Anatomy Of The Digestive System Flashcards
What does the digestive system consist of?
- The gastrointestinal tract
- Accessory organs
- mouth, pharynx, oesophagus, salivary glands
- liver, gallbladder, pancreas
- stomach, small intestine, large intestine
What glands make up the salivary glands?
- Parotid gland
- Sublingual gland
- Submandibular gland
What makes up the large intestine?
- Transverse colon
- Descending colon
- Ascending colon
- Cecum
- Sigmoid colon
- Rectum
- Appendix
- Anal canal
What makes up the small intestine?
- Duodenum
- Jejunum
- Ilium
What makes up / are the sections of the stomach?
- Esophagus = top of tube
- Cardia = below the esophagus
- Fundus = top of stomach
- Body = main bit
- Pyloric antrum = closest to body
- Pyloric canal = after the antrum
- Pylorus = At the end of the canal
- Duodenum connects to bottom of the stomach
Where are sphincters found along the gastrointestinal tract?
- Upper and lower oesophageal sphincters
- Sphincter of Oddi = connected to pancreas and the gallbladder
- Internal & external sphincters at the end of the small intestine
What are sphincters?
- Unitary smooth muscle rings that act as valves, they regulate the movement between segments of the gastrointestinal tract
What are the 4 layers of the gastrointestinal tract wall?
- Mucosa
- Submucosa
- Muscularis Externa
- Serosa
What is the mucosa?
A mucous membrane layer
- surface epithelium
- laminate propria
- muscle layer
What is the submucosa?
A layer of connective tissue
What is the muscularis externa?
Layers of smooth muscle
- longitudinal muscle layer
- circular muscle layer
What is the serosa?
A covering of connective tissue
What is a part of the intrinsic nerve plexuses?
- Myenteric nerve plexus
- Submucosal nerve plexus
What does the mucosa do?
- It has surface epithelium on the mucous membrane
- It has excretory & endocrine secretory cells, transporting epithelial cells & stem cells
- Provides protective, secretory & absorptive functions for the gastrointestinal tract
- Stem cells help produce new epithelium
What does the lamina propria do?
- It is a thin middle layer of connective tissue
- Contains capillaries & lymphatic vessels
- Contains numerous lymph nodules
What does the muscularis mucosa do?
- Thin layer of smooth muscle
- Contractions can alter the surface area for absorption
What does the submucosa do?
- Thick middle layer of connective tissue
- Provides the gastrointestinal wall with distensibility & elasticity, as the nutrient materials move throughout the tract
- Contains larger blood & lymph vessels
- Contains a nerve network, called the submucosal plexus
- Brunner’s glands are found in part of the duodenum
What does the muscularis externa do?
- It is an inner circular layer & outer longitudinal layer of smooth muscle
- Contractions cause mixing & propulsive movements
- Sphincters are formed when the circular layer is thicker
- Myenteric nerve plexus lies between the longitudinal & circular layer
What does the serosa do?
- Connective tissue that surrounds the wall of the gastrointestinal tract
- Secretes a watery fluid that lubricates & prevents friction between gastrointestinal organs
- Offers structural support for the organs, provides the range of movement needed during the digestive process
What is the overall function of the digestive system?
- Moving nutrients from the external environment to the body’s internal environment
What 4 processes occur in the digestive system?
- Motility
- Secretion
- Digestion
- Absorption
