Chapter 16: The Digestive System Flashcards
6 related processes of digestion
ingestion, mechanical processing, digestion, secretion, absorption, excretion
four components of digestive tract
mucosa, submucosa, muscularis externa, and serosa
mucosa
-inner lining of digestive tract; example of a mucous membrane
-stratified squamous in areas of high mechanical stress (mouth, pharynx, esophagus, anus)
-forms villi in the small intestine that further increase surface area for absorption
submucosa
second layer of loose connective tissue that is immediately deep to the muscularis mucosae; involved in controlling/coordinating contractions of smooth muscle layer and regulation of secretion of digestive glands.
Muscularis externa
a band of smooth muscle cells arranged in an inner circular layer and an outer longitudinal layer. (Contractions of these layers propel materials along digestive tract)
serosa
serous membrane which covers the muscularis externa along most of digestive tract within peritoneal cavity; does NOT cover oral cavity, pharynx, esophagus, or rectum
tongue
-manipulates materials inside mouth
-sensory analysis by touch, temperature, and taste receptors innervated by glossopharyngeal nerve
salivary glands
-three pairs: sublingual, submandibular, parotid; each gland produces slightly different saliva
-produce 1-1.5L/day of saliva
saliva
-99.4% water, plus mucins and an assortment of ions, buffers, waste products, metabolites, and enzymes
- Helps lubricate the mouth and dissolve chemicals that stimulate taste buds.
incisors
blade-shaped teeth found at the front of the mouthuseful for cutting or clipping
Canines
are conical, with a sharp ridge line and pointed tip. Used for tearing or slashing.
molars
flattened crowns with prominent ridges; used for crushing, mashing, and grinding
diaphragmatic hernia
abdominal organs slide into the thoracic cavity through the esophageal hiatus; actually very common, usually goes unnoticed
stomach
J-shaped organ located in upper left abdominal quadrant. cardia attaches to esophogus (where it receives food). It has 4 main regions: fundus, cardia, body, pylorus
(When empty ridges/folds called rugae)
fundus of stomach
the bulge of the stomach superior to the cardia
pepsin
proteolytic enzyme (protein-digesting) derived from pepsinogen
gastric lipase
secreted by newborns; initiates the digestion of milk fats
gastrin
Secreted by doudenal cells in response to large quantities of incompletely digested proteins.
duodenum
1/3 Small Intestine
-segment closest to stomach, curves in a C that encloses the pancreas
-receives chyme from stomach and digestive secretions from the liver/pancreas
10 in
jejunum
2/3 Small Intestine
- separated from duodenum by an abrupt bend
-chemical digestion and nutrient absorption occurs here
8 ft
ileum
3/3 Small Intestine
the last and longest portion of the small intestine; ends at ileocecal valve
12 ft
secretin
Released when pH falls in the duodenum as acidic chyme arrives from stomach.
- Primary role is to increase secretion of bile/buffers by liver/pancreas
bile
-secreted by liver
-stored by gallbladder
-consists mostly of water, ions, cholesterol, and bile salts
-released under stimulation of CCK
colon
-external pouches called haustra permit distention and elongation
-four segments: ascending, transverse, descending, and sigmoid
-bacteria within colon generate Vitamin K, Biotin, and B5
Soft palate
-comprised of five muscles that play essential roles in breathing, phonation, and swallowing
-Separates nasalpharynx and oropharynx
Hard palate
-Front bony part of the roof of your mouth
-Separates maxilla and palatine bones
Colostomy
a surgical operation in which a piece of the colon is diverted to an artificial opening in the abdominal wall so as to bypass a damaged part of the colon
Lactose intolerance
Inability to digest lactose (monosaccharides); symtoms include: bloating, diarhhea
Types of hernias
-Diaphragmatic
- Inguinal
-Umbillical
-Femoral
CLINICAL NOTE: pg 593
Appendicitis
-Inflammation of veriform appendix
-Obstruction of lumen
-McBurney’s point (1.5-2 inches above illiac crest, right lower quadrant)
Peptic Ulcers
-Duodenum ulcers (proximal portion)
-Stomach ulcers
-Most likely duodenal
-More common in males
- pain when stomach is empty
Chron’s Disease
-Inflammatory bowel disease
-Chronic inflammation of GI
-Symptoms: Fatigue, weight loss, anemia, diarhhea
Peritonitis
Inflammation of membrane lining of GI
Gastritis
Inflammation of internal lining of stomach
Appendectomy
Surgical removal if appendix
Gastroenteritis
-Inflammation of stomach and intestines
-Causes diarhhea, nausea, vomiting
Pancreatic Enzymes
-Lipase (Triglycerides to fatty acids)
-Protase (breakdown to polypetide chains)
-Nuclease (nucleic acids)
-Caronhydrase (starches and simple sugars)
