Study Guide: Anatomy and Physiology: Digestive System
Portal Triad
(also known as portal field, portal area, or portal tract) is a distinctive arrangement in the liver. It is a component of the hepatic lobule. It contains the hepatic portal vein, artery and duct.
Functions of the Large Intestine
-reabsorption of water and mineral ions such as sodium and chloride, water, and electrolytes. -formation and temporary storage of faeces. -maintaining a resident population of over 500 species of bacteria. -bacterial fermentation of indigestible materials.
Exocrine secretion by the pancreas is....
-stimulated by the hormones cholecystokinin and secretin -stimulated by parasympathetic activity via the vagus nerve -inhibited by activity of the sympathetic division of the ANS
Kupffer cells
AKA hepatic phagocytic cells; lie along the sinusoids of the liver and phagocytize "worn-out" and dying red blood and white blood cells, some bacteria, and other debris that enters the liver through the blood vessels
Mucosa
AKA mucous membrane; has three layers; specialized cells in this are mechanoreceptors and chemoreceptors; Loose CT: lamina propria
Granular Cells
AKA paneth cells; help protect the intestinal lining from bacteria
Mastication
Chewing food; increases the total surface area of food for digestion
The mucosa and submucosa of the small intestine form a series of folds called what?
Circular folds AKA palicae
What enzyme in specific activated trypsin?
Enterokinase (attached to the brush border of the small intestine)
Posterior boundary of the oral cavity?
Fauces (opening into the pharynx)
What is at the junction of the ileum and the larger intestine and remains mildly contracted most of the time?
Ileocecal Sphincter
Secretions from what 2 organs also enter the small intestine?
Liver and Pancreas
LDL
Low density lipoprotein; bad cholesterol because when in excess, it deposits cholesterol on the arterial walls
What surrounds the cardiac opening and is also known as the cardiac Sphincter?
Lower Esophageal Sphincter
Bile salts surround little lipid droplets called what?
Micelles (small morsels)
What helps regulate the movement of gastric contents into the small intestine?
Pyloric Sphincter
Retroperitoneal Organs
S = Suprarenal (adrenal) glands A = Aorta/Inferior Vena Cava D = Duodenum (second and third segments) P = Pancreas U = Ureters C = Colon (ascending and descending only) K = Kidneys E = Esophagus R = Rectum
What nerve causes the bladder to contract?
Vagus nerve
Which cells migrate from intestinal glands to cover the surface of the villi and eventually shed?
absorptive cells and goblet cells
What four major types of cells are in the mucosa of the duodenum?
absorptive, goblet, granular, and endocrine
Secretion
added to lubricate the food, liquify, buffer, and digest.
Swallowing
aka deglutition; moves the bolus from the oral cavity into the esphagus
Nucleases
an enzyme that cleaves the chains of nucleotides in nucleic acids into smaller units.
The pancreas is what kind of organ?
and exocrine and endocrine organs
S-Cells
are cells which release secretin, found in the jejunum and duodenum. They are stimulated by a drop in pH to 4 or below in the small intestine's lumen. The released secretin will increase the secretion of bicarbonate (HCO3−) into the lumen, via the pancreas
Submandibular Glands
are mixed glands with more serous than mucous acini; duct exits each gland, passes anteriorly deep to the mucous membrane on the floor of the oral cavity and opens into the oral cavity beside the frenulum of the tongue
Submucosa
beneath the mucosa; a think CT layer; contains nerves, blood vessels, lymphatic vessels, and small glands; parasympathetic
Esophagus
between the pharynx and the stomach; differs by having skeletal muscles in the upper part and smooth muscle at the bottom part
Bile contains what?
bile salts, bile pigments, cholesterol, lipids, lipid-soluable hormones, and lecithin.
Acinar Glands
branching glands with clusters of acini; produce think and thin serous secretions
Pancreatic Lipases
breaks down lipids into monoglycerides and free fatty acids;
Salivary Amylase
breaks the covalent bonds between glucose molecules in starch and other polysaccharides to produce the disaccharides maltose and isomaltose
Pepsinogen
chief cells with in gastric glands secrete this; it is packed into zygomen granules, which are released by exocytosis when it is stimulated
Proteins synthesized in the epithelial cells attach to droplets of triglycerides, phospholipids, and cholesterol. What are these aggregates called
chylomicrons
Pancreatic Amylase
continues the polysaccharide digestion initiated in the oral cavity
Peristaltic waves
contractions of relaxation of the circular muscles in front of the bolus followed by a wave of strong contractions of the circular muscles behind the bolus
Mass Movements
contractions that move material in distal parts of the large intestine to the anus
Mixing
contractions that move the food back and fourth within the digestive tract to mix it with secretions and help break it into smaller pieces
Endocrine cells in the small intestine are also known as what?
crypts of Leiberkuhn
Trypsin
digests proteins; cleave at arginine and lysine amino acids; activates trysinogen
Chymotrypsin
digests proteins; cleaves at the hydrophobic amino acids; secreted in an inactive form
Bile Salts
emulsify lipids, which is necessary for subsequent digestion by lipase; increase bile secretion through a positive feed back system; over 90% is reabsorbed in the ileum and carried in the blood by hepatic portal circulation
What part(s) of the digestive tract lack a submucosal plexus?
esophagus and the stomach
Upper GI Tract
esophagus, stomach, duodenum, liver, and gallbladder
What ligament attaches the liver to the anterior abdominal wall?
falciform ligament
Cheeks
form the lateral walls of the oral cavity and they include the buccinator muscle; merge anteriorly with the lips
Surface Mucous cells
found on the surface of the gastric pit; protects stomach wall; they produce alkaline mucous
Adventitia
fourth layer of the digestive tract; outer layer of the digestive tract that is from adjacent CT and blends; example are the Esophagus and the Retroperitoneal organs
Serosa
fourth layer of the digestive tract; protrude into the peritoneal cavity (visceral peritoneum).
The flow of Bile
from the gallbladder through the cystic duct into the common bile duct or it can flow back up the cystic duct into the gallbladder
What is the opening from the esophagus to the stomach called?
gastro esophageal opening AKA Cardiac opening
The mucosa of the colon has many of what type of cells?
goblet cells scattered along the length and numerous crypts lined with the goblet cells
What cells remain at the bottom of the glands in the small intestine?
granular cells and endocrine cells
Inner Oblique
helps generate strong contractions that physically break down food into smaller particles
An enlargement where the hepatic and pancreatic ducts come together?
hepatopancreatic ampulla
Peptidases
hydrolyze the peptide bonds between small amino acid chains
The mucosa of the ____________ is equipped with abundant, pea-sized or larger ____________ that help to protect it from encroaching bacteria.
ilieum; Peyer's Patches
Where is vitamin K bacteria housed?
in the large intestine
Ingestion
intake of solid or liquid food into the stomach; route of ingestion is through the oral cavity
Hepatic Portal Vein
is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver and it also filters toxins
Hepatic Artery
is a short blood vessel that supplies oxygenated blood to the liver, pylorus of the stomach, duodenum and pancreas. It arises from the celiac artery.
Chyme
juice; semifluid material; primary function of the stomach is to store this
In the adult, the only remnants of the embryonic ventral mesentery are the what?
lesser omentum and falciform ligament
Which ligament of the liver is the remnant of the fetal umbilical vein?
ligamentum teres
Chylomicrons
made up of 99% lipid and 1% protein; leave epithelial cells and enter the lacteals of the lymphatic system within the villi; enter lymphatic capillaries; travel throughout the lymphatic system via the thoracic duct to the blood stream and then to adipose tissue.
Submucosal plexus
meissner plexus; contains axons, many scattered neuron cell bodies, and glial cells; axons extend in epithelial intestinal glands, stimulating their secretion
Propulsion
movement of food from one end of the digestive tract to another
Mucous Neck Cells
near the openings of the glands and produce mucous; located in the gastric glands
Teeth in Each Quadrant
one central and one lateral incisor one canine first and second premolars first, second, and third molars
Hydrochloric Acid
one of its main functions is to kill bacteria; produces the low pH of the stomach's contents, which is normal between 1 and 3
What are the three layers of the muscularis of the stomach?
outer longitudinal layer, circular layer, and inner oblique layer
Acetylcholine increases the secretory activity of what cells?
parietal cells and the chief cells and also stimulates the secretion of gastrin and histamine in endocrine cells
Pancreatic Islet of Langerhan: Alpha Cells
produce Glucagon, and make up 15-20% of total islet cells.
Enterochromaffin-Like Cells
produce histamine which stimulates acid secretion by parietal cells
Parietal Cells
produce hydrochloric acid and intrinsic factor (glycoprotein that binds with B12); glands of the pylorus region
Pancreatic Islet of Langerhan: Beta Cells
produce insulin and amylin, and make up 65-80% of the total islet cells.
Endocrine Cells
produce regulatory hormones and paracrine factor
Pancreatic Islet of Langerhan:
produce somatostatin, and make up 3-10% of the total islet cells.
Chief Cells
produce the enzyme pepsinogen
Cholecystokinin
produced in the duodenum; stimulates fatty acids and peptides; causes the contraction of the gallbladder and relaxation of the hepatopancreatic ampullar sphincter to release bile into the duodenum
Secretin
produced in the duodenum; stimulates the acidity of chyme; decreases gastric secretions and motility from the parietal cells in the stomach; can also stimulate bile production in the liver
G-Cells
production of gastrin
Peristalsis
propels food through most of the digestive tract using peristaltic waves
What are the lobes of the the liver?
right, left, caudate, and quadrate
Tenaie Coli
run the length of the colon and the contractions cause pouches called haustra, to form along the colon.
Mucus
secreted along the digestive tract, which lubricates the food and the lining of the stomach to protect the epithelial cells from mechanical abrasion, stomach acid, and enzymes
Where are bile salts secreted and then stored?
secreted by the liver and then stored in the gallbladder until needed in the duodenum
Periodontal Ligaments
secure teeth in the alveoli
Lower GI Tract
small intestine, large intestine, and anus and contain accessory organs like the liver and pancreas
Sublingual Glands
smallest of the three glands; mixed with some serous acini, but primarily containing mucous acini; do not have single well defined ducts
Fundus
superior to the cardiac opening; where food is mixed with gastric juice
Palate
superior; separates the oral and nasal cavities
The production of acid and enzymes by the gastric mucosa can be controlled by what?
sympathetic innervation, parasympathetic innervation, and hormones from the mucosa its self
The cystic duct from the gallbladder joins what?
the common hepatic duct to form the common bile duct which then joins the pancreatic duct at the hepatopancreatic ampulla
What ligament holds the liver to the diaphragm?
the coronary ligament
What CT tissue septum separates the right and left lobes of the liver?
the falciform ligament
The hydrophobic ends of the bold salts are directed towards what?
the free fatty acids, cholesterol, and monogylcerides at the center of the micelle
Where does most nutrient absorption occur?
the jejunum
Parotid Gland
the largest of the glands; serous; produce watery saliva and are anterior to the each or each side of the head
What plexus is between the two layers of the stomach?
the myenteris plexus (controls motility of the intestinal tract)
When a dentist performs a root canal, what is removed?
the pulp is removed
What is the outer most layer of the stomach?
the serosa AKA the visceral peritoneum
How are the proteolytic enzymes in the pancreas activated?
they are activated by proteolytic removal of certain peptidases from the precursor protein
Pharynx
throat with the tonsils as the accessory organs
Oral Cavity
tongue, teeth, lips, cheeks, salivary glands, and palate
Hepatic Ducts
transports bile out of the liver; one on each side of the liver and join to form the common hepatic duct (the upper part of the small intestine).
What are the pancreas's major proteolytic enzymes?
trypsin, chymotrypsin, and carboxypeptidase.
