WEEK 5 Flashcards

(33 cards)

1
Q

GASTROINTESTINAL SYSTEM

A
  • GI system responsible for breakdown of ingested food, preparing this matter for uptake by body, providing water and eliminating waste
  • The organs are (in the order in which contents passes through them)
    Mouth, Pharynx, Oesophagus, Stomach, Small intestine, Large intestine
  • Accessory organs vital to GI system function→ salivary glands, liver, gallbladder and pancreas
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2
Q

DIGESTIVE FUNCTIONS

A
  • Main digestive processes performed by the digestive system are:
  • Ingestion of food (food enters the lumen of the GI tract, usually via the mouth)
  • Propulsion of food and wastes from the mouth towards the anus
  • Secretion of mucus, water and enzymes
  • Mechanical digestion of food particles (physical breakdown of food into smaller particles)
  • Chemical digestion of food particles (chemical breakdown of food into smaller particles)
  • Absorption of digested food from the gastrointestinal tract into the bloodstream
  • Elimination of waste products by defecation
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3
Q

4 LAYERS OF THE GI TRACT: Serosa

A

Outermost layer of connective tissue that supports the tract

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4
Q

4 LAYERS OF THE GI TRACT: Submucosa

A

Contains connective tissue and larger blood vessels as well as nerves and secretory glands

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5
Q

4 LAYERS OF THE GI TRACT: Mucosa (Made up of 3 layers)

A

Mucous epithelium

  • Simple columnar epithelium, lines the lumen and is therefore in direct contact with food
  • Scattered amongst layer are goblet cells→ secrete mucus that lubricates during food passage

Lamina Propria
- Consists of connective tissue and provides capillaries to the epithelial layer

Muscularis Mucosae
- Contains smooth muscle and sometimes glands

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6
Q

4 LAYERS OF THE GI TRACT: Muscularis (2 layers)

A
  • Inner layer of muscle orientated around the circumference of the tract
  • Outer layer of longitudinal muscle
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7
Q

BILIRUBIN

A
  • By product of broken down RBC→ haemoglobin in RBC breaks into haem and globin→ bilirubin product of haem breakdown
  • Bound to albumin and transported to liver via bloodstream→ then released in bile by liver to intestine
  • In intestine; processed by bacteria converting to urobilirubin (excreted in faeces; gives faeces brown colour)
  • Bilirubin is a pigment; makes bile green/black, large amounts tinges skin and eyes yellow in jaundice
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8
Q

COMMON SYMPTOMS OF GIS DISORDERS:

A
  • Pain → location
  • Loss of appetite/ vomiting
  • Diarrhoea/ Constipation
  • Maldigestion/ Malabsorption → malnutrition
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9
Q

ACID ENVIRONMENT OF STOMACH

A
  • pH = 2
  • Activating pepsinogen
  • Denatures proteins and kills bacteria
  • Gastric mucosal barrier → Protective layer of mucus and bicarbonate
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10
Q

GASTROESOPHAGEAL REFLUX (GERD) DESCRIPTION

A
  • Reflux of chyme from the stomach into the oesophagus

- The oesophageal mucosa is repeatedly exposed to acids and enzymes (pepsin) in the chyme

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11
Q

GASTROESOPHAGEAL REFLUX (GERD) CAUSE

A
  • Increased abdominal pressure→ vomiting, coughing, lifting, bending
  • Delayed gastric emptying→ peptic ulcers, narrowing of pyloric sphincter
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12
Q

GASTROESOPHAGEAL REFLUX (GERD) DIAGNOSIS

A
  • Heartburn→ important differentiating from other causes of chest pain (e.g. MI)
  • Regurgitation of acid chyme
  • Upper abdominal pain within 1 hour of eating
  • Endoscopy
  • Inflammatory responses
  • Oedema, Tissue fragility, Erosion, Fibrosis and thickening may develop→ May develop into reflux esophagitis
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13
Q

GASTROESOPHAGEAL REFLUX (GERD) TREATMENT

A
  • Antacids to neutralise gastric contents (6 weeks)
  • Smooth muscle stimulants to increase rate of gastric emptying
  • Surgery may be necessary to narrow the gastroesophageal sphincter
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14
Q

PEPTIC ULCER DISEASE

A
  • Exposure to acid-pepsin secretions: a break or ulceration in the protective mucosal lining
  • Superficial ulcers (erosion) erode only the mucosa
  • True ulcers erode through the muscularis mucosae, or even deeper into submucosa or muscularis and can
  • Damage blood vessels causing haemorrhage
  • Perforate the gastrointestinal wall
  • 2 common types: duodenal, gastric

Risk factors

  • Long term use of NSAIDs (aspirin, ibuprofen)
  • Helicobacter (H.) pylori infection of the gastric &/or duodenal mucosa- most common
  • Alcohol or Smoking
  • Traumatic events (e.g. burns, stroke)
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15
Q

DUODENAL ULCERS: DESCRIPTION

A
  • The most common type of peptic ulcer→ Most common in men and age group 20-50
  • Primary defect: hypersecretion of acid & pepsin from the stomach
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16
Q

DUODENAL ULCERS: CAUSES

A
  • Infection with H. pylori, can be transmitted from person to person through close contact and exposure to vomit
  • Long term use of NSAIDs
  • Irregular meal pattern
17
Q

DUODENAL ULCERS: SYMPTOMS

A
  • Chronic intermittent pain in the epigastric area
  • Empty stomach pain: 2-3 hours after eating or in the middle of the night
  • “Pain- food relief” pattern: ingestion of food antacids relieves the pain
  • If asymptomatic, the first sign may be a haemorrhage or perforation
  • Bleeding from duodenal ulcers causes haematemesis (brown) or melena (black stool)
  • Often periods of remission followed by exacerbation
18
Q

DUODENAL ULCERS: TREATMENT

A
  • Triple therapy
  • Antibiotics to kill H. pylori
  • Acid suppressors- proton inhibitors
  • Stomach protectors
  • H. pylori can be transmitted from person to person through close contact and exposure to vomit
19
Q

GASTRIC ULCERS (STOMACH ULCERS)

A
  • Primary defect is the increased permeability of the gastric mucosa to hydrogen ions
  • Occurs equally in males and females between 55-65
  • Major causes are the same as duodenal ulcers

Symptoms

  • Epigastric pain occurs immediately after eating
  • Usually chronic
  • Can progress to cancer
20
Q

THE PANCREAS

A
  • Exocrine pancreas→ releases digestive juices through a duct→ to the duodenum
  • Endocrine pancreas→ releases hormones into the blood
21
Q

ACUTE PANCREATITIS: DESCRIPTION

A
  • Life threatening
  • Common cause→ gallstone or beer BBQ (alcohol and fatty food)
  • Sudden and severe inflammatory reaction
  • Escape of activated pancreatic enzymes: autodigestion of the pancreas
22
Q

ACUTE PANCREATITIS: SYMPTOMS

A
  • Severe pain: Upper left abdominal pain ; radiates to the back
  • Inflammation→
  • Fever, nausea and vomiting,
  • Produces large volumes of exudate into abdominal cavity→ hypovolemia→ decreased BP
  • Bleeding
  • Damage to other organs: acute respiratory distress syndrome, acute renal failure, myocardial insufficiency→ multiple organ failure→ death
23
Q

ACUTE PANCREATITIS: TREATMENT

A
  • ICU
  • Pain relief (i.e. opiods, epidural analgesia)
  • Fasting (including fluids) - putting the pancreas to rest
  • IV fluids, electrolytes, colloid solutions, nutrition
  • Antibiotics
24
Q

CHOLELITHIASIS (GALLSTONES)

A
  • Formation of gallstones
  • Abnormality in bile composition
  • Cholesterol - most common
  • Bile supersaturated with cholesterol forms microstones which aggregate
  • Risk factors→ Obesity, middle age, female, starvation, skipping breakfast, rapid weight loss
25
CHOLECYSTITIS
- Inflammation of the gallbladder: cholecystitis- changed absorption characteristics→ excessive water absorption Symptoms - Asymptomatic - Abdominal pain: upper right quadrant or epigastric area - Radiates to the right shoulder, midscapular region, and upper back - Often occurs after a fatty meal: intolerant to fatty food - Belching
26
MALABSORPTION SYNDROMES: DESCRIPTION
- The failure of intestinal mucosa to absorb digested nutrients - Most are a result of maldigestion rather than malabsorption
27
MALABSORPTION SYNDROMES: CAUSE
- Pancreatic insufficiency → Deficiency of pancreatic enzymes which are required for digestion of proteins, carbohydrates and fats
28
MALABSORPTION SYNDROMES: BILE SALT DEFICIENCY
- Bile salts are necessary for emulsification of fats - Conditions that decrease production and secretion of bile result in fat malabsorption - Advanced liver disease - Obstruction of the common bile duct - Intestinal stasis that prevents bile reabsorption
29
MALABSORPTION SYNDROMES: STEATORRHOEA; INCREASED FAT IN THE STOOL
- Excess fat drags fluids, electrolytes and proteins with it into the stool - Bulky extremely foul smelling stools as colon bacteria digest the extra food source
30
MALABSORPTION SYNDROMES: DECREASED LIPID ABSORPTION
- Decreased absorption of fat soluble vitamins and cholesterol - Vit A deficiency- night blindness - Vit D deficiency→ decreased Ca++ absorption (osteoporosis, bone pain) - Vit E deficiency→ slow healing, nerve damage - Vit K deficiency→ easy bruising, decreased clotting - Decreased cholesterol, decreased steroid hormone synthesis
31
VOMITING
- Protective mechanism - A net blood loss of H20: dehydration - Hypovolemia (low plasma in blood volume) - A decrease in BP and blood perfusion in the tissues - A decrease in O2 and other nutrient delivery to cells - A decrease in the removal of CO2 and other wastes from cells - Nerve cells first to be affected by the lack of O2 and the build up of wastes→ Inattention, drowsiness, coma - Eventually all cells are affected A net blood loss of acid (H+) A blood accumulation of HCO3→ acidosis - Nerve function is the first affected - Decrease in enzyme function - Eventually all cell function is compromised leading to death
32
CONSTIPATION
- The GIT flow rate decreases - Increased contact time of the contents with the lumen of the colon→ increased absorption of water and ions→ hard stools - Insufficient intake of fibre or water retaining substances - Weakness of the abdominal muscles: inactivity and bed rest, pregnancy - Decreased parasympathetic nervous system stimulation - Treatment→ relieving the cause→ laxatives and enemas (should not be used at a regular base)
33
DIARRHOEA
- Excessively frequent passage of stools- acute or chronic (>3 weeks in children, 4 weeks in adults) - Large volumes→ painless, water type - Small volume→ colicky pain, urgency - GIT mobility may be increased by: - Osmotic effect of luminal contents (i.e. increased water- retaining substances→ excess fats, salts, dried fruits etc) - Irritants in food, inflammation, microbial growth, or toxins from bacteria