Chapter 24- The Digestive System Flashcards
What are the functions of the digestive system
Ingestion Mechanical processing Digestion Secretion Absorption Excretion
Mesentaries
- Double sheets of serous membranes.
- Support portions of the digestive tract.
- Access route for vessels and nerves.
- Padding, protection, insulation, energy storage
Falciform ligament
Between the liver and body wall
Lesser omentum
- sickle shape (crescent)
- between the stomach and liver
Greater omentum
- from stomach to transverse colon
- fatty apron (“beer gut”)
Mesentery
- “proper”
- to small intestine
Mesenteries to the colon
Transverse Mesocolon
Sigmoid mesocolon
Mesocolon
-to remainder of large intestine
Retroperitoneal organs
- behind the peritoneal cavity
- duodenum (first part of small intestine)
- ascending/descending colon
- rectum
- kidneys
Mucosa
- inside, moistened by glandular secretions
- epithelium and lamina propria (loose CT)
- smooth muscle as muscularis mucosae
Submucosa
Dense irregular connective tissue
Muscularis externa
Smooth muscle-circular/longitudinal layers
Serosa
Serous membrane (wet, lubricated; surround organs)
Adventitia
Dense connective tissue
In oral cavity, pharynx, esophagus and rectum
Movement of digestive materials
- Rhythmic contractions
- Peristalsis
- Segmentation
Rhythmic contractions
Pacemaker cells
Peristalsis
Waves that move a bolus
Segmentation
(Squeeze food so it gets infiltrated by digestion fluids)
Churn and fragment a bolus
Enteric nervous system
- stretch receptors and chemoreceptors (detects chemicals in food)
- parasympathetic and local reflexes
- myenteric plexus (muscularis externa)
- submucosal plexus
Hormonal mechanisms
- Enteroendocrine cells
- Feedback through bloodstream