Module 18: The Digestive System

Lesson 7: Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder

Cơ Quan Hỗ Trợ Tiêu Hóa: Gan, Tụy, Và Túi Mật

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Dưới đây là danh sách những thuật ngữ Y khoa của module The Digestive System.
Khái quát được số lượng thuật ngữ sẽ xuất hiện trong bài đọc và nghe sẽ giúp bạn thoải mái tiêu thụ nội dung hơn. Sau khi hoàn thành nội dung đọc và nghe, bạn hãy quay lại đây và luyện tập (practice) để quen dần các thuật ngữ này. Đừng ép bản thân phải nhớ các thuật ngữ này vội vì bạn sẽ gặp và ôn lại danh sách này trong những bài học (lesson) khác của cùng một module.

Medical Terminology: The Digestive System

absorption
passage of digested products from the intestinal lumen through mucosal cells and into the bloodstream or lacteals
accessory digestive organ
includes teeth, tongue, salivary glands, gallbladder, liver, and pancreas
accessory duct
(also, duct of Santorini) duct that runs from the pancreas into the duodenum
acinus
cluster of glandular epithelial cells in the pancreas that secretes pancreatic juice in the pancreas
alimentary canal
continuous muscular digestive tube that extends from the mouth to the anus
aminopeptidase
brush border enzyme that acts on proteins
anal canal
final segment of the large intestine
anal column
long fold of mucosa in the anal canal
anal sinus
recess between anal columns
appendix
(vermiform appendix) coiled tube attached to the cecum
ascending colon
first region of the colon
bacterial flora
bacteria in the large intestine
bile
alkaline solution produced by the liver and important for the emulsification of lipids
bile canaliculus
small duct between hepatocytes that collects bile
bilirubin
main bile pigment, which is responsible for the brown color of feces
body
mid-portion of the stomach
bolus
mass of chewed food
brush border
fuzzy appearance of the small intestinal mucosa created by microvilli
cardia
(also, cardiac region) part of the stomach surrounding the cardiac orifice (esophageal hiatus)
cecum
pouch forming the beginning of the large intestine
cementum
bone-like tissue covering the root of a tooth
central vein
vein that receives blood from hepatic sinusoids
cephalic phase
(also, reflex phase) initial phase of gastric secretion that occurs before food enters the stomach
chemical digestion
enzymatic breakdown of food
chief cell
gastric gland cell that secretes pepsinogen
chylomicron
large lipid-transport compound made up of triglycerides, phospholipids, cholesterol, and proteins
chyme
soupy liquid created when food is mixed with digestive juices
circular fold
(also, plica circulare) deep fold in the mucosa and submucosa of the small intestine
colon
part of the large intestine between the cecum and the rectum
common bile duct
structure formed by the union of the common hepatic duct and the gallbladder’s cystic duct
common hepatic duct
duct formed by the merger of the two hepatic ducts
crown
portion of tooth visible superior to the gum line
cuspid
(also, canine) pointed tooth used for tearing and shredding food
cystic duct
duct through which bile drains and enters the gallbladder
deciduous tooth
one of 20 “baby teeth”
defecation
elimination of undigested substances from the body in the form of feces
deglutition
three-stage process of swallowing
dens
tooth
dentin
bone-like tissue immediately deep to the enamel of the crown or cementum of the root of a tooth
dentition
set of teeth
deoxyribonuclease
pancreatic enzyme that digests DNA
descending colon
part of the colon between the transverse colon and the sigmoid colon
dipeptidase
brush border enzyme that acts on proteins
duodenal gland
(also, Brunner’s gland) mucous-secreting gland in the duodenal submucosa
duodenum
first part of the small intestine, which starts at the pyloric sphincter and ends at the jejunum
enamel
covering of the dentin of the crown of a tooth
enteroendocrine cell
gastric gland cell that releases hormones
enterohepatic circulation
recycling mechanism that conserves bile salts
enteropeptidase
intestinal brush-border enzyme that activates trypsinogen to trypsin
epiploic appendage
small sac of fat-filled visceral peritoneum attached to teniae coli
esophagus
muscular tube that runs from the pharynx to the stomach
external anal sphincter
voluntary skeletal muscle sphincter in the anal canal
fauces
opening between the oral cavity and the oropharynx
feces
semisolid waste product of digestion
flatus
gas in the intestine
fundus
dome-shaped region of the stomach above and to the left of the cardia
G cell
gastrin-secreting enteroendocrine cell
gallbladder
accessory digestive organ that stores and concentrates bile
gastric emptying
process by which mixing waves gradually cause the release of chyme into the duodenum
gastric gland
gland in the stomach mucosal epithelium that produces gastric juice
gastric phase
phase of gastric secretion that begins when food enters the stomach
gastric pit
narrow channel formed by the epithelial lining of the stomach mucosa
gastrin
peptide hormone that stimulates secretion of hydrochloric acid and gut motility
gastrocolic reflex
propulsive movement in the colon activated by the presence of food in the stomach
gastroileal reflex
long reflex that increases the strength of segmentation in the ileum
gingiva
gum
haustral contraction
slow segmentation in the large intestine
haustrum
small pouch in the colon created by tonic contractions of teniae coli
hepatic artery
artery that supplies oxygenated blood to the liver
hepatic lobule
hexagonal-shaped structure composed of hepatocytes that radiate outward from a central vein
hepatic portal vein
vein that supplies deoxygenated nutrient-rich blood to the liver
hepatic sinusoid
blood capillaries between rows of hepatocytes that receive blood from the hepatic portal vein and the branches of the hepatic artery
hepatic vein
vein that drains into the inferior vena cava
hepatocytes
major functional cells of the liver
hepatopancreatic ampulla
(also, ampulla of Vater) bulb-like point in the wall of the duodenum where the bile duct and main pancreatic duct unite
hepatopancreatic sphincter
(also, sphincter of Oddi) sphincter regulating the flow of bile and pancreatic juice into the duodenum
hydrochloric acid (HCl)
digestive acid secreted by parietal cells in the stomach
ileocecal sphincter
sphincter located where the small intestine joins with the large intestine
ileum
end of the small intestine between the jejunum and the large intestine
incisor
midline, chisel-shaped tooth used for cutting into food
ingestion
taking food into the GI tract through the mouth
internal anal sphincter
involuntary smooth muscle sphincter in the anal canal
intestinal gland
(also, crypt of Lieberkühn) gland in the small intestinal mucosa that secretes intestinal juice
intestinal juice
mixture of water and mucus that helps absorb nutrients from chyme
intestinal phase
phase of gastric secretion that begins when chyme enters the intestine
intrinsic factor
glycoprotein required for vitamin B12 absorption in the small intestine
jejunum
middle part of the small intestine between the duodenum and the ileum
labial frenulum
midline mucous membrane fold that attaches the inner surface of the lips to the gums
labium
lip
lactase
brush border enzyme that breaks down lactose into glucose and galactose
lacteal
lymphatic capillary in the villi
large intestine
terminal portion of the alimentary canal
laryngopharynx
part of the pharynx that functions in respiration and digestion
left colic flexure
(also, splenic flexure) point where the transverse colon curves below the inferior end of the spleen
lingual frenulum
mucous membrane fold that attaches the bottom of the tongue to the floor of the mouth
lingual lipase
digestive enzyme from glands in the tongue that acts on triglycerides
lipoprotein lipase
enzyme that breaks down triglycerides in chylomicrons into fatty acids and monoglycerides
liver
largest gland in the body whose main digestive function is the production of bile
lower esophageal sphincter
smooth muscle sphincter that regulates food movement from the esophagus to the stomach
main pancreatic duct
(also, duct of Wirsung) duct through which pancreatic juice drains from the pancreas
major duodenal papilla
point at which the hepatopancreatic ampulla opens into the duodenum
maltase
brush border enzyme that breaks down maltose and maltotriose into two and three molecules of glucose, respectively
mass movement
long, slow, peristaltic wave in the large intestine
mastication
chewing
mechanical digestion
chewing, mixing, and segmentation that prepares food for chemical digestion
mesoappendix
mesentery of the appendix
micelle
tiny lipid-transport compound composed of bile salts and phospholipids with a fatty acid and monoacylglyceride core
microvillus
small projection of the plasma membrane of the absorptive cells of the small intestinal mucosa
migrating motility complex
form of peristalsis in the small intestine
mixing wave
unique type of peristalsis that occurs in the stomach
molar
tooth used for crushing and grinding food
motilin
hormone that initiates migrating motility complexes
motility
movement of food through the GI tract
mucosa
innermost lining of the alimentary canal
mucosal barrier
protective barrier that prevents gastric juice from destroying the stomach itself
mucous neck cell
gastric gland cell that secretes a uniquely acidic mucus
muscularis
muscle (skeletal or smooth) layer of the alimentary canal wall
myenteric plexus
(plexus of Auerbach) major nerve supply to alimentary canal wall; controls motility
nucleosidase
brush border enzyme that digests nucleotides
oral cavity
(also, buccal cavity) mouth
oral vestibule
part of the mouth bounded externally by the cheeks and lips, and internally by the gums and teeth
oropharynx
part of the pharynx continuous with the oral cavity that functions in respiration and digestion
palatoglossal arch
muscular fold that extends from the lateral side of the soft palate to the base of the tongue
palatopharyngeal arch
muscular fold that extends from the lateral side of the soft palate to the side of the pharynx
pancreas
accessory digestive organ that secretes pancreatic juice
pancreatic amylase
enzyme secreted by the pancreas that completes the chemical digestion of carbohydrates in the small intestine
pancreatic juice
secretion of the pancreas containing digestive enzymes and bicarbonate
pancreatic lipase
enzyme secreted by the pancreas that participates in lipid digestion
pancreatic nuclease
enzyme secreted by the pancreas that participates in nucleic acid digestion
parietal cell
gastric gland cell that secretes hydrochloric acid and intrinsic factor
parotid gland
one of a pair of major salivary glands located inferior and anterior to the ears
pectinate line
horizontal line that runs like a ring, perpendicular to the inferior margins of the anal sinuses
pepsinogen
inactive form of pepsin
peristalsis
muscular contractions and relaxations that propel food through the GI tract
permanent tooth
one of 32 adult teeth
pharynx
throat
phosphatase
brush border enzyme that digests nucleotides
porta hepatis
“gateway to the liver” where the hepatic artery and hepatic portal vein enter the liver
portal triad
bile duct, hepatic artery branch, and hepatic portal vein branch
premolar
(also, bicuspid) transitional tooth used for mastication, crushing, and grinding food
propulsion
voluntary process of swallowing and the involuntary process of peristalsis that moves food through the digestive tract
pulp cavity
deepest portion of a tooth, containing nerve endings and blood vessels
pyloric antrum
wider, more superior part of the pylorus
pyloric canal
narrow, more inferior part of the pylorus
pyloric sphincter
sphincter that controls stomach emptying
pylorus
lower, funnel-shaped part of the stomach that is continuous with the duodenum
rectal valve
one of three transverse folds in the rectum where feces is separated from flatus
rectum
part of the large intestine between the sigmoid colon and anal canal
reticuloendothelial cell
(also, Kupffer cell) phagocyte in hepatic sinusoids that filters out material from venous blood from the alimentary canal
retroperitoneal
located posterior to the peritoneum
ribonuclease
pancreatic enzyme that digests RNA
right colic flexure
(also, hepatic flexure) point, at the inferior surface of the liver, where the ascending colon turns abruptly to the left
root
portion of a tooth embedded in the alveolar processes beneath the gum line
ruga
fold of alimentary canal mucosa and submucosa in the empty stomach and other organs
saccharolytic fermentation
anaerobic decomposition of carbohydrates
saliva
aqueous solution of proteins and ions secreted into the mouth by the salivary glands
salivary amylase
digestive enzyme in saliva that acts on starch
salivary gland
an exocrine gland that secretes a digestive fluid called saliva
salivation
secretion of saliva
segmentation
alternating contractions and relaxations of non-adjacent segments of the intestine that move food forward and backward, breaking it apart and mixing it with digestive juices
serosa
outermost layer of the alimentary canal wall present in regions within the abdominal cavity
sigmoid colon
end portion of the colon, which terminates at the rectum
small intestine
section of the alimentary canal where most digestion and absorption occurs
soft palate
posterior region of the bottom portion of the nasal cavity that consists of skeletal muscle
stomach
alimentary canal organ that contributes to chemical and mechanical digestion of food from the esophagus before releasing it, as chyme, to the small intestine
sublingual gland
one of a pair of major salivary glands located beneath the tongue
submandibular gland
one of a pair of major salivary glands located in the floor of the mouth
submucosa
layer of dense connective tissue in the alimentary canal wall that binds the overlying mucosa to the underlying muscularis
submucosal plexus
(plexus of Meissner) nerve supply that regulates activity of glands and smooth muscle
sucrase
brush border enzyme that breaks down sucrose into glucose and fructose
tenia coli
one of three smooth muscle bands that make up the longitudinal muscle layer of the muscularis in all of the large intestine except the terminal end
tongue
accessory digestive organ of the mouth, the bulk of which is composed of skeletal muscle
transverse colon
part of the colon between the ascending colon and the descending colon
upper esophageal sphincter
skeletal muscle sphincter that regulates food movement from the pharynx to the esophagus
Valsalva’s maneuver
voluntary contraction of the diaphragm and abdominal wall muscles and closing of the glottis, which increases intra-abdominal pressure and facilitates defecation
villus
projection of the mucosa of the small intestine
voluntary phase
initial phase of deglutition, in which the bolus moves from the mouth to the oropharynx
α-dextrin
breakdown product of starch
α-dextrinase
brush border enzyme that acts on α-dextrins
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Chemical digestion in the small intestine relies on the activities of three accessory digestive organs: the liver, pancreas, and gallbladder (Figure 1). The digestive role of the liver is to produce bile and export it to the duodenum. The gallbladder primarily stores, concentrates, and releases bile. The pancreas produces pancreatic juice, which contains digestive enzymes and bicarbonate ions, and delivers it to the duodenum.
The liver is the largest gland in the body, weighing about three pounds in an adult. It is also one of the most important organs. In addition to being an accessory digestive organ, it plays a number of roles in metabolism and regulation. The liver lies inferior to the diaphragm in the right upper quadrant of the abdominal cavity and receives protection from the surrounding ribs.

The liver is divided into two primary lobes: a large right lobe and a much smaller left lobe. In the right lobe, some anatomists also identify an inferior quadrate lobe and a posterior caudate lobe, which are defined by internal features. The liver is connected to the abdominal wall and diaphragm by five peritoneal folds referred to as ligaments. These are the falciform ligament, the coronary ligament, two lateral ligaments, and the ligamentum teres hepatis. The falciform ligament and ligamentum teres hepatis are actually remnants of the umbilical vein, and separate the right and left lobes anteriorly. The lesser omentum tethers the liver to the lesser curvature of the stomach.

The porta hepatis (“gate to the liver”) is where the hepatic artery and hepatic portal vein enter the liver. These two vessels, along with the common hepatic duct, run behind the lateral border of the lesser omentum on the way to their destinations. As shown in Figure 2, the hepatic artery delivers oxygenated blood from the heart to the liver. The hepatic portal vein delivers partially deoxygenated blood containing nutrients absorbed from the small intestine and actually supplies more oxygen to the liver than do the much smaller hepatic arteries. In addition to nutrients, drugs and toxins are also absorbed. After processing the bloodborne nutrients and toxins, the liver releases nutrients needed by other cells back into the blood, which drains into the central vein and then through the hepatic vein to the inferior vena cava. With this hepatic portal circulation, all blood from the alimentary canal passes through the liver. This largely explains why the liver is the most common site for the metastasis of cancers that originate in the alimentary canal.

A. Histology

The liver has three main components: hepatocytes, bile canaliculi, and hepatic sinusoids. A hepatocyte is the liver’s main cell type, accounting for around 80 percent of the liver’s volume. These cells play a role in a wide variety of secretory, metabolic, and endocrine functions. Plates of hepatocytes called hepatic laminae radiate outward from the portal vein in each hepatic lobule.

Between adjacent hepatocytes, grooves in the cell membranes provide room for each bile canaliculus (plural = canaliculi). These small ducts accumulate the bile produced by hepatocytes. From here, bile flows first into bile ductules and then into bile ducts. The bile ducts unite to form the larger right and left hepatic ducts, which themselves merge and exit the liver as the common hepatic duct. This duct then joins with the cystic duct from the gallbladder, forming the common bile duct through which bile flows into the small intestine.

A hepatic sinusoid is an open, porous blood space formed by fenestrated capillaries from nutrient-rich hepatic portal veins and oxygen-rich hepatic arteries. Hepatocytes are tightly packed around the fenestrated endothelium of these spaces, giving them easy access to the blood. From their central position, hepatocytes process the nutrients, toxins, and waste materials carried by the blood. Materials such as bilirubin are processed and excreted into the bile canaliculi. Other materials including proteins, lipids, and carbohydrates are processed and secreted into the sinusoids or just stored in the cells until called upon. The hepatic sinusoids combine and send blood to a central vein. Blood then flows through a hepatic vein into the inferior vena cava. This means that blood and bile flow in opposite directions. The hepatic sinusoids also contain star-shaped reticuloendothelial cells (Kupffer cells), phagocytes that remove dead red and white blood cells, bacteria, and other foreign material that enter the sinusoids. The portal triad is a distinctive arrangement around the perimeter of hepatic lobules, consisting of three basic structures: a bile duct, a hepatic artery branch, and a hepatic portal vein branch.

B. Bile

Recall that lipids are hydrophobic, that is, they do not dissolve in water. Thus, before they can be digested in the watery environment of the small intestine, large lipid globules must be broken down into smaller lipid globules, a process called emulsification. Bile is a mixture secreted by the liver to accomplish the emulsification of lipids in the small intestine.

Hepatocytes secrete about one liter of bile each day. A yellow-brown or yellow-green alkaline solution (pH 7.6 to 8.6), bile is a mixture of water, bile salts, bile pigments, phospholipids (such as lecithin), electrolytes, cholesterol, and triglycerides. The components most critical to emulsification are bile salts and phospholipids, which have a nonpolar (hydrophobic) region as well as a polar (hydrophilic) region. The hydrophobic region interacts with the large lipid molecules, whereas the hydrophilic region interacts with the watery chyme in the intestine. This results in the large lipid globules being pulled apart into many tiny lipid fragments of about 1 µm in diameter. This change dramatically increases the surface area available for lipid-digesting enzyme activity. This is the same way dish soap works on fats mixed with water.

Bile salts act as emulsifying agents, so they are also important for the absorption of digested lipids. While most constituents of bile are eliminated in feces, bile salts are reclaimed by the enterohepatic circulation. Once bile salts reach the ileum, they are absorbed and returned to the liver in the hepatic portal blood. The hepatocytes then excrete the bile salts into newly formed bile. Thus, this precious resource is recycled.

Bilirubin, the main bile pigment, is a waste product produced when the spleen removes old or damaged red blood cells from the circulation. These breakdown products, including proteins, iron, and toxic bilirubin, are transported to the liver via the splenic vein of the hepatic portal system. In the liver, proteins and iron are recycled, whereas bilirubin is excreted in the bile. It accounts for the green color of bile. Bilirubin is eventually transformed by intestinal bacteria into stercobilin, a brown pigment that gives your stool its characteristic color! In some disease states, bile does not enter the intestine, resulting in white (‘acholic’) stool with a high fat content, since virtually no fats are broken down or absorbed.

Hepatocytes work non-stop, but bile production increases when fatty chyme enters the duodenum and stimulates the secretion of the gut hormone secretin. Between meals, bile is produced but conserved. The valve-like hepatopancreatic ampulla closes, allowing bile to divert to the gallbladder, where it is concentrated and stored until the next meal.
The soft, oblong, glandular pancreas lies transversely in the retroperitoneum behind the stomach. Its head is nestled into the “c-shaped” curvature of the duodenum with the body extending to the left about 15.2 cm (6 in) and ending as a tapering tail in the hilum of the spleen. It is a curious mix of exocrine (secreting digestive enzymes) and endocrine (releasing hormones into the blood) functions (Figure 3).

The exocrine part of the pancreas arises as little grape-like cell clusters, each called an acinus (plural = acini), located at the terminal ends of pancreatic ducts. These acinar cells secrete enzyme-rich pancreatic juice into tiny merging ducts that form two dominant ducts. The larger duct fuses with the common bile duct (carrying bile from the liver and gallbladder) just before entering the duodenum via a common opening (the hepatopancreatic ampulla). The smooth muscle sphincter of the hepatopancreatic ampulla controls the release of pancreatic juice and bile into the small intestine. The second and smaller pancreatic duct, the accessory duct (duct of Santorini), runs from the pancreas directly into the duodenum, approximately 1 inch above the hepatopancreatic ampulla. When present, it is a persistent remnant of pancreatic development.

Scattered through the sea of exocrine acini are small islands of endocrine cells, the islets of Langerhans. These vital cells produce the hormones pancreatic polypeptide, insulin, glucagon, and somatostatin.

A. Pancreatic Juice

The pancreas produces over a liter of pancreatic juice each day. Unlike bile, it is clear and composed mostly of water along with some salts, sodium bicarbonate, and several digestive enzymes. Sodium bicarbonate is responsible for the slight alkalinity of pancreatic juice (pH 7.1 to 8.2), which serves to buffer the acidic gastric juice in chyme, inactivate pepsin from the stomach, and create an optimal environment for the activity of pH-sensitive digestive enzymes in the small intestine. Pancreatic enzymes are active in the digestion of sugars, proteins, and fats.

The pancreas produces protein-digesting enzymes in their inactive forms. These enzymes are activated in the duodenum. If produced in an active form, they would digest the pancreas (which is exactly what occurs in the disease, pancreatitis). The intestinal brush border enzyme enteropeptidase stimulates the activation of trypsin from trypsinogen of the pancreas, which in turn changes the pancreatic enzymes procarboxypeptidase and chymotrypsinogen into their active forms, carboxypeptidase and chymotrypsin.

The enzymes that digest starch (amylase), fat (lipase), and nucleic acids (nuclease) are secreted in their active forms, since they do not attack the pancreas as do the protein-digesting enzymes.

B. Pancreatic Secretion

Regulation of pancreatic secretion is the job of hormones and the parasympathetic nervous system. The entry of acidic chyme into the duodenum stimulates the release of secretin, which in turn causes the duct cells to release bicarbonate-rich pancreatic juice. The presence of proteins and fats in the duodenum stimulates the secretion of CCK, which then stimulates the acini to secrete enzyme-rich pancreatic juice and enhances the activity of secretin. Parasympathetic regulation occurs mainly during the cephalic and gastric phases of gastric secretion, when vagal stimulation prompts the secretion of pancreatic juice.

Usually, the pancreas secretes just enough bicarbonate to counterbalance the amount of HCl produced in the stomach. Hydrogen ions enter the blood when bicarbonate is secreted by the pancreas. Thus, the acidic blood draining from the pancreas neutralizes the alkaline blood draining from the stomach, maintaining the pH of the venous blood that flows to the liver.
The gallbladder is 8–10 cm (~3–4 in) long and is nested in a shallow area on the posterior aspect of the right lobe of the liver. This muscular sac stores, concentrates, and, when stimulated, propels the bile into the duodenum via the common bile duct. It is divided into three regions. The fundus is the widest portion and tapers medially into the body, which in turn narrows to become the neck. The neck angles slightly superiorly as it approaches the hepatic duct. The cystic duct is 1–2 cm (less than 1 in) long and turns inferiorly as it bridges the neck and hepatic duct.

The simple columnar epithelium of the gallbladder mucosa is organized in rugae, similar to those of the stomach. There is no submucosa in the gallbladder wall. The wall’s middle, muscular coat is made of smooth muscle fibers. When these fibers contract, the gallbladder’s contents are ejected through the cystic duct and into the bile duct (Figure 4). Visceral peritoneum reflected from the liver capsule holds the gallbladder against the liver and forms the outer coat of the gallbladder. The gallbladder’s mucosa absorbs water and ions from bile, concentrating it by up to 10-fold.

OpenStax. (2022). Anatomy and Physiology 2e. Rice University. Retrieved June 15, 2023. ISBN-13: 978-1-711494-06-7 (Hardcover) ISBN-13: 978-1-711494-05-0 (Paperback) ISBN-13: 978-1-951693-42-8 (Digital). License: Attribution 4.0 International (CC BY 4.0). Access for free at openstax.org.

The liver, pancreas, and gallbladder are considered accessory digestive organs, but their roles in the digestive system are vital.

The liver receives oxygenated blood from the hepatic artery and nutrient-rich deoxygenated blood from the hepatic portal vein.

The pancreas has a head, a body, and a tail. It delivers pancreatic juice to the duodenum through the pancreatic duct.

The gallbladder stores and concentrates bile, and releases it into the two-way cystic duct when it is needed by the small intestine.

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Script:
  1. The small intestine’s chemical digestion relies on three crucial accessory digestive organs: the liver, pancreas, and gallbladder.
  2. The liver produces bile, which is stored and concentrated by the gallbladder before release into the duodenum.
  3. Additionally, the pancreas secretes pancreatic juice containing digestive enzymes and bicarbonate ions into the duodenum.
  4. The liver, the largest gland in the body, performs various metabolic functions and receives blood from both the hepatic artery and hepatic portal vein.
  5. Histologically, the liver comprises hepatocytes, bile canaliculi, and hepatic sinusoids, facilitating nutrient processing and waste removal.
  6. Bile, primarily composed of bile salts and bilirubin, aids in lipid emulsification and absorption.
  7. The pancreas, with its dual exocrine and endocrine functions, produces pancreatic juice rich in enzymes crucial for digesting carbohydrates, proteins, and fats.
  8. Hormonal and nervous regulation governs pancreatic secretion.
  9. The gallbladder stores and concentrates bile, ejecting it into the duodenum upon stimulation, contributing to the digestive process.
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Hoàn Thành

Quá dữ! Tiếp tục duy trì phong độ nhé!

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