CSB520 Lecture Notes - Lecture 11: Abdominal Pain, Low-Density Lipoprotein, Bile Acid
Week 11 - Gastrointestinal
Tuesday, 7 June 2016 11:22 AM
•GIT
○Mouth-pharynx
○Oesophagus
○Stomach
○Small Intestine
○Large Intestine
○Angus
•Liver
•Pancreas
•Cancers
•Acute inflammation
•Chronic inflammation
•Immune disorders
•Haemodynamic
PathologyPathology
•Obstruction
○Scar tissue
○Stone
○Cancer
•Loss of function
○Paralysis
○Loss of cells
•Infection
•Ulceration
•Autoimmune
•Toxic
•Malabsorption
○Carbohydrates
○Lipids
○Proteins
○Vitamins
•Diarrhoea (indicates malabsorption)
•Gas
•Blood (there shouldn't be any)
○Haematemesis (in saliva)
○Haematochezia (in faeces/red)
○Melena (black)
•Structure of The Tube - the same from mouth to anus, just
altered epithelial cells
○Serosa (outer layer)
○Longitudinal muscle/circular muscle
•2 layers for constant peristalsis
○Submucosa
○Mucosal muscle
○Mucosa
○Epithelial lining
○Lymphoid tissue
○Mucosal gland
○Submucosal gland
○Mesentry
PeristalsisPeristalsis
•Being mixed and pushed along
○Circular + longitudinal
StomachStomach
•Chief cells make pepsinogen
•Low pH acid, pepsin breaking down proteins
•Mixing food
Small Intestine: Increase in Surface AreaSmall Intestine: Increase in Surface Area
•Cyclindrical
•Plicae circulares - x3
•Villi - x10
•Microvilli - x20
•Factor increase - x600
Normal Pancreas & LiverNormal Pancreas & Liver
•Bile has 2 functions - getting rid of waste (cholesterol, etc.)
and important for fat absorption
•Bile emulsifies which allows lipases to work more effectively
•Pancrease makes bicarbonate & digestive enzymes - breaking
down carbs, fats & protein
○So if there is a problem with the pancreas -
malabsorption
Vitamin B12 CyanocobalaminVitamin B12 Cyanocobalamin
•Animal products
•B12 complex
•Heat stable
•Inactivated by light & extreme pH
•Intrinsic factor transport across epithelium
•Stored in liver
•Co-enzyme
Large IntestineLarge Intestine
•Single layer of columnar cells
•Absorb a lot of water & ions from faeces
•Because faeces are getting increasingly hard, we need
lubrication - goblet cells produce mucous
Functional HistologyFunctional Histology
•Oral cavity - stratified squamous epithelium
•Oesophagus - tube with non-keratinising stratified squamous
epithelium
•Stomach - gastric pits & gastric glands
•Small intestine - single surface with microvilli, greatly
increasing surface area
•Large intestine - epithelium composed of columnar &
prominent goblet cells
○Straight tubular glands run from surface to the
muscularis mucosae
•Anus
TermsTerms
•Herniation
•Adhesions
•Intussception
•Volvulus
Vascular DisordersVascular Disorders
•Ischaemic Bowel disease
○Affected region depends on occluded vessel
○Acute occlusion of 1 of 3 major arterial supplies may
lead to infarction of several metres of the bowel
•Celiac
•Superior mesenteric
•Inferior mesenteric
○Severity
•Transmural infarction (across the wall)
•Major vessel compromise
•Mural infarction (in the wall)
•Chronic/acute hypoperfusion
•Mucosal infarction (superficial)
•Chronic/acute hypoperfusion
StomachStomach
•Acute gastritis
○Acute, usually transient, mucosal inflammation
○Common causes:
•Chronic, heavy NSAIDs
•Excessive alcohol
•Heavy smoking
