Microsoft PowerPoint - Digestive 2011.

System Digestivus

Dr.Yani Istadi, M.Med.Ed

FK Unissula

Bagian Anatomi

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Human Digestive System

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Mouth

Salivary glands

Esophagus

Pharynx

Figure 38–10 The Digestive SystemSection 38-2

Stomach

Pancreas (behind

stomach)

Large intestine

Small intestine

Rectum

Gallbladder

(behind liver)

Liver

Esophagus

Human Digestive System

•• The Digestive System:The Digestive System: also called the Gastrointestinal Gastrointestinal

TractTract or the Alimentary canalAlimentary canal, begins with the mouth (the intake of food) and ends with the expulsion of waste from the anus.

• The three Main functions of the Digestive System are:

1. DigestionDigestion:: Chemical and Mechanical break down of food products.

2. AbsorptionAbsorption:: into the blood stream

3. EliminationElimination:: of solid waste from the body

• Food that is taken into the mouth is broken down

mechanically by the teeth and chemically by the saliva,

and then it travels through the remainder of the

gastrointestinal tract.

• Digestive enzymes aid in the breakdown of complex

nutrients (such as fats, proteins, and sugars).

DIGESTION:DIGESTION:

nutrients (such as fats, proteins, and sugars).

ProteaseProtease andand PeptidasePeptidase: Proteins Proteins → amino acids

Carbohydrase:Carbohydrase: SugarsSugars → glucose

LipaseLipase: FatsFats → fatty acids

The Oral Cavity

• The Oral CavityOral Cavity contains the tongue that moves food around during mastication (chewing) and deglutition (swallowing). The tongue has small raised areas called papillae, that contain taste buds that are sensitive to the chemical nature (or taste sensation) of food. sensation) of food.

• The GumsGums (or gingiva) are made up of fleshy tissue that surrounds the sockets of the teeth to provide support. The adult has 32 permanentpermanent teeth and a child between the ages of 6 months to 12 years has deciduousdeciduous teeth (or baby teeth) that total 20 when all have erupted.

Oral Cavity

Major parts of

the oral cavity

• Uvula – prevents food from going up into the pharynx when we swallow

The Oral Cavity cont..•• The ToothThe Tooth consists of a crowncrown, that shows above the

gumline, and a rootroot that lies below the gumline and within the boney tooth socket. The enamelenamel is the white covering and outermost protective layer of the crown; AND is also the hardest substance in the body. The dentindentin is a yellow softer boney tissue that lies below the enamel and throughout the root of the tooth. The cementumcementum layer throughout the root of the tooth. The cementumcementum layer covers, supports, and protects the dentin in the root of the tooth; and there is also a periodontalperiodontal membranemembrane that surrounds the cementum, and holds the tooth in the tooth socket. In the middle of the tooth, beneath the dentin, is the pulppulp. It is a soft delicate tissue that fills the tooth canal and contains blood vessels, nerve endings, connective tissue, and lymphatic vessels (also called the root canal).

Oral Cavity (cont’d.)

Upper

permanent

teeth within the

dental archdental arch

Oral Cavity (cont’d.)

Anatomy of a tooth

Cavities/Dental Caries

Oral Cavity (cont’d.)

Salivary glands

• Three sets of salivary glands produce saliva which moistens food entering the mouth making it easy to swallow

– Saliva production is stimulated by smell, stimulated by smell, hunger and taste of food

– Contains salivary amylase

The Pharynx

• The pharynx

(throat) is a

muscular tube

about 5 inches in

length, and lined length, and lined

with a mucous

membrane.

The Pharynx

• It serves as a common passageway for air to

the trachea (windpipe), and food to the

esophagus. When chewed food, mixed with

saliva (called a bolus; a semisolid mass of saliva (called a bolus; a semisolid mass of

food) is swallowed (deglutition), a flap of

tissue called the epiglottis covers the trachea

so that food cannot enter or become lodged

there.

The Pharynx

DeglutitionDeglutition:: also called swallowing

The Esophagus

• The esophagus is a 9 to 10 inch muscular tube extending from the pharynx to the stomach. Made up of circular and longitudinal muscles which expand and contract to move food to the stomach

• Peristalsis occurs here, which is rhythmical waves • Peristalsis occurs here, which is rhythmical waves of contractions of the wall muscles to propel food toward the stomach.

• Food travels in the esophagus for approx. 5 to 8 seconds, to which it then passes through a ring of muscles called the cardiac sphinctercardiac sphincter (or lower esophageal sphincter).

Swallowing Reflex and Esophageal Peristalsis

Stomach

• J-shaped musculer sac in the middle of the digestive tract and on the left side of the upper abdomen

• Has two sphincters:

1. Cardiac sphincter – allows 1. Cardiac sphincter – allows food into the stomach and keeps acid from enter the esophagus

2. Pyloric sphincter – regulates and releases the amount of food entering the small intestine

Stomach

• The stomach is composed of three

parts the fundusfundus (upper), bodybody

(middle), and antrumantrum (lower) and can

store up to 2 liters of food or liquid.

• The stomach secretes acids and

enzymes that digest food. Ridges/folds enzymes that digest food. Ridges/folds

of muscle tissue called rugaerugae line the

stomach.

• Two types of digestion:

– Mechanical digestion

– Chemical digestion

Stomach - Mechanical Digestion

• Physical breaking up of food into smaller pieces by the

teeth.

• The tongue manipulates the food into a mass called the

bolus and The squishing action in the esophagus

further break up the food mass

• the stomach walls begin to contract to mix and churn • the stomach walls begin to contract to mix and churn

food with gastric juices

– This mixture is called chyme (a semi-liquid form)

• GROSS! This is the stuff that comes up when you

get sick

• Food stays in the stomach approx 2 to 6 hours or longer

after eating ; depending on how much and what was

eaten. (longer if you eat before going to bed)

Stomach – Chemical Digestion

• Gastric glands found in the wall of the stomach (the rugae). It release gastric juices

• Gastric juices contains the enzymes pepsin pepsin (breaks proteins into polypeptides) and hydrochloric acid hydrochloric acid (maintains a pH of 2.0 in the stomach and dissolves food and kills and dissolves food and kills microorganisms).

• Production is stimulated by:– Thought, sight or smell of food

– Food entering the stomach

– Stretching of stomach wall

• With a pH of about 2, these juices are able to efficiently break down food

Stomach: Food Storage and Digestion

Stomach lining is

protected from acid

or gastric juices by…

• Mucous

The Small Intestines

• The Small IntestineSmall Intestine (also known as the small bowelsmall bowel) the longest portion of the digestive tract. It extends 20 ft from the pyloric sphincter to the first part of the large intestines( the cecum).

• Much of the small intestine is coiled and suspended in a thin layer of fat - which gives the intestine a lot of flexibility and mobility; called the mesentarymesentary. flexibility and mobility; called the mesentarymesentary.

• The intestines subdivided into three parts:

1. Duodenum – First 25 cm after the stomach

2. Jejunum – The next 2 metres

3. Ileum – the last 5 metres

• This is the site of most digestion, along with nutrient absorption

The Small Intestines

• The DuodenumDuodenum is the first section of the S. intestine. It receives the thick liquid mixture of partly-digested food and stomach acid (called chymechyme).

• The duodenum also receives bile from the gallbladdergallbladder (that is produced in the liverliver), and other digestive enzymes from liverliver), and other digestive enzymes from the pancreaspancreas. These enter the duodenum through small ducts or tubes.

• The bulk of the digestion of proteins, fats and carbohydrates takes place in the duodenum before the material travels to the second and last sections: the Jejunum and Ileum.

The Small Intestines cont..

• The jejunumjejunum is the coiled mid-section of the small intestine and the ileumileum is the final portion of the small intestine.

• The inner linings of the jejunum and ileum contain very small finger-like bumps or projections called 'villi‘.'villi‘. The villi absorb the nutrients from projections called 'villi‘.'villi‘. The villi absorb the nutrients from the thick liquid digested food and transfer them to the bloodstream, lymph vessels, and the liver.

• Any food that has not been digested in the small intestine (along with some water and vitamins) then reaches the large intestine.

Small Intestine: Site of Digestion and Absorption

Large Intestine• The Large IntestineLarge Intestine (or large bowel)

extends from the ileum to the anus. It is approx. 1.5 meters (or 4 feet 9 inches) and consists of 3 primary parts: the Cecum, Colon and the RectumCecum, Colon and the Rectum.

• The CecumCecum is the first part of the large intestine. It is shaped like a small pouch and accepts and stores processed and accepts and stores processed material from the small intestine and moves it towards the colon. In the cecum, the mixture of digesting food normally contains:

– The undigested food (such as fiber)

– a small amount of water

– non absorbed vitamins and minerals or salts

Large Intestine• The AppendixAppendix is a small projection that

hangs from the cecum and has no known function, but if blocked or clogged can become infected or inflamed (a condition known as Appendicitis).

• Within the colon, the remaining undigested mixture, mixes with mucus and bacteria that live in the large intestine - and starts to form feces (or stool)feces (or stool).form feces (or stool)feces (or stool).

• As feces travels through the colon, the lining of the colon absorbs most of the water and small amounts of vitamins and minerals.

• The bacterium in the colon chemically breaks down some of the fiber to produce nutrients for their survival and to nourish the cells lining the colon. Thus, fiber in your diet is important to maintain the long-term health of the colon.

Large Intestine cont…• The RectumRectum is an 8-inch chamber

that connects the colon to the anus and is the final part of the large intestine.

• When feces enters the rectum, sensors send a message to the brain to decide if the sphincter brain to decide if the sphincter muscles can relax and the rectum can contract, disposing of its contents into the anus.

• If the contents cannot be released, the sphincter contracts and the rectum accommodates so that the sensation temporarily goes away.

Large Intestine cont…• The AnusAnus is a 2-inch long

canal that detect the rectal contents, as to whether the contents are liquid, gas, or solid. The anus has two sphincters, one voluntary and one involuntary. The and one involuntary. The pressure of the feces on the involuntary sphincter causes the urge to defecate and the voluntary sphincter controls whether a person defecates or not.

Food

enters

through

the oral

Food Pathway through the GI Tract

the oral

cavity

and exits

through

the anus

Gangguan sistem pencernaan

Aphthous Stomatitis• Aphthous Stomatitis is an illness that causes small ulcers to appear in the mouth,

usually inside the lips, on the cheeks, or on the tongue. This is also known as "canker sores."The exact cause of this disease is not known, but there are many factors that are thought to be involved with the development of canker sores, including:

• weakened immune system

• allergies to food such as coffee, chocolate, cheese, nuts and citrus fruits

• stress

• viruses and bacteria

• trauma to the mouth

• poor nutrition • poor nutrition

• certain medications

Ulcers• An ulcer is erosion in the lining of the esophagus, stomach, or

duodenum. While acid is still considered significant in ulcer

formation, the leading cause of ulcer disease is currently believed to

be infection of the stomach by a bacteria called "Helicobacter

pyloricus" (H. pylori). Another major cause of ulcers is the chronic use

of anti-inflammatory medications.

ConstipationWhen you are not physically active, consuming dietary fibers, and/or become

dehydrated, you are likely to suffer from constipation. It is common for a

constipated person to experience uncomfortable bowel movements and also

feelings of and/or bouts of bloating. This condition usually happens when waste

substance remains too long in the colon, causing more and more water being

absorbed from the waste which also means the feces/stool passes along the large

intestine too slowly. The end result is the dry, lumpy and hard feces, that causes

difficulty and pain during defecation

Diarrhea• Diarrhea most commonly happens when the intestines and part of the body

gets infected. When this condition happens, the colon is unable to absorb

water quickly enough from liquid waste. The waste is then pushed out of the

anus quickly and simultaneously, causing spasms within the muscles of the

colon, and/or within the abdominal area. Therefore, the feces passes along the

large intestine too quickly and the water is not able to be absorbed from the

waste. Diarrhea causes mushy, loose, watery feces/stool.

Colonic Polyposis• A polyp is an extra piece of tissue that grows inside your body.

Colonic polyps grow in the large intestine, or colon. Most polyps are

not dangerous. However, some polyps may turn into cancer or

already be cancer. To be safe, doctors remove polyps and test them.

Polyps can be removed when a doctor examines the inside of the

large intestine during a colonoscopy.

Ulcerative Colitis• Ulcerative colitis is a disease that causes ulcers in the lining of the rectum and

colon. It is one of a group of diseases called inflammatory bowel disease. Ulcers form where inflammation has killed the cells that usually line the colon.

• Ulcerative colitis can happen at any age, but it usually starts between the ages of 15 and 30. It tends to run in families. The most common symptoms are pain in the abdomen and bloody diarrhea. Other symptoms may include anemia, severe tiredness, weight loss, loss of appetite, and bleeding from the rectum.

Diverticulosis• Diverticulosis is a term for small Diverticulosis is a term for small Diverticulosis is a term for small Diverticulosis is a term for small outpouchesoutpouchesoutpouchesoutpouches, or sacs, that develop along an , or sacs, that develop along an , or sacs, that develop along an , or sacs, that develop along an

intestinal wall, usually the colon. Once diverticulosis occurs, it cannot be intestinal wall, usually the colon. Once diverticulosis occurs, it cannot be intestinal wall, usually the colon. Once diverticulosis occurs, it cannot be intestinal wall, usually the colon. Once diverticulosis occurs, it cannot be reversed, if one of the pouches becomes impacted with waste material, it can reversed, if one of the pouches becomes impacted with waste material, it can reversed, if one of the pouches becomes impacted with waste material, it can reversed, if one of the pouches becomes impacted with waste material, it can lead to infection and inflammation. weakening of the walls of the colon due to lead to infection and inflammation. weakening of the walls of the colon due to lead to infection and inflammation. weakening of the walls of the colon due to lead to infection and inflammation. weakening of the walls of the colon due to aging and obesity are causative factors. Diverticulosis occurs mostly in people aging and obesity are causative factors. Diverticulosis occurs mostly in people aging and obesity are causative factors. Diverticulosis occurs mostly in people aging and obesity are causative factors. Diverticulosis occurs mostly in people over the age of 60, and more than half of the patients who develop it are over the age of 60, and more than half of the patients who develop it are over the age of 60, and more than half of the patients who develop it are over the age of 60, and more than half of the patients who develop it are markedly overweight.markedly overweight.markedly overweight.markedly overweight.

• Overuse of laxatives also weakens the colon. Overuse of laxatives also weakens the colon. Overuse of laxatives also weakens the colon. Overuse of laxatives also weakens the colon.

Colorectal CancerThe wall of the colon and rectum is made up of layers of tissues. Colorectal

cancer starts in the inner layer and can grow through some or all of the other

layers. The stage (extent of spread) of a cancer depends to a great degree on

how deep the cancer goes into these layers. Cancer that starts in these

different areas may cause different symptoms. But colon cancer and rectal

cancer have many things in common. In most cases, colorectal cancers

develop slowly over many years. It is now know that most of these cancers

start as a polyp -- a growth of tissue that starts in the lining and grows into

the center of the colon or rectum. This tissue may or may not be cancer. A the center of the colon or rectum. This tissue may or may not be cancer. A

type of polyp known as an adenoma can become cancer. Removing a polyp

early may keep it from becoming cancer. Over 95% of colon and rectal

cancers are Adenocarcinomas.

Anal Fistula• An anal fistula is a small channel that develops between the end

of the bowel, known as the anal canal, and the skin near the anus

(opening where waste leaves the body).

• On the surface of the skin around the anus, one or more of the

fistula ends may be seen as holes. An anal fistula is painful and

can cause bleeding and discharge when passing stools.

Hemorrhoids• Hemorrhoids, also called piles, are swollen and inflamed veins in your

anus and lower rectum. Hemorrhoids may result from straining

during bowel movements, sitting on the toilet to long, or from the

increased pressure on these veins during pregnancy. Hemorrhoids

may be located inside the rectum (internal hemorrhoids), or they

may develop under the skin around the anus (external hemorrhoids).

Anorexia: Anorexia nervosa is a type of Anorexia nervosa is a type of eating disorder. People who have anorexia have an intense fear of . People who have anorexia have an intense fear of

gaining weightgaining weight. They severely limit the amount of food they eat and can become dangerously thin. . They severely limit the amount of food they eat and can become dangerously thin.

Anorexia affects both the body and the mind. It may start as Anorexia affects both the body and the mind. It may start as dietingdieting, but it gets out of control. These , but it gets out of control. These

people think about food, dieting, and people think about food, dieting, and weightweight the majority of their day. They have athe majority of their day. They have a distorted body image.

When they look in the mirror, they see a fat person.

Literature

• Human Anatomy, First Edition McKinley & O'Loughlin

•• Atlas Atlas sobotasobota

•• Ethel Sloane, Ethel Sloane, AnatomiAnatomi dandan FisiologiFisiologi, , PenerbitPenerbit EGCEGC

•• Kyung Won Chung, Gross Kyung Won Chung, Gross AnatomiAnatomi, , PenerbitPenerbit BinarupaBinarupaAksaraAksaraAksaraAksara

•• Keith Keith L.MooreL.Moore dandan Arthur Arthur F.DalleyF.Dalley. . 2010. 2010. Clinically Clinically oriented oriented AnatomyAnatomy. 6 Ed.. 6 Ed.

• Seeley,R.R., Stephens,T.D., Tate,P.2003. Anatomy &

Physiology. McGraw Hill

Eat up!