Chapter 24 - The Digestive System Flashcards
The digestive system consists of what two things?
The gastrointestinal (GI) & accessory digestive organs
The GI tract portion of the digestive system is a continuous tube that includes? (6)
Mouth, pharynx, esophagus, stomach, small intestine, large intestine
The accessory organs of the digestive system include? (6)
Teeth, tongue, salivary glands, liver, gallbladder, pancreas
Name the basic processes of the digestive system? (6)
Ingestion, secretion, mixing and propulsion, digestion, absorption, defecation
Involved in eating; is the taking of foods and liquids into the mouth
Ingestion
Is the release of water, acids, enzymes, etc into the digestive tract
Secretion
Churning and movement of food through the GI tract
mixing and propulsion
The mechanical and chemical breakdown of food
Digestion
Passage of digested products from the GI tract into the blood and lymph
Absorption
The elimination of feces from the GI tract
Defecation
Made up of wastes, indigestible substances, bacteria, sloughed-off cells
Feces
The wall of the GI tract from the lower esophagus to the anal canal has the same basic 4-layered arrangement of tissues. They are?
Mucosa, submucosa, muscularis, serosa
This is the inner lining of the GI tract?
Mucosa
The mucosa is a mucus membrane that is composed of what 3 things?
Epithelium, lamina propria, muscularis mucosae
What is the epithelium of the mucosa? It is in contact with?
A layer of cells which is in contact with the contents of the GI tract
What is the lamina propria if the mucosa?
A layer of connective tissue
What is the muscularis mucosae of the mucosa?
A thin layer of smooth muscle
The wall of the stomach is composed of?
The same 4 layers as most of the rest of the GI tract with a few differences.
The muscularis in the body of the stomach has how many layers of smooth muscle? As opposed to? The layers are?
3 as opposed to 2 as in the intestines and rest of the stomach / an oblique layer, middle circular layer, outer longitudinal layer
The epithelium of the stomach extends deep down into the mucosa forming channels called?
Gastric pits
Some of the epithelial cells of the stomach secret mucus and are called? The mucus helps to?
Surface mucous cells / protect the stomach from the acidic pH of stomach acid
As the bottom of gastric pits in the stomach, there are these which are composed of secretory cells.
Gastric gland
The gastric glands secret substances into? These substances eventually?
Into the gastric pits. They eventually reach the lumen of the stomach.
The gastric glands contain 4 types of cells. They are?
Mucous neck cells, chief cells, parietal cells, g cells
A type of gastric gland cell that secretes mucus along with the surface mucous cells.
Mucous neck cells
A type of gastric gland cell that secrete pepsinogen and gastric lipase
Chief cells
A type of gastric gland cell that produces intrinsic factor (needed for the absorption of vitamin b12) and hydrochloric acid.
Parietal cells
A type of gastric gland cell that secretes the hormone gastrin into the bloodstream.
G cells
This helps regulate stomach secretions and motility (increases both)
Gastrin
Stomach acid aka?
Gastric juice
This is composed of the secretions of the mucous, parietal, and chief cells
Gastric juice (stomach acid)
How many quarts of gastric juice is secreted each day? What is the pH level?
2-3 quarts / 2 (strongly acidic)
How long does the passage of food from the mouth usually take?
Seconds
Once food enters the stomach, what happens?
Starch digestion by salivary amylase continues for awhile.
After starch digestion y salivary amylase, food becomes mixed with? What happens to the salivary amylase?
Gastric juice and liquified to form chyme and salivary amylase is inactivated.
Hydrochloric acid in the gastric juice kills many microbes in the food and causes?
The conversion of the inactive enzyme pepsinogen into the active version of pepsin.
This digests proteins by breaking bonds between amino acids
Pepsin
This is secreted by chief cells in its inactive form to prevent it from digesting proteins in the cells.
Pepsin
This is secreted by chief cells and digests triglycerides in fat.
Gastric lipase
Not much of this occurs in the stomach? Only for?
Absorption / water, alcohol,certain drugs (aspirin) and a few other substances
After 2-4 hours what has the stomach done?
Emptied contents into the duodenum
A retroperitoneal accessory digestive organ that is about 5-6 inches long and lies posterior to the stomach.
Pancreas
Pancreatic juices passes to the duodenum through what 2 ducts?
Pancreatic duct (duct of Wirsung) and accessory duct (duct of Santorini)
The pancreatic duct generally joins? It then enters the duodenum as a common duct called?
Common bile duct from the liver / hepatopancreatic ampulla (ampulla of Vater)
The accessory duct empties into?
The duodenum about an inch superior to the hepatopancreatic
The pancreas is made up of what two main types of cells?
Acini & Pancreatic islets
99% of the pancreatic cells are of this type. They secrete pancreatic juice
Acini
1% of pancreatic cells are of this type. They are endocrine cells that secrete hormones.
Pancreatic islets (islets of Langerhans)
Ow much pancreatic juice does the pancreas produce each day?
1.2 - 1.5 quarts.
This substance is a clear, colorless liquid composed of water, some salts, sodium bicarbonate, and several enzymes.
Pancreatic juice.
The sodium bicarbonate gives pancreatic juice a pH of about? This buffers gastric juice and stops. What?
7.1 - 8.2 (slightly alkaline) / stops the action of pepsin.
Pancreatic amylase, trypsin, chymotrypsin, carboxypeptidase, pancreatic lipase, ribonuclease, deoxyribonuclease are enzymes found in?
Pancreatic juice
This digests starch
Pancreatic amylase
These pancreatic digestive juice enzymes digest protein. (3)
Trypsin, chymotrypsin, carboxypeptidase
This digest juice enzymes digest triglycerides
Pancreatic lipase
This pancreatic digestive juice enzyme digests RNA
Ribonuclease
This pancreatic digestive juice enzyme digests DNA
Deoxyribonuclease
To prevent them from digesting proteins in the pancreas, these protein digesting enzymes are produced in an inactive form which are? (3)
Trypsinogen, chymotrypsingogen, procarboxypeptidase
This is the inactive form of trypsin
Trypsinogen
This is the inactive form of chymotrypsin
Chymotrypsinogen
This is the inactive form of carboxypeptidase
Procarboxypeptidase
The primary hormones secreted by the pancreas are?
Insulin and glucagon
Insulin is secreted by what cells?
Beta cells
Glucagon is secreted by?
Alpha cells
This raises blood glucose levels?
Glucagon
This lowers blood glucose levels.
Insulin
Low blood glucose levels in a person is termed?
Hypoglycemia
Hypoglycemia stimulate?
The secretion of glucagon
Glucagon targets cells of the? This causes them to convert?
Liver / glycogen into glucose
After glucagon is converted into glucose, the glucose is released into where? This causes?
Into the blood / blood glucose levels to rise
High blood glucose levels
Hyperglycemia
Hyperglycemia inhibits? It stimulates?
The release of glucagon and stimulates the release of insulin.
Insulin acts on? Increasing?
Various body cells increasing the rate at which glucose moves into them.
Most glucose that enters the liver is converted into?
Glycogen
This inhibits the release of both insulin and glucagon.
Somatostatin
Insulin acting on various body cells and glucose entering the liver causes blood glucose levels to?
Decrease
The liver and gallbladder are two accessory digestive organs involved with the secretion of?
Bile
This emulsifies liquids before they are digested.
Bile
The liver is divided into two lobes by the?
Falciform ligament
This suspends the liver in the abdominal cavity?
Falciform ligament
The lobes of the liver are made up of?
Lobules
Liver cells within the lobules that secrete bile
Hepatocytes
The bile leaves the lobules of the liver through small ducts that eventually merge to form these which exit the right and left lobes.
Right and left hepatic ducts
The right and left hepatic ducts united and exit the liver as?
Common hepatic duct
The common hepatic duct joins this duct from the gallbladder? The form?
Cystic duct / common bile duct
The main function of the gallbladder is?
To store and concentrate bile produced by the liver until it is needed by the small intestine.
The wall of the gallbladder consists of what kind of muscle? It contracts and causes?
Smooth / the ejection of stored bile into the cystic duct
Hepatocytes secrete how much bile per day?
1 quart
This is a yellow, brownish, or olive-green liquid?
Bile
Bile has a pH of? It consists mostly of? (6)
7.6 - 8.6 / water, bile salts, cholesterol, lecithin, bile pigments and several ions
The main bile pigment is?
Bilirubin
As old red blood cells are phagocytized, what is formed?
Iron, globin (protein), and bilirubin (derived from heme) are formed.
After bilirubin is formed from the phagocytized red blood cells, the bilirubin is secreted into?
Bile and eventually broken down in the small intestine.
One of the products of the breakdown of bilirubin in bile is?
Stercoblin
This gives feces its normal brown color
Stercoblin
These help to emulsify, or breakdown, large lipid molecules so that enzymes such as pancreatic lipase can digest them.
Bile salts
A yellowish coloration of the whites of the eyes and the skin due to a build up of bilirubin
Jaundice
Jaundice can occur when?
The liver does not function properly to eliminate bilirubin
The liver receives blood from these two sources.
Hepatic artery and hepatic portal vein.
The hepatic artery carries what kind of blood?
Oxygenated
The hepatic portal vein carries what kind of blood? It contains?
Deoxygenated blood containing newly absorbed nutrients, drugs, and microbes and toxins from the GI tract.
Branches of the hepatic artery and the hepatic portal vein carry blood into liver?
Sinusoids
Capillaries that carry oxygen, nutrients, and toxic cub stances to hepatocytes
Sinusoids
These carry deoxygenated blood away from the liver
Hepatic veins
the 3 regions of the small intestine
duodenum, jejunum, ileum
The first and shortest region of the small intestine. About 10 inches long.
Duodenum
The second region of the small intestine. About 3 ft long.
Jejunum
The final and longest region of the small intestine. About 6 ft long.
ileum
This is at the junction of the ileum and the large intestine.
ileocecal sphincter
The wall of the small intestine is composed of?
The same 4 layers that make up most of the rest of the digestive tract.
The epithelium of the mucosa in the small intestine contains these cells what 2 cells?
absorptive and goblet cells
cells which absorb nutrients and found in the small intestine
absorptive cells
Cells in the small intestine which secret mucus
goblet cells
The functions of the liver (9)
carbohydrate metabolism, lipid metabolism, protein metabolism, processing of drugs and hormones, excretion of bilirubin, synthesis of bile salts, storage, phagocytosis, activation of vitamin D
What does the carbohydrate metabolism function of the liver do?
helps to maintain a normal blood glucose level.
During this function of the liver, hepatocytes can store triglycerides, break down fatty acids, and synthesize cholesterol.
lipid metabolism
During this function of the liver, the hepatocytes break down amino acids, producing ammonia, which is toxic; ammonia is converted into urea, which is less toxic. Hepatocytes also synthesize most plasma proteins (immunoglobulins, albumin, prothrombin, and fibrinogen)
protein metabolism
During the processing of drugs and hormones in the liver, what is detoxified?
alcohol and drugs
During excretion function of the liver, what is excreted?
bilirubin
Synthesis of bile salts in the liver is used for?
lipid emulsification
What does the liver store?
glycogen and many vitamins and minerals
In the liver, phagocytosis is used for?
removal of old blood cells and bacteria
Most digestion and absorption of nutrients occurs in?
The small intestine
Along with the skin and kidneys, activation of this also happens in the liver.
Vitamin D
This is about 1 inch in diameter and 10 ft long in a living person. It is about 21 ft long after death due to the loss of smooth muscle tone.
The small intestine
These are deep crevices in the mucosa of the small intestine that secrete intestinal juice.
Intestinal glands
What cells are found in the intestinal glands of the small intestine? What else is found in these glands? (2)
Panted cells / secretin & cholecystokinin CCK
These are found in the intestinal glands of the small intestine and secret lysozyme and are capable of phagocytosis of microbes.
Paneth cells
This hormone is secreted by the cells in the intestinal glands of the small intestine and it causes the buffering of the acids in chyme.
Secretin
This hormone is secreted by the cells found in the intestinal glands of the small intestine. It stimulates secretion of pancreatic juice and causes the contraction of the gallbladder
Cholecystokinin
The are found in the mucosa of the small intestine, particularly in the ileum.
Lymphatic nodules
To increase the surface area for absorption, the small intestinal wall has these features.
Circular folds (plicae circulares), villi, microvilli
These are folds of the wall of the small intestine. They cause the chyme to move in a spiral manner as it passes through.
Circular folds (plicae circulares)
These are found in the small intestinal wall and are finger like projections which contain blood and lymphatic (lacteals) into which absorbers nutrients pass.
Villi
These Are found in the small intestinal wall and are plasma membrane extensions of the absorptive cells.
Microvilli
There are 2 types of movements in the small intestine. They are?
Segmentation, peristalsis
A movement of the smooth intestine in which smooth muscles in the wall contract and relax to slosh the chyme back and forth.
Segmentation
A movement of the small intestine in which successive muscle contractions along thewallthat result in movement of the food through the tract.
Peristalsis.
How much intestinal juice is secreted by the small intestine each day?
1-2 quarts
What is the pH of intestinal juice? It is composed of?
7.6 (slightly alkaline) / mucus, water, and digestive enzymes
Name 4 digestive enzymes found in intestinal juice.
Maltase, lactase, sucrase, peptidase
This is a digestive enzyme found in intestinal juices that digests the sugar maltose?
Maltase
This is a digestive enzyme found in intestinal juices that digests the sugar lactose?
Lactase
This is a digestive enzyme found in intestinal juices that digests the sugar sucrose?
Sucrase
This is a digestive enzyme found in intestinal juices that digests proteins?
Peptidase
Passage of digested nutrients from the GI tract into the blood or lymph is called?
Absorption
The absorptive cells of the epithelium of the small intestine absorb?
Nutrients
Carbohydrates are absorbed as? They pass into?
Monosaccharides / capillaries of the villi
Proteins are absorbed as? They pass into?
Amino acids / into the capillaries of the villi
The villi capillaries of the small intestine lead to?
The hepatic portal vein
This carries nutrients to the liver before they reach general circulation.
The hepatic portal vein
Lipids are absorbed in the small intestine as?
Monoglycerides and fatty acids
These are tiny spheres of bile salts that help transport lipids within the chyme in the small intestine.
Micelles
Instead of passing directly into the bloodstream, lipids pass into?
The lacteals of the villi and then into lymphatic vessels
These are large proteins spheres that help transport lipids within lymphatic vessels
Chylomicrons
This is about 5 ft long and 2.5 inches in diameter
The large intestine
This is a small pouch at the beginning of the large intestine.
The cecum
This is attached to the cecum
The appendix
This is the long, tubular part of the large intestine.
The colon
Name the 4 regions of the colon.
Ascending colon, transverse colon, descending colon, sigmoid colon.
This part of the colon is located on the right side of the abdomen.
The ascending colon.
Tis part of the colon runs horizontally across the abdomen
Transverse colon
This part of the colon is located on the left side of the abdomen
The descending colon
This is the s-shaped part of the colon that is located between the descending colon and the rectum.
Sigmoid colon
This is the last portion of the GI tract.
The rectum
The last inch of the rectum is called?
The anal canal
The anal canal opens exterior at the?
Anus
This is composed of smooth muscle and is located nearest the anal canal
The internal anal sphincter
Is the internal anal sphincter voluntary or involuntary?
Involuntary
This is composed of skeletal muscle and is located outside the internal anal sphincter.
The eternal anal sphincter
Is the external anal sphincter voluntary or involuntary?
Voluntary
The wall of the large intestine is somewhat similar to that of?
The small intestine.
The wall of the large intestine does not contain?
Circular folds of villi
This has the same 4 layers, epithelial, absorptive and goblet cells, intestinal glands, and lymphatic nodules as the GI tract?
The large intestine.
These are longitudinal bands that run most of the length of the large intestine.
Teniae coli
The teniae coli gather the walls of the large intestine into a series of pouches called? This is what gives the colon its puckered appearance.
Haustra
Movement of chyme through the large intestine occurs by peristalsis and?
Haustral churning
Are digestive enzymes secreted by the large intestine?
No
In the large intestine, what is secreted and whatbreaks down the remaining nutrients?
Mucus / bacteria
Bacteria breaking down the remaining nutrients in the large intestine allows for?
The absorption of vitamin K an some B vitamins
What other 3 things does the large intestine absorb?
Water, ions, and vitamins
Chyme is changed into this which is secreted from the body.
Feces
This in the mouth, pharynx, esophagus, and anal canal serves primarily as a protective lining of the GI tract.
Epithelium
The stomach and intestines are line with this which is specialized for secretion and absorption
Epithelium
How often are epithelium cells sloughed off and replaced by new cells?
Every 5-7 days
The lamina propria is a connective tissue found in the GI tract that contains?
Many blood and lymphatic vessels
The lamina propria of the GI tract supports and binds?
The epithelium and binds it to the muscularis mucosae
The lamina propria of the GI tract contains this which protects against diseases.
Lymphatic tissue (nodules)
The muscularis mucosa of the mucosa within the GI tract has numerous? What are these designed to do?
Folds designed to increase the surface area of the mucus membrane for digestion and absorption
This is a connective tissue layered of the GI tract that binds the mucosa to the muscularis.
Sub mucosa
The sub mucosa contains?
Many blood and lymphatic vessels
The sub mucosa also contains this which is a network of neurons involved in control of secretions within the digestive tract
Submucosal plexus
The submucosa may contain?
Glands and lymphatic tissue
The muscularis of the mouth, pharynx, and middle to upper parts of the esophagus contain? This allows for?
Skeletal muscle / voluntary swallowing
This is composed of skeletal muscle to allow for voluntary control of defecation.
External anal sphincter
The parts of the GI tract not included in the mouth, pharynx, and parts of the upper and lower esophagus consists of this that is generally found in 2 sheets.
Smooth muscle
This is the inner layer of smooth muscle found in the muscularis.
Circular muscle
This is the outer layer of smooth muscle found in the muscularis
Longitudinal muscle
This is a network of neurons found between the layers of smooth muscle in the muscularis; this is involved in motility (movement) within the digestive tract.
Myenteric plexus
The portions of the GI tract that are suspended in the abdominopelvic cavity have a superficial layer called?
Serosa
The serosa is composed of?
Epithelial and connective tissue
This consists of a layer of epithelial and an underlying layer of connective issue.
Peritoneum
The peritoneum is divided in what 2 parts? They are separated by?
Parietal & visceral peritoneum / peritoneal cavity
What does the peritoneal cavity contain?
Peritoneal fluid
The part of the peritoneum that lines the wall of the abdominopelvic cavity.
The parietal peritoneum
This part of the peritoneum covers some of the organs in this cavity and is their serosa.
Visceral peritoneum
Name the 5 folds of the peritoneum
Greater momentum, falciform ligament, lesser momentum, mesentery, mesocolon
Tissue is a fatty apron that drapes over the intestines
Greater omentum
The greater omentum varies in?
The amt of adipose tissue it contains.
This is the “beer belly” in some individuals
Greater omentum
The lesser omentum contains these to help fight infection in the digestive tract.
Lymph nodes
This part of the peritoneum suspends the stomach and first part of the small intestine from the liver
Lesser omentum
The lesser omentum also contains these to help fight infection in the GI tract
Lymph nodes
This part of the peritoneum binds the intestines to the posterior abdominal wall
Mesentery and mesocolon
The mesentery and mesocolon contain? (3)
Blood, lymphatic vessels, and lymph nodes.
This part of the peritoneum attaches the liver to the anterior part of the abdominal wall and diaphragm
Falciform ligament
The mouth is also called? Aka?
Oral cavity or buccaneer cavity
The oral cavity is formed by the? (4)
Cheeks, tongue, hard palate, soft palate
This is the anterior portion of the roof of the mouth. It is formed by the maxillae and palatine bones and separates the nasal cavity from the oral cavity.
Hard palate
This forms the posterior portion of the roof of the mouth and is primary muscle.
Soft palate.
This, along with the soft palate, close off the nasopharynx during swallowing.
Uvula
This is the opening between the oral cavity and the oropharynx
Fauces
These release saliva into the oral cavity.
Salivary glands
This helps keep the mucus membrane lining of the mouth and pharynx moist and help to cleanse the mouth and teeth.
Saliva
What 4 things happen when food enters the mouth?
Secretion of saliva increases, it lubricates, dissolves, and begins the chemical breakdown of food.
Name the 3 major salivary glands
Parotid, submandibular, sublingual glands
These salivary glands are located in the cheek near the ears
Parotid glands
These salivary glands are located in the floor of the mouth near the mandible
Submandibular glands
These salivary glands are located beneath the tongue and superior to the submandibular glands
Sublingual glands
Is saliva acidic or non acidic? What is its pH?
Slightly acidic (pH 6.35 - 6.85)
What makes up saliva?
99.5% water and 0.5% splinted
What are the 0.5% solutes that make up saliva? (7)
Ions, mucus, lgA, the enzymes lysozyme and salivary amylase, and the wastes urea and uric acid
What enzyme kills some bacteria within the mouth?
Lysozyme
Salivary amylase acts on?
Starch
what is the secretion of saliva called?
salivation
salivation is controlled by?
the autonomic nervous system (parasympathetic stimulation)
how much saliva is secreted each day?
1-1.5 liters
what two things can cause salivation?
the chemicals in food and the smell, sight, or thought of food.
this is a speciic viral infection of the salivary glands usually the parotid gland.
mumps
This is an accessory digestive organ composed of skeletal muscle covered with mucous membrane.
Tongue
This form the floor of the oral cavity and is attached to the hyoid bone, the styloid process of the temporal bone, and the mandible.
The tongue
The tongue helps maneuver food for chewing and shape it into a rounded mass called?
A bolus
The tongue is also involved in?
speech and swallowing
This is a fold of mucous membrane underneath the tongue which attaches it to the floor of the mouth and limits its movement posteriorly.
lingual frenulum
The upper and lateral surfaces of the tongue are covered with? Many of these contain taste buds which are the receptors for?
papillae / gustation (taste)
These are accessory digestive organs anchoroed (by ligaments) in the sockets of the alveolar processes of the mandible and maxillae.
teeth
These cover the alveolar processes (teeth)
gingivae (gums)
The teeth are composed of this internally and this externally? Both of these substances are harder than bone because?
dentin & enamel / because of their higher content of calcium mineral salts
What two sets of teeth do humans have in their lifetime? How many of each?
deciduous (baby) - 20 and permanent - 32
Where does digestion begin?
The mouth
This type of digestion results from mastication, or chewing, and a bolus is formed.
Mechanical digestion
During this type of digestion, the water in saliva dissolves the food somewhat so enzymes can react with it during?
chemical digestion
Salivary amylase begins the breakdown of this into smaller molecules
starch
Starch is a?
polysaccharide
This is a muscular tube that extends from behind the nasal cavity to the esophagus and larynx
pharynx
Name the order of the passage of food (4)
mouth, oropharynx, laryngopharynx, esophagus
This is a muscular tube that extends from the interior laryngopharynx to the stomach.
esophagus
The esophagus pierces the diaphragm through an opening called?
the esophageal hiatus
This is composed of skeletal muscle and regulates the movement of food from the pharynx into the esophagus.
The upper esophageal sphincter
This is composed of smooth muscle and regulates the movement of food from the esophagus into the stomach.
lower esophageal sphincter
What does the esophagus secrete?
mucus
The esophagus transport food into?
The stomach
The esophagus does not produce any of this? It does not carry out what function?
digestive enzymes / absorption
This is the act of swallowing
deglutition
Where is the deglutition center contained?
the medulla oblongata
name the 3 stages of swallowing
voluntary, pharyngeal, and esophageal stage
During this stage of swallowing, the bolus passes from the mouth into the oropharynx.
Voluntary stage.
Is the voluntary stage of swallowing involuntary or voluntary?
voluntary
During this stage of swallowing, the bolus passes through the pharynx to the esophagus.
Pharyngeal stage
Is the pharyngeal stage of swallowing involuntary or voluntary?
involuntary
During this stage of swallowing, the bolus moves to the stomach by peristalsis.
Esophageal stage
Is the esophageal stage voluntary or involuntary?
involuntary
This is the successive muscular contractions in the walls of the esophagus
peristalsis
This is a j-shaped enlargement of the digestive tract
the stomach
this is located on the left side of the abdomen beneath the diaphragm
the stomach
what connects the esophagus to the small intestine?
the stomach
This mixes the food and holds it temporarily until the small intestine is ready to receive it.
The stomach
Digestion of this continues in the stomach? Digestion of what beings?
starch / proteins and triglycerides
In the stomach, the semisolid bolus is converted into? What is absorbed?
Chyme / various substances.
Name the 4 regions of the stomach.
Cardia, Fundus, Body, Pylorus
this part of the stomach surrounds the opening into the stomach from the esophagus
cardia
this is the rounded superior portion of the stomach
fundus
this is the large central portion of the stomach
body
This part of the stomach connects to the duodenum of the small intestine
pylorus
The first part of the small intestine
duodenum
These are folds of the mucosa layer of the stomach
rugae
This part of the stomach is a ring of smooth muscle between the pylorus and the duodenum of the small intestine
pyloric sphincter
The stomach normally remains closed, but allows small amounts of partially digested food into the duodenum, a little at a time, during a process called?
gastric emptying
