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.