GI Flashcards
What is the major function of the GI system?
- Ingest
- Transport
- Absorb nutrients
Why is the GI tract susceptible , and how does this compare to the respiratory tract?
Both the GI and respiratory tract are open to the environment
-Susceptible for invasion by microbes
What are examples of your bodies defenses that help protect your GI and respiratory tract?
- MALT
- Acidic Stomach
- Normal flora (to outcompete most ingested microbes)
What are the 4 layers of the digestive tract? (inner to outer)
- Mucosa
- Submucosa
- Muscle (longitudinal and circular)
- Serosa
Describe the function of teeth
Teeth break down food by tearing and grinding it
Describe the function of saliva (what does it specifically start to break down?)
Saliva begins carbohydrate digestion
Describe how food gets to the stomach?
Esophagus moves food bolus to the stomach via peristalsis
What are the 3 things that are leased by the stomach?
- Hydrochloric acid
- Pepsinogen
- Gastrin
What does pepsinogen do?
Begins protein digestion
What does gastrin do?
- Stimulates gastric acid secretion
- Stimulates pancreatic enzyme release
- Liver bile production
- Intestinal peristalsis
What does Somatostatin do?
- Inhibits somatotropin
- Inhibits insulin secretion
- Gastrin secretion
What produces Somatostatin?
Pancreas
The small intestine receives 3 components to help in digestion?
- Bile
- Pancreatic lipase/amylase
What does bile do?
Emulsify fat
What does pancreatic amylase and lipase do?
Fat and carbohydrate digestion
What allows the SI to absorb large amounts?
Large surface area with villi and microvilli for ABSORPTION
What does the LI do?
- Absorb water and electrolytes
- Compacts feces and transports them to the rectum for storage
Where are wastes emptied from?
the Anus
Describe the mesentery
-Double layered sheet of peritoneum that SUSPENDS THE BOWEL and ATTACHES IT TO THE BODY WALL
What provides a path for arteries and veins to an from the GI tract?
Mesentery
These are macroscopic folds in the SI that help add to the increase in surface area?
Plicae
_____ are numerous and on the mucosal surface
Villi
The small intestine also contains _________
Submucosal collections of lymphoid tissue (Peyer patches)
What covers each villus?
Columnar epithelial cells with a “BRUSH BORDER” of microvilli
(Further increases surface area)
These are mucus secreting cells that are spread out in the intestinal epithelium
Goblet cells
_______ is caused by bacteria that erode enamel and invade tooth structure (arguably the most common disease in the world).
Caries
______ results from bacterial invasion of gingival pockets around the tooth root
Periodontal disease
______ is inflammation of the superficial gums, leading to retraction and exposure of the root
Gingivitis
What is the root cause of periodontitis
Bacterial invasion downward into the soft tissues around the tooth root
These are small shallow ulcers of unknown etiology that heal quickly
-Also known are Canker sores
Aphthous ulcers
T/F- Most people have been infected by oral herpesvirus by age 5
True
Why/how does reactivation of oral herpesvirus occur?
- Reactivation as cold sores or fever blisters
- Actually represent the reactivation and replication of the dormant virus from within the nerve tissue (usually the trigeminal ganglion)
What are 3 main causes of thrush?
- Immunocomprimised
- On corticosteroids
- Antibiotic therapy
Can you scrape off thrush?
Yes
This is a white patch of oral squamous mucosa
Leukoplakia
What can leukoplakia lead to?
-Squamous cell carcinoma
What are the major risk factors for leukoplakia and squamous cell carcinoma?
- Smoking
- Alcohol abuse
What areas in the mouth are these located and often missed on examination?
- Under the tongue on the floor of the oral cavity
- Survival rates here are worse than the lip
This is inflammation of the salivary glands
Sialadenitis
What causes sialadenitis?
-Sialolith (calcified stone most common in SUBMANDIBULAR GLAND)
What are other causes of sialadentis?
- Bacteria (S. aureus)
- Virus (mumps-effects parotid gland- but yes vaccine)
- Autoimmune
This is a salivary and lacrimal gland autoimmune inflammation
Sjögren syndrome
What are S&S for Sjögren syndrome
- Dry eyes
- Dry mouth
This is a tumor, mostly benign, of the salivary glands
Pleomorphic adenoma
What salivary gland is most effected by pleomorphic adenoma
Parotid gland- removal is difficult because due to the fear of damaging facial nerves
What are some symptoms of esophageal disease?
- Dysphagia
- Odynophagia (pain with swallowing)
- Hematemesis (bleeding)
______ is a spastic (increased muscle tone) condition of the lower esophageal sphincter
Achalasia
What does Achalasia produce?
- Functional partial obstruction in the lower esophagus
- Causes dysphagia and esophageal pain
______ is a protrusion of the cardia region of the stomach through the esophageal hiatus into the thoracic cavity
Hiatal hernia
What are S&S for hiatal hernias?
- Dysphagia
- Pyrosis (heartburn)
________ is lacerations in the esophagus secondary to retching/vomiting (e.g. bulimia, alcoholism).
Mallory-Weiss syndrome
This is esophageal rupture
Boerhaave syndrome
_______ are dilated veins due to re-routing of blood from the portal circulation back to the systemic circulation (they form for the same reasons that hemorrhoids form)
Esophageal varices
Patients with ______ often have esophageal varices
Cirrhosis
Describe why esophageal varices occur in cirrhosis
- Lower esophagus veins drain into the IVC or gastric/portal vein
- Goes through the liver
- Liver becomes fibrotic in cirrhosis
- Back up of portal blood
- Increased pressure
- Reverses flow
- Esophageal veins become more dilated and prone to rupture
- Most common GI disorder
- Backward movement of gastric contents to the esophagus
GERD
Fancy word for heart burn
Pyrosis
What are some risks for GERD
- Large meals
- Fatty meals
- EtOH
- Caffeine
- Smoking
- Chocolate
- Hiatal hernia
Explain the progression from normal to Barretts esophagus
- Weak esophageal sphincter
- Reflux of gastric contents
- Mucosal injury
- Inflammation and hyperemia
- Metaplasia aka Barretts esophagus
Normal esophagus epithelium= _______ cells
Squamous epithelium
Normal stomach epithelium= _______ cells
Columnar cells
S&S of Barretts esophagus
- Painful
- Narrowing because of fibrous scars
- ulcers
- Adenocarcinoma
Risk factors for Barretts esophagus
- Smoking
- Alcohol abuse
What is the most common cancer from Barretts esophagus?
-Esophageal squamous cell carcinoma
This is inflammation of the gastric mucosa
Gastritis
What cause gastritis?
- Aspirin
- NSAIDS
- Excessive alcohol
Pathogenesis of gastritis
- Mucosal breakdown and repeated acid injury
- Acute inflammatory response
- Widespread necrosis
- Erosions develop
- Bleeding may occur
These are multiple superficial ulcers in patients with brain injury
Acute gastric ulcers
What color is the blood on the ulcers surface in an acute gastric stress ulcer
Black- due to the acid environment
Are acute stress ulcers superficial or deep?
Superficial
What causes acute gastric erosions?
- Severe trauma
- Sepsis
- Major surgery
- Grave Illnesses
- Alcohol abuse
- Extensive burns
- CNS trauma or surgery
- Chronic NSAID or corticosteroid use
