DIGESTIVE SYSTEM Flashcards
the layers of the tract wall are called
tunics
what are the 4 layers of the digestive tract
mucosa
submucosa
muscularis
serosa
this is the innermost tunic and it secretes mucus
mucosa
this lies outside the mucosa
submucosa
this lies outside the submucosa
muscularis
inner layer of muscularis
circular smooth muscle
outer layer of muscularis
longitudinal smooth muscle
an extensive network of cell processes forms a __ within the submucosa
plexus
the outermost layer of the digestive tract
serosa
two types of peritoneum
visceral
parietal
the peritoneum that covers the organs
visceral
the peritoneum that lines the wall of the abdominal cavity
parietal
it is a potentially life threatening inflammation of the peritoneal membranes
peritonitis
many of the organs of the abdominal cavity are held in place by connective tissue sheets called __ ; also provide a route for blood vessels and nerves
mesentries
types of mesentries
mesentry proper
lesser omentum
greater omentum
type of mesentry associated w small intestine
mesentry proper
mesentry connecting the lesser curvature of stomach to liver and diaphragm
lesser omentum
mesentry connecting the greater curvature of stomach to transverse colon and posterior body wall
greater omentum
the greater omentum creates a cavity or pocket called
omental bursa
abdominal organs with no mesentries are called
retroperitoneal
are muscular structures formed mostly by orbicularis oric muscle
lips
this structure form the lateral walls of the oral cavity. the buccinator muscles are located within these ; important in the process of mastication or chewing
cheeks
begins the process of mechanical digestion which breaks down large food particles into smaller ones
mastication
this structure is a large muscular organs that occupies most of the oral cavity
tongue
thin fold of tissue in floor of the mouth
frenulum
how many teeth are in the normal adult mouth
32
in each quadrant of teeth there are
central
lateral incisor
canine
premolar
molar
the third molars are called
wisdom teeth
the teeth of adults are called
permanent teeth or secondary teeth
permanent teeth are replacements for
primary teeth or deciduous teeth
what are the three regions of teeth
crown
neck
root
the bulk of the tooth is formed by a living, cellular, calcified tissue called
dentin
in the crown region, the dentin is covered by an extremely hard acellular substance called __ which protects the teeth against abrasions
enamel
the surface of the dentin is covered with __ which helps anchor the tooth in the jaw
cementum
within the center of the tooth is a hollow space called
pulp cavity
the pulp cavity is filled with a material called __ which consists of blood vessels and nerves
pulp
the teeth are held in place within pockets in the bone called
alveoli
the alveolar processes are covered by
gingiva or gums
they secure the teeth in the alveoli by embedding them in cementum
periodontal ligaments
this is the result of the breakdown of enamel by acids produced by bacteria
dental caries or tooth decay
this is the inflammation and degeneration of periodontal ligaments, gingiva, and alveolar bone
periodontal disease
this is the roof of the oral cavity which separated the oral from the nasal cavity
palate
two parts of the palate
soft
hard
the anterior part of the palate and contains bone
hard palate
the posterior part of the palate and consists of skeletal muscles and connective tissue
soft palate
this is a posterior extension of the soft palate
uvula
these are located in the lateral posterior walls of the oral cavity, in the nasopharynx, and in the posterior surface of the tongue
tonsils
what are the three major pairs of salivary glands
parotid
submandibular
sublingual
salivary glands produce
saliva
saliva is a mixture of _ and _ fluids and has multiple roles
serous and mucous
the largest salivary gland which are serous gland located located just anterior to each ear
parotid gland
this is an inflammation of the parotid gland caused by a viral infection
mumps
this type of gland produce more serous than mucous secretions
submandibular glands
this salivary gland is the smallest of the three paired salivary glands and these produce primarily mucous secretions
sublingual glands
what is the normal rate of saliva secretions
0.5L to 1.5L
the serous part of saliva produced mainly by the parotid and submandibular glands contains a digestive enzyme called
salivary amylase
the mucous secretions of the submandibular and sublingual glands contain a large amount of
mucin
this is the throat which connects the mouth with the esophagus
pharynx
what are the three parts of the pharynx
nasopharynx
oropharynx
laryngopharynx
the posterior walls of the orophayrnx and laryngopharynx are formed by the superior, middle, and inferior
pharyngeal constrictor muscles
it is a muscular tube lined with moist stratified squamous epithelium that extends from the pharynx to the stomach ; 25cm long
esophagus
these regulate movement of food into and out of the esophagus
upper and lower esophageal sphincters
what are the three phases of swallowing
voluntary
pharyngeal
esophageal
what are the 4 regions of the stomach
cardiac part
fundus
body
pyloric part
the pyloric part is surrounded by the __ and this helps regulate the movement of gastric contents into the small instestine
pyloric sphincter
the muscular layers in the stomach produce a ___ action
churning
the submucosa and mucosa of the stomach are arranged in large folds called __ when the stomach is empty ; allows to stretch
rugae
the mucosal surface forms numerous tubelike __
gastric pits
as food enters the stomach, the food is mixed with stomach secretion to become a semifluid mixture called
chyme
it is a painful or burning sensation in the chest usually associated with an increase in gastric acid secretion
heartburn or gastritis
regulation of stomach secretions can be divided into three phases which are
cephalic
gastric
intestinal
this phase of regulation of stomach secretions is the brain phase of stomach secretion. it is controlled by the CNS and begins even before the bolus of food enters the stomach
cephalic phase
this phase of regulation of stomach secretions produces the greatest volume of gastric secretions
gastric phase
this phase of regulation of stomach secretions inhibits gastric secretions
intestinal phase
uncomfortable sensations caused by peristaltic waves that lasts 2-3 minutes (stomach growling)
hunger pangs
this is about 6m long and consists of three parts
small intestine
what are the three parts of the small intestine
duodenum
jejunum
ileum
what are the 4 major cell types in the small intestine
absorptive cells
goblet cells
granular cells
endocrine cells
the epithelial cells are located within tubular glands of the mucosa called __ which open at the base of villi
intestinal glands or crypts of lieberkuhn
the submucosa of the duodenum contains mucous glands called __ which open into the base of intestinal glands
duodenal glands
clusters of lymphatic nodules are called __ ; these help protect the intestinal tract from harmful pathogens
peyer patches
the site where the ileum connects to the large intestine is called the
ileocecal junction
secretions from the mucosa of the small intestine contain mainly
mucus, ions and water
what are the two major movements in the small intestine
peristaltic contractions
segmental contractions
this type of contraction proceeds along the length of the intestine for variable distances and cause chyme to move along the small intestine
peristaltic
this type of contraction are propagated for only short distances and mix intestinal contens
segmental contractions
this is the largest internal organ of the body and weight about 1.36 kg or 3 pounds
liver
the liver consists of 4 lobes
right lobe
left lobe
caudate lobe
quadrate lobe
the right and left lobe are separated by a connective tissue septum called the
falciform ligament
visible from an inferior view of the liver is the __ ; where blood vessels, ducts, nerves enter and exit
porta
what are the 2 blood sources of the liver
hepatic artery
hepatic portal vein
delivers oxygenated blood to the liver, which supplies liver cells with oxygen
hepatic artery
carries nutrient rich blood from the digestive tract to the liver
hepatic portal vein
where blood exits the liver and empties into the inferior vena cava
hepatic vein
hexagon shaped regions surrounded by connective tissue septa and defined by a portal triad at each corner and a central vein in the center of the lobule
hepatic lobules
central veins of the lobules unite to form
hepatic veins
are strings of cells that radiate out from the central vein of each lobule like the spokes of a wheel
hepatic cords
the hepatic cords are composed of __, the functional cells of the liver
hepatocytes
are blood channels in the spaces in between the hepatic cords
hepatic sinusoids
is a cleftlike lumen that lies between the cells within each cord
bile canaliculus
produced by hepatocytes flows through bile canaliculi toward the hepatic triad
bile
the liver produces and secretes about __ of bile each day
600-1000mL of bile each day
one common bile pigment is __ which results from breakdown of hemoglobin by hepatocytes
bilirubin
these may form is the amount of cholesterol secreted by the liver becomes excessive and is not able to be dissolved by bile salts
gallstones
it is a complex organ composed of both endocrine and exocrine tissues that perform several functions
pancreas
the portion of the digestive tract extending from the ileocecal junction to the anus
large intestine
how many hours are required for material to pas through the large intestine
18-24 hours
in the colon, chyme is converted to
feces
how many mL of feces are eliminated
80-150mL
the proximal end of the large intestine where it joins with the small intestine ; a sac that extends inferiorly
cecum
attached to the cecum is a tube about 9cm long called
appendix
it is about 1.5-1.8m long and consists of 4 parts
colon
the mucosal lining of the colon contains numerous straight, tubular glands called __ which contain many mucus producing goblet cells
crypts
the longitudinal smooth muscle of the colon forms three bands called
teniae coli
it is a straight muscular tube that begins at the termination of he sigmoid colon and ends at the anal canal
rectum
the last 2-3cm of the digestive tract is the
anal canal
the anal canal begins at the inferior end of the rectum and ends at the
anus
these are enlarged or inflamed rectal or hemorrhoidal veins that supply the anal canal
hemorrhoids
the colon stores the feces until they are eliminated by the process of
defecation
every 8-12 hours, large parts of the colon undergo strong contractions called
mass movements
this reflex consists of local and parasympathetic reflexes
defecation reflex
this is the breakdown of food to molecules that are small enough to be absorbed into the blood
digestion
what are the two types of digestion
mechanical
chemical
this begins in the stomach where some small lipid soluble molecules can diffuse through the stomach epithelium
absorption
this requires carrier molecules and includes facilitated diffusion, cotransport, and active transport
transport
