digestion, absorption and transport objectives for chapter 3 list the organs and accessory organs of...
TRANSCRIPT
![Page 1: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/1.jpg)
Digestion, Absorptionand Transport
![Page 2: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/2.jpg)
Objectives for Chapter 3
• List the organs and accessory organs of the digestive tract.
• Discuss the main roles of each of the organs of the digestive tract.
• Identify how other body systems assist the digestive tract.
• Name a digestive disorder that can occur for each of the following: mouth, esophagus, stomach, and intestines.
![Page 3: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/3.jpg)
What Is Digestion?
Digestion: a multi-step process of breaking down foods into absorbable components using mechanical and chemical means in the gastrointestinal (GI) tract
• Gastrointestinal tract consists of:– Mouth– Esophagus– Stomach – Small and large intestines – Other organs
![Page 4: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/4.jpg)
What is Digestion?
• Anatomy of the GI – mouth esophagus stomach
small intestine large intestine• GI tract is about 23 feet long with
extensive surface area for nutrient absorption.– Cells lining GI tract are replaced every
3–5 days.
![Page 5: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/5.jpg)
What Is Digestion?
• Main roles of the GI tract are to:– Break down food into smallest components– Absorb nutrients– Prevent microorganism or other harmful
compounds in food from entering tissues of the body
• GI tract is highly efficient: 92-97% of nutrients from food are digested and absorbed.
![Page 6: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/6.jpg)
Digestion Is Mechanical and Chemical
Mechanical digestion: chewing, grinding food to aid swallowing– Peristalsis: the forward, rhythmic muscular
contraction that moves food through GI tract
Chemical digestion: digestive juices and enzymes break down food into absorbable nutrients
![Page 7: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/7.jpg)
Digestion• The mouth
– Saliva released: contains water, electrolytes, mucus and a few enzymes
• Softens, lubricates, dissolves food particles
– Bolus (food mass) moves into pharynx, is swallowed, and enters the esophagus.
– Epiglottis closes off trachea during swallowing to prevent food from lodging in the windpipe.
– involves mastication (chewing),
![Page 8: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/8.jpg)
The epiglottis prevents food from entering the trachea when you swallow.
![Page 9: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/9.jpg)
Digestion
• The esophagus – Esophagus leads food into the stomach– Bolus is pushed down esophagus by peristalsis.
• Lower Esophageal Sphincter (LES): at bottom of esophagus relaxes and allows food into stomach
• LES then closes to prevent backflow of hydrochloric acid (HCl) from stomach– “Reflux” of stomach acid causes “heartburn” (irritation
of esophagus lining).
![Page 10: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/10.jpg)
Peristalsis: Muscles around
organs of GI tract constrict in wavelike manner to move food
along.
![Page 11: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/11.jpg)
Digestion
• The stomach – Stomach stores, mixes and prepares food for
digestion – grinds the bolus to a semi-liquid mass called chyme.
• Stomach produces powerful digestive secretions: – HCl: activates enzyme pepsin, enhances absorption
of minerals, breaks down connective tissue of meat• Makes the stomach acidic with a pH of 1.5 – 1.7• Mucus protects stomach lining from damage
– Digestive enzymes, intrinsic factor (for vitamin B12 absorption), stomach hormone gastrin
![Page 12: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/12.jpg)
Digestion
The Stomach (cont’d)• The pyloric sphincter regulates the flow of
partially digested food into the small intestine. Allows about 1 tsp of chyme to enter the small intestine every 30 seconds
• Gastrin: stimulates digestive activities and secretion of HCl, increases gastric motility and emptying
• Liquids, carbohydrates, low-fiber and low-calorie foods exit stomach faster
• High fiber, fat and protein foods exit slower, keep you feeling full longer
![Page 13: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/13.jpg)
![Page 14: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/14.jpg)
![Page 15: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/15.jpg)
Digestion
• The small intestine – Most digestion and absorption occur in the
small intestine – receives digestive juices from the gallbladder
and the pancreas. – long, narrow, coiled, has three segments:
• Duodenum (10 inches)• Jejunum (8 feet)• Ileum ((12 feet)
– Interior surface area tremendously increased by villi, microvilli, circular folds
![Page 16: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/16.jpg)
Surface Area in the Small Intestine
![Page 17: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/17.jpg)
Digestion
– Peristalsis moves chyme through intestine– Segmentation mixes chyme with chemical
secretions– Pendular movement enhances nutrient
absorption
• Chyme moves at rate of 1 cm/minute
• Total contact time 3–10 hours, depending on amount and type of food
![Page 18: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/18.jpg)
Digestion
• The large intestine– Large intestine absorbs water and some nutrients – Ileocecal sphincter: prevents backflow of fecal
matter into ileum• Most of nutrients in chyme have been absorbed
when it reaches large intestine• Large intestine has three sections: cecum,
colon, rectum– About 5 feet long, 2.5 inches in diameter– Absorbs water and electrolytes– No digestive enzymes; chemical digestion done by
bacteria
![Page 19: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/19.jpg)
Digestion & Absorption
• Intestinal matter passes through colon in 12-70 hours depending on age, health, diet, fiber intake– Bacteria in colon produce vitamin K and biotin
and break down fiber and undigested carbohydrates
• Stool stored in rectum
![Page 20: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/20.jpg)
![Page 21: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/21.jpg)
Secretions of Digestion
• Enzymes – protein molecules which facilitates a chemical reaction
• Saliva – made by salivary glands• Gastric Juice – made by the stomach, very
acidic, HCL• Pancreatic Juice/intestinal Enzymes – Contains
bicarbonate to neutralize acidic gastric juices as it enters the small intestine
• Bile – secreted by the liver, stored in the gall bladder, emulsify fat. Only acts on fat
![Page 22: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/22.jpg)
Accessory Organs
Liver: largest gland in body• Produces bile needed for fat digestion• Metabolism of carbohydrates, fats and protein
• Stores nutrients: vitamins A, D, B12, E, copper, iron, glycogen (glucose storage form)
• Detoxifies alcohol
Gallbladder: concentrates and stores bile– Released into GI tract when fat is ingested
![Page 23: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/23.jpg)
Accessory Organs
Pancreas:– Produces hormones: insulin and glucagon,
regulate blood glucose– Sodium bicarbonate neutralizes acidic
chyme, protects enzymes from inactivation by acid
– Digestive enzymes:• Amylase: digests carbohydrate• Lipase: digests fats• Trypsin, chymotrypsin, and carboxypeptidase:
digest protein
![Page 24: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/24.jpg)
![Page 25: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/25.jpg)
Other Body Systems
• Nervous system stimulates your appetite.– Hormone ghrelin signals brain to eat when
stomach is empty.
• Circulatory system transports nutrients, oxygen, waste products through your blood.
• Lymphatic system distributes fat and fat-soluble nutrients through your lymph.
• Excretory system eliminates wastes from circulatory system via the urine.
![Page 26: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/26.jpg)
The Circulatory and
Lymphatic Systems
![Page 27: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/27.jpg)
The Excretory System
![Page 28: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/28.jpg)
Common Digestive Disorders
Disorders of the mouth and esophagus:• Gingivitis and periodontal disease – gum
swelling, bleeding and oral pain
• Swallowing problems: – Choking– Food becomes lodged in the trachea.– The larynx cannot make sounds.– The Heimlich maneuver may need to be used.
![Page 29: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/29.jpg)
![Page 30: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/30.jpg)
Common Digestive Disorders
• Esophageal problems– Heartburn (acid reflux) may be caused by
weak LES (lower esophageal sphincter)• Certain foods, • smoking, • drinking alcohol, • being overweight or obese, • tight-fitting clothes, • reclining after eating
![Page 31: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/31.jpg)
Common Digestive Disorders
Stomach Disorders:– Gastroenteritis – cause by bacteria or virus
“stomach flu”– Peptic ulcers - a sore in the lining of the
stomach (gastric ulcer)
Gallbladder Disease:– Gallstones – cause by high cholesterol bile,
may lead to obstruction of the bile duct
![Page 32: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/32.jpg)
![Page 33: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/33.jpg)
![Page 34: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/34.jpg)
![Page 35: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/35.jpg)
Common Digestive Disorders
Disorders of the Small Intestine:– Nutrient malabsorption disorders
• Celiac disease: inability to digest gluten protein
– Duodenal ulcers - a sore in the lining of the duodenum of the small intestine (duodenal ulcer).
– Intestinal enzyme deficiencies– Short bowel syndrome
![Page 36: Digestion, Absorption and Transport Objectives for Chapter 3 List the organs and accessory organs of the digestive tract. Discuss the main roles of each](https://reader036.vdocuments.us/reader036/viewer/2022062515/56649d165503460f949eb83d/html5/thumbnails/36.jpg)
Common Digestive Disorders
Disorders of the Large Intestine:– Constipation may be due to insufficient fiber
and water intake, inactivity, stress, illness.– Diarrhea is treated by fluid and electrolyte
replacement.– Irritable bowel syndrome (IBS): alternating
patterns of diarrhea, constipation, abdominal pain
– Colon cancer often begins with polyps.• Curable when detected early and treated