The Digestive System

Maintenance Systems

Unit 7

Standards and Objectives05.01 Describe the basic functions of the digestive system: ingestion, digestion, absorption, and excretion.

05.02 Describe the basic functions of the digestive organs (mouth, pharynx, esophagus, stomach, small intestines, large intestines, rectum, and anus) and their role in digestion.

05.03 Describe the diseases and disorders of the digestive system: colon cancer, Crohn’s disease, celiac disease, appendicitis, and inguinal hernia.

05.04 Recognize levels of education, credentialing requirements, employment opportunities, workplace environments, and career growth potential for the following careers relating to the digestive system: dentist, dental assistant, dental hygienist, dietitian, and central services.

Vocabulary• Mastication - chew: biting and grinding food in your

mouth so it becomes soft enough to swallow

• Emulsification – (in digestion) The breakdown of fat globules in the duodenum into tiny droplets, which provides a larger surface area on which the enzyme pancreatic lipase can act to digest the fats into fatty acids and glycerol.

• Deglutition – the act of swallowing

• Peristalsis – involuntary relaxation and contraction of a tubular organ to allow contents to move through.

The Basic Functions of the Digestive System

• Ingestion-taking nutrients into the body, i.e., eating

• Digestion-the mechanical and chemical breakdown of food into a usable form

• Absorption-the movement of molecules through the mucosal lining of the stomach and small intestine, and into the blood

• Excretion-the removal of solid waste from the body

• Sphincters-circular muscles that contract and move food through the GI tract.

The Digestive Organs• Mouth• Pharynx • Larynx• Esophagus• Stomach• Small Intestines – 3

duodenum, jejunum, ileum

• Large Intestines – 4ascending, transverse, descending, sigmoid

• Rectum• Anus

MouthDigestion starts here!!!

• Mechanical digestion-chewing or

“mastication”

• Chemical digestion-digestion of carbohydrates

TeethEnamel – hard, white covering protects tooth from

wear and tear of chewing. The hardest substance in your body.

Dentine – below the enamel, it is the yellow bone-like material that is softer than enamel and carry some of the nerve endings.

Pulp – is the center of the tooth. It contains blood vessels and nerves. Where the tooth receives nourishment

Cementum – covers root of tooth, attaches tooth to the

bones in the jaw.

Pharynx• Also called the throat

Nasopharynx

Oropharynx

Laryngopharynx

• A passageway for food, liquids, and air

Esophagus• Muscular tube located behind the

trachea

• About 10 inches long

• Transports food from the pharynx to the stomach

• Upper and Lower esophageal sphincters

Stomach• J-shaped pouch located below the

diaphragm

• Chemical digestion of protein occurs in the stomach due to gastric juice secretion

• Mechanical digestion occurs in the stomach due to maceration (churning). Three layers of muscles in the stomach create the movement of maceration.

Liver • Largest organ in the body

• Liver has many jobs– Changing food into energy– Cleaning alcohol and poisons from the

blood– Creates Bile, a yellowish-green liquid that

helps with the digestion of food.

Gallbladder• Structure on the underside of the liver

• Function of the gallbladder is to store bile that is produced in the liver

• Bile is secreted into the intestines to help with the emulsification of fats.

Small Intestines• Chemical digestion of nutrients and

absorption of nutrients is completed in the small intestines

• Three divisions of the small intestines:– Duodenum – first portion of the small intestine

where the majority of chemical digestion occurs.

– Jejunum – middle portion of the small intestine where the majority of absorption of nutrients occurs.

– Ileum – final portion of the small intestine where absorption occurs.

Large Intestines• The large intestines are the last part of

the digestive system.

• Absorption of water, vitamins, electrolytes, production of vitamin K, and formation of feces occurs in the large intestines

• Ascending, Transverse, Descending, Sigmoid colons

Rectum• The last portion of the large intestine

which functions as a temporary storage of solid wastes before excretion

Anus• The final portion of the rectum where

solid waste is excreted from the body

Diseases and Disorders of the Digestive System

Colon Cancer• Most of the cancers of the large intestine are believed

to have developed from polyps (benign tumors). • Cancer of the colon and rectum, also called colorectal

cancer can invade and damage adjacent tissues and organs.

• Symptoms include fatigue, weakness, shortness of breath, change in bowel habits including diarrhea or constipation, red or dark blood in stool, weight loss, abdominal pain, cramps, or bloating.

• Surgery is the most common treatment for colon cancer.

• Quick Write: Who is more likely to get colon cancer, men or women?

Crohn’s Disease• Chron’s disease is an ongoing disorder that causes

inflammation of the digestive tract.• The disease can affect any area of the GI tract, from

the mouth to the anus, but it most commonly affects the lower part of the small intestine, the ileum.

• The swelling extends deep into the lining of the affected organ.

• The swelling can cause pain and can make the intestines empty frequently, resulting in diarrhea.

• Chron’s disease may be caused by an abnormally functioning immune system.

• Treatment includes prescription medications, nutritional supplements, surgery, or a combination of these.

• There is no cure.

Celiac Disease• Celiac disease is a digestive disease that damages the

small intestine and interferes with absorption of nutrients from food.

• People who have celiac disease cannot tolerate a protein called gluten, found in wheat, rye, and barley.

• When people with celiac disease eat foods or use products that contain gluten, their immune system responds by damaging the small intestine.

• Celiac disease is an autoimmune disease that is genetic.

• The most common symptoms include pain in the digestive system or other parts of the body.

• The only know treatment is a gluten-free diet.

Appendicitis

• Appendicitis, inflammation of the appendix, is the most common surgical disease.

• It results from the obstruction of the opening to the appendix by a mass, structure or infection.

• Symptoms of appendicitis include generalized abdominal pain, pain localized in the lower right abdomen, nausea, vomiting, possibly fever, and an elevated white blood cell count.

• Treatment involves the removal of the appendix and antibiotics.

Inguinal Hernia• Inguinal hernias occur when a part of the

intestine protrudes through a weak point or tear in the abdominal wall.

• This protrusion creates a buldge which can be painful.

• Some inguinal hernias occur at birth when the abdominal lining does not close properly.

• Other inguinal hernias occur later in life when muscles weaken or deteriorate.

• The most common treatment is surgery.

Careers• Dentist

• Dental Assistant

• Dental Hygienist

• Dietitian

• Central Service Technician

• Proctologist

Dentist• Doctor who study, diagnose, treat and

prevent diseases and disorders of the oral cavity.

• Undergraduate degree plus four years of dental school

• $60,000 to start – over $100,000/yr is common after a few years of practice.

Dental Hygienist• Teach patients oral hygiene, providing

preventive dental care, examination of patient gums and teeth and recording oral problems as well as cleaning teeth.– Some states they can give local anesthetics

by use of syringe, perform filling procedures, and remove stitches.

• Education – 4 years

• Salary - $74,000/yr

Dental Assistant• Help with office services such as

scheduling appointment, updating patient files, setting up tool packs for dentist or hygienist.

• Education – less than 12 month dental assisting course.

• Salary - $33,000/yr

Dietician • Help others to develop and maintain a

healthy diet. Can work in a variety of settings such as: hospitals, health care facilities, schools, and government agencies.

• Education – Bachelor’s degree and state licensure or certification.

• Salary - $50,000/yr

Central Services Technician • Clean medical instruments, assemble

surgical trays and examine medical equipment for repairs. – AKA central sterile supply technicians and

medical equipment preparers.

• Education – technical school or community college, less than 6 months.

• Salary - $30,000/yr

Proctologist • Field of internal medicine that aims to

prevent diseases and disorders of the colon, rectum and anus through preventative medicine and treatments.

• Education – 4 years undergraduate plus 4 years of medical school and 6 years of residency as a proctologist and surgeon.

• Salary - $200,000/yr