Anatomy_Key Terms_Ch23 Flashcards
alimentary canal
aka gastrointestinal (GI) tract, muscular digestive tube that winds trough the body, extending from the mouth to the anus; the organs are the mouth, pharynx, esophagus, stomach, small intestine (small bowel), and large intestine (large bowel), the last of which leads to the terminal opening, or anus
accessory digestive organs
teeth and tongue, gallbladder and large digestive glands–salivary glands, liver, and pancreas–that lie external to and are connected to the alimentary canal by ducts; the accessory digestive glands secerete saliva, bile, and digestive enzymes, all of whic contribute to the breakdown of foodstuffs
peritoneum
most extensive slippery serous membrane, located in the abdominopelvic cavity
visceral peritoneum
covers the external surfaces of most digestive organs
parietal peritoneum
lines the body wall and is continuous with the visceral peritoneum
peritoneal cavity
slitlike potential space between the visceral and parietal peritoneum. the peritoneal cavity lies between the digestive organs and the abdominal body wall. it contains a lubricating serous fluid that is produced by the peritoneum and allows the digestive organs to glide easily along one anotehr and along the body wall as they move during digestion
mesentery
double layer of pertoneum–a sheet of two serous membranes fused together–that extends from the body wall to the digestive organs; hold organs in place, store fat and most important provide a route for circulatory vessels and nerves to reach the organs in the peritoneal cavity
falciform ligament
”"”sickle-shaped””, binds the anterior aspect of the liver to the anterior abdominal wall and diaphragm”
lesser omentum
”"”fatty skin””, runs from the liver to the lesser curvature of the stomach and the beginning of the duodenum”
greater omentum
connects the greater curvature of the stomach to the posterior abdominal wall in a roundabout way
transverse mesocolon
”"”mesentery of the colon””, a nearly horizontal sheet that is fused to the underside of the greater omentum that holds the transverse colon to the posterior abdominal wall”
sigmoid mesocolon
mesentery that connects the sigmoid colon to the posterior pelvic wall
secondarily retroperitoneal
(retro=behind), initially formed within the perioneum but are located behind the peritoneum once thy are fully developed
intraperitoneal/peritoneal
digestive organs that keep their mesentery and remain surrounded by the peritoneal cavity
segmentation
rhythmic local constrictions of the intestine
ingestion
taking of food into the mouth. in humans, the upper limb, as well as the oral cavity, is important for ingestion
propulsion
movement of food through the alimentary canal. it includes swallowing, which is initiated voluntarily, and peristalsis, an involuntary process. peristalsis, the major means of propulsion thorughout the alimentary canal, involves alternate waves of cantraction and relaxation of musculature in the organ walls. its net effect is to squuze food from one organ to the next, but some mixing occurs as well
peristalsis
”"”around contraction””, the major means of propulsion throughout the alimentary canal involves alternate waves of contraction and relaxation of musculature in the organ walls”
mechanical breakdown
physically prepares food for digestion by enzymes breaking it into smaller pieces. mechanical processes include chewing, the churning of food in the stomach, and segmentation, the rythmic local constrictions of the intestine. segmentation mixes food with digestive juices and increases the efficiency of nutrient absorption by repeatedly moving different parts of the food mass over the intestinal wall
digestion
series of steps in which complex food molecules (carbohydrates, proteins, and lipids) are broken down to their cmecila building blocks (simple sugars, amino acids, fatty acids, and glycerol). glands in the gastrointestinal tract and in the accessory organs produce enzymes and other substances and secrete them into the lumen of the alimentary canal, where they carry out digestion
absorption
transport of digested end products from the lumen of the alimentary canal into the blood and lymphatic capillaries located in the wall of the canal
defecation
elimination of indigestible substances from the body as feces
mucosa (GI tract)
more complex than other mucous membranes in the body, the typical digestive mucosa contains three sublayers: a lining epithelium, a lamina propria, and a muscularis mucosae
epithelium (of the gut)
abuts the lumen of the alimentary canal and performs many functions related to digestion, such as absorbing nutrients and secreting mucus; this is continuous with the ducts and secretory cells of the various digestive glands, most of which lie fully within the wall and are called intrinsic glands
lamina propria
loose areolar or eticular connective tissue whose capillaries nourish the lining epithelium and absorb digested nutrients; contains most of the MALT which defends against invasion by bacteria and other microorganisms in the alimentary canal
muscularis mucosae
external to the lamina propria, a thin layer of smooth muscle that produces local movements of the mucosa
submucosa (gut)
“layer of connective tissue containing major blood and lymphatic vessels and nerve fibers; its rich vascular network sends branches to all other layers of the wall; connective tissue is a type intermediate between loose areolar and dense irregular, a ““moderately dense”” connective tissue; the many elastic fibers enable the alimentary canal to return to its shape after food material passes through it”
muscularis externa
aka muscular layer, external to the submucosa; throughout most of the alimentary canal, this tunic consists of two layers of smooth muscle, an inner circular layer whose fibers orient around the circumference of the canal (squeezes the gut tube) and an outer longitudinal layer whose fibers orient along the length of the canal (shortens the gut tube)
serosa
visceral peritoneum, outermost layer of the intraperitoneal organs of the alimentary canal, formed of a simple squamous epithelium (mesothelium) underlain by a thin layer of areolar connective tissue
longitudinal layer
muscle fibers run parallel to the long axis of the organ, more externally located
circular layer
deeper, fibers run around the circumference of the organ
dense bodies
along the tension-resisting intermediate filaments lie _ at regular intervals that anchor the thin filaments, correspond to the Z discs of skeletal muscle
enteric nervous system
(enteric=gut), smooth muscle and glands of the alimentary canal are controlled largely by the independent _
myenteric nerve plexus
”"”intestinal muscle””, in the muscularis externa between the circular and longitudinal layers, innervates the muscularis externa to control peristalsis and segmentation”
submucosal nerve plexus
lies within the submucosa, nerve fibers extend inward and signal the glands in the mucosa to secrete and the muscularis mucosae to contract
oral cavity
or mouth, mucosa-lined cavity whose boundaries are the lips anteriorly, the cheeks laterally, the palate superiorly, and the tongue inferiorly
oral orifice
anterior opening of the oral cavity
oral vestibule
”"”porch””, the slit between the teeth and the cheeks (or lips)”
oral cavity proper
the region of the mouth that lies internal to the teeth
lips/labia
thick flaps extending from the inferior boundary of the nose to the superior boundary of the chin
cheeks
help keep food inside the mouth during chewing, composed of a core of skeletal muscle covered by skin
labial frenulum
”"”little bridle of the lip””, median fold that connects the internal aspect of each lip to the gum”
palatoglossal arches
anchors the soft palate to the tongue
palatopharyngeal arches
anchors the soft palate to the wall of the oropharynx
lingual frenulum
fold of mucosa on the undersurface of the tongue secures the tongue tothe floor of the mouth and limits its posterior movements
ankyloglossia
”"”fused tongue””, congenital condition in which the lingual frenulum is abnormally short or extends exceptionally far anteriorly”
filiform papillae
”"”thread-shaped””, conical, paointed, kerativized, roughen the tongue enabling it to grasp and manipulate food during chewing”
terminal sulcus
groove which marks the border between the mouth and pharynx
teeth
lie in sockets (alveoli) in the gum-covered margins of the mandible and maxilla
deciduous teeth
”"”falling off””, primary dentition (child teeth)”
permanent teeth
last permanent teeth, the wisdom teeth, emergy between the ages of 17 and 25 years
incisors
chisel-shaped, adapted for nipping off pieces of food
canines
cuspids, eyeteeth, cone-shaped, tear and pierce
premolars and molars
“(bicuspids), ““millstones””, have broad crowns with rounded cusps for grinding food”
crown (tooth)
each tooth has two main regions, the exposed _ and the roots, covered by a layer of enamel
root(s) (tooth)
each tooth has two main regions, the crown and the _ in the socket
neck (tooth)
the crown and the root meet near the gum line
enamel
“hardest substance in the body, lacks cells of vessels, 99% of its mass consists of densely packed hydroxyapatite crystals arranged in force-resisting rods or prisms oriented perpendicular to the tooth’s surface”
dentin/tentine
underlies the enamel cap and forms the bulk of the tooth, bonelike tissue with mineral and collagen components but is harder than bone and lacks internal blood vessels
dentinal tubules
dentin contains unique radial striations
pulp cavity
in the center of the tooth is filled with dental pulp
(dental) pulp
“a loose connective tissue containing the tooth’s vessels and nerves, supplies nutrients for the tooth’s hard tissues and provides for tooth sensation”
root canal
part of the pulp cavity in the root
apical foramen (tooth)
opening into the root canal at the tip of each root
root canal therapy
all of the pulp is drilled out, and the pulp cavity is sterized and filled with an artificial, inert material before the tooth is capped
cement
external surface of the tooth root is covered by a ccalcified conective tissue
periodontal ligament
“or periodontium, ““around the tooth””, anchors the tooth in the bony socket of the jaw”
gingiva
gum
cavities or caries
”"”rottenness””, result from a gradual demineralization of the enamel and dentin by bacterial action”
dental plaque
a film of sugar, bacteria, and other debris that adheres to the theeth, whose accumulation begins the decay process
salivary glands
produce saliva, a complex mixture of water, ions, mucus, and enzymes that performs many functions: it moustens the mouth, dissolves food chemicals so that they can be tasted, wets food, and binds the food together into a bolus
parotid gland
(par=near, otid=the ear), largest major gland is a compound acinar gland, lies anterior to teh ear, between the masseter muscle and the skin
parotid duct
runs parallel to the zygomatic arch, penetrates the muscle of the cheek, and opens into the mouth lateral to the second upper molar, secretion is stimulated by the glossopharyngeal nerve (cranial nerve IX)
submandibular gland
“compound tubuloacinar gland, lies along the medial surface of the mandibular body, just anterior to the angle of the mandible, duct opens in the floor of the mouth directly lateral to the nogue’s lingual frenulum”
sublingual gland
also a tubuloacinar gland, lies in the flor of the oral cavity inferior to the tongue, 10-12 ducts open into the mouth directly superior to the gland, innervated by the facial nerve (cranial nerve VII)
esophagus
muscular tube that propels swallowed food to the stomach
cardial orifice
abdominal part of the esophagus joins the stomach at the _
cardiac sphincter
acts to close off the lumen and prevent regurgitation of acidic stomach juices into the esophagus
stomach
J-shaped, widest part of the alimentary canal, temporary storage tank in which food is churned and turned ninto a paste called chyme
pepsin
protein-digesting enzyme that can function only under acidic conditions
fundus
“stumach’s dome, tucked under the diaphragm”
pyloric part
“funnel-shaped end of the stomach’s pody, composed of the wider pyloric antrum (““cave””) and the narrower pyloric canal”
pylorus
”"”gatekeeper””, terminus of the stomach”
pyloric sphincter
controls the entry of chyme into the intestine
greater curvature
convex left surface of the stomach
lesser curvature
concave right margin of the stomach
rugae
”"”wrinkles””, internal surface of the empty stomach contains numerous longitudinal folds of mocusa which flatten as the stomach fills; the resulting expansion in volume accommodates the increasing quantity of food within the stomach”
gastric pits
open into the tubular gastric glands, surface of the stomach mucosa is dotted with millions of cup-shaped _
gastric glands
in the fundus fundus and body contain three types of secretory cells: mucous neck cells, parietal (exyntic) cells, and chief (zymogenic) cells
pepsinogen
enzymatic protein which is activated to pepsin when it encounters acid in the apical region of the gland
gastric intrensic factor
protein necessary for the absorption of vitamin B12 by the small intestine
mucous neck cells
occur in the upper ends or necks of the gastric glands secrete a different type of mucus from that secreted by the surface mucus cells; specific function of this mucus is not known
parietal (oxyntic) cells
“occur mainly in the middle regions of the glands, produce the stomach’s hydrochloric acid (HCl) by pumping hydrogen and cloride ions into the lumen of the gland; also secrete gastric intrinsic factor”
enteroendocrine cells
”"”gut endocrine””, hormone-secreting cells scattered throughout the lining epithelium and glands of the alimentary canal; these cells release their hormones into the capillaries of the underlying lamina propria; one of these hormones, gastrin, signals parietal cells to secrete HCl when food enters the stomach; most enteroendocrine cells that produce gastrin are in the stomach’s pyloric region.<br></br>hormones also to signal the gallbladder to release stored bile and the pancrease to secrete digestive enzymes and a bicarbonate-rich juice to neutralize the acidic chyme entering the duodenum”
undifferentiated stem cells
located throughout the stomach, at the junction ofthe gastric glands and gastric pits, divide continuously replacing the entire lining epithelium of mucus-secreting cells every 3-7 days
small intestine
longest part of the alimentary canal and the site of most enzymatic digestion and virtually all absorption of nutrients
duedenum
”"”twelve fingerwidths long””, shortest subdivios of the small intestine, receives digestive enzymes from the pancrease via the main pancreatic duct and bile from the liver and gallbladder via the bile duct”
jejunum
”"”empty””, contributes almost 40% of the length of the small intestine, forms superior left part of the sausagelike coils that hang from the posterior abdomen by the mesentery and is framed by the large intestine”
ileum
”"”twisted intestine””, contributes almost 60% of the length of the small intestine, forms the inferior right part of sausagelike coils that hang from the posterior abdomen by the mesentery and are framed by the large intestine”
hepatopancreatic ampulla
”"”flask from the liver and pancreas””, bulb inside the wall of the duedenum made of the main pancreatic duct and the bile duct that opens into the duedenum via a mound called the major duodenal papilla”
villi
fingerlike projections of the mucosa that give it a velvety texture
enterocytes
absorptive cells, primary make-up of the simple columnar epithelium covering the villa, specialized for absorbing digested nutrients
lacteal
wide lymphatic capillary inside the core of lamina propria in each villus (with a network of blood capillaries)
microvilli
on apical surface of the absorptive enterocytes, amplify the absorptive surface, the plasma membrane contains enzymes that complete the final stages of the breakdown of nutrient molecules
goblet cells
these cells secrete onto the internal surface of the intestine a coat of mucus that lubricates the chyme and forms a protective barrier that prevents enzymatic digestion of the intestinal wall.
intestinal crypts
invaginations between the villi lined with epithelial cells that secrete intestinal juice, a watery liquid that mixes with chyme in the intestinal lumen; also contains undifferentiated epithelial cells and mature Paneth cells
undifferentiated epithelial cells
line the intestinal crypts and renew the mucosal epithelium by dividing rapidly and moving contiuously onto the villi. these are among the most quickly dividing cells of the body, completely renewing the inner epithelium of the small intesting every 3-6 days
Paneth cells
found at the base of the crypt. these epithelial cells secrete enzymes that destroy certain bacteria and may help determine which kinds of bacteria live in the intestinal lumen. the permanent bacterial residents of the intetinal lumen, called the intestinal flora, manufacture some essential vitamins, which the intestines absorb.
duedenal glands
compound, tubular, whose ducts open into the intestinal crypts, in the submucosa in the duodenum only
large intestine
last major organ in the alimentary canal, main function is to absorb water and electrolytes from the digested mass, resulting in semisolid feces
mass peristaltic movements
pass over the colon a few times a day to force the feces powerfully toward the rectum
teniae (taeniae) coli
”"”ribbons of the colon””, three longitudinal strips, spaced at equal intervals around the circumference of the cecum and colon, thickenings of the longitudinal layer of the muscularis externa”
haustra
”"”to draw up””, sacs puckered from the large intestine”
epiploic appendages
”"”membrane-covered””, aka omental appendices, fat-filled pouches of visceral peritoneum that hang from the intestine (significance unknown)”
ileocecal valve
“formed by two raised edges of the mucosa, surrounds the opening of the ileum of the small intestine into the cecum’s medial wall internally”
transverse colon
extends itraperitoneal to the left across the peritoneal cavity, directly anterior to the spleen it bends acutely downard at the left colic (splenic) flexure
descending colon
descends along the left side of the posterior abdominal wall in a secondarily retroperitoneal position
sigmoid colon
inferiorly the colon becomes intraperitoneal and enters the true pelvis while S-shaped
right colic flexure
aka hepatic flexure, bend between the ascending colon and the transverse colon
left colic flexure
aka splenic flexure, bend between the transverse colon and the descending colon
rectum
descends along the inferior half of the sacrum in a secondarily retroperitoneal position
rectal valves
three transverse folds of the rectum which prevent feces from being passed along with flatus (gas)
internal anal sphincter
smooth muscle thickening of the circular layer of the muscularis, contracts involuntarily
external anal sphincter
skeletal muscle, contracts voluntarily to inhibit defecation
colonocytes
absorptive cells of the large intestine that take in water and electrolytes
bile
green alkaline liqued that is stored in the gallbladder and secreted into the duodenum; bile salts emulsif fats in the small intestine
diaphragmatic surface
of the liver faces anteriorly and superiorly
visceral surface
of the liver faces posteroinferiorly
bare area
superior part of the liver is fused to the diaphragm and is therefore devoid of peritoneum
quadrate lobe and caudate lobe
part of the left lobe of the liver, visible on the visceral surface just to the right of the fissure
porta hepatis
”"”gateway to the liver””, where most of the major vessels and nerves enter and leave the liver”
right and left hepatic ducts
carry bile from the respective liver lobes, exit from the porta hepatis and fuse to form the common hepatic duct
common hepatic duct
extends inferiorly toward the duodenum
round ligament of liver/ligamentum teres
“in the fissure’s inferior half, the remnant of the umbilical vein in the fetus, ascends to the liver from the navel, within the inferior margin of the falciform ligament”
liver lobules
over a million each about the size of a sesame seed, shaped like a hexagonal solid and consists of plates of liver cells, or heptocytes, radiating out from a central vein
portal triad
at almost every corder of the lobule, contains three main vessels: a portal arteriole that is a branch of the hepatic artery, a portale venule that is a branch of the hepatic portal vein, and a bile duct which carries bile away from the liver lobules
liver sinusoids
large capillaries between the plates of hepatocytes, near the portal triads, these sinusoids receive blood from both the portal arteriole and venule and carry this blood inward to reach the central vein
stellate macrophages/hepatic macrophages
in the walls of the sinusoids, destroy bacteria and other foreign particles in the blood flowing past them
bile canaliculi
”"”little canals””, tiny intercellular spaces or channels that lie between adjacent hepatocytes, carry bile outward through each lobule, emptying into the blie ducts in the portal triads”
gallbladder
muscular sac, resting in a shallow depression on the visceral surface of the right lobe of the liver, stores and concentrates bile produced by the liver
cystic duct
“gallbladder’s duct, joins the common hepatic duct from the liver to form the bile duct, which empties into the duedenum”
main pancreatic duct
extends through the length of the pancrease, joins the bile duct to form the hepatopancreatic ampulla and empties into the deudenum at the major duedenal papilla
accessory pancreatic duct
lies in the head of the pancreas and either drains into the main duct or drains directly into the duodenum
acinar cells
make, store, and secrete at least 22 kind sof pancreatic enzymes capable of digesting the various categories of foodstuffs
zymogen granules
”"”fermenting””, intracellular secretory granules that store the enzymes from the acinar cells in inactive form”
gastric ulcers/duodenal ulcers
craterlike erosions of the mucosa in any region of the alimentary canal that is exposed to stomach secretions (e.g. stomach or deodenum)
intestinal obstuction
any hindrance to the movement of chyme or feces through the intestine, most are mechanical
inflammatory bowel disease
noncontagious, periodic inflammation of the intestinal wall characterized by chronic leukocyte infiltration of this wall, symptoms include cramping, diarrhea, weight loss, and intestinal bleeding
hepatitis
general term for any inflammation of the liver, largely of viral origin
viral hepatitis
most types lead to fluelike symptoms and jaundice, major types are A, B, C, and G
vitelline duct
”"”yolk””, initially, the middle region of the primitive gut is open to the yolk sac trhough the _, a key landmark that divides the embryonic gut into three basic regions: foregut, supperior to it, midgut, open to it, and hindgut, inferior to it”
foregut
develops into the first segment of the digestive system, from the pharynx to the point in the duodenum where the bile duct enters. the celiac trunk supplies blood to the obdominal foregut and its derivatives: the liver, gallbladder, and pancreas
midgut
becomes the segment beginning at the duedenum and extending to a point two-thirds of the way olng the transverse colon. the superior mesenteric artery supplies the derivatives of it
hindgut
fors the rest of the large intestine. the inferior mesenteric artery supplies the organs of it
allantois
”"”sausage””, tubelike outpocketing that joins the caudal part of the early hindgut”
cloaca
”"”sewer””, expanded junction between the hundgut and the allantois, gives rise to the rectum and most of the anal canal among other structures”
oral membrane
in the moth region of the embryo, the endoderm-lined gut touches the surface ectoderm to form an _
stomodeum
”"”on the way to becoming the mouth””, depression in which the oral membrane lies”
cloacal membrane
at the end of the hindgut, endoderm meets ectoderm to form the _
proctodeum
”"”on the way to becoming the anus””, pit which hold s the cloacal membrane”
primitive intestinal loop
midgut elongtaes into the _ during weeks 4 and 5
gastroenteritis
inflammation of the alimentary canal, symptoms include nausea, vomiting, cramps, loss of appetite, or diarrhea
laparoscopy
”"”flank viewing””, the use of an endoscope inserted into the peritoneal cavity through the anterior abdominal wall, typically to asses the condition of the digestive organs and the pelvic reproductive organs in women”
aka gastrointestinal (GI) tract, muscular digestive tube that winds trough the body, extending from the mouth to the anus; the organs are the mouth, pharynx, esophagus, stomach, small intestine (small bowel), and large intestine (large bowel), the last of which leads to the terminal opening, or anus
alimentary canal
teeth and tongue, gallbladder and large digestive glands–salivary glands, liver, and pancreas–that lie external to and are connected to the alimentary canal by ducts; the accessory digestive glands secerete saliva, bile, and digestive enzymes, all of whic contribute to the breakdown of foodstuffs
accessory digestive organs
most extensive slippery serous membrane, located in the abdominopelvic cavity
peritoneum
covers the external surfaces of most digestive organs
visceral peritoneum
lines the body wall and is continuous with the visceral peritoneum
parietal peritoneum
slitlike potential space between the visceral and parietal peritoneum. the peritoneal cavity lies between the digestive organs and the abdominal body wall. it contains a lubricating serous fluid that is produced by the peritoneum and allows the digestive organs to glide easily along one anotehr and along the body wall as they move during digestion
peritoneal cavity
double layer of pertoneum–a sheet of two serous membranes fused together–that extends from the body wall to the digestive organs; hold organs in place, store fat and most important provide a route for circulatory vessels and nerves to reach the organs in the peritoneal cavity
mesentery
”"”sickle-shaped””, binds the anterior aspect of the liver to the anterior abdominal wall and diaphragm”
falciform ligament
”"”fatty skin””, runs from the liver to the lesser curvature of the stomach and the beginning of the duodenum”
lesser omentum
connects the greater curvature of the stomach to the posterior abdominal wall in a roundabout way
greater omentum
”"”mesentery of the colon””, a nearly horizontal sheet that is fused to the underside of the greater omentum that holds the transverse colon to the posterior abdominal wall”
transverse mesocolon
mesentery that connects the sigmoid colon to the posterior pelvic wall
sigmoid mesocolon
(retro=behind), initially formed within the perioneum but are located behind the peritoneum once thy are fully developed
secondarily retroperitoneal
digestive organs that keep their mesentery and remain surrounded by the peritoneal cavity
intraperitoneal/peritoneal
rhythmic local constrictions of the intestine
segmentation
taking of food into the mouth. in humans, the upper limb, as well as the oral cavity, is important for ingestion
ingestion
movement of food through the alimentary canal. it includes swallowing, which is initiated voluntarily, and peristalsis, an involuntary process. peristalsis, the major means of propulsion thorughout the alimentary canal, involves alternate waves of cantraction and relaxation of musculature in the organ walls. its net effect is to squuze food from one organ to the next, but some mixing occurs as well
propulsion
”"”around contraction””, the major means of propulsion throughout the alimentary canal involves alternate waves of contraction and relaxation of musculature in the organ walls”
peristalsis
physically prepares food for digestion by enzymes breaking it into smaller pieces. mechanical processes include chewing, the churning of food in the stomach, and segmentation, the rythmic local constrictions of the intestine. segmentation mixes food with digestive juices and increases the efficiency of nutrient absorption by repeatedly moving different parts of the food mass over the intestinal wall
mechanical breakdown
series of steps in which complex food molecules (carbohydrates, proteins, and lipids) are broken down to their cmecila building blocks (simple sugars, amino acids, fatty acids, and glycerol). glands in the gastrointestinal tract and in the accessory organs produce enzymes and other substances and secrete them into the lumen of the alimentary canal, where they carry out digestion
digestion
transport of digested end products from the lumen of the alimentary canal into the blood and lymphatic capillaries located in the wall of the canal
absorption
elimination of indigestible substances from the body as feces
defecation
more complex than other mucous membranes in the body, the typical digestive mucosa contains three sublayers: a lining epithelium, a lamina propria, and a muscularis mucosae
mucosa (GI tract)
abuts the lumen of the alimentary canal and performs many functions related to digestion, such as absorbing nutrients and secreting mucus; this is continuous with the ducts and secretory cells of the various digestive glands, most of which lie fully within the wall and are called intrinsic glands
epithelium (of the gut)
loose areolar or eticular connective tissue whose capillaries nourish the lining epithelium and absorb digested nutrients; contains most of the MALT which defends against invasion by bacteria and other microorganisms in the alimentary canal
lamina propria
external to the lamina propria, a thin layer of smooth muscle that produces local movements of the mucosa
muscularis mucosae
“layer of connective tissue containing major blood and lymphatic vessels and nerve fibers; its rich vascular network sends branches to all other layers of the wall; connective tissue is a type intermediate between loose areolar and dense irregular, a ““moderately dense”” connective tissue; the many elastic fibers enable the alimentary canal to return to its shape after food material passes through it”
submucosa (gut)
aka muscular layer, external to the submucosa; throughout most of the alimentary canal, this tunic consists of two layers of smooth muscle, an inner circular layer whose fibers orient around the circumference of the canal (squeezes the gut tube) and an outer longitudinal layer whose fibers orient along the length of the canal (shortens the gut tube)
muscularis externa
visceral peritoneum, outermost layer of the intraperitoneal organs of the alimentary canal, formed of a simple squamous epithelium (mesothelium) underlain by a thin layer of areolar connective tissue
serosa
muscle fibers run parallel to the long axis of the organ, more externally located
longitudinal layer
deeper, fibers run around the circumference of the organ
circular layer
along the tension-resisting intermediate filaments lie _ at regular intervals that anchor the thin filaments, correspond to the Z discs of skeletal muscle
dense bodies
(enteric=gut), smooth muscle and glands of the alimentary canal are controlled largely by the independent _
enteric nervous system
”"”intestinal muscle””, in the muscularis externa between the circular and longitudinal layers, innervates the muscularis externa to control peristalsis and segmentation”
myenteric nerve plexus
lies within the submucosa, nerve fibers extend inward and signal the glands in the mucosa to secrete and the muscularis mucosae to contract
submucosal nerve plexus
or mouth, mucosa-lined cavity whose boundaries are the lips anteriorly, the cheeks laterally, the palate superiorly, and the tongue inferiorly
oral cavity
anterior opening of the oral cavity
oral orifice
”"”porch””, the slit between the teeth and the cheeks (or lips)”
oral vestibule
the region of the mouth that lies internal to the teeth
oral cavity proper
thick flaps extending from the inferior boundary of the nose to the superior boundary of the chin
lips/labia
help keep food inside the mouth during chewing, composed of a core of skeletal muscle covered by skin
cheeks
”"”little bridle of the lip””, median fold that connects the internal aspect of each lip to the gum”
labial frenulum
anchors the soft palate to the tongue
palatoglossal arches
anchors the soft palate to the wall of the oropharynx
palatopharyngeal arches
fold of mucosa on the undersurface of the tongue secures the tongue tothe floor of the mouth and limits its posterior movements
lingual frenulum
”"”fused tongue””, congenital condition in which the lingual frenulum is abnormally short or extends exceptionally far anteriorly”
ankyloglossia
”"”thread-shaped””, conical, paointed, kerativized, roughen the tongue enabling it to grasp and manipulate food during chewing”
filiform papillae
groove which marks the border between the mouth and pharynx
terminal sulcus
lie in sockets (alveoli) in the gum-covered margins of the mandible and maxilla
teeth
”"”falling off””, primary dentition (child teeth)”
deciduous teeth
last permanent teeth, the wisdom teeth, emergy between the ages of 17 and 25 years
permanent teeth
chisel-shaped, adapted for nipping off pieces of food
incisors
cuspids, eyeteeth, cone-shaped, tear and pierce
canines
“(bicuspids), ““millstones””, have broad crowns with rounded cusps for grinding food”
premolars and molars
each tooth has two main regions, the exposed _ and the roots, covered by a layer of enamel
crown (tooth)
each tooth has two main regions, the crown and the _ in the socket
root(s) (tooth)
the crown and the root meet near the gum line
neck (tooth)
“hardest substance in the body, lacks cells of vessels, 99% of its mass consists of densely packed hydroxyapatite crystals arranged in force-resisting rods or prisms oriented perpendicular to the tooth’s surface”
enamel
underlies the enamel cap and forms the bulk of the tooth, bonelike tissue with mineral and collagen components but is harder than bone and lacks internal blood vessels
dentin/tentine
dentin contains unique radial striations
dentinal tubules
in the center of the tooth is filled with dental pulp
pulp cavity
“a loose connective tissue containing the tooth’s vessels and nerves, supplies nutrients for the tooth’s hard tissues and provides for tooth sensation”
(dental) pulp
part of the pulp cavity in the root
root canal
opening into the root canal at the tip of each root
apical foramen (tooth)
all of the pulp is drilled out, and the pulp cavity is sterized and filled with an artificial, inert material before the tooth is capped
root canal therapy
external surface of the tooth root is covered by a ccalcified conective tissue
cement
“or periodontium, ““around the tooth””, anchors the tooth in the bony socket of the jaw”
periodontal ligament
gum
gingiva
”"”rottenness””, result from a gradual demineralization of the enamel and dentin by bacterial action”
cavities or caries
a film of sugar, bacteria, and other debris that adheres to the theeth, whose accumulation begins the decay process
dental plaque
produce saliva, a complex mixture of water, ions, mucus, and enzymes that performs many functions: it moustens the mouth, dissolves food chemicals so that they can be tasted, wets food, and binds the food together into a bolus
salivary glands
(par=near, otid=the ear), largest major gland is a compound acinar gland, lies anterior to teh ear, between the masseter muscle and the skin
parotid gland
runs parallel to the zygomatic arch, penetrates the muscle of the cheek, and opens into the mouth lateral to the second upper molar, secretion is stimulated by the glossopharyngeal nerve (cranial nerve IX)
parotid duct
“compound tubuloacinar gland, lies along the medial surface of the mandibular body, just anterior to the angle of the mandible, duct opens in the floor of the mouth directly lateral to the nogue’s lingual frenulum”
submandibular gland
also a tubuloacinar gland, lies in the flor of the oral cavity inferior to the tongue, 10-12 ducts open into the mouth directly superior to the gland, innervated by the facial nerve (cranial nerve VII)
sublingual gland
muscular tube that propels swallowed food to the stomach
esophagus
abdominal part of the esophagus joins the stomach at the _
cardial orifice
acts to close off the lumen and prevent regurgitation of acidic stomach juices into the esophagus
cardiac sphincter
J-shaped, widest part of the alimentary canal, temporary storage tank in which food is churned and turned ninto a paste called chyme
stomach
protein-digesting enzyme that can function only under acidic conditions
pepsin
“stumach’s dome, tucked under the diaphragm”
fundus
“funnel-shaped end of the stomach’s pody, composed of the wider pyloric antrum (““cave””) and the narrower pyloric canal”
pyloric part
”"”gatekeeper””, terminus of the stomach”
pylorus
controls the entry of chyme into the intestine
pyloric sphincter
convex left surface of the stomach
greater curvature
concave right margin of the stomach
lesser curvature
”"”wrinkles””, internal surface of the empty stomach contains numerous longitudinal folds of mocusa which flatten as the stomach fills; the resulting expansion in volume accommodates the increasing quantity of food within the stomach”
rugae
open into the tubular gastric glands, surface of the stomach mucosa is dotted with millions of cup-shaped _
gastric pits
in the fundus fundus and body contain three types of secretory cells: mucous neck cells, parietal (exyntic) cells, and chief (zymogenic) cells
gastric glands
enzymatic protein which is activated to pepsin when it encounters acid in the apical region of the gland
pepsinogen
protein necessary for the absorption of vitamin B12 by the small intestine
gastric intrensic factor
occur in the upper ends or necks of the gastric glands secrete a different type of mucus from that secreted by the surface mucus cells; specific function of this mucus is not known
mucous neck cells
“occur mainly in the middle regions of the glands, produce the stomach’s hydrochloric acid (HCl) by pumping hydrogen and cloride ions into the lumen of the gland; also secrete gastric intrinsic factor”
parietal (oxyntic) cells
”"”gut endocrine””, hormone-secreting cells scattered throughout the lining epithelium and glands of the alimentary canal; these cells release their hormones into the capillaries of the underlying lamina propria; one of these hormones, gastrin, signals parietal cells to secrete HCl when food enters the stomach; most enteroendocrine cells that produce gastrin are in the stomach’s pyloric region.<br></br>hormones also to signal the gallbladder to release stored bile and the pancrease to secrete digestive enzymes and a bicarbonate-rich juice to neutralize the acidic chyme entering the duodenum”
enteroendocrine cells
located throughout the stomach, at the junction ofthe gastric glands and gastric pits, divide continuously replacing the entire lining epithelium of mucus-secreting cells every 3-7 days
undifferentiated stem cells
longest part of the alimentary canal and the site of most enzymatic digestion and virtually all absorption of nutrients
small intestine
”"”twelve fingerwidths long””, shortest subdivios of the small intestine, receives digestive enzymes from the pancrease via the main pancreatic duct and bile from the liver and gallbladder via the bile duct”
duedenum
”"”empty””, contributes almost 40% of the length of the small intestine, forms superior left part of the sausagelike coils that hang from the posterior abdomen by the mesentery and is framed by the large intestine”
jejunum
”"”twisted intestine””, contributes almost 60% of the length of the small intestine, forms the inferior right part of sausagelike coils that hang from the posterior abdomen by the mesentery and are framed by the large intestine”
ileum
”"”flask from the liver and pancreas””, bulb inside the wall of the duedenum made of the main pancreatic duct and the bile duct that opens into the duedenum via a mound called the major duodenal papilla”
hepatopancreatic ampulla
fingerlike projections of the mucosa that give it a velvety texture
villi
absorptive cells, primary make-up of the simple columnar epithelium covering the villa, specialized for absorbing digested nutrients
enterocytes
wide lymphatic capillary inside the core of lamina propria in each villus (with a network of blood capillaries)
lacteal
on apical surface of the absorptive enterocytes, amplify the absorptive surface, the plasma membrane contains enzymes that complete the final stages of the breakdown of nutrient molecules
microvilli
these cells secrete onto the internal surface of the intestine a coat of mucus that lubricates the chyme and forms a protective barrier that prevents enzymatic digestion of the intestinal wall.
goblet cells
invaginations between the villi lined with epithelial cells that secrete intestinal juice, a watery liquid that mixes with chyme in the intestinal lumen; also contains undifferentiated epithelial cells and mature Paneth cells
intestinal crypts
line the intestinal crypts and renew the mucosal epithelium by dividing rapidly and moving contiuously onto the villi. these are among the most quickly dividing cells of the body, completely renewing the inner epithelium of the small intesting every 3-6 days
undifferentiated epithelial cells
found at the base of the crypt. these epithelial cells secrete enzymes that destroy certain bacteria and may help determine which kinds of bacteria live in the intestinal lumen. the permanent bacterial residents of the intetinal lumen, called the intestinal flora, manufacture some essential vitamins, which the intestines absorb.
Paneth cells
compound, tubular, whose ducts open into the intestinal crypts, in the submucosa in the duodenum only
duedenal glands
last major organ in the alimentary canal, main function is to absorb water and electrolytes from the digested mass, resulting in semisolid feces
large intestine
pass over the colon a few times a day to force the feces powerfully toward the rectum
mass peristaltic movements
”"”ribbons of the colon””, three longitudinal strips, spaced at equal intervals around the circumference of the cecum and colon, thickenings of the longitudinal layer of the muscularis externa”
teniae (taeniae) coli
”"”to draw up””, sacs puckered from the large intestine”
haustra
”"”membrane-covered””, aka omental appendices, fat-filled pouches of visceral peritoneum that hang from the intestine (significance unknown)”
epiploic appendages
“formed by two raised edges of the mucosa, surrounds the opening of the ileum of the small intestine into the cecum’s medial wall internally”
ileocecal valve
extends itraperitoneal to the left across the peritoneal cavity, directly anterior to the spleen it bends acutely downard at the left colic (splenic) flexure
transverse colon
descends along the left side of the posterior abdominal wall in a secondarily retroperitoneal position
descending colon
inferiorly the colon becomes intraperitoneal and enters the true pelvis while S-shaped
sigmoid colon
aka hepatic flexure, bend between the ascending colon and the transverse colon
right colic flexure
aka splenic flexure, bend between the transverse colon and the descending colon
left colic flexure
descends along the inferior half of the sacrum in a secondarily retroperitoneal position
rectum
three transverse folds of the rectum which prevent feces from being passed along with flatus (gas)
rectal valves
smooth muscle thickening of the circular layer of the muscularis, contracts involuntarily
internal anal sphincter
skeletal muscle, contracts voluntarily to inhibit defecation
external anal sphincter
absorptive cells of the large intestine that take in water and electrolytes
colonocytes
green alkaline liqued that is stored in the gallbladder and secreted into the duodenum; bile salts emulsif fats in the small intestine
bile
of the liver faces anteriorly and superiorly
diaphragmatic surface
of the liver faces posteroinferiorly
visceral surface
superior part of the liver is fused to the diaphragm and is therefore devoid of peritoneum
bare area
part of the left lobe of the liver, visible on the visceral surface just to the right of the fissure
quadrate lobe and caudate lobe
”"”gateway to the liver””, where most of the major vessels and nerves enter and leave the liver”
porta hepatis
carry bile from the respective liver lobes, exit from the porta hepatis and fuse to form the common hepatic duct
right and left hepatic ducts
extends inferiorly toward the duodenum
common hepatic duct
“in the fissure’s inferior half, the remnant of the umbilical vein in the fetus, ascends to the liver from the navel, within the inferior margin of the falciform ligament”
round ligament of liver/ligamentum teres
over a million each about the size of a sesame seed, shaped like a hexagonal solid and consists of plates of liver cells, or heptocytes, radiating out from a central vein
liver lobules
at almost every corder of the lobule, contains three main vessels: a portal arteriole that is a branch of the hepatic artery, a portale venule that is a branch of the hepatic portal vein, and a bile duct which carries bile away from the liver lobules
portal triad
large capillaries between the plates of hepatocytes, near the portal triads, these sinusoids receive blood from both the portal arteriole and venule and carry this blood inward to reach the central vein
liver sinusoids
in the walls of the sinusoids, destroy bacteria and other foreign particles in the blood flowing past them
stellate macrophages/hepatic macrophages
”"”little canals””, tiny intercellular spaces or channels that lie between adjacent hepatocytes, carry bile outward through each lobule, emptying into the blie ducts in the portal triads”
bile canaliculi
muscular sac, resting in a shallow depression on the visceral surface of the right lobe of the liver, stores and concentrates bile produced by the liver
gallbladder
“gallbladder’s duct, joins the common hepatic duct from the liver to form the bile duct, which empties into the duedenum”
cystic duct
extends through the length of the pancrease, joins the bile duct to form the hepatopancreatic ampulla and empties into the deudenum at the major duedenal papilla
main pancreatic duct
lies in the head of the pancreas and either drains into the main duct or drains directly into the duodenum
accessory pancreatic duct
make, store, and secrete at least 22 kind sof pancreatic enzymes capable of digesting the various categories of foodstuffs
acinar cells
”"”fermenting””, intracellular secretory granules that store the enzymes from the acinar cells in inactive form”
zymogen granules
craterlike erosions of the mucosa in any region of the alimentary canal that is exposed to stomach secretions (e.g. stomach or deodenum)
gastric ulcers/duodenal ulcers
any hindrance to the movement of chyme or feces through the intestine, most are mechanical
intestinal obstuction
noncontagious, periodic inflammation of the intestinal wall characterized by chronic leukocyte infiltration of this wall, symptoms include cramping, diarrhea, weight loss, and intestinal bleeding
inflammatory bowel disease
general term for any inflammation of the liver, largely of viral origin
hepatitis
most types lead to fluelike symptoms and jaundice, major types are A, B, C, and G
viral hepatitis
”"”yolk””, initially, the middle region of the primitive gut is open to the yolk sac trhough the _, a key landmark that divides the embryonic gut into three basic regions: foregut, supperior to it, midgut, open to it, and hindgut, inferior to it”
vitelline duct
develops into the first segment of the digestive system, from the pharynx to the point in the duodenum where the bile duct enters. the celiac trunk supplies blood to the obdominal foregut and its derivatives: the liver, gallbladder, and pancreas
foregut
becomes the segment beginning at the duedenum and extending to a point two-thirds of the way olng the transverse colon. the superior mesenteric artery supplies the derivatives of it
midgut
fors the rest of the large intestine. the inferior mesenteric artery supplies the organs of it
hindgut
”"”sausage””, tubelike outpocketing that joins the caudal part of the early hindgut”
allantois
”"”sewer””, expanded junction between the hundgut and the allantois, gives rise to the rectum and most of the anal canal among other structures”
cloaca
in the moth region of the embryo, the endoderm-lined gut touches the surface ectoderm to form an _
oral membrane
”"”on the way to becoming the mouth””, depression in which the oral membrane lies”
stomodeum
at the end of the hindgut, endoderm meets ectoderm to form the _
cloacal membrane
”"”on the way to becoming the anus””, pit which hold s the cloacal membrane”
proctodeum
midgut elongtaes into the _ during weeks 4 and 5
primitive intestinal loop
inflammation of the alimentary canal, symptoms include nausea, vomiting, cramps, loss of appetite, or diarrhea
gastroenteritis
”"”flank viewing””, the use of an endoscope inserted into the peritoneal cavity through the anterior abdominal wall, typically to asses the condition of the digestive organs and the pelvic reproductive organs in women”
laparoscopy
