Functional Histology of the Gut Flashcards
(51 cards)
What structures does the oral cavity consist of?
salivary glands and teeth
What is the function of the oral cavity and what type of epithelia is present?
ingestion, fragmentation and has stratified squamous epithelium
What do the simple passages of the alimentary tract consist of, what’s their function and what type of epithelium is present?
Oesophagus and anus, involved in transport of food and waste and has stratified squamous epithelium
What does the main body of the digestive tract consist of, and what is it’s function?
stomach, intestines and glands which are involved in digestion and absorption
What type of epithelium is present in the stomach?
simple columnar epithelia
What type of epithelium is present in the small intestine?
simple columnar of villi
Name the 4 components of nutrient absorption and elimination
fragmentation, digestion, absorption and elimination
Describe ‘fragmentation’
where food is chewed and broken down by enzymes in the oral cavity using saliva containing amylase
Describe ‘digestion’
where food is broken down by enzymes in the stomach and duodenum
Describe ‘absorption’
where enterocytes absorb nutrients and capillaries and lacteals transport these nutrients from the mucosa
Describe ‘elimination’
liquid residue is passed to the colon where water is absorbed from it and solid faeces is expelled through the anal canal
Outline the structures that food passes through after it is ingested
mouth, oropharynx, oesophagus, stomach, duodenum, jejunum, ileum, large intenstine, anus
What are the four basic layers of the wall of the alimentary tract?
1) mucosa
2) submucosa
3) muscularis propria
4) serosa/adventitia
Describe the mucosa of the gut wall
consists of a lumen, epithelium, lamina propria and muscularis mucosae and varies with region and function
Describe the submucosa of the gut wall
this is a thicker layer of fibrocollaginous tissue which carries vessels and nerves as well as the submucosal neural plexus
Describe the muscularis propria of the gut wall
this consists of two layers; an inner circular layer and an outer longitudinal layer
Describe the adventitia/serosa of the gut wall
the most external part of the gut wall
When is the outside called the adventitia?
where the gut is retroperitoneal it is called adventitia, is referred to as serosa when intraperitoneal
Describe what is meant by the enteric nervous system
consists of autonomic functioning ganglia with inputs from the parasympathetic and sympathetic nervous systems
What does the submucosal plexus innervate?
muscularis mucosae and mucosal glands
What does the myenteric plexus innervate?
muscularis propria (inner circular and outer longitudinal layers)
Define ‘MALT’
mucosa associated lymphoid tissue
Define ‘GALT’
gut associated lymphoid tissue
Name four characteristics that prevent gastroesophageal reflux
the oesophagus joins the stomach at an acute angle (at the cardia), the contracn of the diaphragm on the oesophagus prevents reflux, intra-abdominal pressure on the oesophagus at rest prevents reflux, there is unidirectional peristalsis
