Small Intestine Structure and Function Flashcards
What is the role of the duodenum?
Gastric acid neutralisation
Digestion
Iron absorption
Name the first part of the small intestine.
Duodenum
What comes after the duodenum?
Jejunum
What is the role of the jejunum?
95% of nutrient absorption
What comes after the jejunum?
Ileum
What is the role of the ileum?
Sodium chloride and water absorption-> chyme dehydration
How is the surface area of the small intestine greater?
Has folds and villi
What do the crypts cells mediate?
Secretory processes
What do the villi cells mediate?
Absorptive processes
What do villi cells absorp?
NaCl
Monosaccharides
Amino acids
Peptides
Fats
Minerals
Vitamins
Water
What does a crypt cell secrete?
Chlorine and water
How much water does the small intestine secrete in a day?
1500ml
What are the two types of movement in the intestine?
Peristalsis
Segmentation
Which type of movement is more common during a meal?
Segmentation
Describe what happens during segmentation.
Contraction and relaxation of short intestinal segments to move food along, allowing mixing and adding of enzymes.
What are the segmental contractions initiated by?
Depolarisation generated by pacemaker cells in the longitudal muscle.
What strengthens the contractions?
The number of action potentials
What happens to the basic electrical rhythm of the intestine as food moves down the intestine?
It decreases
What does increased parasympathetic vagal activity do the BER (basic electrical rhythm)?
It increases the strength of contraction
When does peristalsis take place?
After segmentation stops and nutrients are absorped.
What is the name of the peristalitic wave?
Migrating motility complex
