A&P2 digestive system lecture notes

periodontal disease

35+ more susceptible, inflammation or deterioration of gingivae, alveolar sockets, periodontal membrane, and cementum, caused by impacted plaque, smoking, poor diet

what are the layers of the alimentary canal?

4 layers, tunics-mucosa, submucosa, muscularis externa, and serosa

what percentage of people over 50 suffer from some type of digestive disorder?

60%

GI tract response to stimuli

activate or inhibit glands that secrete digestive juices or hormones and stimulate smooth muscles to mix and move contents

appendicitis

acute inflammation of appendix

What are the two parts of the digestive system?

alimentary canal and the accessory organs

What is viscera?

any of the organs

islets of langerhans

area of the pancreas that secretes glucagon and insulin, which control the fate of digested carbohydrates

vermiform appendix

attached to inferior portion of the cecum; helps resist infection--abundance of lymphatic tissue

food poisoning

caused by ingesting pathogenic bacteria or their toxins

nausea

caused by stimuli of vomiting center--may or may not cause vomiting

What reflexes regulate gastric secretion?

cephalic reflex, gastric reflex, intestinal reflex, enterogastric reflex

cirrhosis

chronic disease of liver in which fibrous tissue replaces functional hepatic cells, can be caused by hepatitis, alcoholism, toxins, and parasites

trench mouth

contagious bacterial infection that causes inflammation, ulceration, and painful swelling of floor of the mouth, contracted by kissing infected person, treated with penicillin

plicae circulares

deep folds in the mucosa and submucosa of the small intestines, covered by villi that are covered by microvilli giving walls a carpet-like appearance and promoting absorption

dysphagia

difficulty swallowing, may be due to obstruction or injury to esophagus

cecum

dilated pouch below ileocecal valve that prevents backflow of chyme

pyorrhea

discharge of pus at base of the teeth

muscularis mucosa

double, thin layer of smooth muscle in the mucosa that gives creates folds in the GI tract that increase the surface area, allowing for distension and absorption

emetics

drugs that stimulate the vomit reflex

what are the areas of the small intestines?

duodenum, jujunum, ileum, plicae circulares

peptic ulcers

erosions in mucous membrane of stomach or duodenum, produced by enzyme pepsin; gastric ulcers and duodenal ulcers

why is the digestive system susceptible to a wider variety of disorders than any other system?

exposure to external environment, abuse and unwise food and fluid consumption, and problems that reflect emotional state

colostomy

formation of an abdominal exit of GI tract by bringing a loop of the colon surface to the abdomen

cholelithiasis

formation of gallstones that obstruct bile duct, causing intense pain, jaundice

what are the 4 regions of the stomach?

fundus, cardia, body, and pylorus

what gives the liver its color?

great vascularity

gastrin

hormone released in stomach, triggered by partially digested proteins and caffeine in the stomach

intestinal gastrin

hormone released in the small intestine

colitis

inflammation of colon and rectum

dysentery

inflammation of intestinal mucosa, discharge of loose stool that contains mucus, pus, and blood; main type is amebic dysentery

enteritis

inflammation of intestinal mucosa, referred to as intestinal flu, causes: bacteria, virus, irritating foods/fluids, and emotional stress, symptoms: abdominal pain, nausea, diarrhea

chilitis

inflammation of lips

pancreatitis

inflammation of pancreas, usually caused by blockage of pancreatic duct, caused by build up of enzyme trypsin

gingivitis

inflammation of the gums

hepatitis

inflammation of the liver that can lead to cancer and death, usually caused by virus

diverticulitis

inflammation of walls of colon, may be life threatening, primary cause: lack of bulk/fiber foods in diet

what are the 8 processes of the digestive system?

ingestion, mastication, deglutination, segmentation, absorption, peristalsis, and defecation

cystic fibrosis

inherited disease of exocrine glands, particular in pancreas, pancreatic secretions are too thick to drain easily, causing ducts to become inflamed and promoting connective tissue formation along the drainage passageway

enterogastric reflex

inhibits gastric secretions, effect is to protect small intestines from harm due to excessive acidity and to keep small intestine's processing ability in time with chyme that is entering small intestine

mucosa

innermost layer surrounding lumen of GI tract; contains goblet cells, composed of simple columnar epithelial tissue supported by lamina propria and muscularis mucosa

pernicious anemia

lack of Vitamin B12, needed to produce mature RBCs. Stomach fails to secrete the intrinsic factor, injection of vitamin B12 is most effective treatment

liver

largest internal organ of the body, 2 major lobes

hepatomas

malignant cancerous tumors of liver, usually fatal

botulism

most serious type of food poisoning, occurs very commonly in nature--reason canned foods must be heated, toxins are poisonous, not the organism, poison is a neurotoxin that is readily absorbed

what layer of the alimentary canal is responsible for moving, churning, and pulverizing food?

muscularis externa

cephalic reflex

occurs before food enters the stomach, triggered by aroma, taste, sight, or though of food, can be suppressed if we lack appetite

intestinal reflex

occurs when food reaches the small intestines

gastric reflex

occurs when food reaches the stomach, distension of stomach activates stretch receptors, about 2/3 of gastric juice is released by this reflex

cleft palate

opening between oral and nasal cavity, problem because it interferes with sucking and swallowing

esophageal hiatus

opening through diaphragm for esophagus, straited muscle in upper 1/3, then striated and smooth muscle; transport bolus to stomach by peristalsis

what are the alimentary canal organs?

oral cavity, esophagus, pharynx, stomach, small intestine, large intestine

salmonella

organism that causes food poisoning, usually from uncleanliness of persons preparing the food

serosa

outermost layer of the GI tract, binding and protective layer

chyme

pasty food material that is moved into the small intestine from the stomach

submucosal plexus

provides autonomic nerve supply to muscular submucosa

small intestines

receive chyme from stomach and secretions from liver and pancreas, chemically and mechanically break down chyme, absorb nutrients, transport waste through peristalsis to large intestines, prohibit backflow of intestinal waste from large itnestine

stomach

receives bolus from esophagus, churns bolus with gastric juice, initiates digestion of proteins, moves chyme into the duodenum

large intestine

receives undigested waste from small intestines, absorbs water and electrolytes, forms, stores and expels feces, LITTLE OR NO DIGESTIVE FUNCTION

vomiting center

reflex center to empty stomach through esophagus, pharynx, and oral cavity, controlled by medulla oblongata, activated by GI tract, nauseating odors or sights, sickness, and body stress

submucosa

relatively thick and highly vascularized, contains collagenous fibers, glands, and nerves and the submucosal plexus

muscularis externa

responsible for segmental contractions and peristalsis movement; inner layer of smooth muscle and outer longitudinal layer of smooth muscle

esophageal sphincter

restricts the backflow of food

mechanical activities of the small intestines

rhythmic segmentations, pendular movements, peristalsis

gallbladder

saclike organ attached to inferior surface of liver

mucosa jobs

secrete mucus that protects the GI tract and helps food move, digestive enzymes, and hormones; absorb end products, protect against disease

goblet cells

secrete mucus throughout GI tract

Chemical stimuli of the digestive system

sensors in the wall of the GI tract detect stretch, osmolarity and pH, and substrates and end products

where does digestion officially end?

small intestine

pancreas

soft lobulated glandular organ that secretes pancreatic juice into the duodenum

pyloric sphincter

stomach junction with the small intestines to prevent backflow

mechanisms for vomiting

strong contractions of upper small intestines, contraction of pyloric sphincter, relaxation of gastroesophageal constriction and contraction of pyloric portion of stomach, shallow inspiration and closure of glottis, compression of stomach against liver by contraction of diaphragm and abdominal muscles

mesentery

support and attaches small intestines, contains blood vessels, nerves, and lymphatic vessels

jujunoileal bypass

surgical procedure for creating a bypass of a considerable portion of the small intestine, reduces absorptive capacity of the small intestine and is used to control extreme obesity

vagotomy

surgical removal of a section of the vagus nerve ending where it enters stomach to eliminate innate nerve impulses that stimulate gastric acid secretion; helps cure stomach ulcers

appendectomy

surgical removal of appendix

what are the digestive system accessory organs?

teeth, tongue, salivary glands, liver, gallbladder, and pancreas

what is the most distensible portion of the GI tract?

the stomach

lamina propria

thin, binding layer of connective tissue that contains numerous nodules important in protecting against disease

dental caries

tooth decay, gradual decalcification of tooth enamel and dentin, caused by uncleanliness or sugar/carb rich diet, persons under 35 most susceptible

hemorrhoids

varicose veins of rectum and anus

mumps

viral disease of parotid salivary glands, may involve pancreas and testes

bile

yellowish green fluid used in digestive process