Digestive System Flashcards
_ is also called the gastrointestinal (GI) tract or the gut
alimentary canal
_ is a continuous muscular tube that opens to the outside at both ends; it digests food and absorbs nutrients
gastrointestinal (GI) tract
_ assist in digestion, secrete chemicals and/or mechanically break down particles
accessory digestive organs
_ produce secretions to help breakdown foodstuffs (e.g., salivary glands, liver, pancreas)
digestive glands
_ = eating
ingestion
_ = movement of food through alimentary canal (i.e., swallowing and peristalsis)
propulsion
_ = major means of propulsion of food; alternating waves of contraction-relaxation in adjacent segments of alimentary canal organs
peristalsis
_ = local constriction of intestine to mix food with digestive juices; contraction-relaxation in nonadjacent segments of alimentary canal organs
segmentation
_ includes chewing, mixing food with saliva, churning food in stomach, and segmentation
mechanical digestion
_ is a series of catabolic steps. involving enzymes that break down complex food molecules into chemical building blocks
digestion
_ is a passage of digestive fragments from GI tract lumen into blood/lymph
absorption
_ is the elimination of indigestible substances via anus (i.e., feces)
defecation
_ are serous membranes of abdominal cavity, consisting of the visceral and parietal peritoneum
peritoneum
_ is a membrane on external surface of most digestive organs
visceral peritoneum
_ is a membrane lining body wall
parietal peritoneum
_ is a fluid filled space between two peritoneums (the fluid is used to lubricate mobile organs)
peritoneal cavity
_ is a [fused] double-layer of peritoneum extending from body wall to digestive organs
mesentery
_ provides routes for blood vessels, lymphatics, and nerves, stores fat, and holds organs in place
mesentery
_ organs are within peritoneum
intraperitoneal (peritoneal)
_ organs are outside/posterior to peritoneum (e.g., most of the pancreas, duodenum, and large intestine)
retroperitoneal
_ is inflammation of the peritoneum caused by piercing abdominal wounds, perforating ulcers, or ruptured appendix
peritonitis
_ lines lumen of alimentary canal; functions to secrete, absorb, and protect
mucosa
_ is made of areolar connective tissue, a lot of elastic tissues, and blood-lymphatic vessels/lymphoid follicles/nerve plexus to supply surrounding GI tract tissues
submucosa
_ is the muscular layer of alimentary canal responsible for peristalsis-segmentation
muscularis externa
_ (or visceral peritoneum) is the outermost layer of alimentary canal; adventitia in esophagus
serosa
_ is a blood-containing space
lumen
_ can include mucus, digestive enzymes, and hormones
secretion
_ are the end products of digestion
absorption
_ is used against infectious disease
protection
_ in mucosa is made of areolar connective tissue, capillaries, and lymphoid follicles
lamina propria
_ include lymphoid follicles to defend against microorganisms
mucosa-associated lymphoid tissue (MALT)
_ is smooth muscle producing local movements of mucosa
muscularis mucosae
_ are thick, circular layers
sphincters
_ is a dense connective tissue holding the esophagus to surrounding structures
adventitia
_ are arteries branching off the aorta and serve digestive organs (e.g., hepatic, splenic, L. gastric, and mesenteric arteries)
splanchnic circulation
_ drains nutrient-rich blood from digestive organs for processing in the liver
hepatic portal circulation
_ is the nervous system of the GI tract, controlling motility
enteric nervous system (gut brain)
_ regulates glands and smooth muscle in mucosa
submucosal nerve plexus
_ controls GI tract motility
myenteric nerve plexus
enteric neurons have _ neurons than the spinal cord
more
_ are controlled by enteric nerve plexus to respond to GI tract stimuli
short reflexes
_ respond to stimuli inside/outside of gut (e.g., ANS - sympathetic and parasympathetic)
long reflexes
_ (‘rest and digest’) enhances digestive processes
parasympathetic nervous system
_ (‘fight or flight’) inhibits digestion
sympathetic nervous system
_ involve short reflexes (i.e.,, enteric nervous system)
intrinsic controls
_ involve long reflexes (i.e.,, autonomic nervous system)
extrinsic controls
_ is bounded by lips (anterior), cheeks (lateral), palate (superior), and tongue (inferior)
buccal (oral) cavity
_ is the anterior opening of the mouth
oral orifice
_ are made of orbicularis oris muscle
labia (lips)
_ make up the cheeks
buccinator muscles
_ is recess internal to lips and cheeks, external to teeth-gums
oral vestibule
_ of mouth lies within teeth-gums
oral cavity proper
_ is median attachment of each lip to gum
labial frenulum
_ is formed by palatine bones and palatine processes of maxillae (has midline ridge, raphe)
hard palate
_ is a fold formed mostly of skeletal muscle
soft palate
fingerlike projection that faces downward from free edge of soft palate is _
uvula
_ occupies floor of mouth
tongue
_ gives tongue white appearance and roughness to provide friction; does not contain taste buds
filiform papillae
_ (mushroom shaped) scattered widely over tongue; vascular core causes red appearance
fungiform papillae
8–12 _ form V-shaped row in back of tongue
vallate (circumvallate) papillae
_ is on lateral aspects of posterior tongue
foliate papillae
_ (groove posterior to vallate papillae) marks division between body and root of tongue
terminal sulcus
_ (tongue) resides in oral cavity
body
_ (tongue) posterior third; resides in oropharynx
root
_ (congenital condition) children born with short lingual frenulum and causes distorted speech
ankyloglossia (tongue-tied)
_ (enzyme) breaks down starch
amylase
_ (outside oral cavity) produce most of saliva
major (extrinsic) salivary glands
_ (anterior to ear, exterior to masseter muscle) opens into vestibule next to second upper molar
parotid gland
_ (medial to manidle) opens at base of lingual frenulum
submandibular gland
_ (anterior to submandibular gland under tongue) 10-12 ducts in floor of mouth
sublingual gland
_ (scattered throughout oral cavity) make little saliva
minor salivary glands
_ (in parotid-submandibular glands) mostly secrete water, as well as enzymes, ions, and mucin
serous cells
_ (in sublingual glands) produce mucus
mucous cells
_ is when there’s too little saliva being made
xerostomia (dry mouth)
_ (autoimmune diseases) affects moisture-producing glands throughout body
sjögren’s syndrome
_ is the secretion of saliva
salivation
_ tears-grinds food into smaller pieces
mastication (chewing)
_ (in mandible-maxilla) house teeth
gomphoses
_ (teeth) erupt at 6-24months; 20 total
deciduous (milk, baby)
_ (teeth) erupt at 6-12years to end of adolescence; 32 total
permanent
_ (teeth) erupt at 17-25 years; may/may not emerge
wisdom (third molars)
_ are chisel-shaped; cut
incisors
_ are fanglike; tear-pierce
canines
_ have broad crowns and rounded cusps; grind-crush
premolars (bicuspids)
_ have broad crowns and rounded cusps [best grinders]; lock for crushing force
molars
_of tooth is the exposed part above gingiva; covered by enamel
crown
_ of tooth is embedded n jawbone
root
_ of tooth connects root to crown
neck
_ of tooth covers root
cement (cementum)
_ of tooth provides connective tissue; shock-absorption
peridontal ligament
_ is the space between gum and tooth
gingival sulcus
_ is the yellow tissue that makes up bulk of tooth
dentin
_ are the cells that form dentin
odontoblasts
_is surrounded by dentin
pulp cavity
_ is made up of connective tissue, blood vessels, nerves
pulp
_ is pulp cavity extending to root
root canal
_ (proximal end of root) provides entry for blood vessels, nerves
apical foramen
_ is a tooth trapped in jawbone
impacted tooth
_ are caused by demineralization of enamel-dentin via bacterial action
dental caries (cavities)
_ is a film (sugar, bacteria, debris) adhering to teeth
dental plaque
_ is inflammation of gums by anaerobic bacteria; calculus is formed
gingivitis
_ forms when plaque calcifies; disrupts seal between gums-teeth
calculus (tartar)
_ can occur if gingivitis is untreated; immune cells attack both invaders and own tissue
periodontitis (periodontal disease)
_ passes food to laryngopharynx
oropharynx
esophagus goes through diaphragm at _
esophageal hiatus
esophagus joins stomach at _
cardial orifice
_ (of esophagus) surrounds cardial orifice and keeps it closed when not swallowing
gastroesophageal (cardiac) sphincter
_ (in submucosa) secrete mucus to help move bolus
esophageal glands
_ is caused by stomach acid regurgitating into esophagus
heartburn
heartburn is the first symptom of _
gastroesophageal reflux disease (GERD)
_ is when part of stomach protrudes above diaphragm
hiatal hernia
_ is inflammation of esophagus
esophagitis
_ requires 22 muscles; involves a buccal phase and pharyngeal-esophageal phase
deglutition (swallowing)
bolus is converted into _, a pastelike substance
chyme
_ are stomach folds formed by mucosa; appear when empty
rugae
_ (stomach) surrounds cardial orifice
cardial part (cardia)
_ (stomach) dome-shaped; beneath diaphragm
fundus
_ (stomach) is midportion
body
_ (stomach) is continuous with duodenum via pyloric valve
pylorus
_ (pylorus) narrows into pyloric canal
antrum
_ termines in pylorus
pyloric canal
_ (sphincter) controls stomach emptying
pyloric valve
_ (stomach) convex, lateral surface
greater curvature
_ (stomach) concave, medial surface
lesser curvature
_ (stomach) runs from lesser curvature to liver
lesser omentum
_ (stomach) drapes from greater curvature over intestine, spleen, transverse colon; contains fat, lymph nodes
greater omentum
_ (mesentery) anchors large intestine to abdominal wall
mesocolon
_ secrete thin, acidic mucus (unknown function)
mucous neck cells
_ secrete HCl and intrinsic factor
parietal cells
_ secrete pepsinogen and lipases
chief cells
_ secrete chemical messengers (hormones, paracrines) into lamina propria
enteroendocrine cells
_ is inflammation of stomach, caused by breach of mucosal barrier
gastritis
_ cause erosions in stomach wall (mostly caused by H. pylori)
gastric (peptic) ulcers
_ (only function of stomach essential to life) used for B12 absorption
intrinsic factor
_ varies based on life experience; triggered by aroma, sight, taste, thought of food
cephalic (reflex) phase
_ releases 2/3 gastric juice; lasts 3-4h
gastric phase
_ is brief stimulation followed by inhibition [of stomach]
intestinal phase
_ (enteroendocrine cells) secrete gastric
G cells
_ (mechanism of intestinal phase) neural control; duodenum inhibits acid secretion
enterogastric reflex
_ (mechanism of intestinal phase) hormonal control; duodenal endocrine cells release secretin and CCK
enterogastrone
_ is the increase of bicarbonate in blood leaving stomach
alkaline tide
_ (reflex-mediated relaxation of smooth muscle) coordinated by swallowing center
receptive relaxation
_ (intrinsic ability of smooth muscle to exhibit stress-relaxation) allows hollow organs to stretch without increasing tension-contraction
gastric accommodation
_ is set by enteric pacemaker cells
basic electrical rhythm (BER)
_ is peristaltic waves moving from fundus to pylorus
propulsion
_ (most vigorous peristalsis) mixing action
grinding
_ is when peristaltic waves force-close pyloric valve and forces contents backwards into stomach
retropulsion
_ is caused by extreme stretching or intestinal irritants; signaled by emetic center (medulla)
emesis (vomiting)
_ (yellow-green substance) emulsifies fat
bile
_ stores bile
gallbladder
_ separates right-left lobes of liver; suspends liver from diaphragm and abdominal wall
falciform ligament
_ is a remnant of fetal umbilical vein
round ligament (ligamentum teres)
hepatic artery-vein enter liver at _
porta hepatis
_ (duct) leaves liver
common hepatic
_ (duct) connects to gallbladder
cystic
_ (duct) unites common hepatic and cystic ducts
bile [duct]
_ are hexagonal structural-functional units; made up of hepatocytes
liver lobules
_ form hepatic plates and filter-process nutrient-rich blood
hepatocytes (liver cells)
_ (liver lobule) is in longitudinal axis
central vein
_ (liver) is in each corner of lobule
portal triad
_ remove debris and old RBCs
stellate macrophages (hepatic macrophages)
_ (cholesterol derivatives) function in fat emulsification-absorption
bile salts
_ is a pigment from heme that makes feces brown; bacteria break down bile in intestine
bilirubin
_ is the recycling mechanism to conserve bile salts
enterohepatic circulation
_ is inflammation of liver caused by viral infection, drug toxicity, mushroom poisoning
hepatitis
_ is a progressive inflammation of liver from chronic hepatitis or alcoholism
cirrhosis
_ are caused by too much cholesterol or too little bile salts
gallstones (biliary calculi)
_ caused by bile salts-pigments building up in blood; cause jaundice
obstructive jaundice
_ are clusters of secretory cells produces by pancreas
acini
acini produce _ with proenzymes
zygomen granules
_ is an enzyme bound to plasma membrane of duodenal epithelial cells
enteropeptidase
enteropeptidase activates a pancreatic protease, _, to form trypsin
trypsinogen
_ activates trypsinogen, procarboxypeptidase, and chymotrypsinogen
trypsin
_ forms active carboxypeptidase
procarboxypeptidase
_ froms active chymotrypsin
chymotrypsinogen
_ is formed by the fusion of bile-pancreatic ducts; bulblike
hepatopancreatic ampulla
ampulla opens into duodenum via _ - volcano-shaped structure
major duodenal papilla
_ (small duct) empties into duodenum
hepatopancreatic sphincter
_ is major organ of digestion and absorption
small intestine
small intestine ends at _ and joins large intestine)
ileocecal valve
_ (retroperitoneal) first part of small intestine that curves around pancreas
duodenum
_ is middle of small intestine that attaches via mesentery
jejunum
_ is end of small intestine that attaches via mesentery; ends with ileocecal valve
ileum
_ are permanent folds that allow more time for nutrient absorption; force chyme to go through lumen
circular folds
_ are fingerlike projections of mucosa and contain lacteals
villi
_ contain a brush border and its enzymes
microvilli
_ are cells in villi and crypts
intestinal crypts
_ make up most of epithelial cells; simple columnar absorptive cells bound by tight junctions, contain many microvilli
enterocytes
_ are mucus-secreting cells in epithelia of villi-crypts
goblet cells
_ produce enterogastrones and are scattered in villi
enteroendocrine cells
_ secrete antimicrobial agents and are found deep in crypts
paneth cells
_ continuously divide and produce other types of cells
stem cells
_ protects intestines from microorganisms
mucosa-associated lymphoid tissue (MALT)
_ (aggregated lymphoid nodules) are found in lamina propria of small intestine
peyer’s patches
_ secreted by plasma cells in lamina propria
IgA
_ secrete alkaline mucus to neutralize acidic chyme
duodenal glands
_ is secreted in response to distension-irritation of mucosa and stimulated by hypertonic-acidic chyme; mostly water and some mucus
intestinal juice
_ are bound to plasma. membrane and responsible for final chyme digestion
brush border enzymes
_ mixes-moves contents in small intestine toward ileocecal valve; initiated by intrinsic pacemaker cells
segmentation
_ is initiated by motilin increase
peristalsis
_ (large intestine) three bands of longitudinal smooth muscle
teniae coli
_ (large intestine) pocketlike sacs caused by teniae coli tone
haustra
_ (large intestine) fat-filled pouches of visceral peritoneum
epiploic appendages
_ is the first part of large intestine
cecum
_ (MALT) is mass of lymphoid tissue; stores bacteria
appendix
_ of large intestine has many [retroperitoneal] regions
colon
_ travels up right side of abdominal cavity (up to kidney)
ascending colon
ascending colon ends in _ (right angle turn)
right colic (hepatic) flexure
_ travels across abdominal cavity
transverse colon
colon ends in another right angle turn, _
left colic (splenic) fixture
_ travels down left side of abdominal caivty
descending colon
_ is S-shaped poriton of colon; travels through pelvis
sigmoid colon
_ is made up of 3 rectal valves
rectum
_ stop feces from being passes with gas
rectal valves
_ include cecum, appendix, rectum, and most of colon (except transverse, sigmoid)
retroperitoneal
_ are regions anchored to posterior abdominal wall
intraperitoneal
_ are mesentery sheets that anchor intraperitoneal regions
mesocolons
_ is [acute] inflammation of appendix; caused by fecal blockage
appendicitis
_ are long rifges-folds of anal canal
anal columns
_ [between anal columns] secrete mucus to empty anal canal
anal recesses
_ is a horizontal line parallel to anal sinuses
pectinate line
_ are inflamed superficial hemorrhoidal veins
hemorrhoids
_ consist of 1000s of types of bacteria
bacterial flora
_ is initiated by food in stomach
gastrocolic reflex
_ in gastrocolin reflex are strong peristaltic waves activated 3-4x a day
mass movements
_ are mucus herniations from low-fiber diet
diverticula
_ is the presence of diverticula; most common in sigmoid colon
diverticulosis
_ is inflammation of diverticula; can rupture into peritoneal cavity and may be life-threatening
diverticulitis
_ is determined by recurring abdominal pain , stool changes, bloating, nausea, depression, gas
irritable bowel syndrome (IBS)
_ are mass movements that force feces toward rectum
defecation
_ (spinal reflex) triggered by distesion
defecation reflex
_ is the closing of glottis; diaphragm contraction and abdominal wall muscles increase intra-abdominal pressure
valsalva’s maneuver
_ (watery stools) large ingestine does not have enough time to absorb remaining water
diarrhea
_ (hard stool) food remains in colon for too long and causes too much water to be absorbed
constipation
_ is catabolic; macromolecules break down into monomers for absorption
digestion
_ is when water is added to break chemical bonds; carried out by enzymes
hydrolysis
_ is the process of moving substances from lumen to body
absorption
_ absorbs polar molecules
active transport
_ (single sugars) can be absorbed
monosaccharides
_ are broken down into monosaccharides; begins in mouth via salivary amylase
polysaccharides
_ breaks down starch to oligosaccharides and disaccharides
pancreatic amylase
_ are made up of 3-10 saccharides
oligosaccharides
_ is the enzyme for lactose digestion
lactase
_ are broken down into lactose, glucose, sucrose
polysaccharides
examples of _ include glucose, fructose, galactose
monosaccharides
_ is caused by lactase deficiency, so lactose remains undigested
lactose intolerance
_ are generated when proteins break small poylpeptides-peptides
amino acid monomers
pepsinogen is converted to _ at low pH
pepsin
_ and _ (pancreatic proteases) cleave proteins into smaller peptides
trypsin; chymotrypsin
_ takes one amino acid off [from the end] at a time
carboxypeptidase
_ break oligopepides-dipeptides into amino acids (e.g., aminopeptidase, carboxypeptidase, dipeptidase)
brush border enzymes
amino acids are _ across apical membrane via secondary active transport carriers
co-transported
amino acids exit across _ through facilitated diffusion
basolateral membrane
_ is region of plasma membrane at apex
apical membrane
_ is when fat globules are broken down into fat droplets to increase surface area to lipases
emulsification
_ consist of fatty acids, monoglycerides, bile salts
micelle
_ form when fatty acid and monoglycerides are recombined and packaged with other proteins and fatty substances
chylomicron
_ break chylomicrons down into free fatty acids and glcyerol to be used by cells
lipoprotein lipases
_ hydrolyze nucleic acid to nucleotide monomers
pancreatic nucleases
_ vitamins (e.g., A, D, E, K) carried by micelles and diffuse into absorptive cells
fat-soluble
_ vitamins (e.g., C, B) absorbed by diffusion or passive-active transport
water-soluble
_ are stored in mucosal cells with ionic iron
ferritin
_ transport iron-calcium in blood
transferrin
_ is caused by anything interfering with delivery of bile or pancreatic juice
malabsorption
_ (common malabsorption disease) immune reaction to gluten
gluten-sensitive enteropathy (celiac disease)
