Pharm large int Flashcards
length + diameter colon?
1.5m, 6cm
How long does it take for material to pass through large intestine?
18-24hrs
Fluid reabsorption takes place in the?
Ascending colon, transverse colon
Final “dryging” dessication and storgae takes place in the?
descending colon, sigmoid colon
bacterial fermentation takes place in the
Ascending colon, transverse colon
What is the gastroileal reflex?
peristalsis in the ileum
opening of the ileocecal valve
produces urge to defecate
T/F
Ileocaecal sphincter acts as a ‘one way valve’
T
Gastroileal reflec under control of?
Vagus nerve
sympathetic nerves
enteric neurones
Gastroileal reflec stimulated by?
gastric distension
Major function of LI?
- Fluid reabsorption: H20, Na+, Cl-
- Secretion: K+, HCO3-, mucus
- Absorption of short chain fatty acids
- Sotrage colonic contents
- eliminate faeces
Secretion of bicarbonate serves to
neutralise acid produced by bacterial fermentation
Large I motility consists of?
Mass movements
Haustrations
Defecation reflex
Mass movements triggered by
meal - gastrocolic reflex
Haustration is
non propulsive segmentation caused by contraction of cricular muscle
allows time for reabsorption
How does the defecation reflex start?
- mass movement fills rectum with poop
- this activates rectal stretch receptors
pelvic stretch receptors activate which nerve?
PELVIC
Pelvic nerves leads to activation of which afferents?
- afferents to spinal cord which activates Parasympathetic efferents
- afferents to brain (urge to poop) leads to efferents to spinal cord
efferents to spinal cords stimulate?
contraction of skeletal muscle of EXTERNAL sphincter
Parasympathetic efferents stimulate?
contraction smooth muscle in colon and rectum. INTERNAL ANAL SPHINCTER relaxes
causes EITHER
- contraction or RELAXATIONof skeletal muscle of EXTERNAL sphincter
RELAXATIONof skeletal muscle of EXTERNAL sphincter leads to
defaecation assisted by abdominal contraction and expiration against closed glottis
contraction of skeletal muscle of EXTERNAL sphincter leads to
defaecation delayed, rectal wall gradually relax
Colonic bacteria synthesise _____ and _____ from carbohydrates
Vitamin K2, free fatty acids
5ASA work by?
Inhibit cyclooxygenase and lipooxygenase - Less prostaglandins - Neutrophils TNFa -superoxide generation reduce inflammation
sulfaslazine is a ?
5aminosalicylic acid with a sulfpyridine bonc
breaks down in colon
