Functions of the Gastrointestinal System
- To prepare food for absorption into the body and utilization by the cells
- To excrete any food material of no use to the body
Gastrointestinal System composed of:
- Gastrointestinal tract
- Accessory organs and structures
Gastrointestinal Tract
- Approx 4.5 meters in length
- Almost doubled when no muscle tone
- A fibromuscular tube
Gastrointestinal tract is made up of:
- Mouth
- Pharynx
- Esophagus
- Stomach
- Small intestine
- Large Intestine
Accessory organs & structures are:
- Salivary glands
- Teeth
- Tongue
- Liver
- Gall bladder
- Pancreas
Digestive Processes – 5 stages:
1. Ingestion
2. Movement of food
§ Peristalsis
3. Digestion
§ Mechanical
§ Chemical
4. Absorption
5. Defecation
Mucosal layers (3)
- protection
- secretion
- absorption
Mouth
- Provides an entrance to the gastrointestinal system
- Initiates digestion by the mechanical breakdown of food material
- Normal swallowing mechanisms move the food bolus to the esophagus
- Mediated by Cranial nerves IX, X, and XII
Functions of the Mouth
- Chewing, grinding and mixing of food
- Formation of a bolus
- Initiation of digestive processes
- Swallowing
- Taste
- These functions assisted by teeth, tongue, salivary glands and sensory nerve endings
Pharynx
- Food passes through the oropharynx and laryngopharynx to reach the esophagus
- Once a bolus of food reaches the pharynx swallowing is no longer voluntary
Swallowing
- swallowing initiates peristalsis
Peristalsis
- An involuntary activity of the longitudinal and circular layers of smooth muscle within the wall of the tract
- Rhythmic, pulsatile contractions of these muscle layers move the contents of the tract forward
Esophagus
- Hollow tube connecting mouth to stomach
- Runs through mediastinum
- Attaches to the stomach just below the diaphragm
- Mucus membrane lining secreting protective mucoid substance
Functions of the esophagus
- Transport of food
- Movement of food by peristalsis
- Mechanical dispersion of food as the first part of digestion
Cardiac Sphincter
- A one-way valve preventing reflux of stomach contents into the esophagus
- Relaxes as peristaltic wave approaches so that food can enter the stomach
- Also known as the lower esophageal sphincter
Stomach
- A dilation of the intestinal tract between the esophagus and the beginning of small intestine
- Separated form the small intestine by the pyloric sphincter
- Has three regions:
- fundus
- body
- pylorus
Stomach
- Food bolus enters the stomach moving slowly towards the pylorus (2 – 6 hours)
- Fluid mass in stomach called chyme
- Chyme pumped through pyloric sphincter into the small intestine
- Rate of movement of stomach contents depends on:
- food type and consistency
- rate of pancreatic and biliary secretions
- Functions of the Stomach
- Temporary storage
- Mixing
- Exocrine secretions
- hydrochloric acid
- intrinsic factor
- pepsinogen
- mucus
- Outflow regulation of processed food particles to the small intestine
- Extraction of iron from food
- Limited absorption
Control of Gastric Activity
- Gastric secretion is regulated by nervous and hormonal activity
- Gastric emptying is stimulated in response to stretch, stomach gastrin, and certain food types
- Gastric emptying is inhibited by reflex and hormonal activity
Small Intestine
- 2.5cms wide and 6m long
- Fills most of the abdomen
- Begins at the pyloric sphincter and ends with its connection to the large intestine at the ileocecal valve
- 3 parts:
- Duodenum
- First 25cms of small intestine
- Receives chyme from the stomach through the pyloric sphincter
- Fluids from the pancreas and gall bladder via the common bile duct
- Manufactures intestinal juice
- Susceptible to inflammatory processes
- Duodenum
- Function:
- Neutralizes the acidic chyme from the stomach
- Mixes chyme with pancreatic, biliary and intestinal secretions
- Jejunum
- Jejunum – the largest section of small intestine
- 8 feet
- Absorption of Magnesium, Calcium, Iron
- Ileum
- last 40cms of small intestine
- Chyme moves slowly towards the ileocecal valve (3 – 10 hours)
- Functions of Small Intestine
- Forward propulsion of contents
- Major site of digestion
- 90% absorption
- Protection against infection
- Hormone secretion
- Intestinal juice secretion
Large intestine
- 2.5cms wide 1.5m long
- Stretches from ileocaecal valve to rectum
- Often described in 7 parts
- cecum
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- rectum
- anal canal
- Exit tract controlled by anal sphincters
- Functions of the Large Intestine
- Reabsorption water and electrolytes
- Microbial activity
- Mass movement
- Defecation – reflex action, abdo/diaphragmatic contraction
- Feces
- Water
- Inorganic salts
- Eplithelial cells
- Bacteria – E- Coli is the main bacteria present
- Undigested food
Normal enteroclysis- nasojejunal tube inserted to DJ flexure. Contrast outlines the duodenum and the first bit of jejunum. Note the irregular gas bubble in the stomach.
Upper GI Bleed VS Lower GI Bleed
ü
Melena is described as black tarry in color from an upper GI source, “tarry” feces that are associated with gastrointestinal hemorrhage. The black color is caused by oxidation of the iron in hemoglobin during its passage through the ileum and colon.
ü Hematochezia – passing a large loose, bright red or maroon colored stool, considered frank bleeding usually from the rectum, considered a lower GI Bleed.
ü Coffee ground stool is classic of an upper GI bleed as it is old blood that had been decomposed by the stomach acid.
ü Ischemic bowel disease- - a blood clot or other blockage has cut off blood flow to the colon as a result of reduced blood flow Ischemia seen in the elderly, a twisting of the intestine that is not relived, those with hx of atrial fib throw clots.
ü Mallory –Weiss tear- Repeated or profuse vomiting may cause erosions to the esophagus or small tears in the esophageal mucosa
ü Diverticula -are found throughout the colon, and sustained dark red lower GI bleeding from the large intestine is characteristic of a bleeding diverticula
ü Exanguination ( bleeding out) the fatal process of total hypovolemia ( Blood loss) commonly known as bleeding to death can be from the following caused:
1. Mallory-Weiss tear
2. Esophageal varices ( may be torn- ie: Mallory Weiss seen in protracted vomiting, and by an alcoholic vomiting with end-stage liver disease,
3. or distended varices due to backed up hepatic/portal circulation with loss of clotting factors in end stage Liver disease – cirrhosis
4. Slitting the throat in suicide (cutting any of the arteries carotid, radial, brachia, ulnar, and femoral.
Treatment of an Upper GI Bleed
1. Fluid resuscitation by restoring blood volume with Normal Saline.
2. Maintain open airway – us of oxygen, and mechanical ventilation if needed.
3. Coffee ground, melena indicative of upper GI. Bleeding
4. If unable to stabilize, usually if flushing NGT does not clear, patient will go stat to GI lab for endoscopy.
Treatment of Lower GI Bleed
1. Establish underlying cause, and location of bleed,
2. Hematochezia
3. If unstable based on labs and patient VS – IV Fluids and will go to GI Lab for colonoscopy STAT
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Follow-up comment rss or Leave a TrackbackCirrhosis with liver failure with hepatic encephalopathy
Cirrhosis
• A degenerative liver disorder caused by generalized cellular damage. Cirrhosis is when the liver cells are damaged then are replaced by scar tissue as the damage increase the liver becomes unable to carry out its functions.
• People most at risk are alcoholics, hepatitis positive and exposure to toxins
• Signs:
– Chronic fatigue, anorexia, dyspepsia, nausea and vomiting, diarrhea or constipation with accompaning weight loss, bleeds, easy bruising, dark or “tea colored” urine, clay colored or whitish stool and pruritus
• Symptoms:
– Skin,sclera or oral mucous membranes are jaundice, edema in legs and feet, veins are dilated over abdomen, cutaneous spider angiomata
• Diagnostic tests
– Liver biopsy
– Surgical incision
– Ultra sound
– CT scan
– MRI
– Radioisotope liver scan
• Treatment:
– NO TREATMENT. You can only try to prevent further deterioration
– Vitamin and supplements given:
• Vitamin K,B,C and iron may be prescribed
• IV albutamin may be given if hypoproteinemia is severe
– Patient education on discontinuation of alcohol
Liver Failure
• As the disease progresses it is referred to decompensated cirrhosis.
• Signs and symptoms are very pronounced and it indicates liver failure.
Hepatic encephalopathy
• CNS manifestation of liver failure due to an increase of ammonia in the blood
• Pathophysiology
– Due to the liver failure the body is unable to convert the ammonia to the urea that is normally exerted in the urine. The excess amonia is able to cross the blood brain barrier (Blood brain barrier is a physiological mechanism that alters the permeability of brain capillaries, so that some substances, such as certain drugs, are prevented from entering the brain tissue, while other substances are allowed to enter freely)that damages brain cells that perfoms metabolism and neurotransmission
Signs and symptoms (Due to the damage to the brain cells patient will show signs and symptoms)
– Disorientation
– Confusion
– Personality changes
– Asterixis aka liver flap(Asterixis is a flapping tremor of the wrist upon extension (dorsiflexion))
– Lethary
– Deep coma
– Foul oder refered to fetor hipaticus(breath)
Symptoms usually increase with high protein meals and if there is an active GI BLEED
• Diagnostic tests
– Electroencephalogram (Electro encephalogram will show abnormal waveforms. IT is Attached to scalp and electrical activity recorded on a graph)
– The cbc with differential will show low RBC counts but the cells appear large
– Blood test
• LFT
• Serum ammonia levels
• CBC with differential (The cbc with differential will show low RBC counts but the cells appear large)
– Decreased white blood cells
– Decreased thrombocytes
– Decreased Platelet counts
– Decreased albumin level
– Decreased Potassium
– Prolonged PT
• Treatment:
– Eliminate dietary protein
– Eliminating intestinal microorganisms
– Abx neomycin and kanamycin (Neomycin and kanamycin are used because those antibiotics are poorly absorbed into the GI Ttract and they will kill the microorganisms that produce ammonia)
– Lactulose(Lactulose is used to reduce serum ammonia concentration. The colon lactulose is broken down into lactic and acetic acid which attracts ammonia and make it so it can be eliminated in the feces.)
– Levadopa(Levadopa is used as precurser to dopamine which help restore normal function of neurotransmitters)
– IV fluids containing electrolytes with Vit K
– Multivitamins
– TPN without proteins
– Liver transplant
• Survival rate is grim without a liver transplant
Introductory medical surgical nursing by Timby and Smith pages 878-894
HEPATITIS B
HBV is transmitted through activities that involve percutaneous (i.e., puncture through the skin) or mucosal contact with infectious blood or body fluids (e.g., semen, saliva), including
• Sex with an infected partner
• Injection drug use that involves sharing needles, syringes, or drug-preparation equipment
• Birth to an infected mother
• Contact with blood or open sores of an infected person
• Needle sticks or sharp instrument exposures
• Sharing items such as razors or toothbrushes with an infected person
HBV is not spread through food or water, sharing eating utensils, breastfeeding, hugging, kissing, hand holding, coughing, or sneezing.
Scenario: Lack of knowledge about transmission and prevention of Hepatitis B among teenagers
Assessment: Teenager stated “What is Hepatitis B and how do you prevent it?”
Diagnosis: Risk for Infection Transmission related to contagious nature of virus type B
Plan: Teach teenagers about HBV transmission prevention
Intervention to Avoid Transmission from infected person
• Educate about HBV and how it is transmitted
• Know the HBV status of your sexual partner
• Use a new latex or polyurethane condom every time you have sexual intercourse
• If you use a needle to inject illicit drugs, make sure it’s sterile, and don’t share it. Take advantage of needle exchange programs in your community and consider seeking help for your drug use
• If you’re planning an extended trip to a region where hepatitis B is endemic, ask your doctor about the hepatitis B vaccine well in advance
• If an emergency requires that you receive blood or blood products in another country, get tested for HBV as soon as you return home
Intervention to avoid transmission if you are infected:
• Follow guidelines for safe sex, including using a new latex condom every time you have sexual intercourse and using a dental dam, condom or piece of plastic wrap during oral sex. If you use sexual devices, don’t share them
• Tell your sexual partner(s) you have HBV
• If you use IV drugs, never share your needles and syringes with anyone.
• Don’t donate blood or organs
• Don’t share razor blades or toothbrushes
• If you’re pregnant, tell your doctor you have HBV
Evaluation
Teenagers are more aware of how they can transmit and prevent Hepatitis B virus
GI Bleeding
By: Dianna Orozco
Jen Young
Paolo Villena
What is GI bleeding?
GI bleeding is referred to any bleeding from the mouth to the anus.
Bleeding in the GI tract is often divided into two sections:
Upper GI bleeding
Lower GI bleeding
Upper vs. Lower
Upper: originates in the first part of the GI tract; esophagus, stomach, duodenum.
Usually caused by stomach cancer, peptic ulcers, gastritis, and esophageal varices, Mallory-Weiss tear
Lower: originates in the portions further down the digestive system; large intestine, rectum, and anus
Usually caused by diverticular disease, anal fissures, hemorrhoids, angiodysplasia, polyps,
Causes of upper GI bleeding…
Peptic ulcer disease: localized erosions on the wall of the digestive tract. The breakdown of the wall is what causes the bleeding.
NSAIDS, aspirin, alcohol, and cigarette smoking promote gastric ulcer formation
Gastritis is the inflammation of the stomach wall which results in bleeding.
NSAIDS, steroids, alcohol, burns, and trauma can be the cause of gastritis
Esophageal varices: swellings in veins of the esophagus or stomach usually as a result of liver disease.
Most commonly a result of liver cirrhosis
Mallory-Weiss tear: a tear in the esophagus or stomach, often as a result of vomiting or retching
Could also occur from seizures, forceful laughing or coughing, lifting, straining, or childbirth
Causes of lower GI bleeding…
Diverticulitis: inflammation of the diverticulum.
After a person has diverticulosis, which is little pockets in the colon, one of those pockets will rupture and bleed, causing the inflammation.
Angiodysplasia: malformation in the blood vessels in the wall of the GI tract
Tiny blood vessels lining the colon that sometimes can bleed briskly or ooze chronically.
Polyps: intestinal noncancerous tumors of the GI tracts
Occur mostly in people older than 40 yrs. Of age
Hemorrhoids: swellings of the veins in and around your rectum
Repeated stretching from straining from stool
Anal fissures: tears in the anal wall.
Forceful straining during passage of hard stool
Symptoms of bleeding:
Acute GI bleeding will first appear as vomiting blood, bloody bowel movements, or black, tarry stools.
Long-term GI bleeding may go unnoticed or may cause fatigue, anemia, or black tarry stools
Fatigue, SOB, weakness, abdominal pain, and pale appearance
Tests and Exams:
Digital rectal exam- a test using your finger to test for visible or microscopic blood from the rectum
Endoscopy- tube is inserted through the nose into the stomach to help identify the cause of the bleeding
Treatment:
For hemorrhoids or anal fissures, eat a diet high in fiber and lots of fluids to keep the stool soft
For a lower GI bleed:
Establish underlying cause , and location of the bleed
Hematochezia
If unstable based on labs and patient will go to GI lab for colonoscopy STAT
For an upper GI:
Fluid resuscitation by restoring blood volume with Normal Saline.
Maintain open airway
If unable to stabolize, usually patient will go stat to GI lab for endoscopy
Prevention:
You can avoid GI bleeding by avoiding foods and factors that increase gastric secretions, such as:
Alcohol
Smoking
Foods not tolerated by your body
Eat a high fiber diet to increase bulk in your stool, which helps prevent diverticulosis and hemorrhoids.
Sources:
http://www.emedicinehealth.com/gastrointestinal_bleeding/page9_em.htm
http://www.umm.edu/ency/article/003133.htm
http://www.lvnstudy.com
Cancer of the Colon and Rectum
- cancer that begins in the colon is colon cancer, and cancer that begins in the rectum is called rectal cancer
- cancers affecting either of these organs also may be called colorectal cancer
- It occurs when some of the cells that line the colon or rectum become abnormal and grow out of control
- The abnormal growing cells create a tumor which is the cancer
Risk factors for colon cancer
- age – screening should start at 50 years of age
- diet – high fat, high calorie, low fiber
- excessive intake of alcohol
- smoking
- a sedentary lifestyle
- growth hormone disorders
- inflammatory intestinal conditions
- inherited disorders that affect the colon
Symptoms of colon cancer
- most cases of colon cancer begin as small, benign clumps of cells called polyps
- over time some of these polyps may become colon cancers
- symptoms include: weakness or fatigue, unexplained weight loss, a change in bowel habits, rectal bleeding or blood in stool, persistent abdominal discomfort
- typically, right-sided cancers cause anemia due to the slow loss of blood over a long period of time
- the left colon is narrower than the right colon, therefore, cancers of the left colon are more likely to cause partial or complete bowel obstruction
Diagnosing colon cancer
– common screening and diagnostic procedures: stool blood test, stool DNA test, flexible sigmoidoscopy, barium enema, colonscopy, virtual colonoscopy
Treating colon cancer
- 4 main types of treatment
- Colectomy (may lead to a colostomy bag)
- Chemotherapy: Fluoroplex blocks the growth of abnormal cells; Xeloda slows or stops cancer cell growth and decreases tumor size
– Radiation therapy
– Targeted drug therapy: Avastin works to prevent tumors from developing new blood vessels which can deliver oxygen and nutrients cancers need to survive; Erbitux & Vectibix target a chemical signal that tells cancer cells to divide and reproduce
– these drugs can be given alone or with chemotherapy drugs
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