4. Stomach, abdominal wall & hernias Flashcards
Name 2 substances released in the stomach that help prevent ulceration
Mucus
HCO3-
Name 2 substances the stomach releases to break down food & state which cells release these substances
Pepsinogen - chief cells
HCL (activates pro-enzymes) - parietal cells
During the gastric phase, what effect does food entering the stomach have on the production of gastrin & why?
Gastrin production increases when food enters stomach:
Because stomach distension stimulates release of Ach from vagal preganglionic nerve fibres. Stimulates Gastrin releasing hormone, stimulates G cells to release Gastrin
Dietary peptides in stomach lumen also stimulate G cells
Food buffers stomach & acid. pH rises. Releases G cells from inhibition of somatostatin
During intestinal phase, what mechanisms reduce production of Gastrin?
Fall of pH due to unbuffered HCL in stomach stimulates D cells to produce somatostatin
Somatostatin inhibits G cells from producing Gastri
Name 3 things that when detected in duodenum, slow rate of gastric emptying
Fatty acids
Low pH
Hypertonicity
Draw a cross sectional diagram of the anterior abdominal wall
http://thehealthscience.com/showthread.php?844706-Rectus-Sheath-Hematoma
What potential organ damage might occur from a stab wound to the following areas:
Umbilical
Left hypochondrium
Right flank
Small bowel
Small bowel, large bowel, spleen
Large bowel (ascending colon)
What muscle layers would be penetrated if a stab wound occurs either side of the right or left flank?
External oblique
Internal oblique
Transversus abdominus
Name 2 consequences of an abdominal stab wound, other than death
Blood loss = shock
Peritonitis due to blood or gut contents entering peritoneal cavity. Causes irritation (inflammation) of peritoneum & infection (leading to peritonitis)
Discuss the mechanisms of diffuse & localised pain
Diffuse = visceral pain:
Can be linked to embryological foregut, midgut & hindgut structures.
Due to viscera not having dedicated pain fibres; instead use sympathetic afferents.
Pain felt from viscera usually felt in midline and in either:
Epigastrium (foregut)
Umbilicus (midgut)
Suprapubic region (hindgut)
Localised = parietal pain:
Parietal peritoneum stimulated (derived from somatic mesoderm).
Somatic neurones relate pain to dorsal root ganglions in spinal cord.
Pain localised to dermatome nearest to pathological process; more specific than visceral pain
Describe a direct inguinal hernia
Result from weakening in abdominal wall in Hesselbach’s triangle.
Hernia bulges outwards & medial to inferior epigastric vessels.
Pushes into superficial inguinal ring (a further area of weakness)
Describe the boundaries of Hesselbach’s triangle
Rectus abdominus
Inguinal ligament
Inferior epigastric artery
Describe an indirect inguinal hernia
Passes into deep inguinal ring (lateral to inferior epigastric vessels) & into inguinal canal.
Passes through canal or out through superficial ring
Can you easily distinguish the different inguinal hernias in a clinical setting?
No.
2 types of hernias can present in similar ways
Whats the difference between an incarcerated & strangulated hernia
Incarcerated: irreducible
Strangulated: compromised blood supply
Draw a diagram of the femoral canal
https://www.studyblue.com/notes/note/n/lecture-10-antmed-thighknee/deck/1019399
Why is a femoral hernia more likely to be incarcerated than an inguinal hernia?
Femoral canal has a tighter entrance: harder for things to get in, but also more likely for things to get stuck
What are the potential clinical consequences of an incarcerated hernia?
If bowel become herniated, can become obstructed = vomiting (esp small bowel), electrolyte imbalance, perforated bowel, colicky abdo pain.
Herniated tissue may also become strangulated; blood supply compromised = tissue death. High mortality rate
What are the boundaries of an umbilical hernia?
Same as boundaries of the umbilicus:
Gap in linea alba, bounded on either side by rectus abdominus muscles
Explain why an umbilical hernia is commonly seen as a congenital disorder
During embryological dev, midgut herniates out of umbilical ring before returning a few weeks later.
Failure to properly close the defect in abdominal wall provides route for abdominal contents to herniate out through umbilicus.
Mostly resolve in children
Can occur in adults esp if regularly increase intra-abdominal pressure (e.g. Chronic cough, constipation)
Define dyspepsia
Includes a variety of symptoms including:
Upper abdominal pain, heart burn, acid reflux, nausea, vomiting
Define gastro-oesophageal reflux disease
A digestive disorder characterised by Ineffective LOS.
Results in reflux of stomach contents into oesophagus
What is H.Pylori?
A gram negative, helical, aerobic, urease-producing bacteria
A major cause of peptic ulcerations
How does H.Pylori survive the acidic conditions of the stomach?
Using its flagellum & chemotaxis, maintains preferred position within mucus layer of stomach, avoiding more acidic lumen.
Produces enzyme urease: converts urea (found in stomach) to ammonia & CO2.
Ammonia then converts to Ammonium.
Ammonium uses H+ ion to create NH4.
Neutralises acidic conditions surrounding bacteria
