alimentary canal Flashcards
2 categories of organs
alimentary canal (GI tract):
-mouth, pharynx, esophagus
-stomach, small intestine, and large intestine
accessory organs:
-teeth and mouth
-salivary glands, liver, gallbladder and pancreas
bones of the chewing apparatus
mandible: lower jaw
maxilla: upper jaw, hard palate
muscles of mastication and action
temporalis muscle: elevates mandible, retracts
masseter muscle: elevates mandible,
lateral pterygoid muscle: protracts mandible, lateral chewing motions
medial pterygoid muscle: elevates mandible
buccinator: compresses the cheeks
innervation of muscles of mastication and buccinator
mandibular branch of trigeminal nerve CN V3
-buccinator: buccal branch of facial nerve
accessory digestive organs in the oral cavity
-molars
salivary glands
salivary glands
produce clear fluid
-assist oral cavity: keep oral mucosa moist and held prevent food decay
-assist digestion: moisten food and prepare for digestion, contain enzymes that can start the physiological digestion of starches (amylase)
types of salivary glands
-parotid: largest salivary gland, located in front of the ear
-submandibular gland: lie along the body midline
-sublingual gland: smallest, sits deep to the tongue
tongue location and function
oral cavity and oropharynx
primary muscle, taste, manipulation, taste, and speech
extrinsic muscles of the tongue
-genioglossus: tongue protraction
-hypoglossus: tongue depression
-styloglossus: tongue retraction and elevation
innervation of muscles of tongue
hypoglossal nerve (motor)
intrinsic muscles:
change shape of the tongue
pharynx
- nasopharynx
- oropharynx
- laryngopharynx
deglutition
process that transfers food bulus from the oral cavity through the oropharynx, into the pharync eventually through the esophagus into the mouth
steps of swallowing
- the bolus of food is squeezed to the back of the oral cavity by pushing the tongue against the palate
- the nasopharynx is sealed off by the epiglottis and the larynx is elevated, enlarging the pharynx to recieve food
- the pharyngeal constrictors contract and squeeze food into the esophagus
- the bulus of food moves down the esophagus by peristaltic contractions
innervation of the pharynx
vagus nerve
epiglottis
cartilage that opens and closes the airway, prevents food bulus from entering the trachea during swallowing
composition: elastic cartilage covered by mucous membrane
pharyngeal constrictors muscles
superior, middle, and inferior
palatopharyngeus, salpingpharyngeus, and stylopharyngeus
elevate the pharynx during swallowing
esophagus
function: muscular tube that propels swallowed food to the stomach
-begins as a cont of the pharynx
descends inferiorly through the thorax
-joins the stomach inferior to the diaphragm
composition of esophagus
-voluntary muscle: striated, upper 1/3
-involuntary muscle: smooth muscle in the lower 1/3
-mixture: middle 1/3
innervation of esophagus
vagus nerve and fibers from the cervical sympathetic trunk. motor, sensory, parasympathetic, sympathetic, and visceral sensory fibers present
the esophagus pierces through the ______ and enters the ______
diaphragm
stomach
stomach
location
function
superior left part of the peritoneal cavity
function: mechanical breakdown of food to chyme by peristalsis. chemical breakdown of proteins via acids and enzymes. (hydrochloric acid and pepsin).
features of stomach
cardiac region: at the junction with esophagus
fundus: stomachs dome
pylorus: termination of the stomach
greater curvature: convex
lesser curvature: concave
rugae: longitudinal folds
small intestine
tube that runs from the pyloric sphinctor of the stomach to the large intestine
-longest part of the alimentary canal
site of enzymatic digestion and all nutrient absorption
what are the three subdivisions of the small intestine
- duedenum: recieves digestive enzymes from the pancreas, bile from the liver and gallbladder
- jejunum: has more blood supply; vasa recta
- ileum:
large intestine
last major organ of alimentary canal
-function: absorption of water and electrolytes
what is included in the large intestine
cecum, colon: ascending, transverse, descending, and sigmoid, rectum, and anal canal
ascending and descending colon
secondarily retroperitoneal
rectum
secondary retroperitoneal
cecum, transverse colon, and sigmoid
intraperitoneal dialysis
features of the large intestine
-teniae coli: 3 thick bands of longitudinal smooth muscle fibers
-haustra: puches of the colon between the teniae
-amental appendces: small, fatty appendices of visceral peritoneum
-caliber: internal diameter
large intestine
rectum
terminal
anal canal
last subdivision of large intestine
anal canal
internal anal sphincter
involuntary
anal canal
external anal sphincter
voluntary
accessory organ : liver
largest internal organ and gland
function: metabolic, storage of glycogen, bile secretion
4 lobes of liver
right, left, caudate, quadrate
liver
porta hepatis
passage of hepatic portal vein , artery, ducts, nerve plexus, and lymphatics
liver
falciform ligament
binds the liver to the anterior ab wall
liver
round ligament
ligamentum teres
extends from the umbilicus to the lover, remnant of umbilical vein that carries oxy blood from thee placenta to the fetus
ligamentum venosum
cord like remnant of ductus venosus; shunted blood from the umb vein to the IVC
segmentation of the liver
8 segments, supplied by a branch of the right and left hepatic artery and hepatic portal vein and drained by a branch of the right or left hepatic duct
gallbladder
muscular sac
stores and concentrates bile by absorbing water and salts, expels bile into the duodenum
right and left hepatic ducts drain
the right and left portal lobes of the liver
right and left hepatic unite and form
common hepatic ductt
the common hepatic duct is joined by the ______ and forms ______
cystic duct
bile duct
accessory: pancreas
location: lies retroperitoneally, in the C shaped curve of the duodenum
function: digests sugars
the main pancreatic duct:
joins the bile duct from the gallbladder and both empty in the duodenum
