The gastrointestinal tract

What is the major function of the GI

Digestion and movement of food, absorption of nutrients and elimination of waste.

Where is the esophagus located

Posterior to the trachea, and the two structures develop in close relation to one another. Also located close to the aortic arch

How is the movement of food accomplished?

Through peristalsis

What is peristalsis

the coordinated contraction of the smooth muscle that lines the entire intestinal tract. Stimulation involves both neural and hormonal mechanism

Name two types of Congenital esophageal disease

* Blind pouch
* Tracheo-esophageal fistula

Both require surgery

Explain Blind pouch

when the esophagus is constricted due to abnormal development which results in vomiting up of food. Atresia???

What is a fistula

An abnormal connection between two organs or two different part of the same organ

What is the most common type of Tracheo-esophageal fistula

The upper esophagus ends in a blind pouch and the lower esophagus is connected to the trachea

What does the lower esophagus causes in Tracheo-esophageal fistula

Air passes into the trachea from normal breathing and may find its way into the esophagus which leads to bloating → air accumulation in the stomach

What does the Upper esophagus causes in Tracheo-esophageal fistula

When there is a fistula in upper esophagus and the trachea. This may permit swallowed food to get into the lungs causing aspiration pneumonia

What is esophagitis

When the lower pert of the esophagus pierces the diaphragm

What is the sphincter composed of

Thickening of the esophageal wall and also involves diaphragmatic muscles

What is the similarity between peristalsis and a sphincter

They are both under the control of nerve impulses and hormones

What can damage the cells that line the esophagus

gastric juices

What is hiatal hernia

A defect in the opening of the diaphragm that allows part of the stomach to protrude into the thoracic cavity.

They can interfere with the normal functioning of the lower esophageal sphincter which leads to REFLUX

What are the symptoms of esophageal disease and define them

* Dysphagia: difficulty swallowing food
* Pyrosis: burning retrosternal pain(pain behind the sternum) which is commonly called heartburn

What is the most common cause of reflux

Esophagitis

What is GERD caused by

the abnormal movement(reflux) of gastric juice from the stomach to the esophagus

What does gastric juices cause

A chemical inflammation, since the esophagus does not have the same protective mechanism as the stomach against acids and enzymes

What does the acids form the stomach cause

It causes necrosis of the esophageal epithelium which evokes an inflammatory response

In attempt to protect the esophagus what happens

Metaplasia, in which the normal squamous epithelium is replaced by the epithelium that appears glandular and columnar(similar to that of the stomach and the intestines)

With time what does reflux cause

Scarring(fibrosis) which results to the narrowing of the esophagus which results to dysphagia

What population do we see infections in esophagitis and what type of organisms does it involve

rImmunocompromised patients and it involves opportunistic organism . Example: candida, cytomegalovirus and HSV

What is a Varix or Varices

Is a dilated, tortuous vein

How can a person develop Varices and what does it lead to

It can be developed in the submucosa of the distal esophagus due to abnormally high pressure in blood flowing from the portal vein

Rupture can lead to massive hemorrhage

What is the common cause of death in patients with cirrhosis of the liver

varices

What are the two signs of bleeding in the GI tract

* Hematemesis
* Melena

What is Hematemesis

It’s the vomiting of blood

Appears bright red, indicates sudden and massive bleeding or

Appears like coffee ground, indicates slow and chronic, allowing partial digestion of blood

What is Melena

It’s the presence of partially digested blood and is usually due to bleeding in the upper GI tract

Large amounts of bleeding is needed to produce melena

Bleeding form hemorrhoids usually results

Bright red blood appearing in the stool: BRBPR→ Bright red blood per rectum

No digestion of blood because the hemorrhoids are located distally

What is the test to detect occult blood in stool and what is the treatment of hemorrhoids

Stool guaiac and the treatment can include ligation(banding) of the varices

Is carcinoma of the esophagus common in the US and what is the age group and sex

No, males over the age of 50

What is the initial symptoms of Esophageal carcinoma

* They are often non-specific which makes it difficult to diagnose
* dysphagia due to obliteration of the lumen by the tumor
* weight loss
* Hematemesis as the tumor erodes into vessels and pain

Where does the tumor of the esophageal ulcerate

* trachea resulting in acquired tracheo-esophageal fistula
* Aorta resulting in massive bleeding

What are the two therapy that is not very effective for esophageal carcinoma

Radiation and Chemotherapy

In other countries where is the common placement of esophageal tumors and where do they originate

* Middle or the upper esophagus
* They originate from the squamous mucosa and are classified as squamous cell carcinoma

In the US, where is the common placement of esophageal tumors and where do they originate

* Lower esophagus
* Originates from glands in the setting of Barrett esophagus and are classified as adenocarcinomas because of their glandular origin

Where does the esophagus join the stomach

The cardia

What is the upper, middle and lower section of the stomach called

* Upper: fundus
* Middle: corpus(body)
* Lower: mucin-secreting antrum

Where is the pylorus located and what does it do

* Located where the antrum joins the duodenum
* It controls movements of substances from the stomach to the duodenum

What are the four important types of cells in the stomach and explain them

Chief cells: makes digestive enzymes such as pepsinogen→ pepsin in the lumen of the stomach. The inactive precursor forms of these enzyme are called zymogens

Parietal cells: make hydrochloric acid and intrinsic factor→ needed for the absorption of Vitamin B12

Mucus-producing cells: secrete a mucous layer that protects the lining of the stomach

G cells: serves the hormone gastrin and stimulates parietal cells to make HCl

Secretion of the acid by the parietal cells is controlled by

Neural stimulation via ACH which is triggered by the smell of food →gastrin made by G cells, Histamine made by mast cells

How is the health of the gastric mucosa maintained

Intact mucous layer, a normal flow of blood, normal production of acid and bicarbonate and normal secretion of gastrin

What bacteria promotes the destruction of the gastric mucosa and what does it do

H.pylori and it alters the normal function mucous layer

Define Acute gastritis

* It’s a relatively severe but short-lived inflammation and results from exposure to an irritant.
* Can also happen because of physiological stress

Acute gastritis with hemorrhage can lead to

shock and death

What is chronic gastritis mediated by and what does what is mediated why do

H.pylori and it disrupts the normal mucous layer, allowing acid and enzymes to injure the underlying cells which results in atrophy of the lining cells and may lead to lymphoma

Explain the autoimmune cause of Chronic gastritis

Autoimmune destruction of the parietal cells may lead to pernicious anemia since Vitamin B12 cannot be absorbed in the absence of intrinsic factor

What is the definition of ulcer

Discrete area of necrosis in the epithelial or mucosal lining of an organ

What is the classification of Gastric ulcer and what is it due to

Acute(stress) or chronic(peptic) and it’s due to erosion of the gastric mucosa by peptic ulcer

What does acute ulcers arise and what is the characteristics of acute ulcers

Arise as an extension of gastric gastritis or from severe physiological shock to the body.

Stress ulcers are often small but multiple and can cause massive bleeding. They tend to resolve quickly once the source of the stress is removed

What are the characteristics of chronic ulcers

They are deep and are often solitary and bigger than stress ulcer.

They are common and are frequent and affects mostly the duodenum and sometimes the stomach itself.

How does Chronic ulcers arise

When there is an imbalance between normal protective mechanisms and the inherent destructive tendencies of the gastric juices

What play a major role of cases of peptic ulcers

H.pylori

What is a high characteristic of chronic ulcers

Epigastric pain that occurs one to three hours after a meal

How does chronic ulcers work

They may erode into an artery in the stomach or duodenal wall leading to hemorrhage or they may even bore completely through the wall, resulting in massive peritonitis

What is the most common complication in chronic ulcers and which one causes the most deaths

* Upper GI bleeding which accounts for a small amount of deaths
* Perforation is a rarer event, it’s so serious and is the most common cause of death

What can perforation cause

It can cause air to accumulate beneath the diaphragm

What is the treatment of Chronic ulcers

Decrease production of acid using an acid pump inhibitor(PPI) or drugs that block H2 receptors for histamine as well as eliminating H.pylori with antibiotics

What is a triple therapy

Combines a PPI with two kinds of antibiotics

Is Gastric cancer high or low in the US, where is it high

Low and high mostly in Japan but also in Chile, chin and near east

What might causes Gastric cancer

Environmental factors especially diet: countries with high dietary levels of nitrosamines have the highest incidences such as Japan with the highest incidences

Who is in common in

People over 50 but it can happen to younger people

What are the symptoms

They are vague and non-specific and the diagnosis is unusual

What does Gastric adenocarcinoma resemble

* Majorly Ulcers
* Fungating(filling up the stomach)
* More diffusing in their growth

What is are the features of diffuse tumors

Stomach a stiff, “leather-bottle” quality called linitis plastic

Where does Gastric cancer spread to

Spreads to the regional lymph nodes, the peritoneal cavity, the liver and the ovaries

Where does Gastric cancer develop from

Glandular cell lining of the stomach→ Adenocarcinoma

what is the most common maladies of the intestine and what is the most common manifestation

Infection and the most common manifestation is diarrhea

Does Tumor occur in the small intestine

Yes but rarely

What is Gastroenteritis

Infections of the stomach and/or small intestine

What is the major function of the small intestine and what is need for the function

* Absorption of digested food
* A very large surface area and is provided by mucosal folds, villi, and microvilli on individual cells.

What is the order of the intestine

Ascending colon, transient, Descending colon, sigmoid colon, and the rectum

Between the Ascending area(cecum) and the descending(sigmoid) colon which one is wider

the Ascending area(cecum)

What is the function of the colon

absorption of water and electrolytes and production of the waste products known as stool.

Describe Celiac disease

The immune system recognize a glycoprotein in wheat, called gliadain. The cell transports gliadin from the gut are attacked by T cytotoxic lymphocytes, resulting in damages to the intestinal absorptive cells, loss of vili and decreased absorption.

What is the glycoprotein that the immune system recognizes

gliadain

Where is the appendix located

It is located off the cecum in the proximal part of the colon

What is the function of the appendix and what is it rich in

It has no known function and is rich in lymphoid tissue

Is appendicitis common or uncommon and what age group

common in people under 20

Where does appendicitis usual develop

Develops due to an obstruction at the base of the appendix such as food, fecolith or hyperplasia of lymphoid tissue

What is fecolith

hardened stool

What can obstruction lead to

ischemia and bacterial overgrowth

What is the symptoms of appendicitis

Pain in the right lower quadrant and the pain may be periumbilical, elevated WBC

What can rupture of the appendix result to

Acute peritinotis due to spillage of intestinal contents

What is interval appendectomy

It is when the appendix gets ruptured and the person is treated with antibiotics and have a surgery once the inflammation has subsided.

What are the two conditions that causes inflammatory bowel disease

* Crohn’s disease(regional enteritis)
* Ulcerative colitis(UC)

What are the similarities of Crohn’s disease and Ulcerative colitis

* Idiopathic
* No infection has been identified
* May have autoimmune and genetic component


* Chronic, relapsing disease
* Affect more women than men and seen in people in their 20s
* Intermittent(non continuous) diarrhea
* The severity and therapy is quite variable

What are the unique features of Crohn’s disease (8)

* Affect anywhere in the GI but **mostly the terminal ileum**
* Causes **transmural inflammation** affecting all layers of the intestinal wall
* Patchy, discontinuous inflammation→ skip lesions
* **Granulomas** and they spread to the lymph
* Fistulas tend to form
* Perforations may occur and can lead to peritonitis
* Elongated, linear ulcerations give the intestinal wall a **cobblestone** appearance
* Fibrosis, resulting in narrowing of the intestinal lumen

What are the unique features of Ulcerative colitis(5)

* involves the rectum; may involve variable lengths of the distal colon
* Inflammation is usually confined to the mucosal layer
* Pseudopolyps may form, normal mucosa resemble polyps
* Inflammation is continuous, no skipped areas
* Long-standing→ risk of developing colon cancer

Between Crohn’s disease and Ulcerative colitis is easier to treat and why

Ulcerative colitis because the disease is confined to a certain area

Surgery in the setting of Crohn’s disease may increase the risk of developing?

Fistulas

Severe cases of UC may require what

total removal of the colon

What is the medical treatment of inflammatory bowel disease

steroids and antibiotics

What is diverticulosis

An abnormal outpouching of the lining and wall of the colon

What group of people is diverticulosis common to

people 50 and older

Where does diverticulosis commonly occur and why

The distal colon because the lumen of the distal colon is narrower, higher pressure are found there than more proximally

Where is diverticulosis most common in and why

Wester countries because the diet tends to be low in fiber

What has been theorized because of low-fiber diet

Slower passage of stool, and more pressure is required to pass these less bulky stools

Are there symptoms of diverticuli

No but the diverticuli may be inflammed due to the obstruction by food or fecal matter