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