ILA5 Flashcards
Describe the anatomy of the upper GI tract (pharynx, oesophagus, stomach and duodenum) including the course through the thoracic cavity
the oral cavity
2, oropharyngeal cavity. Which contains the palatine tonsil.
The pharyngeal (adenoids) tonsil is in the nasopharynx (extending to the hyoid bone).
larengealpharynx from the hyoid bone to the cricoid cartilage. The larengealpharynx has a piriform recess (a small cavity between the larynx and pharynx).
All muscles of the pharynx are supplied by the vagus nerve but the styloglossal which is supplied by the hypoglossal nerve
All muscles of the larynx are supplied by the recurrent laryngeal nerve apart from the cricothyroid muscle which is supplied by the superior laryngeal nerve.
The oesophagus is divided in to 3 parts depending on what part of the body it is in. they are cervical , thoratic and abdominal
4, The stomach- the stomach is divided into zones based on the type of epithelia that it contains.
5, The duodenum-
The duodenum is split into 4 parts-
What happens in the oral cavity
The first part is the oral cavity where the food is mechanically digested and digestion starts. There is the salivary glands which secrete saliva which contains mucus, enzymes (starch to maltose or dextrin).
Where does the oral cavity lie?
The main oral cavity lies between the hard and soft palate. And the tongue below.
Where does the oropharyngeal cavity lie?
Moving back from the oral cavit
What does the oraphargenal contain
Which contains the palatine tonsil.
What does the nasopharynx contain ?
The pharyngeal (adenoids) tonsil is in the nasopharynx (extending to the hyoid bone).
What is below the oropharynx
Below the oropharynx is the larengealpharynx from the hyoid bone to the cricoid cartilage.
What dopes the larengeal pharynx contain
The larengealpharynx has a piriform recess (a small cavity between the larynx and pharynx). There are many muscles of the pharynx and larynx-
What are the muscles of the pharynx supplied by ?
All muscles of the pharynx are supplied by the vagus nerve but the styloglossal which is supplied by the hypoglossal nerve
Wha are the muyscles of the larynx supplied by ?
All muscles of the larynx are supplied by the recurrent laryngeal nerve apart from the cricothyroid muscle which is supplied by the superior laryngeal nerve.
How many parts is the oesophagus divided into ? what are they called
3, The oesophagus is divided in to 3 parts depending on what part of the body it is in. they are cervical , thoratic and abdominal.
Where do the parts of the oesphagus lie?
It lies onfront of C6 and C7 covered in prevertebral fascia. Behind the trachea.
What structures lie either side of the thoracic oesphagus
There are multiple structures either side of the thoracic oesophagus. On the patients right of the oesophagus lies the thoracic duct which brings lymph from the rest of the body. The vagus nerves and the recurrent laryngeal nerves also travel either side of the oesophagus.
Where does the addominal oesphagsus begin
The abdominal oesophagus begins at T10 when it passes through the diaphragm. Here the vagus nerves become anterior (left) and posterior (right). At the junction with the stomach is the lower esophageal sphincter.
what is the stomach divided into and how?
4, The stomach- the stomach is divided into zones based on the type of epithelia that it contains.
How many layers of muscle does the stomach have?Why?
It has a triple layer of muscle for churning.
What is innervation of the stomanc?
Innervation of the stomach is by both symphatic and parasympathetic fibres. The parasympthatetic fibres are from the vagus nerve and the sympthatetic from the greater splenic nerve.
What does the splenic artery belong to ?
The splenic artery off the celiac trunk
Why is the splenic artery bendy ?
is bendy to slow down the blood before it asomoses.
How many parts is the duodenum divedid into?
5, The duodenum-
The duodenum is split into 4 parts-
What are the four parts of th eduodenum
Superior- this is connected to the underside of the liver (porta hepatis) by a ligament the hepatoduodenal ligament. Which contains the hepatic artery, portal vein and common bile duct.
descending- the head of the pancreas lies in the concavity of the C
inferior-
ascending- this is the junction of the jejunum called the duodenojejunal flexure.
What is the function of the oral cavity
1, oral cavity- begin digestion, chews, mixes and combines with saliva. Increasing SA and also the sense of taste due to taste buds
salivary glands- produce saliva
What is the function of pharynx
pharynx- a flexible tube connecting the oral cavity to the oesophagus carrying food but also air to the trachea.
What is the function of oesphagus
oesophagus- also to carry food to the stomach
What is the function of stomasch
stomach – sterilize foods, start protein digestion, churn the food in to chyme,
What is the function of duodenum superior
duodenum superior part up to joining of the common bile duct- start chemical digestion by enzymes and also start small amounts of absorption.
What is oesphageal motility
oesphageal motility is the contraction of the digestive muscles in sequence causing peristalsis. There fore pushing the food bolus down.
how does gastro motility occur
Gastro motility occurs by the 3 layers of muscle.
Where do the contractions of motility occur?
The contractions begin in the gastric body, but are weak.
Where are the powerful contractions of motility?
The powerful contractions occur in the pylorus antrum.
Wwhat closes to stop release of contents during powerful contractions?
The pyloric sphincter closes to stop the release of the contents.
What cuases churning ?
Antral contents forced against the wall and back causing churning
What is gastro esophageal relux
gastro-esophageal reflux is where stomach acid leaks out of the stomach and into the oesophagus.
What is usually the casue of reflux?
It is usually thought to be a failure of the lower esophageal sphincter that does not fully close.
What happens during relflux?
The acid causes irritation of the oesophagus, which gives a feeling of heart burn.
What is common about reflux and motility
All of the above are rhymic and occur at constant intervals.
What are the pacemakers of the intestine called?
The pacemakers of the intestine are called the interstitial cells of Cajal.
What produces acid in the stomach
this is done by parietal cells.
How does parietal cells produce acidic environemtn
It involves the active pumping of H+ ions in to the lumen of the stomach.
How do the parietal cells pump ?
This is done by a protein pump which exchanges it for potassium using ATP. Cl- ions move into the gastro lumen separately down to ensure the cell stays electrically neutral k+ ions are also pumped out. H+ is gained from the breakdown of water.
What system controls acid prodcution ?
This is controlled by the parasympathetic nervous system
How does the PNS CONTROL acid production
secretes acetylcholine which it’s self activates protein pumps but also causes the release of gastrin which also acts on parietal cells and causes the release of histamine which acts on partial cells. The stomach can also release gastrin,
To turn off this response gastrin secretion is inhibited so also is histamine. Somarostain which inhibits parietal cells.
Also enterogastrones secrete secretin and CCK which inhibit parietal cells, gastrin release and increase somarostain release.
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Describe the defenses of the gastric and duodenal mucosa against acid damage
the stomach defends it’s self by producing an alkaline mucus caused by the release of bicarbonate ions in to the mucus via the mucus cells.
How are mucus cells joined
The cells are joined by tight junctions and old damaged cells are replaced. There is also regulation of the amount of stomach acid.
What is reflux
reflux is- the flowing back of a liquid
What is dyspepsia
dyspepsia is- indigestion (pain and discomfort in the stomach)/ difficulty eating
What are signs of reflux/ dyspepiag
–
Weight loss means organic cause probable
– Heartburn history suggests peptic stricture
– Cough indicates spillover into bronchial tree
– Odynophagia often accompanies dsyphagia in oesophagitis (reflux or infective - candida, herpes) and diffuse oesophageal spasm
– The interval of eating to pain can tell you where a potential problem is
– Type of food (solids, liquids, both) solids are more likely mechanical oesophageal problems where as liquids will usually be pharengeal.
– Pattern(how long has pain been felt) progressive is an organic cause (carcinoma), short indicates malignancy and intermittent indicates dysmotility (problem with muscles of the digestive system)
