Digestive Flashcards
describe the histological structure and function of the alimentary canal wall
histology:
inner epithelium (mucosa)
layer of connective tissue (submucosa)
layer of smooth muscle (muscularis externa)
outer layer of connective tissue (serosa)
function:
motility of alimentary canal is key process in every region of canal, this includes swallowing, churning, peristalsis, and defecation
describe the major functions of the digestive system
takes food into body and breaks it down into its component nutrients; critical role in fluid, electrolyte, and acid-base homeostasis; ingesting vitamins and minerals, producing hormones, and excreting metabolic wastes
trace the pathway of food through the alimentary canal and explain the function of each region
esophagus - transports bolus from pharynx to stomach
gastroesophageal sphincter - regulates passage of bolus into stomach; prevents contents of stomach from re-entering esophagus
stomach - cephalic, gastric, and intestinal phases
pyloric sphincter -
small intestine - absorption, secretion, digestion, and propulsion
duodenum -
hyaluric sphincter -
jejunum - most active site for chemical digestion and absorption
ileum -
large intestine - receives material from small intestine that was not digested or absorbed and is passageway for feces to exit body; absorbs water; synthesizes vitamins; secretion; propulsion; defecation
ileocecal valve - sphincter that controls movement of materials from ileum into cecum
ascending colon -
transverse colon -
descending colon -
sigmoid colon -
rectum -
internal and external anal sphincters
identify the 6 basic digestive functions and processes
ingestion- food and water are brought into the digestive system; occur via mouth
secretion- digestive organs contain both endocrine and exocrine glands that secrete variety of substances to aid other digestive processes, such as mucus, enzymes, acid, and hormones
propulsion- ingested foods and liquids pass from one digestive organ to the next; accomplished largely by rhythmic contractions of smooth muscle of alimentary canal (peristalsis)
mechanical & chemical digestion- digestive organs physically break food down into smaller pieces by chewing and mixing food by muscular movements of alimentary canal (mechanical); enzymes secreted by digestive organs catalyze reactions; break chemical bonds within food particles until only small molecules remain (chemical)
absorption- once food particles are digested, they move through the wall of alimentary canal into blood or lymphatic vessels
defecation- simply a specialized form of propulsion; certain ingested materials are not digestible or usable by the body; also a way to eliminate metabolic wastes
identify and discuss the functions of accessory organs of the digestive system, including salivary glands, teeth, tongue, and appendix
liver-
gallbladder-
pancreas-
oral cavity- where food enters and digestive process begins
teeth- main roles in mastication (chewing) and mechanical digestion
salivary glands- secrete saliva and functions primarily in chemical digestion by moistening oral cavity, detering pathogenic bacteria growth in mouth, and helping form bolus
tongue- plays role in mechanical digestion by help turning food into bolus and pushes food against hard palate during chewing & aids in swallowing
appendix-
describe the processes of peristalsis and segmentation as functions to move and churn food
peristalsis - alternating contractions of longitudinal and circular layers of smooth muscle in muscularis externa; primary function is to propel chyme toward ileum and ultimately through ileocecal valve to cecum
segmentation - churning; contractions of only circular layer of smooth muscle; produces squeezing motion; primary function is mechanical digestion and mixing chyme with intestinal and pancreatic enzymes as well as bile
alimentary canal includes
oral cavity, pharynx, esophagus, stomach, small intestine, and large intestine
