Digestive System Flashcards
Remember
In the vascular system, the alpha 1 receptors cause constriction
In the GI tract, they cause paralysis
Stylopharyngeal muscle
Elevated pharynx and larynx
Innervation: Glossopharyngeal nerve
Gingivitis
Gingiva = gums
-itis = inflammation
Periodontitis can occur if gingivitis is not treated
Periodontitis
Peri = around
don = tooth
-itis = inflammtion
Inflammation and destruction of structures around the teeth
or
Inflammation in periodontal ligament, alveolar bone, cementum of teeth
What is the hardest substance in the human body?
Enamel
Herpes simplex virus
Some people have symptoms and some not
Mouth and genitals are areas affected
Two types: HSV1 and HSV2
HSV1 affects the mouth usually and HSV2 affects below the waist usually
Herpes virus very typically settles inside the ganglia of the face and close to the genitals for LIFE!
Oral and genital herpes
Primary infection is often asymptomatic
When it does cause symptoms:
- Usually affects children
- Causes lesions, with fever and enlarged lymph nodes
Leukoplakia
condition in which one or more white patches or spots (lesions) forms inside the mouth. Leukoplakia is different from other causes of white patches such as thrush or lichen planus because it can eventually develop into oral cancer.
Pharyngitis
Concomitant with viral upper resp. infection.
Bacterial cause often beta-hemolytic strep
Squamous Cell carcinoma
Smoking
Tend to grow silently until become unresectable
Spread to cervical LN or elsewhere
Hiatal hernia
95% are sliding type - meaning they are accustomed to moving based on pressure.
Often due to increased abdominal pressure
Results in GERD
Esophageal varices
Secondary to portal hypertension, alcoholic cirrhosis
Distal esophagus and proximal stomach, asymptomatic until rupture
Esophagitis: GERD
Irritation, alcohol, food intolerance, infections
Decreased lower esophageal tone - hematemesis (vomiting blood) in worst cases.
Sequele is Barret’s esophagus = metaplasia of the distal esophagus
Squamous cells convert to columnar gastric cells
Sequele = adenocarcinoma
Squamous Cell Carcinoma
Alcohol, smoking, fungal, nitrosamine containing foods
Zinc and other vitamin and mineral deficiencies may predispose
What ar the parts of the stomach?
Cardiac and pyloric sphincters, lesser and greater omentum, fundus, greater and lesser curvature, body, musculature: internal, circular, longituginal
What are the parts of the stomach?
Cardiac and pyloric sphincters, lesser and greater omentum, fundus, greater and lesser curvature, body, musculature: internal, circular, longitudinal
What are the attachments of the stomach?
Lesser omentum
Greater omentum
What artery supplies the stomach?
Arteries derived from the CELIAC trunk
Acute gastritis
Acute gastritis is a sudden inflammation or swelling in the lining of the stomach
NSAIDs, ETOH, smoking, stress, idiopathic
Erosion of superficial epithelium, ulcer-like pain
Chronic gastritis
Often without erosions
Autoimmune cause of loss of parietal cells and intrinsic factor
H. pylori, hypo/ achlorhydria, B12 deficiency
Most are asymptomatic or smoldering
Hypochlorhydria
Chronic gastritis leading to atrophy of fundal mucosa cells.
Immune-mediated destruction of parietal cells
Associated with:
Hashimoto’s thyroiditis, Addison’s; B12 def, macrocytic anemia
Gastric ulcer
25% of all peptic ulcer diseases (PUD)
Male = female
H. pylori ~ 75% of cases
- Blood type A, NSAIDS, SMOKING, Bile reflux
Lesser curvature
COmplications: Perforation and bleeding
Burning epigastric pain post-eating. Pain WORSE with food.
Duodenal Ulcer
75% of all PUD
Male/Female 2:1
Burning epigastric pain, 1-3 hours after eating BETTER EATING
H. pylori > 90% of cases
Gastric carcinoma (cancer)
Always in DDX of gastritis or ulcer Sn/Sx which d not respond to treatment
Better to have biopsy/endoscopy done to rule out gastric carcinoma
More common in the upper stomach (cardia). Faster aggressive growth.
Antrum, pyloric and lesser curvature. Slow insidious
Increased risk:
- blood type A
- ulcers of the greater curvature
Increase incidence:
- Smoking, chronic gastritis, nitrosamines, pickled foods.
Remember
THree parts of the small intestine:
Duodenum, jejunum, and ileum.
Jejunum is shorter than the ileum
In the jejunum, there are fewer arterial arcades than the ileum and fewer lymphatics
In the ileum, you will find Peyer’s patches, more arterial arcades than jejunum, more lymphatics.
adynamic ileus
paralysis of intestinal motility.
What is the main blood supplier of the small intestine?
Superior mesenteric artery
Why is there collateral circulation to the small intestine?
Because the small intestine has a high demand for oxygen and is highly susceptible to injury from ischemia.
Intussusception
Most common intestinal obstruction in infants and young children.
Not normal in adults - this is BAD
Happens in the ileocecal region. Ileum into the cecum.
Gastroenteritis
Gastrointestinal tract viral infection (lasts 12hrs - 3 days).
Primary transmission - Oral-fecal route
Viruses - epithelium damage- osmotic diarrhea (three stools daily), vomiting.
Children: rotavirus
Adult: norovirus
Fever, diarrhea, vomiting, cramps, dehydration
Large intestine
The muscularis layer goes away and is replaced by the teniae coli which runs longitudinally.
Lar intestine has haustra (sacs)
Remember
The internal sphincters (rectal or urinary) are mediated by stretch reflexes. They are invonlutary.
Appendicitis
Inflammation of vermiform apprendix. Adolescents and young adults Bacterial McBurney's point rebound tenderness Periumbilical pain RLQ with nausea and vomiting, constipation, no gas
Diverticulitis
Inflammation of the diverticula of the haustra of the colon due to insoluble material and bacteria. Pain Fever Nausea Change in bowel pattern
Diverticulosis
Added haustrations to the colon
Not everyone has it.
Usually found in people > 60 yrs of age
Colorectal carcinoma
60-70 yo males > females
Associated with ulcerative colitis, polyposis coli, Chron’s disease.
Hemorrhoids
Varicosities in inferior hemorrhoidal plexus
Symptoms:
Lumps on the anus may become swollen and painful
Mucus in your rectum that may make you feel like you haven’t passed stool
ItchingCauses:
Overweight, pregnancy, heavy objects, constipation or diarrhea for a long time, anal sex
Chronic granulomas disease
Development of granulomas which are collections of immune cells that cluster together when they can’t kill pathogens
Autoimmune
Fever, diarrhea, vitamin B12 def
Skip lesions
Chronic ulcerative colitis
More common in 20-25 years May affect only rection Ulceration with pseudopolyps Bloody mucoid diarrhea Iritis is common
Celiac disease
Gluten-sensitive enteropathy
Malabsorption secondary to inflammatory luminal swelling
Celiac sprue presents with bulky, greasy stools, diarrhea, flatulence
Can be genetic or autoimmune
Weight loss, fatigue any age
Abates with gluten removal
Irritable Bowel syndrome
Recurrent abdominal pain and abnormal bowel motility (diarrhea or constipation)
The pain improves after a bowel movement.
Functional disorder
females more than males
pain after eating
It is a dx of exclusion (chronic gastritis, cancer, etc)
Inflammatory bowel disease
Share same characteristics of IBS, but has inflammation, ulcers, or other damage to the bowel.
Acute pancreatitis
a great amount of variation of symptom picture
It is very painful
causes:
- heavy alcohol use, choline deficiency, gallstones
Constant epigastric pain radiating to mid-back
Elevated serum amylase and lipase
Pancreas being digested by enzymes, that is why it is painful
Pancreatic cancer
Asymptomatic almost until the end
heavy tobacco smoking triples risk
Heavy consumption of fats and meat
Diagnosed at high stage and high grade due to being asymptomatic
Renal failure from liver failure because kidneys are getting all the toxins
Acute liver failure
Fulminant hepatitis, toxic damage from acetaminophen, halothane, carbon tetrachloride, antidepressants
DIC, renal failure
Chronic liver failure
Hepatitis, cirrhosis, inherited metabolic disorders
Clotting dysfunction
Cholestasis
Chole = bile Statis = static, inactivity
Hepatocellular cholestasis
intra-hepatic
Estrogen inhibits the excretion of bile acids, keeping them in the hepatic cells
Conjugated bilirubin builds up in the cell, crossing through the membrane getting into the bloodstream
High levels of estrogen have been linked to this.
Obstructive cholestasis
outside the liver
physical blockage
gallstones
How is the descending aorta divided?
Celiac trunk, superior, and inferior mesenteric.
How many blood supplies does the stomach have?
3
Gastro epiploic - a branch of the splenic artery
Direct branch out of the celiac trunk called left gastric artery
Right gastric artery coming from the hepatic artery
What would cause portal hypertension?
Right-side heart failure, pregnancy, and hepatic disease Signs: - Esophageal varices - Rectal hemmorhoids - Capite medusa
Remember
GI structure
Submucosal plexus - mucus membrane activity
Myenteric - longitudinal smooth muscle activity
GI tract innervation
Extrinsic Innervation
- Parasympathetic NS - excitatory, carried by Vagus and Pelvic Splanchnic nerves
- Sympathetic NS - Inhibitory, carried by prevertebral ganglia T8-L2
Intrinsic Innvervation
- Enteric Nervous system
Two plexi - myenteric plexus and submucosal plexus
GI Regulation
Stomach
Histamine stimulates gastric acid
G Cells = gastrin stimulates H+ and gastric mucosa
GI Regulation
Duodenum/Jejunum
I Cells = CCK stimulates gall bladder contraction and Oddi Relaxation; Pancreatic enzymes and bicarbonate secretion - inhibits gastric emptying
S cells - secretin: stimulates pancreatic and gallbladder bicarbonate secretion - inhibits gastric emptying
GIP stimulates insulin secretion - inhibits gastric acid secretion
What does histamine do in the stomach?
Stimulates the gastric acid pump
Histamine type 2 receptors activate de proton pump.
G cells make what?
Gastrin stimulates acid production and mucosal activity
What does the CCK do?
It stimulates the gallbladder to contract and also the relaxation of the sphincter of Oddi.
It also makes pancreatic enzymes and bicarbonate to be secreted. Also, it stops stomach emptying
Hormone
used to be released from ductless glands, endocrine glands into the bloodstream, they go peripherally and make something happen
Paracrine
Short enteroendocrine secretion
Somatostatin: inhibits GI hormones release and acid secretion
Histamine: Stimulates gastric acid secretion
Neurocrines
Neuronal synthesis, synaptic release, target cell activation
Enkephalins: Stimulate GI contraction at sphincters, stop fluid and electrolyte release
What do chief cells produce?
Where are they located?
pepsinogen.
chief cells are located at the base of glands distributed throughout the fundus and corpus of the stomach.
Pepsinogen and pepsin
a substance that is secreted by the stomach wall and converted into the enzyme pepsin by gastric acid.
Pepsin is a stomach enzyme that serves to digest proteins found in ingested food. Gastric chief cells secrete pepsin as an inactive zymogen called pepsinogen.
Parietal cells
Parietal cells within the stomach lining secrete hydrochloric acid that lowers the pH of the stomach.
They also secrete intrinsic factors for complexing with B 12 to absorb B12
Where are carbs absorbed?
Duodenum and jejunum
Where are amino acids absorbed?
Duodenum and jejunum
Where is iron absorbed?
duodenum
Vit. B12?
terminal duodenum
Fatty acids?
terminal duodenum
How is iron absorbed as?
Fe2+
How is iron transported?
Transported as ferritin
How is iron stored as?
Stored as ferritin and hemosiderin
What duct received sources from the liver and gallbladder?
Common bile duct receives sources from the common hepatic duct and cystic duct.
Major duodenual papila
AKA Oddi
received information from the common bile duct and pancreas (pancreatic duct)
What percentage is the bile acid recycled?
about 98% of it after it does its job which is to micelle fats (separate the fat)
Where is bile produced
In the liver by hepatocytes and stored inside the gallbladder
What is bilirubin?
Bilirubin is a yellow compound that occurs in the normal catabolic pathway that breaks down heme in vertebrates. This catabolism is a necessary process in the body’s clearance of waste products that arise from the destruction of aged or abnormal red blood cells.
bilirubin has been shown to possess important functions as an antioxidant, but it also serves simply as a means to excrete unwanted heme, derived from various heme-containing proteins such as hemoglobin, myoglobin, and various P450 enzymes.
Where are bile acids synthesized?
Synthesized from cholesterol in the liver only
How are bile salts regulated?
The rate-limiting step in bile acid synthesis is the introduction of a hydroxyl group at carbon 7 of the steroid ring by 7-alpha-hydroxylase which is inhibited by cholic acid (a primary bile acid stored in the gall bladder).
What is the function of bile acids?
Emulsifying agents in the intestine helping to prepare dietary triacylglycerol and other complex lipids for degradation by pancreatic enzymes. Bile salts also provide the only significant mechanism for cholesterol excretion
Cirrhosis
Hepatitis C or C, Alcohol-induced
Primary biliary cirrhosis, Wilson’s disease (copper), iron etc
Signs and symptoms
- Jaundice, ascites, edema, encephalopathy, cachexia, palmar erythema
- Caput medusa, esophageal varices, portal hypertension
- Liver failure, renal failure secondary to liver disease
Cholecystitis
inflammation of gallbladder gallstone in neck or cystic duct RUQ or epigastric pain pain when you eat Usually resolves in 1-7 days
Cholelithiasis
aka gallstones
70-80% are asymptomatic for decades
Remember
3/4 of the body for lymphatics - left side of the face, left pec and arm, the whole abdomen down to the legs
1/4 - right face, right chest, and arm.
Where do most of the absorption of water happen in the body?
Small intestine
Diarrhea
excretion of water through feces 150 ml to 1.5 leters
Dysenteric
about 1.5L of excretion of water
Vitamin A
Part of Rhodopsin/Vision
Deficiency: Night blindness
Vitamin D
GI (increase calcium absorption)
Def.: Rickets
Vitamin E
Antioxidant
Def.: Ataxia
Vitamin K
Carboxylation of glutamate/calcium chelation with glutamate
Def.: Factor 2, 7, 9, 10 bleeding disorder
Vitamin B1 - Thiamine
Aldehyde transfer/ decarboxylation
Beriberi
Vitamin B2 - Riboflavin
H+ transfer/FMN - FAD (flavins)
Cheilosis/Glossitis
Vitamin B3 - Niacin
H+ transfer / NAD-NADP
Pellagra - 4 Ds:
Diarrhea, dementia, dermatitis, death
Vitamin B5 - Pantothenic acid
Acyl group transfer / Co-A
Burning feet / HA / Nausea
Vitamin B6 - pyroxidine
Amino group transfer
Microcytic anemia, Neuropathy
Vitamin B7 - Biotin
carboxylation
Seborrheic dermatitis, nervous system disorders
Vitamin B9 - Folate
Methyl transfer
Macrocytic anemia/ Glossitis/ colitis
