esophageal sphincter where nutrient base on balls through the cardiac opening into the tummy, greater and lesser curvatures, and the pyloric sphincter, which relaxes as nutrient is propelled through the pylorus into the duodenum. Functional countries are the fundus, organic structure and antrum.

Gastric motility additions with the inductions of peristaltic moving ridges. The rate of peristaltic contractions is influenced by nervous an hormonal activity

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Due to eating stimulation, the tummy secretes big volumes of stomachic juices including mucous secretion, acid, enzymes, endocrines, intrinsic factor and gastroferrin.

( Sue & A ; Kathryn, 2008 )

Terminology Of The Stomach Cancer

Cancer of the tummy is besides known as tummy carcinoma or stomachic carcinoma/cancer.

Adenocarcinoma is the most important malignant tumour of the tummy and histories for 97 % of all malignant lesions in the stomach.A This name implies that the malignant neoplastic disease is located in the tummy ( stomachic ) , affects cells that would usually do up secretory organs ( adeno- ) and has malignantA possible ( -carcinoma ) . Other signifiers of tummy malignant neoplastic disease include lymphomas, which involve the lymphatic system and sarcomas, which involve the connective tissue ( such as musculus, fat, or blood vass ) .

Morphologically, stomachic carcinoma is classified into four distinguishable types: ( 1 ) the fungating or polypoid type, which has the best forecast ; ( 2 ) the ulcerating type, which arises as growing off from the lms and may be confused with a benign ulcer ; it appears in the early life of the malignant neoplastic disease and is the most common type of malignant neoplastic disease, accounting for 30 % of all the tummy malignant neoplastic diseases ; ( 3 ) the superficial spreading type ; and ( 4 ) a diffuse distributing type referred to as linitis plastic/ scirrhous carcinoma, which accounts for 10 % of all stomachic carcinomas. It is common for the diffuse type to infiltrate the walls before the beds bulge into the lms. The involved portion becomes contracted, thick-walled, and house. It begins and encircles the pylorus and causes obstructor. The forecast is highly hapless, and remedy is rare because of the early disease promotion prior to sensing. Gastric carcinoma metastasizes really early to the liver and other organ and constructions including the lungs and bone. Metastasiss grow in the liver, and emboli are discharged and dispersed via the portal venous system to the lungs and finally to the bone. . ( PATHO FOR JXR,89 )

Histologically, stomachic malignant neoplastic diseases tend to fall into one of two types ( Lauren Classification ) : ( 1 ) intestinal, malignant cells arranged in acini invade through the musculus of the tummy wall ; ( 2 ) diffuse, typically seen in linitis plastic. These tumours consist of signet ring cells. Extracellular mucin may besides be present. Globules of mucin push the karyon to one side. ( robin & A ; Fiona )

Gastric carcinomas are aggressive tumours with both local and distant spread. Local spread to oesophagus, mucosal and submucosal lymphatic spread to duodenum, to run outing lymph nodes, to adjacent entrails including liver. Distant spread by lymphatics to supraclavicular node, to lungs but normally to late, hematogenous to liver via portal vena and transcoelomic to ovaries. ( robin & A ; Fiona )

Chapter TWO


2.1 Causes

Helicobacter pylori infection is believed to be the cause of most stomach malignant neoplastic disease while assorted familial factors and autoimmune atrophic gastritis, enteric metaplasia are associated with increased degree of hazards. Smoked nutrients, salted fish and meat, and pickled veggies appear to increase the hazard of tummy malignant neoplastic disease. Nitrates and nitrites are found in healed meats. They can be converted by certain bacteriums, such as into compounds that have been found to do tummy malignant neoplastic disease in animals.. In more item, H. pylori are the chief hazard factor in 65-80 % of stomachic malignant neoplastic diseases, causes mechanism in which it induces tummy malignant neoplastic disease potentially involves virulency factor or chroni redness.

Tobacco smoke is a really of import but preventable cause of stomachic malignant neoplastic disease. Smoking increases the hazard of developing stomachic malignant neoplastic disease well ; from 40 % increased hazard for current tobacco users to 82 % addition for heavy tobacco users which is about twice the hazard for non-smoking population. Alcohol and baccy ingestion are hazard factors for the disease.

Gastric malignant neoplastic disease shows a male predomination in its incidence as up to three males are affected for every female. Estrogen may protect adult females against the development of this malignant neoplastic disease signifier.

2.2 Incidence

Stomach malignant neoplastic disease is an of import cause of decease among patients with malignances in Malaysia and ranked as the 7th most common malignant neoplastic disease in males in Peninsular Malaysia and 10th among females pdf. Adenocarcinomas formed the bulk ( 72.3 % ) of tummy malignant neoplastic diseases in Malaysia. Pdf.

The Malayan National Cancer Registry ( NCR ) study for the period 2003-2005 shows an incidence of tummy malignant neoplastic disease of 2.2 for Malay, 11.3 for Chinese and 11.9 for Indian males per 100,000 population. Malay ( 1.3 ) , Chinese ( 7.2 ) and Indian ( 7.2 ) adult females have rates lower than work forces. Malayans in Peninsular Malaysia have five times less tummy malignant neoplastic disease than Chinese and Indians. This racial difference is more pronounced than that noted in the Singapore malignant neoplastic disease register. Regional information from Kelantan has an even lower rate for Malays there ( 1.5 for males and 0.9 for females per 100,000 population ) . The incidence of Helicobacter pylori infection, a known hazard factor for tummy malignant neoplastic disease, is low among Malays.

Gastric malignant neoplastic disease incidence varies markedly with geographics. In Japan, Chile, Costa Rica, and Eastern Europe, the incidence is up to 20-fold higher than in North America, northern Europe, Africa and Southeast Asia. Mass endoscopic testing plans can be successful in parts where the incidence is high, such as Japan, where 35 % of freshly detected instances are early stomachic malignant neoplastic disease, tumours limited to the mucous membrane and submucosa. Unfortunately, mass showing plans are non cost effectual in parts where the incidence is low. And fewer than 20 % of instances are detected at an early phase in North America and northern Europe. In the United States, stomachic malignant neoplastic disease rates dropped by over 85 % during the 20th century.

figure tummy malignant neoplastic disease international comparings

2.3 Mortality & A ; Morbidity

This really of import malignant tumour has an particularly high incidence in Japan, Chile and Italy. Its incidence has fallen in the United Kingdom and the U.S.A. since the 1930s.

Gastric malignant neoplastic disease is still the 2nd most common fatal malignance after lung malignant neoplastic disease in the universe, with an estimated three quarters of a million new instances diagnosed yearly.

Adenocarcinoma of the tummy was the common cause of malignant neoplastic disease decease in the united provinces in 1930 and remains a taking cause of malignant neoplastic disease decease worldwide, but now accounts for fewer than 2.5 % of malignant neoplastic disease deceases in the United States.The age specific incidence curve increased exponentially with age. The crisp rise occurred after 60 old ages of age. The difference between the age specific incidence curve in males and females widened with increasing age. Survival of patients with stomachic malignant neoplastic disease is dependent on the phase at which diagnosing is made.

2.4 Signs And Symptoms

Stomach malignant neoplastic disease in early phases frequently produce no noticeable symptoms ( symptomless ) or symptoms which are non specific to merely stomach malignant neoplastic disease ( non particular symptoms ) , but besides to other related or unrelated upsets. The malignant neoplastic disease has frequently reached an advanced phase which may besides metastasise and bring on hapless forecast by the clip the noticeable symptoms occur. ( Internet ca 1 )

Table: marks and symptoms of tummy malignant neoplastic disease

Phase 1 ( Early )

Phase 2 ( Middle )

Phase 3 ( Late )

Indigestion, pyrosis

which produces firing esthesis

Appetite loss particularly for meat

Irritation or abdominal uncomfortableness

Fatigue and failing

Bloating of the tummy normally after repasts

Upper abdominal hurting

Occasional emesis and sickness

Constipation or diarrhoea

Loss of weight

Blood nowadays in puke referred to as haematemesis. This bleeding is normally from the tummy

Melena, the transition of dark, tarry stools


Dysphagia, this characteristic suggests a tumour in the cardia or extension of the stomachic tumour in to the gorge

2.5 Pathophysiology

H.pylori has now been accepted as the major of chronic gastritis, it is logical to implicate this infection in the causing of stomachic malignant neoplastic disease. The prevalence of H.pylori infection often runs analogue with the incidence of stomachic malignant neoplastic disease in the same populations. Long-run infection leads to glandular wasting which leads to a gradual diminution in acerb secernment. Hypochlorhydria allows other bacteriums to proliferate in the stomachic juice ; these bacteriums are capable of cut downing nitrate ions to nitrite and can catalyze nitrosation of aminoalkanes and amides present in the diet to give rise to potentially carcinogenic compounds.

H.pylori is capable of bring forthing ethanal. Acetaldehyde is a extremely reactive merchandise which amendss epithelial cells and can do DNA harm and can be minimized by anti-oxidant vitamins. Diets rich in fresh fruits and veggies as protective against stomachic malignant neoplastic disease.

The most of import factor underlying the relationship between H.pylori and stomachic malignant neoplastic disease is a promotional consequence through high cell turnover. The production of cytotoxins and ammonium hydroxide by the being, and indirect epithelial harm brought approximately by cytokines and polymorph merchandises, induce increased cell turnover. DNA fix is compromised by increased cell proliferation, and the chance of a mutant get awaying fix and being transmitted to daughter cells is increased.

Several molecular familial alterations have been demonstrated in stomachic malignant neoplastic disease. Mutants and omissions of tumour surpressor cistrons have been

However while some of these mutants are consistent with exogenic chemical carcinogens or exposure to endogenous free extremist hurt, one can non deduce the nature of the mutational agent from the familial lesions with any certainty. Nevertheless the overall grounds favors link between H.pylori infection and stomachic malignant neoplastic disease.

2.6 Histopathology

Gastric glandular cancer are classified harmonizing to their location in the stomach.gastric malignant neoplastic disease with diffuse infiltrative growing form are more frequently composed of signet ring cells. Although enteric type glandular cancer may perforate the gastric wall, they typically grow along wide cohesive foreparts to organize either an exophytic mass or an cankerous tumour. The neoplastic cells frequently contain apical mucin vacuoles, and abundant mucin may be present in the secretory organ lumens. In contrast, diffuse stomachic malignant neoplastic disease is by and large composed of discohesive cells that do non organize secretory organs but alternatively hold big mucin vacuoles that expand the cytol and force the karyon to the fringe, making a signet-ring cell morphology. These cells permeate the mucous membrane and tummy wall separately or in little bunchs, which makes tumour cells easy to confound with inflammatory cells, such as macrophages, at low magnification. Extracellular mucin release in either type of stomachic malignant neoplastic disease can ensue in formation of big mucin lakes that dissect tissue planes. Kumar ababss

A mass may be hard to appreciate in diffuse stomachic malignant neoplastic disease, but these infiltrative tumours frequently evoke a demoplastic reaction that stiffens the stomachic wall and may supply a valuable diagnostic hint. When there are big countries of infiltration diffuse rugal thickener and a stiff, thickened wall may leave a leather bottle visual aspect termed linitis plastic. Breast and lung malignant neoplastic diseases that metastasize to the tummy may besides make a linitis plastic-like visual aspect Kumar ababss


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