small intestine structure and function Flashcards
Why is the jejunum empty when we are not eating
Jejunum is absorpative and not for storing
What is the function of the duodenum
Gastric acid neutralisation, digestion and iron absorption
What is the function of the jejunum
Nutrient absorption
What is the function of the ileum
NaCl/H20 absorption
What is the function of crypt cells
Secrete Cl and water
What is the function of villi
Absorbs:
NaCl
Monosaccharides
Amino acids
Peptides
Fats
Vitamins
Minerals
Water
Describe segmentation of the small intestine
During a meal:
Contraction and relaxation of short intestinal segments
Contraction in different areas of the intestine moves the chyme up and down
What generates segmentation contractions in the small intestine
Pacemaker cells in longitudinal muscle cells
Intestinal basic electrical rhythm
What determines the strength of the segmental contraction
Frequency of action potentials
How does more material go down the small intestine than up
the basic electrical rhythm which controls the frequency of the segmental contractions decreases as you go down so there are less contractions further down the small intestine which results in material always going down more than coming up
After absorption of nutrients what happens after segmentation
Peristalsis
What is a migrating motility complex
Pattern of peristaltic activity travelling down small intestine - as one ends another begins
What ends the migrating motility complex
Food arrival at the stomach which initiates the segmentation
