chapter 23 Flashcards
exam 2
functions of the digestive system
- ingestion
- movement
- mechanical breakdown
- digestion
- absorpion
- excretion
membranes of the digestive system
1.peritoneum
2. mesentery
peritoneum
serous membrane that covers organs of the abdominopelvic cavity
what are the 2 layers of the peritoneum
visceral peritoneum :covers organs
parietal peritoneum: clings to body wall
Peritoneal cavity
fluid-filled sac in between the visceral and parietal peritoneum
prevents friction from organ/organ or organ/body wall contact
mesentary
double layer of peritoneum extending from digestive organs to body wall
functions of mesentery
- hold organs in place
- provide passage for blood lymphatic and nerve supply to the digestive system
- fat storage: adipose clings to mesentery can be used for energy and shock absorber
alimentary canal
portion of digestive system that forms a long tube into/out of the body
what is included in the alimentary canal
mouth, pharynx, esophagus, stomach small intestine, and large intestine
what are the layers of the alimentary canal (deep to superficial)
- mucosa
- submucosa
- muscularis externa
- serosa
mucosa
innermost layer that has 3 subdivisions
epithelium
lamina propia
muscularis mucosa
what type of tissue makes up epithelium of mucosa
simple columnar
functions of epithelia in mucosa
secretes mucus, digestive enzymes, hormones, and absorptive surface
what tissue is epithelia in the mouth esophagus and anus
stratified squamous
What tissue is lamina propria
loose areolar connective tissue
The lamina propria is vascularized
blood vessels that monomers enter into
muscularis mucosae
has smooth muscle cells
creates movement to increase digestion and secretion
submucosa
superficial to mucosa
the rich supply of blood, lymphatic vessels, lymphoid follicles, and nerve supply
allows 2 layers above to be healthy
what tissue makes up submucosa
areolar connective tissue with elastic fibers
the organ can fill and empty allowing it to stretch and return to the original size
muscularis externa
muscular layer that generates movement in GI tract
what are the 2 layers of the muscularis externa
- circular layer
- longitudinal layer
when circular layer constricts
organ becomes narrow and longer
when longitudinal layer constricts
organ becomes shorter and more wide
sphincters
thickenings in muscularis externa
where 1 organ meets another
prevents back movement of ingested food and controls movement from one alimentary organ to another
serosa
outermost layer
visceral peritoneum
in organs not found in the abdominopelvic cavity what is serosa replaced w
adventitia
tissue of adventitia
dense connective tissue
anchors organ in place: prevents bending/ twisting
Splanchic circulation
blood supply to digestive organs
includes arteries that branch off the aorta and hepatic portal circulation
arteries in splanchic circulation
branches of the celiac trunk that serve the spleen liver and stomach
hepatic artery
left gastric artery
splenic artery
hepatic portal circulation
collects nutrient-rich blood draining from digestive organs and transports it to the liver
given to the liver so it can filter out any toxic materials
enteric nervous system
nerve supply of the alimentary canal
lets brain know what is happening in digestive organs
two major intrinsic nerve plexuses of enteric nervous system
- submucosal nerve plexus
- myenteric nerve plexus
supply walls of GI tract and help regulate motility through it
submuscosal nerve plexus
found in submucosa
myenteric nerve plexus
found in between circular and longitudinal layers in muscularis externa
long reflex
initiated by stimuli inside and outside the GI tract
involves CNS
short reflex
mediated entirely by the enteric nervous system in response to stimuli within the GI tract
ex. peristaltic movement
the mouth includes
lips, cheeks and palate
lips and cheeks
contain several skeletal muscles
produce chewing movement and allow us to open and close the mouth
hard palate
rigid ribbed surface on roof of the mouth
helps break down food
soft palate
soft mobile surface posterior to the hard palate
uvula: projects from soft palate and helps close nasopharynx
the tongue
contains bundles of skeletal muscle
intrinsic muscles and extrinsic muscles
intrinsic muscles
confined within the tongue , not attached to bone
allow tongue to change shape
extrinsic muscles
origin of muscle is found on bone
allow the tongue to change position in the mouth
important functions of saliva
- cleanses mouth
- dissolves food chemicals for taste
- moistens food
- contains digestive enzymes salivary amylase and lingual lipase
salivary amylase
starches
lingual lipase
lipids
major salivary glands
- parotid
- submandibular
- sublingual
parotid gland
- largest salivary gland
- empties saliva from roof of mouth
- facial nerve found her: if damaged facial paralysis
submandibular gland
opens at floor of mouth under the tongue
sublingual
smallest salivary gland
opens at floor of mouth via 10-20 different ducts
teeth
tear/ grind food into smaller pieces during chewing
types of teeth
deciduous teeth
permanent teeth
deciduous teeth
baby teeth
20
permanent teeth
will eventually replace baby teeth that fall out
32
classification of teeth
- incisors: cutting teeth
- canines: tearing teeth
- premolars and molars : grinding teeth
structure of teeth
- crown
2.root
crown
exposed portion
enamel: tough mineralized substance covering exposed tooth surface
root
portion embedded in jaw bone
anchored to periodontal ligament
odontoblast
cell that continuously lays down dentin
what are teeth composed of
dentin
pulp cavity
surrounded by dentin and contains connective tissue, blood supply and nerve supply through cavity
pharynx
contractions of muscle in walls propel food into the esophagus
where does the stomach join w the esophagus
cardiac orifice
cardiac sphincter
thickening of smooth muscle at cardiac orifice
prevent backward movement from the stomach to the esophagus
