Small Intestine Structure and Function Flashcards
What is the approximate length of the small intestine?
- six metres
Name the parts of the small intestine and give their brief function.
- duodenum - gastric acid neutralisation, digestion and iron absorption
- jejunum - nutrient absorption
- ileum - salt and water absorption for chyme dehydration
How is the absorptive surface of the small intestine enhanced?
- folds
- villi
- microvilli
What kind of epithelium covers the villi of the small intestine?
- simple columnar epithelium
What lies in the centre of each villi?
- a lacteal
What lies in between each villi of the small intestine?
- crypts of Leiberkuhn
What does a villus cell absorb?
- NaCl
- monosaccharides
- amino acids
- peptides
- fats
- minerals
- vitamins
- water
What is the function of crypt cells?
- secretion of chloride and water
True or False?
The small intestine secretes approximately 1000ml water per day.
False.
The small intestine secretes approximately 1500ml water per day.
Give four reasons why the secretion of water is important for normal digestive processes.
- maintains lumenal contents in liquid state
- promotes the mixing of nutrients with digestive enzymes
- aids nutrient presentation to the absorbing surface
- dilutes and washes away potentially injurious substances
True or False?
Water the secreted by the crypt cells will be reabsorbed by the villi.
True
Name the two types of movement in intestinal motility.
- segmentation
- peristalsis
When is the most common time for segmentation to occur?
During a meal.
When does peristalsis occur in the small intestine?
- after the absorption of nutrients
What is the movement of boli in the small intestine mediated by?
- neurons in the myenteric plexus
