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.
Explain the process of bile secretion?
Chyme stimulates the endocrine cells of the small intestine.
The hormone, cholecystokinin is secreted into the bloodstream.
The hormone travels to the gallbladder and stimulates bile secretion that travels into the small intestine.
What is perforation of the duodenum caused by?
Ulceration of the simple columnar exposes blood vessels, blood vessels can rupture.
If the duodenum is perforated what can that lead to?
Wide spread peritonitis.
Infection of the peritoneum
What is the purpose of the jejunum?
Digestion and absorption.
What is the function of the ileum?
Absorption only.
In the jejunum and the ileum; name the specialisation that increase the surface area.
Transverse folds (can be seen with the eye)
Villi.
Microvilli.
Describe the vasa recta arteries of the jejunum in comparison to that of the ileum.
Jejunum: Longer and straighter.
Ileum: Smaller and more winding.
What are payer’s patches? Where are they found?
An area of inflammatory cells.
Found in the ileum.
What are enterocytes?
Absorptive cells with brush border enzymes/microvilli.
What is Merkel’a diverticulum?
Out pouching of the small intestine.
What is the rule that goes alongside Merkel’s diverticulum?
Rule of 2: Problems occur after the age of 2. 2 Inches long. 2 ft from oleo-caecal valve. 2% of population affected.
When would Merkel’s diverticulum cause problems?
If there are other tissues contained within in. Causes diverticulitis (inflamed pouches)
e.g. acid producing gastric mucosa contained within.
Name the sections of the large intestine?
Caecum, ascending colon, transverse colon, descending colon, sigmoid colon, the rectum.
Where is the connection between the large intestine and the appendix?
The caecum.
What attaches the caecum to the appendix?
The vermiform ligament.
What does the sigmoid pass its contents to?
The rectum.
Name the flexures of the large intestine.
Hepatic flexure (right) and the splenic flexure (left).
Explain the structures on the large intestine
Haustrations: Poches formed by tight circular muscle.
Taenia coli: Longitudinal muscle ONLY ON ONE SIDE.
Epiploic appendices: ‘Fatty tags’ Sections of peritoneum that store fat.
List the differences between the small and large intestine.
Large:
No villi. Has haustrations, taenia coli,
Name the control of both the internal and external sphincter of the anus.
Internal: Involuntary, smooth muscle controlled by the ANS.
External: Voluntary, striated/skeletal muscle.
What treatment is used to investigate problems of the intestines?
Barium meal.
What is located at the junction between the small and large intestine?
Ileo-caecal valve.
What is unique about this valve?
Looks and acts like a valve, however is not.
What is the epithelium of the large intestine?
Simple columnar. (Like small intestine/stomach ) Lots of goblet cells.
What is present in the large intestine that has a minor digestion role and is responsible for some vitamins?
Intestinal bacterial flora.
What vitamins are intestinal flora responsible for? What are their functions?
Vitamin B: Cell metabolism
Vitamin K: Blood clotting
What effect do antibiotics have on the flora? What does this lead to?
Antibiotics alter the flora causing diarrhoea.
What is ‘flatus’?
The gases produced by the respiring intestinal flora.
Segmentation occurs in both the small and large intestine. How does this work?
Circular muscle segments the bolus.
Longitudinal muscle passes the bolus along.
What reflex is triggered in a mass movement?
Gastro-colic reflex: When the digestive process occurs before eating.
What happens locally that leads a mass movement?
Peristalsis leads to mass movement.
List the characteristics of diarrhoea.
Excessively watery stools, more than three time per day.
What can diarrhoea lead to?
Dehydration/loss of electrolytes.
List the characteristics of constipation.
Hard stools that are difficult to pass, less than 3 times per week.
What can cause constipation?
Some drugs.
What is an ileostomy?
Small intestine brought to the surface. Watery faces due to lack of absorption.
What is a colostomy?
Large intestine brought to the surface.
What percentage of the pancreas in endocrine?
1%
What percentage of the pancreas is exocrine?
99%
What is present in the endocrine portion of the pancreas?
Islets of Langerhans.
What cells are produced by the islets of langerhans? What does each cell produce?
Alpha: Glucagon
Beta: Insulin
Delta: Somatostatin
What is produced by the exocrine portion of the pancreas?
Bicarbonate ions passes to the duodenum via the major duodenal papilla (neutralises the acid.) and digestive enzymes.
What cells secrete the enzymes in the exocrine portion?
Acinar cells.
Cystic fibrosis is a multi organ disease; how does this effect the pancreas?
Affects the exocrine portion, no enzymes produced.
How does cystic fibrosis affect the salivary glands?
Makes the secretions much thicker, causes a dry mouth and the optimum pH is not maintained.
Why is pancreatic cancer particularly dangerous?
When tumour is removed pancreas starts auto digestion. Starts to release enzymes that digests itself.
What are the symptoms of pancreatic cancer?
Jaundice and sclera.
Name the 4 secretions of the liver.
Right, left, caudate and quadrate.
What are some functions of the liver? (5)
*** Produces clotting factors. Liver disease patient can bleed out.
Releases glucose when necessary.
Stores excess glucose.
Purifies blood.
Produces bile which is stored in the gallbladder.
Name the ligaments of the liver.
Round ligament, falciform ligament.
What is the function of the ductus venous?
In a baby; Directs blood away from the liver and to the heart.
When is the ductus venous closed?
When the umbilical chord is cut.
What structures produce bile?
Hepatocytes.
What does bile contain?
Contains emulsifiers that break down fat.
Waste products i.e. bilirubin.
What is the purpose of the hepatic portal vein?
Carried blood from the GI tract to the liver.
What does the hepatic portal vein drain?
Unpaired abdominal organs
What is the purpose of the hepatic vein?
Drains deoxygenated blood from the liver to the vena cava
What is the hepatic artery the first branch of?
The abdominal aorta.
What is a portal triad? Where is located?
Portal triad: Hepatic portal vein, hepatic artery and the bile canaliculus (moves bile in the opposite direction)
Portal triad at the edge of the hepatocytes.
What is the clinical term for a larger liver?
Hepatomegaly.
What is the clinical term for liver shrinkage?
Cirrhosis.
What can cause hepatomegaly?
Tumour, blockage.
What can cause cirrhosis?
Alcohol abuse.
What is obstructive jaundice?
A lesion that blocks bile flow, causes back flow into the blood.
What structures are present in the foregut?
Oesophagus, Stomach, (part of) duodenum.
Which artery supplies the foregut?
Coeliac trunk.
What structures are present in the midgut?
(Part of) Duodenum, small intestine, caecum, ascending colon and half of the transverse colon.
Which artery supplies the midgut?
The superior mesenteric artery
What structures are present in the hindgut?
Half of the transverse colon, descending colon, sigmoid, rectum and upper anal canal.
Which artery supplies the handgun?
The inferior mesenteric artery.
With regards to the regions of the abdomen; Name the structure(s) in the r. hypochondrium.
Liver
With regards to the regions of the abdomen; Name the structure(s) in the epigastric region.
Stomach
With regards to the regions of the abdomen; Name the structure(s) in the L. hypochondrium.
Stomach, spleen.
With regards to the regions of the abdomen; Name the structure(s) in the R. lumbar.
Large intestine (ascending)
With regards to the regions of the abdomen; Name the structure(s) in the umbilical region.
Belly button.
With regards to the regions of the abdomen; Name the structure(s) in the L. lumbar.
Large intestine. (descending)
With regards to the regions of the abdomen; Name the structure(s) in the R. iliac fossa.
Appendix
With regards to the regions of the abdomen; Name the structure(s) in the hypogastric/suprapubic region.
Bladder.
With regards to the regions of the abdomen; Name the structure(s) in the L. iliac fossa.
Descending colon/Sigmoid colon.
What tissue/cell types can be present in Merkel’s diverticulum?
Colonic,gastric, pancreatic. Or a mix.
What is the duct from the gallbladder called?
Cystic duct
What is a gallstone?
A crystalline body. Composed of cholesterol, bilirubin and Ca salts.
Name the pancreatic blood supply.
Superior and inferior pancreaticoduodenal arteries.
What is portal hypertension? Why is this dangerous?
Increased pressure in the liver.
Can rupture oesophageal and gastric vessels.
What is the purpose of the falciform ligament of the liver?
Separates left and rigth sections of the liver.
What is the round ligament of the liver?
Remnant of the umbilical vein.
What are the nerve roots for the phrenic nerve? (That innervate the diaphragm)
C3,4,5 keeps the diaphragm alive.
Why does the nerve supply of the diaphragm arise from such a far distance?
Back of the embryo develops faster than the front so it pulls the diaphragm down along with the nerves.
Clinically, what is the jugular notch used to assess?
The position of the trachea/tracheal displacement.
What kind of innervation does the phrenic nerve produce?
Sensory and motor.
Where does the phrenic nerve supply motor function to?
The diaphragm.
Where does the phrenic nerve supply sensory function to?
The pericardium and peritoneum.
