DIGESTIVE SYSTEM

Digestive system.

The human digestive system is a complex series of organs and glands that processes food. In order to use the food we eat, our body has to break the food down into smaller molecules that it can process; it also has to excrete waste.

Most of the digestive organs (like the stomach and intestines) are tube-like and contain the food as it makes its way through the body. The digestive system is essentially a long, twisting tube that runs from the mouth to the anus, plus a few other organs (like the liver and pancreas) that produce or store digestive chemicals.

The Digestive Process:

The start of the process - the mouth: The digestive process begins in the mouth. Food is partly broken down by the process of chewing and by the chemical action of salivary enzymes (these enzymes are produced by the salivary glands and break down starches into smaller molecules).

On the way to the stomach: the esophagus - After being chewed and swallowed, the food enters the esophagus. The esophagus is a long tube that runs from the mouth to the stomach. It uses rhythmic, wave-like muscle movements (called peristalsis) to force food from the throat into the stomach. This muscle movement gives us the ability to eat or drink even when we're upside-down.

In the stomach - The stomach is a large, sack-like organ that churns the food and bathes it in a very strong acid (gastric acid). Food in the stomach that is partly digested and mixed with stomach acids is called chyme.

In the small intestine - After being in the stomach, food enters the duodenum, the first part of the small intestine. It then enters the jejunum and then the ileum (the final part of the small intestine). In the small intestine, bile (produced in the liver and stored in the gall bladder), pancreatic enzymes, and other digestive enzymes produced by the inner wall of the small intestine help in the breakdown of food.

In the large intestine - After passing through the small intestine, food passes into the large intestine. In the large intestine, some of the water and electrolytes (chemicals like sodium) are removed from the food. Many microbes (bacteria like Bacteroides, Lactobacillus acidophilus, Escherichia coli, and Klebsiella) in the large intestine help in the digestion process. The first part of the large intestine is called the cecum (the appendix is connected to the cecum). Food then travels upward in the ascending colon. The food travels across the abdomen in the transverse colon, goes back down the other side of the body in the descending colon, and then through the sigmoid colon.

The end of the process - Solid waste is then stored in the rectum until it is excreted via the anus.

Digestive diseases

DEFINITION

Digestive diseases are disorders of the digestive tract, which is sometimes called the gastrointestinal (GI) tract.

In digestion, food and drink are broken down to small parts (called nutrients) that the body can absorb and use as energy and building blocks for cells.

The digestive tract is made up of the esophagus (swallowing tube), stomach, large and small intestines, liver, pancreas, and the gallbladder.

INFORMATION

The first sign of problems in the digestive tract often includes one or more of the following symptoms:

·         Bleeding

·         Bloating

·         Constipation

·         Diarrhea

·         Heartburn

·         Incontinence

·         Nausea and vomiting

·         Pain in the belly

·         Swallowing problems

·         Weight gain or loss

A digestive disease is any health problem that occurs in the digestive tract. Conditions may range from mild to serious. Some common problems include cancer, irritable bowel syndrome, and lactose intolerance.

Other digestive diseases include:

·         Gallstones, cholecystitis, and cholangitis

·         Rectal problems, such as anal fissure, hemorrhoids, proctitis, and rectal prolapse

·         Esophagus problems, such as stricture (or narrowing) and achalasia

·         Liver problems, such as hepatitis B or hepatitis C, cirrhosis, liver failure, and autoimmune and alcoholic hepatitis

·         Pancreatitis and pancreatic pseudocyst

·         Intestinal problems, such as infections, celiac disease, Crohn's disease,ulcerative colitis, diverticulitis, malabsorption, short bowel syndrome, andintestinal ischemia

·         Gastroesophageal reflux disease (GERD), peptic ulcer disease, and hiatal hernia

Diagnostic tests for digestive problems can include colonoscopy, upper GIendoscopy, capsule endoscopy, endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound.

Many surgical procedures are performed on the digestive tract. These include procedures done using endoscopy, laparoscopy, and open surgery. Organ transplants can be performed on the liver, pancreas, and small intestine.

Many health care providers can help diagnose and treat a patient’s digestive problems. A gastroenterologist is a physician specialist who has received extra training in the diagnosis and treatment of the digestive disorders. Other health care providers involved in the treatment of digestive diseases include:

·         Nurse practitioners (NPs) or physician assistants (PAs)

·         Nutritionists or dietitians

·         Primary care doctors

·         Radiologists

·         Surgeons

 Abdominal exam

The abdominal exam, in medicine, is performed as part of a physical examination, or when a patient presents with abdominal pain or a history that suggests an abdominal pathology.

The exam includes several parts:

§  Setting and preparation

§  Inspection (for example, "nondistended" or "ND")

§  Auscultation (for example, "BS normoactive" or "BS+")

§  Percussion

§  Palpation (for example, "no hepatosplenomegaly" or "HSM", "soft", "nontender" or "NT")

setting and preparation

Position - patient should be supine and the bed or examination table should be flat. The patient's hands should remain at his/her sides with his/her head resting on a pillow. If the neck is flexed, the abdominal musculature becomes tensed and the examination made more difficult. Allowing the patient to bend his/her knees so that the soles of their feet rest on the table will also relax the abdomen.

Lighting - adjusted so that it is ideal.

Draping - patient should be exposed from the pubic symphysis below to the costal margin.

 above - in women to just below the breasts. Some surgeons would describe an abdominal examination being from nipples to knees.

Physicians have had concern that giving patients pain medications during acute abdominal pain may hinder diagnosis and treatment. Separate systematic reviews by the Cochrane Collaboration and the Rational Clinical Examination refute this claim.

inspection

The patient should be examined for: -

§  masses

§  scars, sinuses

§  lesions

§  signs of trauma

§  bulging flanks - best done from the foot of the bed

§  jaundice/scleral icterus

§  abdominal distension

§  caput medusae - dilated blood vessels radiating from the umbilicus (may be present in liver failure)

§  cough impulse

Stigmata of liver disease

There are several stigmata of liver disease. Though not all of these are observed in the abdomen, they can indicate liver disease, and are sometimes grouped with local hepatic findings. These stigmata include:

§  General: spider angiomata, temporal wasting, fetor hepaticus, asterixis (flapping tremor)

§  Hands: clubbing, thenar wasting, Dupuytren's contracture, palmar erythema

§  Estrogen related: spider nevi

§  Estrogen-related in males: testicular atrophy, gynecomastia

§  Associated with portal hypertension: hematochezia (blood in stool), hematemesis - gastric bleed, esophageal varices, caput medusae (rare) - venous distension, ascites

Auscultation

Auscultation is sometimes done before percussion and palpation, unlike in otherexaminations. It may be performed first because vigorously touching the abdomen may disturb the intestines, perhaps artificially altering their activity and thus the bowel sounds. Additionally, it is the least likely to be painful/invasive; if the person has peritonitis and you check for rebound tenderness and then want to auscultate you may no longer have a cooperative patient.

Pre-warm the diaphragm of the stethoscope by rubbing it on the front of your shirt before beginning auscultation. One should auscultate in all four quadrants, but there is no true compartmentalization so sounds produced in one area can generally be heard throughout the abdomen. To conclude that bowel sounds are absent one has to listen for 5 minutes. Growling sounds may be heard with obstruction. Absence of sounds may be caused by peritonitis.

Palpation

§  All 9 areas - light then deep.

§  In light palpation, note any palpable mass.

§  In deep palpation, detail examination of the mass, found in light palpation, and Liver & Spleen

§  Palpate the painful point at the end.

Assessing muscle tone- This is done by pressing a hand against the abdominal wall. There are 3 reactions that indicate pathology:

§  guarding (muscles contract as pressure is applied)

§  rigidity (rigid abdominal wall- indicates peritoneal inflammation)

§  rebound (release of pressure causes pain)

 §  hernial orifices if positive cough impulses

Percussion

§  it is common practice to start percussing in a quadrant where there is no pain/discomfort and to percuss the painful quadrant(s) last. making sure to percuss all the 9 areas.

§  percuss the liver from the right iliac region to right hypochondrium

§  percuss for the spleen from the right iliac region to the left hypochondrium and the left iliac to the left hypochondrium.

Examination of the spleen

§  Castell's sign or alternatively Traube's space

Imaging technique

Medical imaging is the technique and process used to create images of the human body (or parts and function thereof) for clinical purposes (medical procedures seeking to reveal, diagnose, or examine disease) or medical science (including the study of normal anatomy and physiology). Although imaging of removed organs and tissues can be performed for medical reasons, such procedures are not usually referred to as medical imaging, but rather are a part of pathology.

As a discipline and in its widest sense, it is part of biological imaging and incorporates radiology (in the wider sense), nuclear medicine, investigative radiological sciences, endoscopy, (medical) thermography, medical photography, and microscopy (e.g. for human pathological investigations).

Measurement and recording techniques which are not primarily designed to produce images, such as electroencephalography(EEG), magnetoencephalography (MEG), electrocardiography (EKG), and others, but which produce data susceptible to be represented as maps (i.e., containing positional information), can be seen as forms of medical imaging.

Up until 2010, 5 billion medical imaging studies had been conducted worldwide. Radiation exposure from medical imaging in 2006 made up about 50% of total ionizing radiation exposure in the United States.

In the clinical context, "invisible light" medical imaging is generally equated to radiology or "clinical imaging" and the medical practitioner responsible for interpreting (and sometimes acquiring) the images is a radiologist. "Visible light" medical imaging involves digital video or still pictures that can be seen without special equipment. Dermatology and wound care are two modalities that utilize visible light imagery. Diagnostic radiography designates the technical aspects of medical imaging and in particular the acquisition of medical images. The radiographer or radiologic technologist is usually responsible for acquiring medical images of diagnostic quality, although some radiological interventions are performed by radiologists. While radiology is an evaluation of anatomy, nuclear medicine provides functional assessment.

As a field of scientific investigation, medical imaging constitutes a sub-discipline of biomedical engineering, medical physics or medicine depending on the context: Research and development in the area of instrumentation, image acquisition (e.g. radiography), modeling and quantification are usually the preserve of biomedical engineering, medical physics, and computer science; Research into the application and interpretation of medical images is usually the preserve of radiology and the medical sub-discipline relevant to medical condition or area of medical science (neuroscience, cardiology, psychiatry, psychology, etc.) under investigation. Many of the techniques developed for medical imaging also have scientific and industrial applications.

Medical imaging is often perceived to designate the set of techniques that noninvasively produce images of the internal aspect of the body. In this restricted sense, medical imaging can be seen as the solution of mathematical inverse problems. This means that cause (the properties of living tissue) is inferred from effect (the observed signal). In the case of ultrasonography the probe consists of ultrasonic pressure waves and echoes inside the tissue show the internal structure. In the case of projection radiography, the probe is X-ray radiation which is absorbed at different rates in different tissue types such as bone, muscle and fat.

The term noninvasive is a term based on the fact that following medical imaging modalities do not penetrate the skin physically. But on the electromagnetic and radiation level, they are quite invasive. From the high energy photons in X-Ray Computed Tomography, to the 2+ Tesla coils of an MRI device, these modalities alter the physical and chemical environment of the body in order to obtain data.

Liver disease 

Liver disease (also called hepatic disease) is an umbrella term referring to damage to or disease of the liver.

§  Hepatitis, inflammation of the liver, is caused mainly by various viruses (viral hepatitis) but also by some liver toxins (e.g. alcoholic hepatitis), autoimmunity (autoimmune hepatitis) or hereditary conditions.

§  Alcoholic liver disease is a term used to describe any hepatic manifestation of alcohol overconsumption, including fatty liver disease, alcoholic hepatitis, and cirrhosis. Analogous terms such as "drug-induced" or "toxic" liver disease are also used to refer to the range of disorders caused by various drugs and environmental chemicals.

§  Fatty liver disease (hepatic steatosis) is a reversible condition where large vacuoles of triglyceride fat accumulate in liver cells. Non-alcoholic fatty liver disease is a spectrum of disease associated with obesity and metabolic syndrome, among other causes. Fatty liver may lead to inflammatory disease (i.e. steatohepatitis) and, eventually, cirrhosis.

§  Cirrhosis is the formation of fibrous tissue (fibrosis) in the place of liver cells that have died due to a variety of causes, including viral hepatitis, alcohol overconsumption, and other forms of liver toxicity. Cirrhosis causes chronic liver failure.

§  Primary liver cancer most commonly manifests as hepatocellular carcinoma and/or cholangiocarcinoma; rarer forms include angiosarcoma and hemangiosarcoma of the liver. (Many liver malignancies are secondary lesions that have metastasized from primary cancers in the gastrointestinal tract and other organs, such as the kidneys, lungs, breast, or prostate.)

§  Primary biliary cirrhosis is a serious autoimmune disease of the bile capillaries.

§  Primary sclerosing cholangitis is a serious chronic inflammatory disease of the bile duct, which is believed to be autoimmune in origin.

§  Budd-Chiari syndrome is the clinical picture caused by occlusion of the hepatic vein, which in some cases may lead to cirrhosis.

§  Hereditary diseases that cause damage to the liver include hemochromatosis, involving accumulation of iron in the body, and Wilson's disease, which causes the body to reta in copper. Liver damage is also a clinical feature of alpha 1-antitrypsin deficiency and glycogen storage disease type II.

§  In transthyretin-related hereditary amyloidosis, the liver produces a mutated transthyretin protein which has severe neurodegenerative and/or cardiopathic effects. Liver transplantation can provide a curative treatment option.

§  Gilbert's syndrome, a genetic disorder of bilirubin metabolism found in about 5% of the population, can cause mild jaundice.

There are also many pediatric liver disease, including biliary atresia

, alpha-1 antitrypsin deficiency, alagille syndrome, progressive familial intrahepatic cholestasis to name but a few.

Rectal Cancer

The rectum is the lower part of the colon that connects the large bowel to the anus. The rectum's primary function is to store formed stool in preparation for evacuation. Like the colon, the3 layers of the rectal wall are as follows: 

·         Mucosa: This layer of the rectal wall lines the inner surface. The mucosa is composed of glands that secrete mucus to help the passage of stool.

·         Muscularis propria: This middle layer of the rectal wall is composed of muscles that help the rectum keep its shape and contract in a coordinated fashion to expel stool.

·         Mesorectum: This fatty tissue surrounds the rectum.

In addition to these 3 layers, another important component of the rectumis the surrounding lymph nodes (also called regional lymph nodes). Lymph nodes are part of the immune system and assist in conducting surveillance for harmful materials (including viruses and bacteria) that may be threatening the body. Lymph nodes surround every organ in the body, including the rectum.

Of the 150,000 cases of colorectal cancer diagnosed each year in the United States, more than 40,000 people are diagnosed with rectal cancer. The most common type of rectal cancer is adenocarcinoma, which is a cancer arising from the mucosa. Cancer cells can also spread from the rectum to the lymph nodes on their way to other parts of the body.

Like colon cancer, the prognosis and treatment of rectal cancer depends on how deeply the cancer has invaded the rectal wall and surrounding lymph nodes. However, although the rectum is part of the colon, the location of the rectum in the pelvis poses additional challenges in treatment when compared with colon cáncer.

Appendicitis

The appendix is a small, tube-like organ attached to the first part of the large intestine, also called the colon. It is located in the lower right area of the abdomen. It has no known function. A blockage inside of the appendix causes appendicitis. The blockage leads to increased pressure, problems with blood flow and inflammation. If the blockage is not treated, the appendix can break open and leak infection into the body.

Symptoms may include

• Pain and/or swelling in the abdomen
• Loss of appetite
• Nausea and vomiting
• Constipation or diarrhea
• Inability to pass gas
• Low fever

Not everyone with appendicitis has all these symptoms.

Appendicitis is a medical emergency. Treatment almost always involves removing the appendix. Anyone can get appendicitis. It happens most often to people between the ages of 10 and 30.