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249 Cards in this Set

  • Front
  • Back
The alimentary canal or gastrointestinal tract functions to
digest and absorbs food
The alimentary canal includes what structures
mouth, pharynx, esophagus, stomach, small intestine, and large intestine
The accessory digestive organs include what structures
teeth, tongue, gallbladder, salivary glands, liver and pancreas
What are the six essential activities of the digestive process
ingestion, propulsion, and mechanical digestion, chemical digestion, absorption and defecation
Taking food into the digestive tract
ingestion
swallowing and peristalsis are a part of what function
propulsion
What are waves of contraction and relaxation of muscles in the organ walls
peristalasis
Chewing, mixing, and churning food are a part of what function of the digestive process
mechanical digestion, mastication and chewing
Catabolic breakdown of food are a part of what function of the digestive process
chemical digestion
Movement of nutrients from the Gi tract to the blood of lymph is what function of the digestive system
absorption
Elimination of ingestible solid wastes is what digestive function
defecation
Regulation of digestion involves what
mechanical and chemical stimuli stretch receptors, osmolarity, and presence of substrate in the lumen
Intrinsic regulation of digestion takes place where
by local centers inside the gut
Extrinsic regulation of digestion takes place where
by CNS centers directly in brain
what responds to stretch b y presence of food, osmolarity, ph of contents, and presence of end products of digestion
mechano- and chemoreceptors
What initiates reflexes that activate or inhibit digestive glands to secrete digestive juices, and mix lumen contents and move them along
receptors of the GI tract
What controls nerve plexuses near the GI tract initiate short reflexes that are mediated by local enteric plexuses (gut brain)
Intrinsic controls
What controls long reflexes arising within or outside the GI tract and involve CNS centers and autonomic nerves
Extrinsic controls
What covers external surface of most digestive organs
visceral peritoneum
what lines the body wall
parietal peritoneum
This functions to lubricate digestive organs and allows them to slide across one another
peritoneal cavity
What is the double layer of peritoneum that provides vascular and nerve supplies to the viscera and holds digestive organs in place and stores fat
mesentery
What is the name for the organs outside the preitoneum
retroperitoneal organs
The retroperitoneal organs include what
rectum, anus, esophagus
The organs surrounded by the peritoneum are called
peritoneal organs or intraperitoneal organs
Splanchnic circulation including the the arteries and organs they serve include what
the hepatic, splenic, and left gastic, spleen, liver, and stomach, interior and superior mesenteric: small and large intestines
This circulation collects nutrient-rich venous blood from digestive viscera, and delivers this blood to the liver for metabolic processing and storage
hepatic portal circulation
Layers of the alimentary canal include what
mucosa, submucosa, muscularis externa or muscularis, and serosa
This functions to secrete mucus, enzymes and hormones; absorption of end products of digestion into blood; protection against disease
mucosa
This is dense connective tissue with blood, lymph and nerves
submucosa
This is responsible for peristalsis and segmentation
muscularis externa or muscularis
The actual name of the visceral peritoneum is
Serosa
What is found between the visceral eand the parietal pleurae
potential space
What is composed of two major intrinsic nerve plexuses and regulates glands and smooth muscle in the mucosa. Also involves segmentation and peristalsis in local reflex arcs
enteric nervous system -
This cavity is bounded by lips, cheeks, palate and tongue; has the oral orifice as its anterior opening; is continuous with the oropharynx posteriorly
oral or buccal cavity
Why is the mouth lined with stratified squamous epithelium and the gums, hard palate and dorsum of tongue are slightyl keratinized
for protection and to withstand abrasions
What is the skeletal muscle of lips
orbicularis oris
What are the cheek muscles
buccinators
This is bound by lips and cheeks externally and teeth and gums internally
vestibule
What is the area that lies within the teeth and gums
oral cavity proper
What is the median fold that joins the internal aspect of each lip to the gum
libial frenulum
What assists the tongue in chewing, is slightly corrugated on either side of the raphe creating friction
hard palate
What is the mobile fold mostly made up of skeletal muscle that closes off the nasopharynx during swallowing
soft palate
Occupies floor of mouth
tongue
Functions of this include gripping and repositions food during chewing, mixing food with saliva and forming bolus, intitiation of swallowing and speech
tongue
What changes the shape of tongue
intrinsic muscles
what alters the tongues positionex
extrinsic muscles
What secures the tongue to the floor of the mouth
lingual frenulum
These produce and secrete saliva that cleanses mouth, moistens and dissolves food chemicals, aids in bolus formation and contains enzymes that break down starch
salivary glands
What are the three pairs of extrinsic glands
parotid, submandibular, and sublingual
Where are the intrinsic salivary glands or buccal glands
scattered throughout the oral mucosa
This gland lies anterior to the ear between masseter muscle and skin
parotid duct - opens into vestibule next to second upper molar
This gland lies along the medial aspect of the mandibular body
submandibular - ducts open at the base of the lingual frenulum
This gland lies anterior to submandibular gland under the tongue
sublingual - opens via 10-12 ducts into the floor of the mouth
This is secreted from serous and mucous cells of salivary glands
saliva
Saliva is 97-99.5% water, hypo-osmotic, slightly acidic solution containing what
electrolytes, digestive enzyme (salivary amylase), proteins (mucin, lysozyme, defensins), and metabolic waste (urea and uric acid)
What controls salivation?
intrinsic glands keep the mouth moist, extrinsic salivary glands secrete serous, enzyme-rich saliva
Extrinsic salivary glands secrete serous, enzyme-rich saliva in response to what
ingested food which stimulates chemoreceptors and pressoreceptors, the thought of food
Strong sympathetic stimulation inhibits salivation and results in what?
dry mouth
Primary and permanenet dentitions teeth have formed by what age
21
How many deciduous teeth erupt between 6-24 months
20
Permanent teeth enlarge and develop causing the root of the deciduous teeth to be reabsorbed and fall out between what ages
6-12
There are usually how many permanent teeth
32
All but which molars have erupted by end of adolecence
thiid molars
These are chisel shaped teeth adapted for cutting and nipping
incosors
These are conical or fang-like teeth that tear or peirce
canines
These teeth have broad crowns with rounded tips and are best suited for grinding or crushing
premolars (bicuspids or molars)
During chewing, which teeth lock together generating crushing force
upper and lower molars
What are the two main regions of tooth
crown and root
What is the exposed part of the tooth above the gingiva (gum)
crown
what is the acellular brittle material composed of calcium, salts and hydroxyapatitie crystals that is the hardest substance in the body
enamel - encapsulates crown of tooth
portion of tooth embedded in jawbone
root
Gradual demineralization of enamel and dentin by bacterial action
dental caries
Dental plaque, a film of sugar, bacteria, and mouth debris adheres to teeth
dental caries
The name for tooth and gum disease is
peridontitis
What is it called when plaque accumulates and forms calculus or tartar disrupting the seal between gingiva and teet,h and puts gums at risk for infection
gingivitis
Serious gum disease resulting from an immune response with risk factors such as smoking, diabetes, and oral tongue or lip piercing
peridontitis
Accounts for 80-90% of tooth loss and 95% of people over 35 have it
gingivitis
This structure is from the mouth and the oro and laryngopharynx allow passage of food and fluids to the esophagus and air to the trachea
pharynx
The pharynx is lined with what type of cells and what type of glands
stratified squamous epithelium and mucus glands
What are the two muscle layers of the pharynx
inner longitudinal and outer pharyngeal constrictors
What is the muscular tube going from the laryngopharynx to the stomach
esophagus
This travels through the mediastinum and pierces the diaphragm
esophagus
The esophagus joins the stomach at the what
cardiac orifice
What do glands secrete as volus moves through esophagus
mucus
The empty esophagus is folded longitudinally and flattens when what
food is present
List the digestive functions of the mouth
food is ingested, chewing or mechanical digestion begins, propulsion is initiated by swallowing, salivary amylase begins to chemically break down of starch, the pharynx and esophagus serve as conduits to pass food from mouth to stomach
This function involves the coordinated activity of the tongue, soft palate, pharynx and the esophagus and 22 separate muscles
swallowing or deglutition
During what phase is the bolus forced in to oropharyx
buccal phase
This phase of swallowing is controlled by the medulla and lower pons
pharyngeal esophageal phase which all routes but the digestive tract are sealed off
This process moves the food through the pharynx to the esophagus
peristalsis
When the chemical breakdown of food takes place in stomach it is converted to
chyme
This region surrounds the cardiac orifice
cardiac region
What is the dome shaped region below the diaphragm called
fundus
The midportion of the stomach is called what
body
What area is made up of the antrum and canal which terminates at the pylorus
pyloric region
What is the entire extent of the of the convex lateral stomach called
greater curvature
What is the concave medial surface of the stomach called
lesser curvature
What runs from the liver to the lesser curvature of the stomach
lesser omentun
What drapes inferiorly from the great curvature of the stomach to the small intestine
greater omentum
What microscopic structure has an additional oblique layer that allows the stomach to churn, mix and pummel food, physically breaking it down into smaller fragments
muscularis
In the muscularis, what structure contains gastric glands that secrete gastric juices, mucus, and gastrin
gastric pits
Gastric glands of the fundus and body have a variety of what kinds of cells
mucous neck cells (secrete acid mucus) and parietal cells (secrete HCI and intrinsic factor)
To keep the stomach from digesting itself, it has a what
mucosal barrier
What has a thick coat of bicarbonate-rich mucus on the stomach wall, epithelial cells that are joined by tight junctions and gastric glands that have cells impermeable to HCI?
mucosal barrier
What type of damaged cells are quickly replaced in the stomach
epithelial cells
What re the functions of the stomach
holds ingested food, degrades food both physically and chemically, delivers chyme to the small intestine, enzymatically digests proteins with pepsin, secretes intrinsic factor required for vitamin B-12 absorption
Neural and hormone mechanisms regulates the release of what in the stomach
gastric juices
Stimulatory and inhibitory events in the stomach occur in what three phases
cephalic, gastric phase, intestinal phase
The cephalic or reflex phase occurs when
prior to food entry
When does the gastric phase occur in the stomach
once food enters the stomach
When does the intestinal phase of the stomach occur
as partially digested food enters the duodenum
What are the excitatory events that take place in the cephalic phase in stomach
sight, smeall or thought of food, stimulation of taste and smell receptors
What are the inhibitory events in the cephalic phase in stomach
loss of appetite or depression, decrease in stimulation of the parasympathetic division
What re the excitatory events in the gastric phase in stomach
stomach distention, activation of stretch receptors (neural), activation of chemoreceptors, release of gastrin to the blood
What are the inhibitory events of the gastric phase in stomach
a ph lower than 2, emotional upset that overrides the parasympathetic division
What are the events that take place in the excitatory phase of the stomach
low ph, partially digested food enters the duodenum and encourages gastric gland activity. i.e. pyloric sphincter opening and closing
What are the events that take place in the inhibitory phase of the stomach
distention of duodenum, presence of fatty, acidic, or hypertonic chyme, and/or irritatants in the dudenum;
What phase of gastric regulation of stomach includes initiates inhibition of local reflexes and vagal nuclei, closes the pyloric sphincter and releases enterogastrones that inhibit gastric secretion
Inhibitory intestinal phase
Stomach pressure remains constant until about how much food is ingested
1L
The relative unchanging pressure in the stomach results from what
reflex-mediated relaxation and plasticity
Reflex mediated events include what two things
receptive relaxation and adaptive relaxation
What is receptive relaxation in the stomach
as food travels in the esophagus, stomach muscles relax
What is adaptive relaxation in stomach
the stomach dialates in response to gastric filling
Peristalic waves move toward the pyloris at what rate
3 per minute
Where doe the most vigorous peristalsis and mixing occur
near the pylorus --near small intestine
This substance is either delivered in small amounts to the duodenum or forced backwards into stomach for further mixing
chyme
The process of moving food backwards in the digestive tract is called what
segmentation
The cephalic, gastric and intestinal phases include what organ.
cephalic - brain, gastric - stomach, intestinal - intestines
Gastric emptying is regulated by what
neural enterogastric reflex (midbrain from medulla pons), and hormonal (enterogastrone) mechanisms
What mechanisms inhibit gastric secretion and duodenal filling
neural enterogastric reflex (midbrain from medulla pons), and hormonal (enterogastrone) mechanisms
Carbohydrate-rich chyme quickly moves through what
duodenum
Fat-laden chyme is digested more slowly causing what
food to remain in the stomach longer
All absorption takes place where
small intestine
What structure runs from pyloric sphincter to ileocecal valve
small intestine
What are the 3 subdivisions of the small intestine
duodenum, jejunum, and ileum
What extends from duodenum to ileum
jejunum
What joins the large intestine at the ileocecal valve
ileum
In the microscopic anatomy of the small intestine, what are the deep circular folds of the mucosa and submucosa called
Plicae circulares (the largest plicae)
In the microscopic anatomy of the small intestine, what are the fingerlike extensions called
villi
In the microscopic anatomy of the small intestine, what are the tiny projections of absorptive mucosal cells' plasma membranes called
microvilli
What is secreted by intestinal glands in response to distention or irritation of the muccosa
intestinal juice
Is intestinal juice slightly alkaline or sligtly acidic
slightly alkaline
Intestinal juice is isotonic with what substance
blood plasma
What substance is made up of mostly water, is enzyme poo, but contains mucus
intestinal juice
What is the largest gland in the body
liver
How long is the small intestine
20 feet
How long is the duodenum
10 inches
What is the diameter of the small intestine
1 to 1 1/2 inches
How many lobes does liver have
4 - right, left, caudate and quadrate
What separates at the right and left lobes anteriorly of the liver
falciform ligament
What suspends the liver from the diaphragm and anterior abdominal wall
falciform ligament
Bile leaves the liver via the what
bile ducts which fuse into the common hepatic duct
What two ducts form the bile duct
the common hepatic duct, cystic duct
In the microscopic anatomy of the liver, what are the structural and functional units of the liver
hexagonal-shaped liver lobules
What is composed of hepatocyte (liver cells) plates and radiate outward from central vein of liver
hexagonal-shaped liver lobules
in the microscopic anatomy of liver, what are found at each of the six corners of each liver lobule
portal triads
How is bile regulated after we eat fat
fat pours into duodenum; releases enzyme cholecystokinen (CCK); tells smooth muscle of GB to contract; squeezes out bile; bile goes to duodenum to emulsify fat
In the microscopic anatomy of liver, portal triads consist of what
hepatic artery and hepatic portal vein, and bile duct
What supplies oxygen rich blood to the liver
hepatic artery
What carries venous blood with nutrients from digestive viscers
hepatic portal vein
In the microscopic anatomy of the liver, the hepatocytes functions include what
production of bile, processing bloodborne nutrients, storage of fat soluable vitamins (ADEK), detoxification, phagocytes producing macrophages to clean up old RBC
What is an alkaline solution containing bile salts, bile pigments, cholesterol, neutral fats, phospholipids, and electrolytes
bile
What are cholesterol derivatives that emulsify fat, facilitate fat and cholesterol absorption and help solubilize cholesterol
bile salts
What is the chief bile pigment called that is a waste product of heme (hemoglobin breakdown)
bilirubin
What is the main function of bile?
emulsify fat
What structure is a thin-walled, green muscular sac on the ventral surface of the liver
gallbladder
What structure stores and concentrates bile by absorbing its water and ions
gallbladder
What structure releases bile via the cystic duct which then flow into bile duct
gallbladder
What is the main function of liver
detoxifying
List several functions of the liver
detoxifying, forms bile, stores glycogen, stores vitamins (A, K, E, B-12), in fetus liver forms RBC, forms plasmic protiens, gives up macrophages to detroy old RBC, detoxifies nitrous wastes
Acidic fatty chyme causes the duodenum to release what into the bloodstream
cholecystokinin (CCK) and secretin which break down chyme
What stimulates liver to produce bile
bile salts and secretin transported in blood
What substance causes the gallbladder to contract
cholecystokinin (CCK)
What causes the hepatopancreatic sphincter to relax allowing bile to enter duodenum
cholecystokinin (CCK)
What structure lies deep to the greater curvature of the stomach
pancreas
What structure is encircled by the duodenum and the tail abuts the spleen
pancreas
The exocrine function of the pancreas
secretes pancreatic juice which breaks down food
What are the clusters of secretory cells called in the pancreas (exocrine function) that contain zygomen granules with digestive enzymes
Acini
What is the endocrine function of the pancreas
release of insulin and glugagon
Pancreatic juice is a water solution of enzymes and electrolytes that does what
neutralizes acid chyme, provides environment for pancreatic enzymes
Enzymes from the pancreas are released in inactive form and activated where
duodenum
Active enzymes secreted by the pancreas require ions or bile for optimal activity. What are the three active enzymes
amylase, lipases, and nucleases
Cholesystokinin (CCk) is made where
gallbladder and pancreas
In the regulation of pancreatic secretion, what is released when fatty of acidic chyme enters the duodenum
secretin and CCK
CCK enters the bloodstream and upon reaching the pancreas, CCK induces the secretion of what enzyme-rich substance
pancreatic juice
What kind of stimulation causes release in the pancreas
vagal stimulation
The pancreas provides CCK which helps to break down products where
duodenum
What happens during digestion in small intestine as chymer enters duodenum
carbs and proteins are partially digested, no fat digestion has taken place, chyme is released slowly into duodenum, mixing is required for proper digestion, virtually all nutrient absorption takes place
What is the most common motion of the small intestine
segmentation
What is initiated by intrinsic pacemaker cells in small intestine
segmentation
When segmentation takes place in small intestine it moves contents steadily toward the what
ileocecal valve
What happens after nutrients have been absorbed by small intestine
peristalsis begins with each wave starting distal to the previous; meal remnants, bacteria, mucosal cells, and debris are moved into the large intestine
What coordinates intestinal motility in the GI tract
local enteric neurons
What causes contraction and shortening of muscle layer and distention of the intestine
cholinergic neurons
What relaxes the ileocecal spinchter and allows chyme to pass into the large intestine
gastroileal reflex and gastrin
Large intestine has three unique features. List them
teniae coil, haustra, epiploic appendages
What are the three bands in large intestine called
teniae coli
what are the pocketlike sacs caused by muscle tone in the large intestine called
haustra
What are fat filled pouches of visceral peritoneum called in the large intestine
epiploic appendages
What structure is subdivided into cecum, appendix, colon, rectum, and anal canal
large intestine
Where does the saclike cecum lie in the large intestine that contains wormlike veriform appendix
below ileocecal valve in the right iliac fossa
The colon has 6 distinct regions. Name them
ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, and sigmoid colon
The transverse and sigmoid portions are anchored via menenteries called what
mesocolons
The sigmoid colon joins the what
rectum
What is the last segment of the large intestine that opens to the exterior of the anus
the anal canal
What do the three valves of the rectum do
stop feces from being passed with gas
The anus has two sphincters. What are they and what kind of muscle are they made of
internal anal sphincter - smooth muscle; external anal sphincter - skeletal muscle
The anal sphincters remain closed unless during what
defecation
The bacteria flora of the large intestine consist of
bacteria surviving the small intestine that enters cecum and those entering the anus
What do the bacteria flora of the large intestine do
colonize colon, ferment indigestible carbs, release irritating gases and acids (flatulence), synthesizes B complex vitamins and vitamin k
Funtions of the large intestine/colon
other than digestion of enteric bacteria no further digestion takes place; vitamins, water and electrolytes are reclaimed; propulsion of fecal matter toward anus; not essential for life
What are slow segmenting movements that move contents of the colon called
haustral contractions
Haustra sequentially contract as they are stimulated by what in the colon
distention
The presence of food in stomach activates what in large intestine
gastrocolic reflex
The presence of food in stomach initiates what process to force contents toward rectum
peristalsis
Distention of rectal walls caused by feces stimulate what 2 processes
contraction of the rectal walls; relaxes internal anal sphincter
Distention of rectal walls relaxes what for defecation to occur
external anal sphincter
Do voluntary or involuntary signals stimulate relaxation of the external sphincter
voluntary
In chemical digestion, what enzymes are used to breakdown carbs
salivary amylase, pancreatic amylase, and brush border enzymes
In chemical digestion, what enzymes are used to breakdown proteins in stomach
pepsin
In chemical digestion, what enzymes are used to breakdown fat
bile salts, pancreatic lipase
In chemical digestion, absorption via what takes place into intestinal cells
diffusion
Up to how much food, drink, and GI secretions enters the GI tract daily
10L
Of the 10L of food, drink, and GI secretions entering the GI tract daily, how much reaches the large intestine
1L or less
Virtually all food, 80% of electrolytes and water are absorbed by the what
small intestine
It is nearly impossible to exceed what capacity of the GI tract
absorptive capacity
All the remains at the end of the illeum is what
some water, indigestible food and millions of bacteria
The debris from the small intestine is passed on to what
large intestine
How much water enters the small intestine daily
9L mostly derived from GI trcat secretions
What is the most abundant substance in chyme
water
95% of water is absorbed in small intestine by what process
osmosis
normal rate of water absorption is what
300-400ml per hour
water moves in both directions across what
intestinal mucosa
What occurs from anything that interferes with delivery of bile or pancreatic juice
malabsorption
What occurs from damage to the intestinal mucosa (bacterial infection)
malabsorption
What happens as a result of Gluten enteropathy (adult celiac disease)
gluten damages the intestinal villi and reduces the length of miltivilli so malabsorption occurs
How is celiac disease treated
elimination of all grains but corn and rice
During fetal life nutrition is via the what
placenta
What causes maturation of the GI tract in fetus
swallowing of amniotic fluid
At birth, feeding is the the most important function and is enhanced by what
rooting reflex which aids in swallowing
Digestive problems has few problems until when
old age
During old age what happens to GI tract
activity declines, absorption is less efficient and peristalsis is slowed
Does GI cancer have early signs?
No, not usually
Mestastasized colon cancer frequently causes what
secondary liver cancer
Prevention of GI cancer is by regular what
dental and medial exams
Colon cancer is the what largest cause of cancer deaths in males
2nd (lung cancer is 1st)
GI cancer forms from benign mucosal tumors called what that increases with age
polyps
Regular colon exams should be done for all those over what age
50