E5 Ch. 23 Flashcards
what 2 groups are the organs of the digestive system divided into
alimentary canal and accessory digestive organs
list the organs that belong to the alimentary canal
mouth, pharynx, esophagus, stomach, small intestine, and large intestine
list the accessory digestive organs
teeth, tongue, gallbladder, salivary glands, liver, and pancreas
how are accessory organs and alimentary canals connected
via ducts
list the 4 lines that divide the abdominal wall
midclavicular (vertical lines), subcostal plane (superior horizontal), transtubercular plane (inferior horizontal
peritoneum
serious membrane
visceral peritoneum
surrounds digestive organs
parietal peritoneum
lines body wall
peritoneal cavity
slitlike potential space
what is a mesentery and its function
double layer of peritoneum; holds organs in place, fat storage, provide route for circulatory vessels/nerves
name the structures found in the ventral mesenteries
falciform ligament and lesser omentum
function of falciform ligament
binds anterior part of liver to anterior abdominal wall
function of lesser omentum
attaches liver to lesser curvature of stomach
list the dorsal mesenteries
greater omentum, transverse mesocolon, and sigmoid mesocolon
function of greater omentum
connects greater curvature of stomach to posterior abdominal wall, “fatty apron”
function of transverse mesocolon
holds transverse colon in place
function of sigmoid mesocolon
connects sigmoid colon to posterior pelvic wall
retroperitoneal organs
behind the peritoneum
peritoneal organs
digestive organs that keep their mesentery
where does ingestion occur
mouth
propulsion
movement of food
peristalsis
major means of propulsion; adjacent segments of alimentary canal relax and contract
mechanical breakdown
preps food for chemical digestion; chewing, churning food in stomach, and segmentation
what is segmentation
rhythmic local constrictions of intestine; mixes food w/ digestive juices
what is chemical digestion and where does it occur
complex molecules broken down to chemical components; mouth, stomach, and small intestine
absorption
transport of digested nutrients
defecation
elimination of indigestible substances as feces
list the 4 layers of the alimentary canal
mucosa, submucosa, muscularis externa, and serosa
what are the sublayers of the mucosa
epithelium, lamina propria, muscularis mucosae
what structures are found in the submucosa
blood and lymphatic vessels, and nerve fibers
name the 2 layers that make up the muscularis externa
circular muscularis (inner layer) and longitudinal muscularis (outer layer)
what is the serosa
the visceral peritoneum
where is smooth muscle found
walls of viscera
describe the longitudinal layer
parallell to long axis of organ
describe the circular layer
deeper layer, fibers run around circumference of organ
what is the mechanism of contraction with smooth muscles
myofilaments operate by interaction w/ cytoskeleton, dense bodies correspond to Z-discs of skeletal muscle; sliding myofilaments shorten muscle cells by pulling on ctoskeleton
what is the rate of contraction with smooth muscles
contraction slow and sustained (30X longer to contract/relax), resistant to fatigue, low energy requirements
innervation of smooth muscles via
ANS
single-unit innervation
few fibers per sheet innervated; sheet of smooth muscle contracts as a unit
multiunit innervation
each smooth muscle cell innervated (e.g. iris of eye and arrector pili muscles)
where is the myenteric nerve plexus lie and what does it control
leis b/t circular and longitudinal muscularis; controls peristalsis and segmentation
where is the submucosal nerve plexus located and function
lies in submucosa; signals glands to secrete
list the boundaries of the mouth (oral cavity)
lips (anteriorly), cheeks (laterally), palate (superiorly), tongue (inferiorly), fauces of oropharynx (posteriorly)
what type of cells are found in the mucosal layer of the oral cavity
stratified squamous epi
what muscles are the lips and cheeks formed from
orbicularis oris and buccinator
function of labial fernulum
connects lips to gum
name the boundaries of the fauces
palatoglossal and palatopharyngeal arches
function of the tongue
grips food, repositions, helps form some consonants
function of the lingual frenulum
secures tongue to floor of mouth
where are intrinsic and extrinsic muscles of the tongue located
intrinsic muscles- w/in tongue
extrinsic muscles-external to tongue
list the types of tongue papillae
filiform (no taste buds), fungiform, and vallet papillae
what is the sulcus terminalis
marks border b/t mouth and pharynx
where does the posterior 1/3 of the tongue lie
in oropharynx; lined w/ lingual tonsil
how many deciduous teeth do we have and when do they appear
20; 6 months of age
how many permanent teeth de we have and when do they appear
32, most erupt by end of adolescence
what is the dental formula
shorthand; formula for adult dentition indicates number and position of teeth (e.g. 2K, 1C, 2P, 3M
what type of innervation is in the upper teeth
superior alveolar nerves branching from maxillary division of CN V
what type of innervation is in the lower teeth
inferior alveolar nerves branching from mandibular branch of CN V
crown
exposed surface of tooth
root
in tooth socket
what is the outer layer of the tooth
enamel
dentin
underlies enamel
pulp cavity
center of tooth
what type of cells are found in parotid glands
only serious cells
where are submandibular glands located
lie along medial surface of mandible
where are sublingual glands located and why type of cells do they contain
lie in floor or oral cavity, contain primarily mucous cells
what type of epi are found in the oropharynx and laryngophary x
stratified squamous epi
function of the cardiac sphincter
closes lumen to prevent stomach acid from entering esophagus
what type of tissue is found in the esophagus
stratified squamous epi
what type of muscle is found in the esophagus
mixture of skeletal and smooth (middle 1/3), smooth (inferior 1/3)
the stomach is the site for what
where food is churned into chyme
what type of chemical does the stomach secret
pepsin; beings protein digestion
how long does food typically remain in the stomach
approximately 4 hours
name the 3 muscularis layers of the stomach
circular, longitudinal, and oblique layers
what type of tissue is found in the stomach
simple columnar epi
what is found in the mucosa of the stomach
gastric pits; gastric glands deep to gastric pits
list the gastric glands of the fundus and body regions of the stomach
mucous neck cells, parietal (oxyntic) cells, and chief (zymogenic) cells
what do mucous neck cells secrete
special mucus
what do parietal (oxyntic) cells secrete
hydrochloric acid and gastric intrinsic factor
wha do chief (zymogenic) cells secrete
pepsinogen; activated into pepsin when encounters acid in gastric glands
what organ is the longest portion of the alimentary canal
small intestine
what are the 3 subdivisions of the small intestine
duodenum, jejunum, and ileum
what type of innervations are in the small intestine
parasympathetic fibers from vagus nerves, sympathetic from thoracic splanchnic nerves
what chemicals does the duodenum receive
digestive enzymes and bile
what structures enter the duodenum
main pancreatic and common bile duct; sphincters control entry of bile and pancreatic juices
what are some modifications for absorption found in the small intestine
circular folds, billi, and microvilli
what are circular folds
transverse ridges of mucosa and submucosa
what are villi
fingerlike projections of mucosa, covered w/ simple columnar epi
what are microvilli
further increase surface area for absorption
function of absorptive enterocytes
uptake digested nutrients
function of goblet cells
secrete mucus that lubricates chyme
function of enteroendocrine cells
secrete hormones
intestinal crypts
epi cells secrete intestinal juice
functions of the large intestine
small amount of digestion by bacteria, main function- absorb water and electrolytes
list the subdivisions of the large intestine
cecum, appendix, colon, rectum, anal canal
list the special features found on the large intestine
teniae coli, haustra, epiploic appendages
teniae coli
thickening of longitudinal muscularis
haustra
puckering created by teniae coli
epiploic appendages
fat-filled pouches of visceral peritoneum
cecum
blind pouch, beginning of large intestine
what does the appendix contain and function
contains lymphoid tissue; neutralizes pathogens
what is the anal canal and what type of tissue lines it
last subdivision of large intestine, lines w/ stratified squamous epi
name the artery that supplies the first half of the large intestine
superior mesenteric artery
innervations of the first half of large intestine
sympathetic- superior mesenteric and celiac ganglia
parasympathetic- vagus nerve
name the artery that supplies the distal half of large intestine
inferior mesenteric artery
innervations of the distal half of large intestine
sympathetic- inferior mesenteric and hypogastric plexuses
parasympathetic- pelvic splanchnic nerves
type of tissue found in large intestine
simple columnar epithelial tissue, becomes stratified squamous epi at anal canal
what is the largest gland in the body
liver
what is the digestive function the liver
bile production
hepatocyte
functional cells of liver
what is the portal triad of the liver composed of
bile duct tributary, branch of hepatic portal vein, branch of hepatic artery
function of hepatic macrophages
destroy bacteria
function of gallbladder
stores and concentrates bile which emulsifies fats
where does the gallbladder expel bile into
duodenum
where and when is cholecystokinin released
from enteroendocrine cells in response to fatty chyme
what type of functions does the pancreas carry out
both exocrine and endocrine functions
what is the endocrine function of the pancreas
produce insulin and glucagon, regulates blood sugar
what is the exocrine function of the pancreas
produces most enzymes that digest food in small intestine
what structures form the hepatopancreatic ampulla
area where main pancreatic duct joints bile duct; empties into duodenum
where does the pancreas receives arterial supply from
hepatic, splenic, and superior mesenteric arteries
what are the pancreas exocrine functions
acinar cells make, store, and secrete pancreatic enzymes which are activated in the duodenum
what are peptic ulcers
erosions of the mucosa of a region of the alimentary canal
where do gastric ulcers occur
in pyloric region of stomach
where do duodenal ulcers occur
in duodenum of small intestine
name and describe the pathogen that causes peptic ulcers
Helicobacter pylori; acid-resistant, binds to gastric epi, induces over secretion of acid and inflammation
what are the 2 types of intestinal obstructions
mechanical and nonmechanical
list the types of mechanical obstructions
adhesions, tumors, or foreign objects
what are some causes of non-mechanical obstructions
halt in peristalsis; trauma, intestines touched during surgery
what is fnflammatory bowel disease and list the 2 types
inflammation of intestinal wall; Crohn’s disease and Ulceratice colitis
list the major types of viral hepatitis and what are some general symptoms
A, B, C and G; jundice and flulike symptoms
describe how cystic fibrosis affects the pancreas
pancreatic ducts become blocked w/ mucus, which prevent pancreatic juices from entering small intestine, leads to malabsorption of fats and other nutrients
during embryonic development, when is the alimentary canal formed and what does it enclose
week 3, encloses tubular portion of yolk sac
what is the vitelline duct during embryonic development
landmark dividing into 3 regions: foregut, midgut, an hindgut
