Alimentary System Flashcards
Name the 3 divisions of the pharynx
Nasopharynx, Oropharynx, Laryngopharynx
What is the nerve supply to the pharynx?
Motor - Vagus nerve, CNX
Sensory - Glossopharyngeal, CNIX
What makes up Waldeyer’s Ring?
Adenoid tonsils, tubal tonsils and palatine tonsils
Where can elastic cartilage be found?
Epiglottis
What is the role of the epiglottis?
To move down when swallowing, ensuring no food enters the trachea, only enters the oesophagus
What epithelium is in the oesophagus?
non-keratinised, stratified squamous epithelium
What is Barrett’s Oesophagus?
After GORD, the epithelium of the oesophagus is destroyed, and repairs as simple columnar epi.
Describe the musculature of the oesophagus?
At the top - skeletal, under conscious control
In the middle - mix of skeletal and smooth, transition
At the bottom - Smooth muscle, peristalsis involuntary
What problems are associated with TOF?
tracheal-oesophageal fistula - regurgitation and chest infections
What compartment of the abdomen is the stomach found?
Epiglottis and left hypochondrium
What is the main function of the stomach?
Digestion and churning of food to make chyme
What organ has an extra layer of muscle?
stomach - oblique layer
What does the chief cells of the stomach secrete?
Pepsinogen
What does the parietal cells of the stomach secrete?
HCl
What does the endocrine cells of the stomach secrete?
Gastrin
How is HCl secreted into the lumen of the stomach?
parietal cells take CO2 from blood - use carbonic anhydrase to combine with H2O to produce carbonic acid - H then taken from this and Cl taken from blood
Where does the greater omentum extend from?
the greater curvature of the stomach
What is the blood supply of the stomach?
R. Gastric artery - common hepatic artery
L. Gastric artery - coeliac trunk
R. & L. Gastroepiploitic arteries - gastroduodenal artery
what are oesophageal varices and how do they occur?
increased pressure in liver (portal hypertension) is spread throughout collateral system around the oesophageal and gastric arteries
What is the ucinate process?
An extension of the head of the pancreas, lies behind blood vessels
what type of cells release digestion enzymes in the pancreas?
exocrine cells - acinus
what type of cells release insulin?
beta cells in the islets of langerhans
How can cystic fibrosis effect the pancreas?
It causes very thick mucous secretions, resulting in a blockage of the pancreatic duct. Therefore, digestive enzymes cannot get into the duodenum and digestion is reduced, meaning absorption is reduced. malabsorption can be associated with steatorrhea
List 5 roles of the liver
Protein synthesis, bile synthesis, glycogen storage, glucose release, detoxification, metabolism
What is contained in the portal triad?
Hepatic artery, hepatic portal vein, bile duct
What is a sinusoid?
A large blood vessel, allows the mixing of hepatic artery and hepatic portal vein in the hepatocyte
What blood vessels drain into the hepatic portal vein?
Splenic vein, inferior and superior mesenteric vein
What is in bile?
Fat emulsifiers and bilirubin
What is the role of the gallbladder?
To store and concentrate bile
What are the lobes of the liver?
Right, left, caudate and quadrate
What is the ductus venosus?
A blood vessel in fetus, shunting blood past liver and straight to heart. After birth, want blood to go through the liver so this is closed off and forms the falciform and round ligament.
What is the role of the greater omentum?
To move around the abdomen, searching for pathologies. If one is found, the omentum wraps around this and prevents it from spreading or perforating.
What do brunners glands secrete and where can they be found?
They secrete an alkaline fluid into the duodenum, to neutralise the stomach acid
Name 4 things secreted into the duodenum.
Pancreatic juice, bile, chyme, alkaline fluid
Where is the sphincter of oddi?
At the major duodenal papilla, controlling the release of pancreatic juice and bile
What is the blood supply of the duodenum?
superior and inferior pancreaticoduodenal artery - superior from hepatic, inferior form superior mesenteric
What major blood vessels are located near the duodenum?
Inferior vena cava and superior mesenteric artery
What is the role of the muscularis mucosae in the jejenum and ileum
To direct the absorbed nutrients from the lumen to the submucosa
How many surface specialisations can be found on the jejenum and ileum and what are they.
3 - transverse folds, villi and microvilli
How can surface specialisations be damaged and what happens when they are
Certain food intolerances can destroy or damage villi and microvilli, as well as infections. When this occurs, nutrients cannot be absorbed and bloating can be seen. However, if the patient stops eating the food or the infection passes, the villi and microvilli will regrow
What are peyer’s patches and where can they be found
collection of lymphoid tissue for infection, found only in the ileum
What are enterocytes and where can they be found?
These are epithelial cells containing brush border enzymes for digestion, found in jejneum
What is the difference in vasa recta between jejenum and ileum
in ileum they are shorter and there is many more - more absorption so needs bigger blood supply
What is the caecum?
Meeting point between small and large intestine
What disease follows the rule of 2’s and what is this?
Merkel’s diverticulum, an out-pouching of mucosa, 2 feet from ileo-caecal valve, 2 inches in length, in 2% of population and presents after 2 y.o.
What problems are associated with merkel’s diverticulum?
If the mucosa is gastric, this will produce acid, which can destroy the lining of nearby ileum, which could result in perforation or peritonitis
How can dietary deficiencies affect the oral mucosa?
Malabsorption can lead to anaemia - lack of red blood cells. This can lead to gingivitis or oral ulcers
In which ways is the large intestine similar small intestine?
Has intestinal crypts, has simple columnar epithelium and has goblet cells and mucosal glands
In which ways is the large intestine different to the small intestine?
Has taenia coli, appendices epiploicae and haustra
What is the function of the large intestine?
reabsorption of water and electrolytes (bicarbonate, sodium, potassium and chloride)
What does the micro-flora in the large intestine do?
Ferments dietary fibre, produces gases and produces vitamins B and K
What musculature makes up the external sphincter of the anus and what nerves supply this?
striated muscle - voluntary control, sacral nerves 2, 3 and 4
When are mass movements used and what do they do?
As food enters stomach the gastro-colic reflex, food enters stomach and stimulates the mass movements in large intestine. This breaks up the chyme and moves it from proximal to distal colon. Distends the rectum to prepare it for expulsion
What is the barium drink?
When a patient swallows the barium so the colon can be seen, if there is any blockages, it wont pass through
When is a colostomy bag used?
If a patient has a tumour at the sigmoid colon or rectum area, this is removed. While it heals, the descending colon is passed through the abdomen to empty into a bag.
