Alimentary Physiology Flashcards
Name the functions of the digestive system?
Digestion, secretion, absorption and motility
What is the function of the mouth?
Foodstuffs broken down by chewing; saliva used as lubricant
What is the function of the stomach?
Digestion of proteins, foodstuffs reduced to liquid form, storage and sterilisation
What is the function of oesophagus?
Conduit between mouth and stomach
What is the function of the pancreas?
Digestive enzymes for digestion of fats, carbohydrates and proteins
What is the function of the liver?
Produce bile salts for digestion/absorption for fats in small intestine
What is the function of the gallbladder?
Stores and concentrates bile
What is the function of the small intestine?
Final stages of chemical digestion and nutrient absorption
What is the function of the large intestine?
Water absorption, bacterial fermentation and formation of faeces
Describe the structure of the alimentary canal
Continuous hollow tube which runs from oesophagus to rectum
Name the four distinct layers of the alimentary canal
Mucosa, submucosa, muscularis externa and serosa/adventitia
What lies within the mucosal layer of the alimentary canal?
Epithelium, lamina propria, muscularis mucosae
What epithelium lines the mouth, oesophagus and anal canal?
Stratified squamous
What epithelium lines the stomach, small and large intestine?
Simple Columnar
What are the functions of the mucosa of the GI system?
Synthesis and secretions of digestive enzymes, hormones and mucus, absorbs production of digestion
What lies within the lamina propria?
Loose connective tissue (glands, blood/lymph vessels)
What makes up the muscularis mucosae?
Thin smooth muscle layer
What makes up the submucosa?
Thick, irregular connective tissue
What lies within the submucosa?
Contains neurones, blood vessels and lymphatic vessels
Where do submucosal glands lie?
In the oesophagus and the duodenum
What is the function of the outer later of the muscularis externa?
Shortens the tube
What is the function of the inner layer of the muscularis externa?
Constricts the lumen
What is the action of the muscularis externa ?
Produce motility (peristalsis and segmentation)
What lies within the muscularis externa?
Myenteric plexus
What makes up the enteric system ?
The submucosal and myenteric plexus
What nerves provide parasympathetic control to the alimentary system?
Vagus nerve and CNVII, CNIX (salivation)
What does parasympathetic action do to the alimentary system?
Increase secretion and motility
What nerves provide sympathetic innervation to the alimentary system?
Splanchnic nerve
What does the celiac trunk supply?
Stomach, small intestine, pancreas, liver
What does the superior mesenteric artery supply?
Small intestine, caecum, ascending colon, transverse colon
What does the inferior mesenteric artery supply?
Descending colon, sigmoid colon and the rectum
