Class notes
GI & Metabolism (BS)
- Course
- Institution
Body Systems STRAND 3 - GI & metabolic medicine and abdominal anatomy
[Show more]
3 reviews
By: cristianlungu • 2 year ago
By: madoulami • 2 year ago
By: niamhmillar • 2 year ago
Seller
Follow
medicsummaries
Reviews received
Content preview
BODY SYSTEMSGI & METABOLISM
,Medic_Summaries (Body Systems)
GI & Metabolism Strand
Burden of GI illness:
- GI diseases affect huge numbers of people worldwide
- Symptoms referable to the GIT are common
Major functions of GIT:
- Motility (peristalsis):
- Smooth muscle contraction
- Co-ordinated to move bolus forwards
- Need relaxation of sphincters
- Digestion
- Secretion
- Absorption
Organs of the GIT:
- Stomach:
- Storage vessel
- Churns food
- Produces acid to start breakdown
- Pancreas:
- Exocrine secretions aid digestion:
- Discharge into intestine via pancreatic duct (amylase, lipase, trypsin)
- Need basic medium for efficiency, so pancreas also produces bicarbonate
- Endocrine secretions regulate carbohydrate metabolism:
- Glucagon, insulin, gastrin, somatostatin
- Liver:
- Synthesises bile (stored in gall bladder), proteins (clotting factors)
- Metabolises carbohydrates, proteins, fats
- Stores carbohydrates, fat-soluble vitamins
- Detoxifies blood from GIT
- Intestine:
- Small: major role in absorption, mostly jejunum (impossible to survive without it)
- Large: major role in water absorption (possible to survive without it)
2 Adapted from Lectures at the University of Leeds Medical School
,Medic_Summaries (Body Systems)
Diseases of the GIT:
- Oral:
- Mucous membrane (Apathy’s ulcers)
- Anywhere (cancer)
- Salivary glands (inflammation, stones, cancer)
- Oesophagus:
- Reflux symptoms (oesophagus, Hiatus hernia)
- Cancer (squamous (middle), Aden (lower))
- Motility problems (achalasia (failure to open lower sphincter when swallowing))
- Stomach:
- Ulcers (Helicobacter pylori (H. Pylori), aspirin/NSAIDs)
- Cancer (H. Pylori)
- Pyloric stenosis due to ulceration
- Duodenum:
- Ulcers (H. pylori, aspirin/NSAIDs)
- Rarely, invasion by cancer from the pancreas
- Liver:
- Viral hepatitis (acute (any), chronic (HBV, HCV))
- Autoimmune hepatitis, primary biliary cirrhosis
- Cirrhosis (caused by chronic liver inflammation of any aetiology, alcoholic liver
disease, fatty liver, viral or autoimmune liver disease)
- Biliary tree:
- Gallstones (often silent)
- Present with biliary colic, cholecystitis, cholangitis, biliary obstruction
- Pancreas:
- Acute pancreatitis (gallstones, alcohol)
- Chronic pancreatitis (usually from repeated attacks of acute pancreatitis)
- Pancreatic cancer
- Small intestine:
- Crohn’s disease or Meckel’s diverticulum
- Small bowel obstruction
- Acute ischaemia (may lead to large resection)
- Large intestine:
- Appendicitis
- Cancer
- Ulcerative colitis or Crohn’s disease
- Diverticular disease (often silent, can inflame (diverticulitis), perforate or bleed)
Symptoms of GI disease:
- Dysphagia/odynophagia (difficulty/pain in swallowing)
- Nausea/vomiting (feeling of/act of being sick)
- Dyspepsia (feeling of early fullness/discomfort after eating normal-sized meal)
- Heartburn (regurgitation of acid causing a burning sensation)
- Bloating (sensation of abdominal swelling or visible distension of abdomen)
- Abdominal pain
- Diarrhoea (three or more liquid stools per day)
- Constipation (fewer than three stools per week; often straining and incomplete evacuation)
- Steatorrhoea (bulky, fatty, pale stools; difficult to flush)
- Haematochezia/malaena (passage of bright red blood, black and sticky stools)
Healthy diet supplies:
- Energy
- Building blocks for metabolism
- Essential nutrients
Guidelines for nutritional requirements:
- Energy balance key to maintenance of healthy weight, ideally: INTAKE = EXPENDITURE
- Energy expenditure depends on metabolic rate
- Metabolic rate depends on age, weight, sex, amount/intensity of physical activity
3 Adapted from Lectures at the University of Leeds Medical School
, Medic_Summaries (Body Systems)
Macronutrients:
- Can be used immediately for energy generation
- Excess carbohydrates and fats can be stored
- Fat stores are the main source of energy (80-90%)
- No storage of protein, but in starvation, muscle tissue can be metabolised for energy or to
provide amino acids for other reactions
Protein:
- Average adult requires ca. 0.75g/kg/day (eg. 75kg man requires ca. 50g protein/day)
- Athletes/body builders often recommended 1.2-1.7g/kg/day
- Proteins are constantly being synthesised and degraded (average 250g/day)
- Individual proteins vary in rate of turnover from minutes to years
Nitrogen balance:
- Healthy adult:
- N2 intake = N2 excretion
- Negative nitrogen balance:
- N2 intake < N2 excretion
- Occurs during fasting or illness
- Body is breaking down proteins for energy
- Positive nitrogen balance:
- N2 intake > N2 excretion
- Occurs during growth or pregnancy
- Body is building new tissue
Essential amino acids:
- Nine AAs cannot be synthesised by humans (must be obtained from diet)
- Other AAs may be required in diet under certain conditions
- Essential AAs: Met, Val, His, Leu, Phe, Trp, Iso, Lys, Thr
Problem for vegetarians?:
- Not all sources of protein contain the complete range of amino acids
- Animal proteins are complete, but plant proteins generally are not
- CYSTEINE, METHIONINE and TRYPTOPHAN most commonly lacking in plant proteins
- A good source of these amino acids include beans, rice, nuts and corn
We need lipids:
- Triacylglycerols for energy (1g fat provides 9kcal (39kJ))
- Carbohydrate and protein only provide 4kcal (17kJ)
- Cholesterol/fatty acids as precursors for important molecules (hormones, prostaglandins)
- The body can store unlimited amounts of triacylglycerol in adipose tissue
- Adipose tissue protects vital organs and gives our body and face shape
Fat in the diet:
- Saturated: no double-bonds; found in meat/dairy products (RDI: 10%)
- Mono-unsaturated: one double-bond; found in olive/peanut oil (RDI: 12%)
- Polyunsaturated: more than one double-bond; found in corn/sunflower oil (RDI: 6%)
- Trans (hydrogenated): trans double-bonds, found in cakes/biscuits/pastry (RDI: <2%)
- Total fat RDI: <35%, though <30% is desirable
Carbohydrates:
- Polysaccharides (mainly starch)
- Disaccharides (mainly sucrose)
- Monosaccharides (mainly glucose/fructose)
- Non-starch polysaccharides (dietary fibre)
4 Adapted from Lectures at the University of Leeds Medical School
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller medicsummaries. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.31. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
84866 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now