Chapter 24 Flashcards
alimentary canal
GI tract
tonus def/length of GI tract
state of contraction
GI tract is 5-7m during tonus
six basic processes of digestive system
- Ingestion: taking food into mouth.
- Secretion: release of water, acid,
buffers, and enzymes into lumen
of GI tract. - Mixing and propulsion: churning
and movement of food through GI
tract. - Digestion: mechanical and
chemical breakdown of food. - Absorption: passage of digested
products from GI tract into blood
and lymph. - Defecation: elimination of feces
from GI tract.
four layers of GI tract (deep to superficial)
mucosa
submucosa
muscularis
serosa/adventita
mucosa layer of GI tract has what layers (3)
inner epithelium
lamina propria
muscularis mucosae
inner epithelium of mucosa layer of GI tract (functions/rate or renewal/contains what special cells)
protective (mouth, pharynx, esophagus, anal canal), secretion./absorption (stomach, intestines)
rate of renewal 5-7 days
enteroendocrine cells secrete hormones
lamina propria of mucosa layer of GI tract (what CT, function, contains majority of what cells)
aerolar CT
has vessels for absorbed nutrients
contains majority of the cells of the mucosa-associated lymphatic tissue (MALT) (lymphatic nodules for immune system)
muscularis mucosae of mucosa of GI tract (function)
creates folds in MM of stomach/SI=more SA for digestion/absorption
movements ensure all absorptive cells are exposed to GI contents
submucosa of GI tract (CT, function, plexus)
areolar CT
vessels for digested nutrients
has submucosal plexus (network of neurons)
muscularis of GI tract (types, plexus)
skeletal ( mouth, pharynx, and superior and middle parts of the esophagus, external anal sphincter)
smooth : inner circular fibers outer longitudinal
has myenteric plexus (network of neurons)
serosa of GI tract (location, tissue, AKA)
only in abdominal cavity
serous membrane with areolar CT/simple squamous
AKA visceral peritoneum
adventita location/tissue
found on esophagus
single layer areolar CT
two plexuses of enteric nervous system
myenteric plexus (plexus of Auerbach)
submucosal plexus ( plexus of Meissner)
myenteric plexus location/function
between circular/longitudinal fibers of muscularis
control GI tract motility (frequency/strength of contraction)
submucosal plexus location/function
within submucosa
control secretions of organs of GI tract
2 major sensory receptors of GI tract
chemoreceptors, mechanoreceptors
parasympathetic innervation of GI tract
Psymp preG neurons of the vagus/pelvic splanchnic nerves synapse with Psymp postG neurons located in the myenteric and submucosal plexuses. Some of the psymp postG neurons in turn synapse with neurons in the ENS; others directly innervate smooth muscle and glands within the wall of the GI tract
increase in GI secretion and motility by increasing the activity of ENS neurons
sympathetic innervation of GI tract
arise from the thoracic and upper lumbar regions of the SC
symp postG neurons synapse with neurons located in the myenteric plexus and the submucosal plexus
cause a decrease in GI secretion and motility by inhibiting the neurons of the ENS
gastrointestinal reflex pathways
regulate GI secretion/motility by responses to stimuli in lumen of GI tract
receptors ot CNS, ANS, or ENS then activate or inhibit glands/smooth
five major peritoneal folds
greater omentum
falciform ligamen
lesser omentum
mesentery
mesocolon
Ascites
Distension of parental cavity due to fluid buildup from disease
greater omentum (size, folds, function)
longest
4 layers over transverse colon and coils of SI (fatty apron)
lots of adipose cells (beer belly)
lymph nodes contribute macrophages and antibody-producing plasma cells that help combat and contain infections of the GI tract
falciform ligament (function)
attatches liver to the anterior abdominal wall and diaphragm
lesser omentum function
connects the stomach and
duodenum to liver
pathway for blood vessels entering the liver and contains the hepatic portal
vein, common hepatic artery, and common bile duct, along with
some lymph nodes
mesentery (size, shape, function, lots of, extends)
biggest fold
fan shaped
binds jejunum and ileum of SI to post abdominal wall
lots of fat
extends from the posterior abdominal wall to wrap around the small intestine and then returns to its origin, forming a
double-layered structure. Between the two layers are blood and lymphatic vessels and lymph nodes.
mesocolon (function)
bind the transverse colon and
sigmoid colon of the LI to the post abdominal wall
carries blood and lymphatic vessels to the intestines.
labial frenulum
inner surface of each lip is attached to its corresponding gum by a midline fold of MM called labial frenulum
muscles for chewing
buccinator (cheek) orbicularis oris (lips)
oral vestibule
space between chekks/lips and teeth/gums
oral cavity proper
space fro gums/teeth to fauces (opening to oropharynx)
palate (Function/parts)
allows breathing while chewing
hard: palatine and maxilla with MM
soft: muscle with MM
uvula
drawn superiorly during swallowing to prevent food from entering the nasopharynx
palatine vs lingual tonsil location
between palatoglossal/paalatopharyngeal arch vs at base of tongue
small salivary glands (4)
labial, buccal, palatal, lingual
major salivary glands- 3 paired (location/open to)
parotid: inferior and
anterior to the ears, between the skin and the masseter muscle open to the vestibule opposite the second
maxillary (upper) molar tooth
submandibular: floor of the mouth open to oral cavity proper lateral to the lingual frenulum
sublingual: beneath the tongue and superior to the submandibular glands open to floor of mouth into oral cavity proper
saliva composition
99.5% water and 0.5% solutes
solutes:
1. ions: sodium, potassium, chloride, bicarbonate, and phosphate.
- dissolved gases/organic substances: including urea and uric acid, mucus, immunoglobulin A, the bacteriolytic enzyme lysozyme, and salivary amylase, a digestive enzyme that acts on starch
parotid vs submandibular vs sublingual glands release
watery amylase vs fluid amylase thickened with mucus vs mostly mucus with little amylase
salivary amylase function
breaks starch into maltose, maltotriose, a-dextrin
tongue attached inferiorly to
hyoid bone, styloid process of temporal bone and mandible
extrinsic muscles of tongue (movement of tongue/function)
Move tongue from side to side and in and out
Food maneuvered for mastication, shaped into bolus, and
maneuvered for swallowing
intrinsic muscles of tongue (movement of tongue/function)
Alter shape of tongue
swalloing of speech
lingual frenulum
fold of MM on inferior surface of tongue to limit posterior movement
lingual glands
secrete lingual lipase=30% triglycerides (fats/oils) broken down into fatty acids and diglycerides
periodontal ligament
dense fibrous CT that anchors the teeth to the socket walls and acts as a shock absorber during chewing
three major external regions of tooth
crown, neck, root
enamel
outer covering of tooth
(made of calcium salts)
protects the tooth from wear and tear
dentin
underneath enamel
(calcified connective tissue)
makes up the majority of the tooth.
Cementum
a bone-like substance that attaches the root to the periodontal ligament.
pulp cavity
inner part of crown
contains pulp (connective
tissue containing nerves and blood vessels)
root canal
is an extension of the pulp
cavity that contains nerves and blood vessels
apical foramen
is an opening at the base of a root canal through which blood vessels, lymphatic vessels, and nerves enter a tooth
endodontics vs orthodontics vs periodontics
prevention, diagnosis, and treatment of diseases that affect the pulp, root, periodontal ligament, and alveolar bone
vs
prevention and correction of abnormally aligned teeth
vs
treatment of abnormal conditions of the tissues immediately surrounding the teeth, such as gingivitis (gum disease)
two denditions
deciduous (primary teeth, milk teeth, or baby teeth): begin at 6m lost between 6-12y; 20
permanent (secondary) teeth: replace deciduous; 32
incisors (location/function/root)
4 front teeth (central or lateral incisors), cut into food; one root
canines (location/function/roo)
behind incisors; one cusp to tear/shred food; one root
first/second molars
behind canines; 4 cusps; upper (maxillary) have 3 roots,
lower (mandibular) have two; crush/grind food to prepare for swallowing
salivary amylase vs lingual lipase
secreted by the salivary glands, initiates the breakdown of starch into monosaccharides, starts acing in mouth until 1 hour after eating
vs
secreted by lingual glands, breaks down dietary triglycerides (fats and oils) into fatty acids and diglycerides, activated by acidic enviro of stomach (starts acting after swallowed)
esophageal hiatus
opening in the diaphragm that esophagus passes through to enter the stomach
mucosa of esophagus (location/histology(layers))
inner layer
non-keratinized stratified squamous
lamina propria
muscularis mucosae
mucus glands near stomach
submucosa of esophagus (location.histology)
second from inner layer (superficial to mucosa, deep to muscularis)
areolar connective tissue, blood vessels, and mucous glands
muscularis of esophagus (what each third consists of)
sup 1/3: skeletal
middle 1/3: skeletal+smooth
inf 1/3: smooth
has sphincter on each end of esophagus
two sphincters of esophagus (name and what they are made of)
upper esophageal sphincter: skeletal
muscle
lower esophageal (cardiac) sphincter (LES): mooth muscle, near the heart
adventita of esophagus (why is it called that instead of serosa)
areolar CT of this layer is not covered by mesothelium and because the
CT merges with the CT of surrounding
structures of the mediastinum through which it passes
Relaxation of upper esophageal sphincter
Permits entry of bolus from laryngopharynx into esophagus
Esophageal stage of deglutition (peristalsis)
Pushes bolus down esophagus.
Relaxation of lower esophageal sphincter
Bolus into stomach
secretion of mucus (esophagus)
Lubricates esophagus for smooth passage of bolus
deglutition involves/3 stages
mouth, pharynx, esophagus
- voluntary: into oropharynx
- pharyngeal: to esophagus
- esophageal: to stomach
deglutition center location
medulla oblongata and lower pons of the brain stem.
peristalsis (def, what contracts where)
progression of coordinated contractions and relaxations of the circular and longitudinal layers of the muscularis, pushes the bolus onward
(circular contract above bolus, and longitudinal contract below)
4 regions of stomach
cardia: surrounds opening of esophagus
fundus: rounded sup part L to cardia
body: large central portion
pyloric part: 3 parts to duodenum
3 regions of pyloric part
pyloric antrum: connects to body of stomach
pyloric canal: leads to 3rd region
pylorus: connects to duodenum
rugae
mucosal folds in stomach when empty
lesser vs greater curvature of the stomach
concave/medial vs convex/lateral
surface mucous cells
simple columnar epithelial cells that make up surface of mucosa of stomach
gastric glands
columns of secretory cells in stomach
gastric pits
narrow channels that several gastric glands release secretions into to enter the stomach
3 exocrine cells in gastric glands and what they secrete
mucous neck cells: secrete mucous
chief cells: secretes pepsinogen and gastric lipase
parietal cells: secretes hydrochloric acid and intrinsic factor (needed for B12 absorption)
gastric juice is made by the secretions of what cells and what other cells
mucous neck cell, chief cells, parietal cells
G cell (enteroendocrine cell): secretes gastrin
what is different about the muscularis of the stomach
3 layers instead of 2 (outer longitudinal, middle circular, inner oblique)
propulsion, retropropulsion, and gastric emptying in stomach
propulsion: peristalsis in body/antrum to pyloric sphincter every 15-25s
retropropulsion: food too big to fit through pyloric sphincter=back to body to mix with gastric juice
gasric emptying: food turned into chyme and can fit through pyloric sphincter
Surface mucous cells and mucous neck cells activity and result (1)
A: secretes mucus
R: Forms protective barrier that prevents digestion of stomach wall.
parietal cells action and result (2)
A: secrete intrisnic factor
R: Needed for absorption of vitamin B12 (used in RBC formation)
A: secrete hydrochloric acid
R: Kills microbes in food; denatures proteins; converts pepsinogen into pepsin
chief cells action and results (2)
A: secrete pesinogen
R: Pepsin (activated form) breaks down proteins into peptides
A: secret gastric lipase
R: Splits triglycerides into fatty acids and monoglycerides
G cells action and result (1)
A: secrete
R:Stimulates parietal cells to secrete HCl and chief cells to secrete pepsinogen; contracts lower esophageal sphincter, increases motility of stomach, and relaxes pyloric sphincter
pancreas 3 main regions
head (near duodenum) body tail
pancreatic duct, or duct of Wirsung
larger duct of pancres, inferior
hepatopancreatic ampulla or ampulla of Vater
where pancreatic duct and common bile duct meet in pancreas
has sphincter of Oddi
major duodenal papilla
elevation of the duodenal mucosa where hepatopancreatic ampulla is
accessory duct (duct of Santorini)
smaller/sup to pancreatic duct
acini vs pancreatic islets in pancreas
99 percent; exocrine (pancreatic juice) vs 1 percent; endocrine (hormones)
pancreatic juice
clear, colorless liquid consisting mostly of water,
some salts, sodium bicarbonate, and several enzymes
pancreatic amylase
starch digesting enzyme
trypsin, chymotrypsin, carboxypeptidase, elastase
enzymes that digest proteins into peptides; released by pancreas
pancreatic lipase
triglyceride digesting enzyme; released by pancreas
ribonuclease vs deoxyribonuclease
nucleic-acid digesting enzyme; released by pancreas
vs
digest RNA/DNA into nucleotides; released by pancreas
enterokinase
enzyme in SI that turns trypsinogen into trypsin
gallbladder location
in post depression of liver, hangs from the anterior inferior margin of the liver
what seperates the larger R lobe and smalller L lobe of liver
falciform ligament
ligamentum teres (round ligament)
in falciform ligament, remnant of umbilical vein of the fetus this fibrous cord extends from the liver to the umbilicus
coronary ligaments
narrow extensions of the parietal peritoneum that suspend the liver from the diaphragm
hepatocytes (volume of liver/function/form/secrete)
80 percent of liver volume
major functional cells of the liver and perform a wide array of metabolic, secretory, and endocrine functions
form hepatic laminae
secrete bile
Bile canaliculi
small ducts between hepatocytes that collect bile produced by the
hepatocytes
hepatic sinusoids
highly permeable blood capillaries between rows of hepatocytes that receive oxygenated blood from branches of the hepatic artery and nutrient-rich deoxygenated blood from branches of the hepatic portal vein
stellate reticuloendothelial cells (hepatic macrophages) (where/function)
in hepatic sinusoid
destroy worn out R/WBC, bacteria, and other foreign matter in the venous blood draining from the GI tract
portal triad
a bile duct, branch of the hepatic artery, and branch of the hepatic vein together
cystic duct
Contraction of the smooth muscle fibers ejects the contents of the gallbladder into this
gallbladder function basic
Stores, concentrates, and delivers bile into duodenum via common bile duct.
liver function basic
Produces bile (bile salts) necessary for emulsification and absorption of lipids
blood supply of liver (pathway back to heart)
hepatic artery/hepatic portal vein -> sinusoids -> central vein -> hepatic vein -> inf vena cava -> right atrium
other vital functions the liver performs (9)
Carbohydrate metabolism
Lipid metabolism
Protein metabolism
Processing of drugs/hormones
Excretion of bilirubin
Synthesis of bile salts
Storage
Phagocytosis
Activation of vitamin D
