The Alimentary System Flashcards
What are the two groups of organs in the alimentary system?
The digestive tract and the accessory organs.
Name the accessory organs of the alimentary system.
Salivary glands, gallbladder, liver, pancreas.
Where does most of digestion take place?
The stomach and both intestines.
Name the 4 layers of the gastrointestinal system and what their purpose is. (From the shallowest layer to the deepest layer)
Mucosa: Luminal surface, in contact with food and fluids.
3 layers within: Epithelium(glands contained within), lamia proper (connective tissue) and muscularis mucosa (for local movements).
Submucosa: Glands, smaller blood vessels and nerves present.
Muscular externa: Smooth muscle where contractions occur for peristalsis. C.I.L.O.
Adventitia: Major blood vessels and nerves.
Where do the 4 layers run from?
Mouth to anus.
What epithelium is used for protection?
Stratified squamous.
What is metaplasia?
Epithelial tissue’s nature is changed to one that it shouldn’t be.
Name pathologies that involve metaplasia.
Barrett’s oesophagus: Epithelium changes at the junction between the stomach and the oesophagus. Stomach epithelium travels to the oesophagus.
Caused by :
G.O.R.D: Stomach acid enters the oesophagus and alters the epithelium. The metaplasia can lead to dysplasia causing precancerous conditions.
What structures does the stomach have that increases the absorptive surface area?
Villi.
What is coeliac disease?
Loss of grooves on the villi.
A coeliac has atrophy of the villi and hyperplastic crypts.
Name a pathology that only affects the bowel. What is this?
Ulcerative colitis. Breakdown of the tissue in the colon.
Name the pathology of the gastrointestinal tract that results in granulomas forming.
Crohn’s disease.
Name the boundaries of the mouth? (Anterior, lateral, inferior, superior and posterior)
Anterior: Lips. Posterior: Fauces (pillars) Lateral: Cheeks. Superior: Hard palate. Inferior: Mylohyoid and tongue.
Name the 3 salivary glands and the type of secretion they produce.
Parotid: Serous
Sublingual: Mucous.
Submandibular: mixed seromucinous.
What is the virus that attacks the parotid glands?
Mumps.
Name pathologies of the salivary glands. (3)
Sialolithiasis: Calcified saliva forms salivary stones.
Sialadenitis: Inflammation of the salivary glands due to viral/bacterial infection.
Tumours of the salivary glands.
Name the 3 parts of the pharynx.
Nasopharynx: Nose
Oropharynx: Mouth
Laryngopharynx: Throat
Name the sets of tonsils. (4)
Tubal, palatine, pharyngeal (adenoids) and lingual.
What is the purpose of the uvula?
Prevents fluid from entering up the nasopharynx whilst swallowing.
What is the function of the epiglottis?
Acts as a valve, preventing anything from entering the wind pipe.
What is waldeyer’s ring?
Pharyngeal, tubal,lingual and palatine tonsils. Act as the first line of defence from microbes.
Name the boundaries of the laryngopharynx.
Superior: epiglottis.
Inferior: Cricoid cartilage.
What is unique about the cricoid cartilage?
Only entire ring of cartilage in the body.
What hormone causes the voice box to grow outwards during male puberty?
Testosterone.
Name the 3 muscles of the pharynx.
Superior constrictor, middle constrictor and the inferior constrictor.
What is unique about the hyoid bone?
Not attached to any other bone.
What sits more posteriorly in the body; the trachea or the oesophagus?
The oesophagus is posterior to the trachea.
Which oesophageal sphincter is anatomical? Upper or lower?
Upper.
Which oesophageal sphincter is physiological? Upper or lower?
Lower
What epithelium does the oesophagus have?
Stratified squamous non-keratinised epithelium.
What muscle type is in the upper oesophagus?
Skeletal
What muscle type is in the middle oesophagus?
Mixed
What muscle type is in the lower oesophagus?
Smooth muscle
Name the epithelium at the gastro-oesophageal junction.
Stratified squamous to simple columnar (stomach).
What is the clinical term for difficulty when swallowing?
Dysphagia.
Name a developmental abnormality of the oesophagus.
Trachea-oesophageal fistula.
Define fistula.
An abnormal communication between a hollow organ and a body surface or a communication between two hollow organs.
Name the 9 regions of the abdomen.
Right & left hypochondrium Epigastric Right & left lumbar umbilical Right & left iliac fossa suprapubic
Name the sections of the stomach.
Cardia, fundus, body, pylorus and pyloric sphincter.
What is unique about the stomach muscle layers.
Only area to have C.I.L.O and a third oblique layer that ensures churning.
Why are there lots of mucous secreting cells in the gastric pits of the stomach?
So that lots of mucous is produced to protect the stomach from the acid.
What is the function of parietal cells?
To secrete HCL and intrinsic factor. (IF: Binds to b12 aiding absorption.)
What is the function of the endocrine cells?
Secrete gastrin which stimulates the production of HCL.
What is the function of the chief cells?
Convert pepsinogen to pepsin for protein digestion.
Explain the cascade that occurs in the gastric pits.
Endocrine cells activate parietal cells that secrete HCL. HCl activates chief cells. Chief cells convert pepsinogen to pepsin.
In a parietal cell what is exchanged with Cl?
Bicarbonate.
What is oesophageal varices?
Abnormally enlarged veins caused by portal hypertension.
What is collateral circulation?
Alternative circulation via smaller vessels around a blockage.
What can occur if there are problems with the liver?
Blood vomit from a back flow through vessels into the stomach.
What gastric by-pass procedure creates a Y shape?
Roux-en-y
Name the 3 parts of the small intestine.
Duodenum, jejunum and the ileum.
What is unique about the muscles of the pharynx?
EXCEPTION TO C.I.L.O.
Inner is longitudinal and outer is circular.
What lining has the small intestine got?
Partial retroperitoneal.
What is the peritoneum?
A serous membrane that lines the abdominal cavity.
What does the mesentery peritoneum cover?
The liver.
What is the special role of the greater omentum?
It encases infection and keeps it local.
What does the great omentum cover?
The stomach
what part of the small intestine does most of digestion occur in?
The duodenum.
Name the 4 parts of the duodenum.
Ascending, descending, superior and inferior.
What glands does the duodenum have to prevent damage from stomach acid occurring?
Brunners glands, secrete alkaline mucous.
What is the purpose of the sphincter of oddi?
Secretes bile and pancreatic juices into the duodenum.