Prelim | Intestines Flashcards
MEASUREMENT OF SMALL INTESTINE
2.5cm (1”) in diameter
3m (10ft) long
Length of the SI in a cadaver
6.5 m (21 ft)
The SI starts at the (1) until the (2)
- pyloric sphincter
- opening of large intestine
Parts of the SI and their meaurements
Duodenum: 25cm (10in)
Jejenum: 1m (3ft)
Ileum: 2m (6ft)
The ileum joins the large intestine at a smooth muscle sphincter called the —
ileocecal sphincter
Layers of the SI
A. Mucosa
a. Epithelium
b. Lamina Propria
c. Muscularis mucosae
B. Submucosa
C. Muscularis
D. Serosa
Epithelium of the epithelial layer of SI
Simple columnar epithelium
What are found in the SI’s epithelilum?
Absorptive cells
Goblet cells
Paneth cells
Enteroendocrine cells
Contain enzymes that digest food and possess microvilli that absorb nutrients in small intestinal chyme.
Absorptive cells
Cells that produces mucus
Goblet cells
Secrete lysozyme, a bactericidal enzyme, and are capable of phagocytosis.
Paneth cells
Have a role in regulating the microbial population in the small intestine
Paneth cells
Three types of enteroendocrine cells found in the intestinal glands of the small intestine and their functions
S Cells: Secretes secretin (regulates secretion of stomach, liver, and pancreas)
K Cells: Secretes glucose-dependent insulinotropic peptide (regulates glucose)
CCK Cells: Secretes cholecystokinin (stimulates GB)
The lamina propria of the small intestinal mucosa contains (1) and has an abundance of (2)
- areolar connective tissue
- mucosa-associated lymphoid tissue (MALT).
— are most numerous in the distal part of the ileum.
Solitary lymphatic nodules
Groups of lymphatic nodules present in the ileum
Peyer’s patches
The muscularis mucosae of the small intestinal mucosa consists of —
smooth muscle
The submucosa of the duodenum contain which gland? and what is its function?
Brunner’s glands: Secretes an alkaline mucus that helps neutralize gastric acid in the chyme.
What makes up the muscularis of the SI?
Inner circular m and outer longitudinal m
Special structural features of the small intestine which facilitate the process of digestion and absorption
Circular folds/ Plicae circulares
Villi
Microvilli
When viewed through a light microscope, the microvilli are too small to be seen individually; instead they form a fuzzy line, called —, extending into the lumen of the small intestine
brush border
About — of intestinal juice, a clear yellow fluid, is secreted each day
1–2 liters (1–2 qt)
Intestinal juice contains (1) and is slightly alkaline with pH of (2).
- water and mucus
- 7.6
Among the brush-border enzymes are:
4 Carbohydrate-digesting
enzymes
- α-dextrinase
- maltase
- sucrase
- lactase
Protein-digesting enzymes
- peptidases (aminopeptidase and dipeptidase)
2 Types of nucleotide digesting enzymes
- nucleosidases
- phosphatases
The two types of mechanical digestion movements of the small intestine
Segmentations
Migrating motility complex (MMC)