Large Intestine Structure and Function Flashcards
What are the four parts of the large intestine?
Ascending, transverse, descending and sigmoids
What are the two types of muscle in the large intestine?
Circular muscle layer - complete
Longitudinal muscle layer - incomplete (three bands -teniae coli)
What is the role of the large intestine?
Absorption of sodium and water and dehydration of chyme
What is the role of the bacterial colonies in the large intestine?
Fermentation of undigested carbohydrate
Absorption of short chain fatty acids and vitamin K
What is the innervation of the internal anal sphincter?
Autonomic control (smooth muscle)
What is the innervation of the external anal sphincter?
Voluntary control (skeletal muscle)
What nervous system controls the defaecation reflex?
Parasympathetic - via pelvic splanchnic nerves
What is the defaecation reflex?
Contraction of the Rectum
Relaxation of internal and contraction of external sphincters
Increased peristaltic activity in the colon
What are the symptoms associated with constipation?
Headaches, nausea, loss of appetite and abdominal distension
What are the causes of diarrhoea?
Pathogenic bacteria, protozoans, viruses, toxins, food and stress
What effect do enterotoxigenic bacteria have on the intestine?
They produce protein enterotoxins which maximally turns on chloride secretin which increases water secretion
What is the treatment of secretory diarrhoea?
Give sodium/glucose solution and rehydrate - oral rehydration therapy
