the digestive system
continuous, coiled, hollow, muscular tube that winds through the ventral body cavity and is open at both ends.
Alimentary canal/ GI tract
what are the 6 organs of the alimentary canal?
mouth, pharynx, esophagus, stomach, small and large intestine
mucous membrane lined cavity
protect mouths anterior opening
form the mouth lateral walls
form the mouths anterior roof
forms the mouths posterior roof
fleshy fingerlike projection of the soft palate
space between the lips and cheeks externally and the teeth and gums internally
area contained by the teeth
oral proper cavity
occupies the floor of the mouth
fold of mucous membrane, secures the tongue to the floor of the mouth and limits its posterior movements
posterior end of oral cavity are paired masses of lymphatic tissue
covers the base of the tongue just beyond
walls contain 2 skeletal muscle layers - cells of the inner =___________, cells of the outer =_______
pharynx; run longitudinally ; run around the wall in a circular fashion
from the mouth food passes posteriorly into the oropharynx and laryngopharynx which are ?
common passageways for food, fluids, and air
posterior to the oral cavity
continuous with the esophagus below
(gullet), runs from the pharynx through the diaphragm to the stomach
passageway that conducts food to the stomach
walls of the alimentary canal organs from the _____ to the large intestine are made up of four basic tissue layers
innermost layer; moist membrane lines lumen of the organ
what type of tissue is the mucosa made up of?
surface epithelium; small amount of connective tissue(lamina propria)
scanty smooth muscle layer; esophagus has friction resisting _______; just beyond the esophagus is ________
mucosa; stratified squamous; simple columnar
just beneath the mucosa; soft connective tissue containing blood vessels, nerve endings, lymph noduls, lymphatic vessels
third tissue layer; muscular layer made up of an inner circular layer and an outer longitudinal layer of smooth muscle cells
outermost layer; single layer of flat serous producing cells
continuous with the slick slippery parietal peritoneum
lies the abdominopelvic cavity by way of a membrane extension called ______
parietal peritoneum, mesentery
what are the two intrinsic nerve plexuses of the alimentary canal? what are they apart of and what do they do?
1. submucosal nerve plexus 2.myenteric; part of the autonomic nervous system; help regulate the mobility and secretory activity of GI tract organs
where is the stomach located?
left side of the abdominal cavity
stomach region positioned near the heart; surrounds the cardio esophageal sphincter
through which food enters the stomach from the esophagus
cardio esophageal sphincter
expanded part of the stomach lateral to the cardiac region
mid portion of stomach; as it narrows it becomes the ______
Body; pyloric antrum
funnel shaped, terminal part of the stomach; continuous with small intestine through the pyloric sphincter
when the stomach collapses inward on itself and mucosa is thrown into large folds
convex lateral surface of stomach
stomachs concave medial surface
double layer of peritoneum; extends from liver to the lesser curvature
extension of the peritoneum
draps downward and covers the abdominal organs, attaches to the posterior body wall; riddeled with fat for insulation, cushion, protection
large collections of lymph nodules containing macrophages and defensivr cells of the immune system
acts as a temporary storage
what does the third layer of the stomach do? (oblique layer)
allows it to churn, mix, and pummel the food= physically breaking it down into smaller pieces
Where does the chemical breakdown of proteins begin?
mucosa of the stomach composed entirely of mucous cells that produce a protective layer of what?
bicarbonate-rich alkaline mucus
what is the smooth lining of the stomach dotted with?
gastric pits leading to gastric glands that secrete gastric juices
substance needed for absorption of vitamin B12
produce protein digesting enzymes (pepsinogens)
produce hydrochloric acid
makes stomach contents acidic and activates enzymes
produce thin acidic mucous
mucous neck cells
produce local hormones (gastrin)
Where does most digestive activity occur?
pyloric region or stomach
heavy cream formed after food has been processed
body's major digestive organ
muscular tube extending from the pyloric sphincter to the large intestine
____ hangs in sausaglike coils in the abdominal cavity, suspended by the fan shaped _______
small intestine; mesentery
What are the three subdivisions of the small intestine?
Duodenum, jejunum, ileum
joins the large and small intestine
Where does chemical digestion of food begin?
Controls food movement into the small intestine from the stomach
How is bile formed?
by the liver
nearly all food absorption occurs where?
tiny projections of plasma membrane, give the cell a fuzzy appearance known as brush border
fingerlike projections of mucosa, give a velvety apperance
within each ______ is a rich capillary bed and modified lymphatic capillary bed called ?
Bear enzymes that complete the digestion of proteins and carbohydrates
deeps folds of both mucosa and submucosa layers
circular folds (plicae ciculares)
collections of lymphatic tissue, found in submucosa increase in number toward the end of small intestine
extends from the ileocecal valve to the anus
what is the major function of the large intestine?
to dry out the indigestible food residues from the body as feces
First subdivision of the large intestine; saclike; appendix hangs from it
second subdivision of the large intestine; what are the different parts?
colon; ascending, transverse, descending
descending colon becomes the ?
third subdivision of the large intestine
fourth subdivisions of the large intestine; ends at the anus
what are the sphincters of the anal canal? what are they made of?
External voluntary sphincter- skeletal muscle; Internal involuntary sphincter- smooth muscle
what are present in the large intestine, that produce alkaline mucus
goblet cells (act as lubricant)
teniae coli display muscle tone which cause the wall to pucker into small pocket like sacs called?
what are the accessory digestive organs?
teeth, salivary glands, pancreas, liver, gallbladder
large glands that lie anteriorly to the ears, when inflamed= mumps
empty their secretions into the floor of the mouth through tiny ducts
submandibular and sublingual glands
mixture of mucous and serous fluid; contains salivary amylase, lysozymes, antibodies
soft, pink, triangular gland extends across the abdomen from the spleen to the duodenum
secreted into the duodenum in an alkaline fluid that neutralizes the acid chime coming from stomach
produces hormones insulin and glucagon
largest gland in the body and one of the most important
where is the liver located?
under the diaphragm more to the right side of the body
liver is suspended from the diaphragm and abdominal wall by a delicate mesentery cord called?
how does bile leave the liver?
through the common hepatic duct
small, thin walled, green sac that snuggels in the surface of the liver
what does the gall bladder do?