The GIT part 2 Flashcards
What makes up the foregut
Oesophagus, stomach, duodenum (+liver and pancreas)
What makes up the midgut
Jejunum + ileum + large intestine + appendix
What makes up the hindgut
Rectum + anus
3 constrictor muscles of the pharynx
Superior, middle and inferior - they contract sequentially to propel the bolus towards the oesophagus
What are the 3 pairs of longitudinal muscles
Stylopharyngeus
Palatopharyngeus
Salpinogphayngeus
Type of epithelium in the oesophagus
Non- keratinised stratified squamous
What type of muscle is in the oesophagus
Skeletal muscle 2/3 - allows for conscious swallowing
Smooth muscle 1/3 - unconscious control of passage of food into the stomach
What shape is the stomach
J shaped
Four divisions of the stomach
Cardia - superior opening
Fundus - Rounded portion superior and left ofcardia
Body - Large central portion below fundus
Pylorus - Connects stomach to duodenum (contains pylorus canal, antrum and sphincter)
4 sections of the duodenum
1st superior
2nd descending
3rd inferior
4th ascending
Function of liver
Secretes bile
Neutralises acidic chyme and emulsifies lipids
What are peyer’s patches
Found in ileum
Lymphoid tissue
Function of large intestine
Reabsorption
Function of crypts of lieberkuhns
Provide stem cells for the renewal of the intestinal epithelium - found in the small intestine (produce new cells to replace those lost to abrasion)
Function of brunners glands
Located in submucosa of duodenum
Secrete an alkaline fluid containing mucin - protects the mucosa from the acidic stomach contents entering the duodenum
What are enterocytes
Express catabolic enzymes; role in absorption - absorbing molecules from the gut and transporting them to the inner connective tissue
Function of goblet cells
Secrete mucus
Function of enter- endocrine cells
Gastro-intestinal hormone secretion
Secretin; pancreozymin; enteroglugagon etc. Sensory function – synapsing with afferent nerves
Function of paneth cells
Synthesis of anti- microbial peptides
Function of M (microfold) cells
Antigen presenting cells
Function of the hepatopancreatic sphincter (Also known as the sphincter of oddi)
Controls the passage of bile and pancreatic enzymes into the duodenum - stops them from coming back up
What stimulates bile being released into the duodenum
CCK - Cholecytoskinin
Function of amylase
Breaks starch down into maltose and
What are plicae circulares
Circular folds - found in the jejenum and ileum
What is the ileocaecal valve
A sphincter that regulates the flow of material from the ileum to the large intestine
What shape is the large intestine
Horseshoe shaped
What are haustra
Pouches formed by the large intestine in the wall
Function of sigmoid colon
Empties content into the rectum
What are the vitamins synthesised by the intestinal bacteria (large intestine)
Vitamin k - clotting
Biotin - glucose metabolism
Pantothenic acid - vitamin B5
What is bilirubin converted to in the large intestine
Bacteria convert bilirubin (what is made after red blood cells die) to urobilinogens and stercobilinogens
What type of epithelium is the anus lined by
Keratinised epithelium
Disorders of the small intestine
Ulcers Coeliac disease - gluten enteropahy Cancer Inflammatory bowel disease Infections
Function of glycocalyx cells in the small intestine
Lubrication
Optimum pH of amylase
5.6-6.9
