Week 1 GI lectures Flashcards
What is enteropathy?
Damage to the small bowel
With what condition in young women should coeliac disease be checked for?
Iron deficiency
What is TTG?
Tissue Transglutaminase
What grains contain gluten?
Wheat, rye, barley and oats
What is necessary but not sufficient for coeliac disease?
DQ2/8
If you don’t have DQ2/8 can you have coeliac disease?
no
Are people with coeliac disease born with it?
No - there is a genetic disposition but to develop the disease you must be exposed to gluten (needs a trigger)
What are the GI symptoms of coeliac disease?
Diarrhea, indigestion, constipation, vomiting, chronic abdo pain, weight loss, anorexia, inadequate growth in children
What other symptoms (non-GI) does coeliac disease cause?
- bone symptoms
- iron deficiency
- hepatitis
- neuro symptoms (anxiety, depression, cerebellar ataxia, chronic fatigue, epilepsy and seizures)
What should be done when it is suspected that a patient has coeliac disease?
A duodenal biopsy
What are the muscular layers of the digestive tract wall?
Outer longitudinal and inner circular
How is the function of the smooth muscle in the digestive tract wall controlled?
The interstitial cells of Cajal
How do the interstitial cells of Cajal control the smooth muscle in the digestive tract?
They set the basal electrical rhythm (BER) - create action potential Ca2+ influx K+ efflux
What is the function of the intrinsic - myenteric/submucosal nerve plexus?
Controls all facets of the GI tract
What nerve supplies fibres to the myenteric/submucosal nerve plexus?
Sympathetic and parasympathetic fibres of the vagus nerve
What is the function of the extrinsic nerve plexus?
Modifies the intrinsic pathways
What situation does parasympathetic innervation predominate in?
Relaxed situations
What substance promotes excitation (contraction) in the digestive tract wall?
Acetyl choline
What substances promote relaxation in the digestive tract wall?
VIP and nitric oxide
Are the muscles of mastication under voluntary or involuntary control?
Voluntary (skeletal muscle)
What secretions occur in the mouth?
Saliva
What is the function of saliva?
- Lubrication for swallowing (and speech)
- Antibacterial - lysozyme, thiocyanate
- Amylase (carbohydrate digestion)
What digestion begins in the mouth?
Complex carbohydrate digestion (starch - plants, and glycogen - animals)
How does the digestion of complex carbohydrates begin in the mouth?
Amylase breaks alpha1,4 linkage - hydrolyses into a mixture of maltose and glucose