Describe the functions of the GIT
Nutrients: movement, breakdown, absorption
Vitamins: absorption, synthesis
Hormones: synthesizes, augments, responds
Keeps dangerous gut contents out of blood
Keeps blood contents from being lost into gut
What are the four layers of the tubular structure of the gut?
Mucosa - innermost layer which secretes digestive juices, involved in absorption. Mucosa is thrown into folds known as villi which greatly increase surface area for absorption
Submucosa - layer of connective tissues containing blood vessels, lymphatics and nerves
Muscular layer - smooth muscle arranged in circular and longitudinal layers
Peritoneum - outermost layer – double layered serous membrane – parietal and visceral. Does not cover oral cavity, pharynx, oesophagus or rectum
Gastroduodenal mucosa can withstand the digestive action of hydrochloric acid, pepsin and bile due to...?
- Mucous bicarbonate barrier
- Prostaglandin E2 (PGE2)
- Renewal of epithelial cells
- Delivery of bicarbonate ion
Give some predisposing factors for inflammatory bowel disease
Which condition does the following describe?
- Recurrent granulomatous type of inflammatory response that can affect any part of the GI tract
- Slowly progressive, often disabling disease
- Sharply demarcated granulomatous lesions surrounded by normal-appearing mucosal tissue – Skip lesions
- All layers of bowel involved (transmural)
- Marked inflammatory and fibrotic changes of the sub-mucosal layer
- Fissures and crevices develop, surrounded by areas of mucosal oedema
- Bowel wall becomes thickened and inflexible – narrow lumen which may become totally obstructed
- Adjacent mesentery may become inflamed and regional lymph nodes and channels become enlarged
Describe some signs and symptoms a patient presenting with Crohn's disease may have
Periods of exacerbations & remissions
Colicky pain (right lower quadrant)
Melena (if ulcer erodes blood vessels)
Anorexia, weight loss
Fluid & electrolyte imbalances
Nutritional deficiencies – malabsorption
Abscess and fistula formation
- Which inflammatory bowel disease is A showing?
- Which inflammatory bowel disease is B showing?
- Ulcerative Colitis
What is Ulcerative Colitis?
(Give a detailed description of it's features)
- Nonspecific inflammatory condition of the colon
- Usually begins in rectum and spreads proximally affecting primarily the mucosal layer
- Inflammatory process is confluent & continuous
- Lesions form in the crypts of Lieberkühn
- Inflammatory process leads to formation of pinpoint haemorrhages – suppurate and become crypt abscesses
- Become necrotic and ulcerate
- Often develop pseudopolyps
Bowel wall thickens in response to repeated ulcerations
How might Ulcerative Colitis present?
- Presents as a relapsing disorder marked by attacks of diarrhoea – blood and mucus
- Mild abdominal cramping
- May be classified as mild, moderate, severe or fulminant
Name 5 investigations which may help in the diagnosis of inflammatory bowel disease
- History and physical examination
- Sigmoidoscopy, colonoscopy
- Stool cultures
- Radiology – radiographic contrast e.g. Barium Enema/Meal, CT scan
Describe the pharmacological management of inflammatory bowel disease
- Corticosteroids e.g. prednisolone, hydrocortisone
- 5-aminosalicylic acid e.g. balsalazide, mesalazine
- Immunosuppressant e.g. azathioprine, 6-mercaptopurine
- Anti- TNF therapies e.g. infliximab
- Antibiotic therapy e.g. metronidazole
In which quadrant is the liver located?
How many lobes does the liver have?
4: right, left, caudate and quadrate
Describe the blood supply of the liver
Portal Vein (75%)
Hepatic Artery (25%)
How does blood leave the liver?
Blood leaves the liver via the hepatic vein, draining into the inferior vena cava
Name the functions of the liver
Excretory/Secretory – bile excretion Protective
Circulatory – large blood storage organ Coagulation – production of clotting factors
What is hepatitis?
inflammation of the liver, caused mainly by various viruses but also by some poisons, autoimmunity or hereditary conditions
What is cirrhosis?
the formation of fibrous tissue in the liver, replacing dead liver cells. The death of the liver cells can for example be caused by viral hepatitis, alcoholism or contact with other liver- toxic chemicals
What is Haemochromatosis?
a hereditary disease causing the accumulation of iron in the body, eventually leading to liver damage
What is Budd-Chiari Syndrome?
obstruction of the hepatic vein
What is Gilbert's Syndrome?
a genetic disorder of bilirubin metabolism, found in about 5% of the population
What is Glycogen storage disease type II?
The build-up of glycogen causes progressive muscle weakness (myopathy) throughout the body and affects various body tissues, particularly in the heart, skeletal muscles, liver and nervous system
What is an acute liver disease?
Acute onset of liver disease with coagulopathy but with no previous evidence of liver disease.
Describe a chronic liver disease
Chronic liver disease tends not to be defined - it is discussed in terms of cirrhosis.
In chronic liver disease - hepatocytes are destroyed faster than they can be regenerated – irreversible
Describe the characteristics of liver cirrhosis
Consequence of chronic liver disease Represents end stage of chronic liver disease
– replacement of liver tissue by fibrotic scar tissue as well as regenerative nodules, leading to progressive loss of liver function.
– the formation of macro- and micro-nodules, affect the structure of the liver and its blood supply.
– These structural changes impede blood flow through the liver, causing portal hypertension (high pressure in the portal vein).
Name some causes of chronic liver disease
Alcoholic liver disease
Chronic Viral Hepatitis
Non-alcoholic Steatohepatitis (obesity, coronary artery disease)
Metabolic causes – for example, Wilson’s disease, genetic Haemochromatosis, alpha1-antitrypsin deficiency
Name some causes of liver cirrhosis
Biliary disease – for example, extrahepatic biliary obstruction, primary biliary cirrhosis, primary sclerosing cholangitis,
Venous outflow obstruction – for example, Budd-Chiari syndrome
Drugs or toxins – for example, methotrexate, amiodarone– Immunological causes – for example, autoimmune disease
What are the signs and symptoms of liver cirrhosis?
Ranges from asymptomatic hepatomegaly to hepatic failure
May be no symptoms until disease is far advanced
- Weight loss, anoxeria
- Weakness, fatigue
- Abdominal pain – epigastric region, dull, aching, sensation of fullness
Name some late manifestations of liver cirrhosis
- Jaundice –hepatocellular
- Ascites – Portosystemic shunts - variceal haemorrhage, haemorrhoids, caput medusae
- Splenomegaly Hepatomegaly
- Fetor hepaticus
- Spider angiomata (spider nevi)
Describe the pathophysiology of portal hypertension