Function of the small and large intestine Flashcards
Why are muscle contractions important?
they mix the content, ensure that the luminal content is in contact with the wall and transports chyme along the tract
What are the two types of contraction?
Segmentation and Peristalsis
How does peristalsis work?
Circular muscle and longitudinal mucle relaxes
Migrating Motility Complex
propulsive movement’s that occur in the inter-digestive period, it sweeps the intestine clean between meals and gets rid of bacteria
How are the movements controlled?
by pacemaker cells (ICC) that are embedded inside neurones- stimuli causes depolarisation that stimulates contraction
What does increased parasympathetic activity do?
Increases contraction strength
What does increased sympathetic activity do?
decreases contraction strength
Small intestine in non-ruminants
digestion of chyme has not proceeded far when it leaves the stomach as most digestion occurs in the SI
What occurs in the small intestine of non-ruminants?
Breaks down Carbs and Protein, if it’s not broken down then it moves to the large intestine for microbial digestion
What structures does the small intestine have to increase surface area?
folds in the inner surface (mucosa), mucosa is also covered in villi, the villi also contain microvilli
What is the structure of enterocytes?
has an Apical membrane: which is in contact with the intestinal lumen,- Tight junctions which connect adjacent enterocytes and a basolateral membrane, which is an extracellular space
Transcellular
Organic nutrients are transported from intestinal lumen to the
interstitial fluid across the enterocytes
Paracellular
Inorganic ions and water can diffuse through tight junctions
connecting enterocytes
Tight junctions
allows the passage of substances from one enterocyte to another easily
How can nutrients be transferred into the lumen
across the apical membrane into the enterocyte, or across/between enterocytes (water and ions)
