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Digestive System CHAPTER 12. 2 Digestive System Overview Digestive System –Known as gastrointestinal tract Also known as digestive tract or alimentary.

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Presentation on theme: "Digestive System CHAPTER 12. 2 Digestive System Overview Digestive System –Known as gastrointestinal tract Also known as digestive tract or alimentary."— Presentation transcript:

1 Digestive System CHAPTER 12

2 2 Digestive System Overview Digestive System –Known as gastrointestinal tract Also known as digestive tract or alimentary canal –Approximately 30 feet long Begins with mouth (oral cavity), ends with anus –Functions Prepare foods for absorption into the bloodstream Prepare foods for use by the body cells Responsible for elimination of solid wastes from the body

3 3 Oral cavity (Buccal cavity) –Lips –Cheeks –Hard palate Rugae –Soft palate –Uvula –Tongue Principle organ of the sense of taste Also assists in process of chewing (mastication) and swallowing (deglutition) Digestive System Structures

4 4 Salivary glands –Three pairs Parotids Submandibulars Sublinguals –Secrete saliva Mostly water, but contains mucus and digestive enzymes that aid in digestive process –Digestive enzymes contained in saliva Amylase – aids in digestion of carbohydrates Lipase – aids in digestion of fats Digestive System Structures

5 5 Pharynx –Known as the throat –Serves as passageway for both respiratory and digestive systems –Oropharynx Section leading away from oral cavity –Nasopharynx Behind nasal cavity –Laryngopharynx Lower portion – opens into esophagus and larynx Digestive System Structures

6 6 Esophagus –Receives food from pharynx and propels it to stomach –Cardiac sphincter (lower esophageal sphincter) controls passage of food from esophagus into the stomach Relaxes = food enters stomach Contracts = stomach contents prevented from reentering the esophagus Digestive System Structures

7 7 Stomach –Fundus Upper rounded portion –Body Central part Digestive System Structures

8 8 Stomach –Pylorus Lower tubular part (also called the gastric antrum) Pyloric sphincter regulates passage of food from stomach into the duodenum –Folds in mucous membranes of stomach = Rugae Digestive System Structures

9 9 Stomach –Gastric juices breakdown food in stomach –Muscular action of stomach causes churning of food Mixes food with the secretions Chyme = liquidlike mixture of partially digested food and digestive secretions Digestive System Structures

10 10 Small intestine –Approximately 20 feet long –Also known as the small bowel –Divided into three parts Duodenum Jejunum Ileum Digestive System Structures

11 11 Large intestine –Cecum Appendix hangs from lower portion of cecum –Ascending colon Hepatic flexure –Transverse colon Splenic flexure –Descending colon –Sigmoid colon –Rectum –Anus Digestive System Structures

12 12 Accessory Organs of Digestion Liver –Located immediately under diaphragm, slightly to the right –Only digestive function Production of bile for emulsification of fats in small intestine

13 13 Accessory Organs of Digestion Liver –Additional functions of liver Excretion of bile pigments into bile Synthesis of vitamin K-dependent plasma proteins Amino acid metabolism Carbohydrate metabolism Fat metabolism Phagocytosis Detoxification Storage of vital nutrients

14 14 Accessory Organs of Digestion Gallbladder –Pear-shaped sac, located under surface of liver –Main function: To store and concentrate bile produced by the liver Releases bile in response to presence of fatty content of food present in duodenum Emulsifies fats

15 15 Accessory Organs of Digestion Pancreas –Located in upper left quadrant of abdomen, behind stomach –Functions as exocrine gland to manufacture digestive juices Trypsin – breaks down proteins Pancreatic lipase – breaks down fats Pancreatic amylase – breaks down carbohydrates Sodium bicarbonate – neutralizes acidic stomach contents

16 16 Accessory Organs of Digestion Pancreas –Functions as endocrine gland to manufacture insulin and glucagon Insulin – hormone that makes it possible for glucose to pass from blood through cell membranes to be used for energy Insulin also promotes conversion of excess glucose into glycogen Glucagon – hormone that stimulates the liver to convert glycogen into glucose in time of need

17 17 Accessory Organs of Digestion Teeth –Primary responsibility Chewing (mastication) Food is ground by teeth and softened by saliva –Primary teeth = deciduous teeth Set of 20 teeth – appears around age 6 months –Secondary teeth = permanent teeth Begin to appear around age 6

18 18 Accessory Organs of Digestion Teeth –Incisors Chisel shape with sharp edges for biting food –Canine or cuspid teeth Useful for grasping and tearing food –Bicuspids (premolars) and molars Flat surfaces, multiple projections for crushing and grinding food

19 19 Accessory Organs of Digestion Teeth –Crown Visible part of the tooth Covered with enamel – hardest substance in body –Neck Lies just beneath the gum line –Root Embedded in bony socket of the jaw bone –Root canal = pulp cavity Central core of the tooth

20 20 Accessory Organs of Digestion Layers of Teeth

21 21 Common Signs and Symptoms Achlorhydria –Abnormal condition characterized by the absence of hydrochloric acid in the gastric juice Anorexia –Lack or loss of appetite, resulting in the inability to eat

22 22 Aphagia –Condition characterized by the loss of the ability to swallow as a result of organic or psychologic causes Ascites –Abnormal accumulation of fluid within the peritoneal cavity Fluid contains large amounts of protein and electrolytes Common Signs and Symptoms

23 23 Borborygmus –An audible abdominal sound produced by hyperactive intestinal peristalsis Borborygmi are rumbling, gurgling, and tinkling noises heard when listening with a stethoscope Common Signs and Symptoms

24 24 Constipation –Difficulty in passing stools, or an incomplete or infrequent passage of hard stools Diarrhea –Frequent passage of loose, watery stools Common Signs and Symptoms

25 25 Dyspepsia –Vague feeling of epigastric discomfort after eating –Involves an uncomfortable feeling of fullness, heartburn, bloating, and nausea Dysphagia –Difficulty in swallowing, commonly associated with obstructive or motor disorders of the esophagus Common Signs and Symptoms

26 26 Emaciation –Excessive leanness caused by disease or lack of nutrition Emesis –Material expelled from the stomach during vomiting –Vomitus Common Signs and Symptoms

27 27 Eructation –Act of bringing up air from the stomach with a characteristic sound through the mouth –Belching Flatus; Flatulence –Air or gas in the intestine that is passed through the rectum Common Signs and Symptoms

28 28 Gastroesophageal Reflux –Backflow of contents of stomach into esophagus –Often result of incompetence of the lower esophageal sphincter Icterus –A yellowish discoloration of the skin, mucous membranes, and sclera of the eyes, caused by greater than normal amounts of bilirubin in the blood –Also called jaundice Common Signs and Symptoms

29 29 Melena –An abnormal, black, tarry stool containing digested blood Nausea –Unpleasant sensation often leading to the urge to vomit Pruritus ani –A common chronic condition of itching of the skin around the anus Common Signs and Symptoms

30 30 Steatorrhea –Greater than normal amounts of fat in the feces Characterized by frothy, foul-smelling fecal matter that floats Vomit –To expel the contents of the stomach through the esophagus and out of the mouth Common Signs and Symptoms

31 PATHOLOGICAL CONDITIONS Digestive System

32 32 Achalasia Pronounced –(ak-al-LAY-zee-ah) Defined –Decreased mobility of the lower two-thirds of the esophagus along with constriction of the lower esophageal sphincter

33 33 Anal Fistula Pronounced –(AY-nal FISS-too-lah) Defined –Abnormal passageway in the skin surface near the anus usually connecting with the rectum May occur as the result of a draining abscess

34 34 Aphthous Stomatitis Pronounced –(AFF-thus stoh-mah-TYE-tis) Defined –Small inflammatory noninfectious ulcerated lesions occurring in the lips, tongue, and inside the cheeks of the mouth –Also called canker sores

35 35 Appendicitis Pronounced –(ap-pen-dih-SIGH-tis) Defined –Inflammation of the vermiform appendix Usually an acute condition that can lead to rupture (perforation) with resultant inflammation of the peritoneum (peritonitis)

36 36 Celiac Disease Pronounced –(SEE-lee-ak disease) Defined –Nutrient malabsorption due to damaged small bowel mucosa

37 37 Pronounced –(sih-ROH-sis) Defined –Disease of the liver that is chronic and degenerative causing injury to the hepatocytes (functional cells of the liver) Fat infiltrates lobules of the liver, causing tissue covering the lobes to become fibrous Functions of liver eventually deteriorate Cirrhosis

38 38 Colorectal Cancer Pronounced –(koh-loh-REK-tal CAN-sir) Defined –Presence of a malignant neoplasm in the large intestine

39 39 Constipation Pronounced –(kon-stih-PAY-shun) Defined –A state in which the individual’s pattern of bowel elimination is characterized by a decrease in the frequency of bowel movements and the passage of hard, dry stools Individual experiences difficult defecation

40 40 Crohn’s Disease Pronounced –(KROHNZ dih-ZEEZ) Defined –Digestive tract inflammation of a chronic nature causing fever, cramping, diarrhea, weight loss, and anorexia

41 41 Dental Caries Pronounced –(DEN-tal KAIR-eez) Defined –Tooth decay caused by acid-forming microorganisms

42 42 Pronounced –(DISS-en-ter-ee) Defined –A term used to describe painful intestinal inflammation typically caused by ingesting water or food containing bacteria, protozoa, parasites, or chemical irritants Person has frequent stools that often contain blood Dysentery

43 43 Diverticular Disease Pronounced –(dye-ver-TIK-yoo-lar dih-ZEEZ) Defined –Expression used to characterize both diverticulosis and diverticulitis Diverticulosis = non-inflamed outpouchings or herniations of the muscular layer of the intestines, typically the sigmoid colon Diverticulitis = inflammation of these outpouchings

44 44 Esophageal Varices Pronounced –(eh-soff-ah-JEE-al VAIR-ih-seez) Defined –Swollen, twisted (tortuous) veins located in the distal end of the esophagus

45 45 Gallstones (Cholelithiasis) Pronounced –(koh-lee-lih-THIGH-ah-sis) Defined –Pigmented or hardened cholesterol stones formed as a result of bile crystallization

46 46 Hemorrhoids Pronounced –(HEM-oh-roydz) Defined –Hemorrhoid is an unnaturally distended or swollen vein (varicosity) in distal rectum or anus

47 47 Hepatitis Pronounced –(hep-ah-TYE-tis) Defined –Acute or chronic inflammation of the liver due to a viral or bacterial infection, drugs, alcohol, toxins, or parasites

48 48 Hernia Pronounced –(HER-nee-ah) Defined –Irregular protrusion of tissue, organ, or a portion of an organ through an abnormal break in the surrounding cavity’s muscular wall

49 49 Herpetic Stomatitis Pronounced –(her-PEH-tic stoh-mah-TYE-tis) Defined –Inflammatory infectious lesions in or on the oral cavity occurring as a primary or a secondary viral infection caused by herpes simplex

50 50 Pronounced –(HIRSH-sprungz dih-ZEEZ) –(kon-JEN-ih-tal meg-ah-KOH-lon) Defined –Absence at birth of the autonomic ganglia in a segment of the intestinal smooth muscle wall that normally stimulates peristalsis Hirschsprung’s Disease (Congenital Megacolon)

51 51 Pronounced –(ILL-ee-us) Defined –Obstruction of the intestine May occur due to twisting of the bowel, absence of peristalsis, or presence of adhesions or tumor Ileus

52 52 Intestinal Obstruction Pronounced –(in-TESS-tin-al ob-STRUCK-shun) Defined –Complete or partial alteration in the forward flow of the contents in the small or large intestines

53 53 Pronounced –(in-tuh-suh-SEP-shun) Defined –Telescoping of a portion of proximal intestine into distal intestine usually in the ileocecal region causing an obstruction Typically occurs in infants and young children Intussusception

54 54 Pronounced –(EAR-it-ah-b’l BOW-el SIN-drom) –(SPAS-tik COH-lon) Defined –Increased motility of the small or large intestinal wall resulting in abdominal pain, flatulence, nausea, anorexia, and the trapping of gas throughout the intestines Irritable Bowel Syndrome Spastic Colon

55 55 Oral Leukoplakia Pronounced –(OR-al loo-koh-PLAY-kee-ah) Defined –Precancerous lesion occurring anywhere in the mouth

56 56 Pancreatitis Pronounced –(pan-kree-ah-TYE-tis) Defined –Acute or chronic destructive inflammatory condition of the pancreas May be acute or chronic

57 57 Pronounced –(PEP-tik ULL-sir) –(GAS-tric, doo-oh-DEE-nal, PER-foh-ray-ted) Defined –Break in the continuity of the mucous membrane lining of the gastrointestinal tract as a result of hyperacidity or the bacterium, Helicobacter pylori Peptic Ulcers (Gastric, Duodenal, Perforated)

58 58 Peptic Ulcers Peptic ulcer descriptions –Acute or chronic –Singular or clustered –Shallow or deep Symptoms of an ulcer –Gnawing epigastric pain –Heartburn or indigestion –Nausea and vomiting –Bloated feeling after eating

59 59 Periodontal Disease Pronounced –(pair-ee-oh-DON-tal dih-ZEEZ) Defined –Group of inflammatory gum disorders –May lead to degeneration of teeth, gums, and sometimes surrounding bones

60 60 Polyps, Colorectal Pronounced –(PALL-ips koh-loh-REK-tal) Defined –Small growths projecting from the mucous membrane of the colon or rectum May be sessile (attached by a base) or pedunculated (attached by a stalk) May vary in size and may be benign or pre- cancerous

61 61 Thrush Pronounced –(THRUSH) Defined –Fungal infection in the mouth and throat producing sore, creamy white, slightly raised curdlike patches on the tongue and other oral mucosal surfaces Caused by Candida albicans

62 62 Pronounced –(ULL-sir-ah-tiv koh-LYE-tis) Defined –Chronic inflammatory condition resulting in a break in the continuity of the mucous membrane lining of the colon in the form of ulcers Characterized by large watery diarrheal stools containing mucus, pus, or blood Ulcerative Colitis

63 63 Volvulus Pronounced –(VOL-vyoo-lus) Defined –Rotation of loops of bowel causing a twisting on itself that results in an intestinal obstruction


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