Lab: The Digestive System Part 3 Flashcards
The organs of the digestive tract are lined with a serous membrane consisting of what 3 parts?
- Superficial mesothelium covering a layer of areolar tissue
- Serosa (aka visceral peritoneum)
covers organs within peritoneal cavity - Parietal peritoneum: (lines inner surfaces of body wall)
What kind of tissue composes the mesentaries?
Areolar Tissue
During embryonic development, the digestive tract and accessory organs are suspended in peritoneal cavity by what 2 things?
Dorsal and Ventral Mesentary
What is the function of the lesser omentum?
- Stabilizes position of stomach
2. Provides route for blood vessels and other structures entering or leaving liver
The Dorsal Mesentery enlarges to form an enormous pouch known as what?
The greater omentum
What is the position of the greater omentum?
Extends inferiorly between:
the body wall and the anterior surface of small intestine
Hangs like an apron:
from lateral and inferior borders of stomach
What is the function of the greater omentum?
- conforms to shapes of surrounding organs
- pads surfaces of abdomen
- insulates
- stores lipid energy reserves
What is the mesocolon?
A mesentery associated with a portion of the large intestine
What are Enteroendocrine cells?
Scattered amongst columnar cells. Secrete hormones coordinate activities of the digestive tract.
What are plicae circulares?
Permanent transverse folds in the digestive tract
What are the longitudinal folds in the digestive tract for, and what happens to them?
- Increase surface area for absorption
2. The folds disappear as digestive tract fills
What is the Muscularis mucosae?
Narrow band of smooth muscle and elastic fibers in lamina propria
How are the smooth muscle cells of the Muscularis mucosae arranged?
- inner concentric layer encircles lumen (circular muscle)
2. outer concentric layer contains longitudinal layer
Which layer of the digestive lining has large blood and lymphatic vessels and may contain exocrine glands?
The submucosa
Which layer of the digestive lining Is made of dense, irregular connective tissue?
The submucosa
What innervates the mucosa and submucosa?
The Submucosal Plexus
What is another name for the plexus of Meissner?
The submucosal plexus
Which layer of the digestive lining is Is dominated by smooth muscle cells arranged in and Inner circular layer and Outer longitudinal layer?
The Muscularis (Externa)
What coordinates the movements of the muscularis?
The enteric nervous system (ENS)
What does the Muscularis do?
- Churns food for mechanical prossessing
2. Moves materials along digestive tract
What regions lack Serosa and instead have adventitia?
Oral cavity, Pharynx, Esophagus, and Rectum
What are pacesetter cells?
Cells in the muscularis that control rhythmic cycles of the digestive tract
What triggers a wave of contraction through the muscularis?
Spotaneous deploraization of the muscle cells
Where are pacesetter cells located?
In the muscularis mucosae and muscularis externa