Makalah Gastrointestinal EIN

CHAPTER I

INTRODUCTION

1.1.BACKGROUND

The gastrointestinal tract (GIT) consists of a hollow muscular tube starting from the oral cavity, where food enters the mouth, continuing through the pharynx, oesophagus, stomach and intestines to the rectum and anus, where food is expelled. There are various accessory organs that assist the tract by secreting enzymes to help break down food into its component nutrients. Thus the salivary glands, liver, pancreas and gall bladder have important functions in the digestive system. Food is propelled along the length of the GIT by peristaltic movements of the muscular walls.

The primary purpose of the gastrointestinal tract is to break food down into nutrients, which can be absorbed into the body to provide energy. First food must be ingested into the mouth to be mechanically processed and moistened. Secondly, digestion occurs mainly in the stomach and small intestine where proteins, fats and carbohydrates are chemically broken down into their basic building blocks. Smaller molecules are then absorbed across the epithelium of the small intestine and subsequently enter the circulation. The large intestine plays a key role in reabsorbing excess water. Finally, undigested material and secreted waste products are excreted from the body via defecation (passing of faeces).

In the case of gastrointestinal disease or disorders, these functions of the gastrointestinal tract are not achieved successfully. Patients may develop symptoms of nausea, vomiting, diarrhea, malabsorption, constipation or obstruction. Gastrointestinal problems are very common and most people will have experienced some of the above symptoms several times throughout their lives.

1.2.PURPOSE

1.2.1.      GENERAL PURPOSE

The students and readers understand the importance of gastrointestinal system.

1.2.2.      SPECIFIC PURPOSE

                 The students be able to :

1)      Explain and describe anatomy and physiology of Gastrointestinal System

2)      Expressing various kinds vocabulary about Gastrointestinal System

3)      Apply their knowledge about Gastrointestinal System in hospital and society

CHAPTER II

THEORETICAL REVIEW

2.1. ANATOMY AND PHYSIOLOGI OF GASTROINTESTINAL SYSTEM

1. Oral Cavity (Mouth)

Food enters the gastrointestinal system via the mouth or oral cavity, mucous membrane lined. The lips (labia) protect its outer opening, cheeks from lateral walls, hard palate and soft palate form anterior/posterior roof. It communicate with nasal cavity behind soft palate. Floor is muscular tongue. Tongue has bony attachments (styloid process, hyoid bone) attached to floor of mouth by frenulum. Posterior exit from mouth guarded by a ring of palatine/lingual tonsils. Enlargement of this organ called sore throat or tonsillitis.

Food is first processed (bitten off) by teeth, especially the anterior incisors. Suitably sized portions then retained in closed mouth and chewed or masticated (especially by cheek teeth, premolars, molars) aided by saliva. Ducted salivary glands open at various points into mouth. This process involves teeth (muscle of mastication move jaws) and tongue (extrinsic and intrinsic muscles). Mechanical breakdown, plus some chemical (ptyalin, enzyme in saliva). Taste buds allow appreciation, also sample potential hazards (chemical, toxins).

2.    Throat

In leaving the mouth a bolus of food must cross the respiratory tract (trachea is anterior to esophagus) by a complicated mechanism known as swallowing or deglutination which empties the mouth and ensures that food does not enter the windpipe swallowing involves coordinated activity of tongue,soft palate pharynx and esophagus.The first (buccal) phase is voluntary, food being forced into the pharynx by the tongue. After this the process is reflex. The tongue blocks the mouth, soft palate closes off the nose and the larynx rises so that the epiglottis closes off the trachea.Food thus moves into the pharynx and onwards by peristalsis aided by gravity.if we try to talk whilst swallowing food may enter the respiratory passages and a cough reflex expels the bolus.

3.    Esophagus

The esophagus is the first part of the digestive tract proper and shares its distinctive structure. Basic tissue layers of the gut are :

1)      Mucosa

Innermost, moist lining membrane. Epithelium (friction resistant stratified squamous in esophagus, simple beyond) plus a little connective tissue and smooth muscle.

2)      Submucosa

Soft connective tissue layer, blood vessels, nerves, lymphatics.

3)      Muscularis externa

Typically circular inner layer, longitudinal outer layer of smooth muscle.

4)      Serosal fluid producing single layer

4.    Stomach

Stomach is located below the body cavity constriction or above abdominal cavity. Stomach has some primary functions, such as storing food, mixing food, and preparing the hydrolysis process of protein enzymes.

Stomach consists of three parts. Firstly, food enters the stomach through cardiac. Then, it goes toward fundus and pylorus. Pylorus is close to the lock muscle (valve) that controls food transfer into the intestine.

Stomach wall is composed of some muscular layers, longitudinal muscles in the outer layer, circular muscles in the middle layer, and oblique muscle in the inner layer. When these muscle contract, the food in gastric will mix all together with gastric acid and become chymus.

Stomach wall has stomach glands producing mucosa, gastric acid, and gastrin hormone.

1)      Mucus is produced by mucose cells.

2)      Gastric acid consists of several substances as follows :

a.       Hydrochloride acid (HCl) is produced by parietal cells. It is necessary to kill germs, create acidic environment (with a pH nearly to 1), stimulate secretion of intestine juice, stimulate the opening and closing of pylorus sphincter, and activate pepsinogen into pepsin.

b.      Pepsin is a protease enzyme which breaks down protein into pepton.

c.       Rennin is an enzyme which has function to curdle the milk protein (casein). Generally, it is found in young mammals.

d.      Lipase is an enzyme which breaks down lipid into fatty acid and glycerol. It is produced by salivary gland that is accumulated in gastric.

3)      Gastrin hormone is a hormone that stimulates secretion of gastric acid in gastric.

5.    Small Intestine

Small intestine has the length of about 8.5 meters. On the wall, there are some glands producing intestine secretion. Small intestine is composed of three parts which are as follows :

a)      Duodenum (twelve-finger intestion) is the inferior section of small intestine with about 25 cm in length, U-shaped, and an end section of gall bladder and pancreas.

b)      Jejunum is the central section of small intestine with the length of about 7 m.

c)      Ileum (absorption intestine) is the final section of small intestine with the length of about 1 m.

Intestinal cells absorb nutrient needed by body. The waste material that cannot be used by body is transferred to large intestine.

In lipid absorption, fatty acid reacts with bile salt to form an emulsion, and with glycerol, it is absorbed by villous. In villous, fatty acid is separated from bile salt, and it bonds glycerin to form lipid (phospholipid). Phospholipid is released into lymph system in the form of small spheres layered with protein (chylomicron) and then it is carried to venous.

Other nutrients, such as vitamin, mineral, and water, will be absorbed by capillary vessel. The remain bile salt will enter the blood, and then it is carried to liver to be converted into bile again.

6.    Large Intestine (Colon) and Anus

Human colon is divided into three sections, ascendence, transcendence, and descendence. The colon tract ends in an area which is so-called rectum. Rectum ends in a hole at body surface which is called anus. Rectum has muscle that plays a role to hold the feces not to go into the anus, known as Houston valve.

Large intestine and small intestine are separated by a valve called ileosecum which is necessary to prevent food from coming back into small intestine. At the end of ileosecum, there is a appendix and cecum. Colon reabsorbs water and mineral that come from material waste of small intestine.

Large intestine contains a population of symbion bacteria that function in the substrate of plant cellulose, pectin, removed intestinal cells, and polysaccharide from intestinal mucosa. The fermentation results are organic acid, metan gas, and hydrogen. During digestion, there are also bacteria population producing vitamin B and K. The vitamin is absorbed by the cell of large intestinal surface. The waste materials of digestive process is thrown away through anus (defecation).

7. Accessory Digestive Organs

     7.1. Salivary Glands

Three pairs of salivary glands communicate with the oral cavity. Each is a complex gland with numerous acini lined by secretory epithelium. The acini secrete their contents into specialised ducts. Each gland is divided into smaller segments called lobes. Salivation occurs in response to the taste, smell or even appearance of food. This occurs due to nerve signals that tell the salivary glands to secrete saliva to prepare and moisten the mouth. Each pair of salivary glands secretes saliva with slightly different compositions.

     7.2. Pancreas

     The pancreas is a lobular, pinkish-grey organ that lies behind the stomach. Its head communicates with the duodenum and its tail extends to the spleen. The organ is approximately 15cm in length with a long, slender body connecting the head and tail segments. The pancreas has both exocrine and endocrine functions. Endocrine refers to production of hormones which occurs in the Islets of Langerhans. The Islets produce insulin, glucagon and other substances and these are the areas damaged in diabetes mellitus. The exocrine (secretrory) portion makes up 80-85% of the pancreas and is the area relevant to the gastrointestinal tract.

It is made up of numerous acini (small glands) that secrete contents into ducts which eventually lead to the duodenum. The pancreas secretes fluid rich in carbohydrates and inactive enzymes. Secretion is triggered by the hormones released by the duodenum in the presence of food. Pancreatic enzymes include carbohydrases, lipases, nucleases and proteolytic enzymes that can break down different components of food. These are secreted in an inactive form to prevent digestion of the pancreas itself. The enzymes become active once they reach the duodenum.

     7.3. Liver and Gallbladder

Bile, a watery greenish fluid is produced by the liver and secreted via the hepatic duct and cystic duct to the gall bladder for storage, and thence on demand via the common bile duct to an opening near the pancreatic duct in the duodenum. It contains bile salts, bile pigments (mainly billirubin, essentially the non-iron part of haemoglobin) cholesterol and phospholipids. Bile salts and phospholipids emulsify fats, the rest are just being excreted. Gallstone are usually cholesterol based, may block the hepatic or common bile duct causing pain, jaundice.

2.2. TYPES AND CLASSIFICATION

2.2.1. Mechanical Digestion

Mechanical digestion is simply the aspects of digestion achieved through a mechanism or movement. There are two basic types of mechanical digestion.

Mastication: The first step when it comes to digestion actually begins as soon as food enters the mouth. Mastication (chewing) begins the process of breaking down food into nutrients. As a type mechanical digestion, chewing our food is an important part of the digestive process because smaller pieces are more readily digested through chemical digestion.

Peristalsis: Mechanical digestion also involves the process known as peristalsis. Peristalsis is simply the involuntary contractions responsible for the movement of food through the esophagus and intestinal tracts.

2.2.2. Chemical Digestion

Chemical digestion is much like it sounds – those aspects of digestion achieved with the application of chemicals to our food. Digestive enzymes and water are responsible for the breakdown of complex molecules such as fats, proteins, and carbohydrates into smaller molecules. These smaller molecules can then be absorbed for use by cells. The presence of these digestive enzymes accelerates the digestion process, where absence of these enzymes slows overall reaction speed. Currently, there exist eight digestive enzymes mainly responsible for chemical digestion.

2.3. ETIOLOGY

2.3.1. Gastritis

Gastritis is an acute or chronical inflammation on mucosa layer of stomach wall. Weaknesses in the mucus-lined barrier that protects your stomach wall allow your digestive juices to damage and inflame your stomach lining. A number of diseases and conditions can increase your risk of gastritis. Gastritis can develop suddenly (acute gastritis) or gradually and last for an extended period (chronic gastritis).

2.3.2. Diarrhea

Diarrhea is an irritation on the membrane of colon wall caused by bacteria dysentriae, bad diet, poiosonous matters, and stress.

Diarrhea can be described as an abnormal increase in the frequency, volume or liquidity of your stools. The condition usually lasts a few hours to a couple of days. Diarrhea is typically associated with abdominal cramps.

The most common causes of diarrhea include:

-Viruses

-Bacteria

-Parasites

Diarrhea that persists for more than a couple of days is considered chronic and may be a sign of an underlying condition, such as inflammatory bowel disease or an infection. In these cases, diarrhea may lead to dehydration and requires the care of your doctor. Dehydration occurs when the body has lost too much fluid and electrolytes -- the salts potassium and sodium. The fluid and electrolytes lost during diarrhea need to be replaced promptly because the body cannot function properly without them.

2.3.3. Appendicitis

Appendicitis is an inflammation and swelling of blind gut. The cause of appendicitis isn't always clear. Sometimes appendicitis can occur as a result of:

·         An obstruction. Food waste or a hard piece of stool (fecal stone) can block the opening of the cavity that runs the length of your appendix.

·         An infection. Appendicitis may also follow an infection, such as a gastrointestinal viral infection, or it may result from other types of inflammation.

In both cases, bacteria inside the appendix multiply rapidly, causing the appendix to become inflamed, swollen and filled with pus. If not treated promptly, the appendix can rupture.

2.4. CLINICAL APPEARANCES

2.4.1. Gastritis

The signs and symptoms of gastritis include:

·         Gnawing or burning ache or pain (indigestion) in your upper abdomen that may become either worse or better with eating

·         Nausea

·         Vomiting

·         A feeling of fullness in your upper abdomen after eating

Gastritis doesn't always cause signs and symptoms.

2.4.2. Diarrhea

Signs and symptoms associated with diarrhea may include:

·                Frequent loose, watery stools

·                Abdominal cramps

·                Abdominal pain

·                Fever

·                Bleeding

·                Dizziness from dehydration

2.4.3. Appendicitis

Signs and symptoms of appendicitis may include:

·                Aching pain that begins around your navel and often shifts to your lower right abdomen

·                Pain that becomes sharper over several hours

·                Tenderness that occurs when you apply pressure to your lower right abdomen

·                Sharp pain in your lower right abdomen that occurs when the area is pressed on and then the pressure is quickly released (rebound tenderness)

·                Pain that worsens if you cough, walk or make other jarring movements

·                Nausea

·                Vomiting

·                Loss of appetite

·                Low-grade fever

·                Constipation

CHAPTER III

CLOSING

3.1. CONCLUSION

The Gastrointestinal Tract starting from the mouth and ends at the anus. In every phase of the movement of food involves many organs and substances, such as : enzyme (ptyalin, rennin, pepsin, HCl), pancreas, liver, etc.

Nursing students as candidates for future nurses have to understand about this theme. Because, a nurses should be give provide nursing care in gastrointestinal disease.

REFERENCES

Nursalam. 2010. English in Nursing-Midwifery Science and Technology. Jakarta : Salemba Medika

Keshav, Satish and Bailey, Adam. 2013. The Gastrointestinal System at a Glance 2^nd Edition. UK : Wiley-Blackwell

Martini. 2001. 5^th Edition Fundamentals of Anatomy and Physiology. US : Pearson