Histology of Digestive Tract and Regulation of Digestive System Flashcards
What are the major tunics of the digestive tract wall, from inside to outside?
Mucosa, Submucosa, Muscularis and Serosa
Name the three divisions of the autonomic nervous system (ANS).
Enteric NS, Parasympathetic NS and Sympathetic NS
What is the system that is that part of of autonomic nervous system (ANS)? Where is it located? Can it work independently of the ANS?
Enteric Nervous System (ENS). It is located within the walls of the digestive tract. Yes.
What are the functions of the Parasympathetic (Rest-and-digest) NS?
Can increase or decrease ENS activity. Also increases motility, salivary and gastric acid secretions
What is the function of the Sympathetic (Fight and flight) NS?
Decrease motility.
Describe the chemical regulation of the digestive system.
Endocrine secretions:
Endocrine cells secrete hormones like gastrin, secretin and cholecystokinin to help regulate other functions of tract.
What are the main functions of saliva?
Keep oral cavity moist
Salivary amylase - starch splitting enzyme that breaks down 3-5% of carbs
Lingqual lipase - digests small amounts of lipids
What are the protective functions of saliva?
Wash oral cavity
Neutralise acids from bacteria through bicarbonate ions
Prevent bacterial infection through enzyme Lysozome
What are the functions of the uvula and soft palate?
Prevent food from entering Nasopharynx and nasal cavity
What is the function of the epiglottis?
Covers larynx to prevent food from entering respiratory passages
From where does the oesophagus extend to?
Pharynx to stomach
What controls food from entering and exiting the oesophagus?
Upper and Lower Oesophageal sphincters
What are the 3 phases of swallowing in order?
Voluntary phase, Pharyngeal phase and Esophageal phase.
What is the pyloric sphincter and where is it situated?
It is a band of smooth muscle and regulates the release of food from the stomach into the small intestine. It is situated in the stomach between the pylorus and duodenum.
