BIOL G220: Ch. 26 Flashcards
Terms and concepts from Ch. 26: Digestive System
The digestive system includes organs that.. (5)
- ingest the food
- transport the ingested material
- digest the material into smaller usable components
- absorb the necessary digested nutrients into the blood stream
- expel waste products from the body
accessory digestive organs
not part of long GI tube, but often develop as outgrowths of that tube
accessory digestive organs (6)
teeth tongue salivary glands liver gall bladder pancreas
digestive system functions (6)
ingestion digestion propulsion secretion absorption elimination
propulsion
involves peristalsis and segmentation
peristalsis
ripple-like wave of muscular contraction that forces material to move further along the GI tract
segmentation
churning and mixing of material helping to disperse the material and mix it and combine it with digestive organ secretions
oral cavity contains… (4)
cheeps, lip, and palate
tongue
salivary glands
teeth
cheeks
form the lateral wall of the oral cavity and are comprised mainly of the buccinator muscles
cheeks end anteriorly as..
lips
gingivae
cover the alveolar processes of the teeth
labial frenulum
thin, midline mucosa on the internal surface of the upper and lower lips that are attached to the gingivae
palate
forms the roof of the oral cvity
hard palate
anterior two-thirds of the palate comprised of bone
soft palate
posterior one-third of palate; soft and muscular
uvula
extending from the soft palate posteriorly, it elevates during swallowing and closes off the posterior entrance to the nasopharynx
fauces
represent the opening from the oral cavity to the oropharynx
fauces are bounded laterally by paired muscular folds: (2)
palatoglossal arch
palatopharyngeal arch
palatine tonsils
housed by the two arches that bound fauces
tongue
manipulates and mixes ingested materials during chewing and helps compress the partially digested materials into a bolus
bolus
globular mass of ingested materials that can be more easily dwallowed
lingual frenulum
thin, midline mucous membrane that attaches the inferior surface of the tongue and the floor of the oral cavity
salivary glands
produce and secrete saliva into the oral cavity
saliva functions (5)
- moistens ingested materials to become a slick bolus
- moistens, cleanses, and lubricates the structures of the oral cavity
- chemical digestion of ingested materials
- antibacterial action
- dissolves materials so that taste receptors on the tongue can be stimulated
saliva production rate
1-1.5 L/day
saliva solute components (3)
immunoglobin A
lysozyme
mucin
immunoglobin A
helps decrease bacterial infections
lysozyme
antibacterial enzyme
salivary glands are located..
external to the oral cavity
pairs of salivary glands (3)
- parotid glands
- submandibular glands
- sublingual glands
parotid salivary glands are the __ of the three
largest
parotid salivary glands secrete -% of total saliva
25-30%
parotid salivary glands include a __ ___ that runs parallel to the zygomatic arch and pierces the ___ muscle
parotid duct; buccinator
parotid salivary glands also secrete..
amalase
submandibular salivary glands produce the __ of the saliva (-%)
majority; 60-70%
submandibular salivary glands contain a __ ___ that transports saliva from each gland through a papilla in the floor of the mouth
submandibular duct
sublingual salivary glands contribute -% of total saliva
3-5%
sublingual salivary glands contain multiple, tiny __ ___ that open into the inferior surface of the oral cavity
sublingual ducts
types of secretory cells found in salivary glands (2)
mucous cells
serous cells
mucous cells
secrete mucin, which forms mucus upon hydration
serous cells
secrete a watery fluid containing ions, lysozyme, and salivary amylase
parotid (type of secretion)
only serous
submandibular (type of secretion)
both mucus and serous
sublingual (type of secretion)
both mucus and serous
teeth are collectively known as
dentition
a tooth has an exposed ___, a constricted __, and one or more ___ that fit into __ ___
crown; neck; roots; dental alveoli
dentin
forms the primary mass of the tooth; harder than bone
each root of a tooth is covered with..
cementum
enamel
covers the external surface of the dentin and forms the crown of the tooth
pulp cavity
center of the tooth
pulp
connective tissue contained in the pulp cavity of a tooth
root canal
opens into the connective tissue (pulp) of the tooth
apical foramen
opening throughwhich a root canal opens into the connective tissue
apical foramen has.. which are housed by the ___
blood vessels and nerves passing through; pulp
teeth surfaces (6)
mesial distal buccal labial lingual occlusal
sets of teeth (2)
- deciduous
2. permanent
deciduous teeth
erupt between 6-30 months, are 20 in numbers, and are often called milk teeth
permanent teeth
replace the deciduous teeth and are 32 in number
permanent teeth types (4)
incisors
canines
premolars
molars
incisors
most anteriorly placed, shaped like chisels, and have a single root
canines
posterolateral to the incisors, pointed tips for puncturing and tearing
premolars
posterolateral to canines, have flat crowns with prominent ridges called cusps for crushing and grinding
cusps (premolars)
prominent ridges for crushing and grinding
molars
thickest and most posterior teeth, also adapted for rushing and grinding of ingested materials
gingivae composed of..
dense irregular connective tissue and nonkeratinized stratified squamous epithelium
gingivae function
surrounds necks of teeth and cover alveolar processes
hard plate composed of..
bony shelf covered by dense CT and nonkeratinized stratified squamous epithelium
lips are covered with..
keratinized stratified squamous epithelium
lips function to..
close oral cavity during chewing
soft palate is covered with..
nonkeratinized stratified squamous epithelium
teeth are..
hard structures projecting from the alveolar processes of the maxillae and mandible
teeth function
masticate (chew food)
tongue is
primarily skeletal muscle and covered by stratified squamous epithelium; surface covered in papillae
tonsils are..
aggregates of partially encapsulated lymphatic tissue
tonsils function to
detect antigens in swallowed food and drink and initiate immune response if necessary
vestibule is..
space between cheek and gums
vestibule function
space between lips/checks and gums where ingested materials are mixed with saliva and mechanically digested
pharynx is shared by..
the respiratory and digestive system
pharyngeal constrictors (3)
superior, middle, and inferior
pharyngeal constrictors
form the wall of the pharynx and participate in swallowing
CN _ innervates most pharyngeal muscles
X
the abdominopelvic cavity is lined with moist __ membranes
serous
parietal peritoneum
lines the inside surface of the body walls
visceral peritoneum
covers the surface of internal organs within the cavity
intraperitoneal organs
organs completely surrounded by visceral peritoneum
retroperitoneal organs
organs in direct contact with the posterior abdominal and pelvic walls and are only covered on their anterolateral surfaces with visceral peritoneum
mesenteries
folds of peritoneum that support and stabilize intraperitoneal GI tract organs
blood vessels, lymphatic vessels, and nerves are sandwiched between the two fold and supply the __ organs
digestive
greater omentum
extends inferiorly like an apron from the greater curvature of the stomach and covers most of the abdominal organs
lesser omentum
conects the lesser curvature of the stomach and the proximal end of the duodenum to the liver
mesentery proper
suspends most of the small intestines from the posterior abdominal wall
mesocolon
peritoneal fold that attaches parts of the large intestine to the posterior abdominal wall
tunics of GI wall (deep to superficial, 4)
mucosa
submucosa
muscularis
adventitia or serosa
mucosa
superficial epithelium with an underlying connective tissue called lamina propria and a thin layer of smooth muscle called the muscularis mucosae
submucosa
composed of lymphatic ducts, mucin-secreting glands, blood vessels, and nerves including the submucosal nerve plexus
muscularis
two layers of smooth muscle (inner circular layer, outer longitudinal layer)
inner circular layer
constricts the lumen and forms sphincters
outer longitudinal layer
shortens the tube
nerve fibers and associated ganglia between the two smooth muscle layers of muscularis tunic is called the..
myenteric nerve plexus
adventitia or serosa
outermost layer composed of areolar CT with collagen and elastic fibers
serosa
same as adventitia but is covered by visceral peritoneum
unpaired arteries supplying the abdominal GI tract (3)
- celiac trunk
- superior mesenteric artery
- inferior mesenteric artery
lacteals
lymph ducts that are present in villi of small intestine
lacteals transport lymph to..
cisterna chyli, which drains into the thoracic duct
MALT
mucosa-associated lymphatic tissue
MALT are lymphatic structures found..
in the small intestine and appendix and are called Peyer patches
autonomic plexuses following unpaired arteries (3)
- celiac plexus
- superior mesenteric plexus
- inferior mesenteric plexus
esophagus
a tubular passageway that conducts ingested materials from the pharynx to the stomach
esophageal hiatus
opening in the diaphragm allowing passage of the esophagus as it connects to the stomach
esophagus length
25 cm
esophagus sphincters (2)
superior esophageal sphincter
inferior esophageal sphincter
superior esophageal sphincter
junction of the pharynx `and the esophagus; closes during inhalation preventing air from entering the GI tract
inferior esophageal sphincter
junction of the esophagus and the stomach; prevents material from regurgitating from the stomach into the esophagus
stomach
continues the mechanical and chemical digestion of the bolus
bolus is eventually processed into..
chyme
four regions of stomach
- cardia
- fundus
- body
- pyloris
greater curvature of stomach
inferior border of stomach
inferior curvature of stomach
superior border of stomach
gastric folds (rugae)
internal surface of the stomach thrown into folds
stomach is line by..
simple columnar epithelium
gastric pits
numerous depressions indented within stomach lining
gastric glands
several branched tubular glands at the base of each gastric pit
secretory cells (gastric epithelium, 5)
- surface mucous cells
- mucous neck cells
- parietal cells
- chief cells
- enteroendocrine cells
surface mucous cells secrete..
alkaline mucin for protection and armor (thick)
mucous neck cells secrete..
acid mucin that helps break down food (thin)
parietal cells secrete..
hcl
chief cells secrete..
pepsinogen and lipase
enteroendocrine cells secrete..
hormone gastrin
small intestine
finishes the chemical digestion process and is responsible for absorbing most of the nutrients
ingested materials spend at least _ hours in the small intestine as chemical digestion and absorption are completed
12
segments of small intestine (3)
- duodenum
- jejunum
- ileum
duodenum
c-shaped portion found in the upper right quadrant of the abdomen; is continuous with jejunum at duodenojejunal flexure and contains the major duodenal papilla
duodenal papilla
site where bile and pancreatic secretions enter the duodenum
jejenum
middle portion of the small intestine that is primary region for chemical digestion and nutrient absorption
ileum
last segment of the small intestine with its distal end terminating at the ileocecal valve
ileocecal valve
a sphincter that controls the entry of materials into the large intestine
circular folds
folds of mucosal and submucosal tunics in small intestine
villi
microscopic fingerlike projections seen on the surface of circular folds
microvilli
microscopic fingerlike projections seen on the surface of the villli (apical surface of columnar epithelial cells)
circular folds function to..
slow down the passage of materials undergoing digestion; increases surface area for both absorption and chemical digestion
villi function
increase surface area for absorption and chemical digestion
microvilli
increase surface area for both absorption and digestion
intestinal glands
invaginations into mucosa between villi
intestinal glands (function)
increase surface area for both absorption and chemical digestion; enteroendocrine cells lining intestinal glands secrete digestive hormones
submucosal glands
coiled tubular glands within submucosa with ducts opening into intestinal lumen
submucosal glands function
secrete alkaline mucin to protect and lubricate lining of small intestine
large intestine
forms three-sided perimeter around the centrally located small intestine
large intestine function (2)
absorbs fluids and ions and compacts undigestable wastes and solidifies them into feces; stores feces until defecation
large intestine structures (7)
cecum ascending colon transverse colon descending colon sigmoid colon rectum anal canal
cecum
first part of large intestine; blind sac located in lower right quadrant of abdomen
ileocecal valve represents..
junction between small intestine and large intestine
acsending colon
originates at the ileocecal valve and ascends right side of the abdomen
right colic flexure (hepatic flexure)
90-degree turn toward left side of abdominal cavity of the ascending colon
transverse colon
originates at the right colic flexure and approaches the spleen in the upper left abdominal quadrant
transverse colon is suspended by..
transverse mesocolon
left colic flexure (splenix flexure)
transverse colon making 90-degree turn inferiorly
descending colon
originates at the left colic flexure and makes contact with iliac fossa and termiantes into the sigmoid colon
sigmoid colon
shape resembles the letter S; turns inferomedially and is sudpended by the sigmoid mesentery
sigmoid colon terminates at the ..
rectum
rectum
muscular tube that readily expands to store accumulated fecal material prior to defecation
rectal valves
three thick, transverse folds of the rectum that ensure fecal material is retained during the passage of gas
rectum terminates at the..
anal canal
anal canal
terminal few centimeters of the large intestine
anal columns
lines the internal surface of the anal canal
internal and external anal sphincters
open and close the anal canal during defecation
large intestine is lined with
simple columnar epithelium and goblet cells, which secrete mucin to lubricate the fecal material
longitudinal muscle is incomplete in large intestine and form bundles called..
teniae coli
teniae coli bunch up the large intestine into many sacs collectively called..
haustra
omental appendices
lobules of fat extending off the external surface of the haustra
lobes of liver (4)
- right lobe
- left lobe
- caudate lobe
- quadrate lobe
structures found on inferior surface of liver (5)
inferior vena cava ligamentum venosum gall bladder round ligament porta hepatis
porta hepatis
where the blood and lymph vessels, bile ducts, and nerves enter and leave the liver
portal triad
bile ductule, branch of hepatic portal vein, brain of hepatic artery
gall bladder
functions to store and concentrate bile
cystic duct
connects the gall bladder to the common bile duct
pancreas
has both endocrine and exocrine functions
exocrine functions of pancreas
involve secreting digestive enzymes and bicarbonate, collectively called pancreatic juices, into the duodenum via the pancreatic ducts
biliary apparatus
network of thin ducts that transport bile from liver and gall bladder to duodenum
left and right lobes of the liver drain bile into the..
left and right hepatic ducts
left and right hepatic ducts merge to form the..
common hepatic duct
cystic duct and common hepatic duct merge to form..
common bile duct
common bile duct and main pancreatic duct enter the duodenum through the..
hepatopancreatic ampulla
intraperitoneal or retroperitoneal/serosa or adventitia:
cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectu,
cecum - intraperitoneal (serosa)
ascending colon - retroperitoneal (adventitia)
transverse colon - intraperitoneal (serosa)
descending colon - retroperitoneal (adventitia)
sigmoid colon - intraperitoneal (serosa)
rectum - retroperitoneal (adventitia)
