Digestive System
Identify the structures that chyme will pass through, starting with the small intestine and ending with elimination.
1. Ileocecal junction 2. Cecum 3. Colon 4. Rectum 5. Anal canal
Place the events of the cephalic phase of gastric regulation in order beginning from initiation of the cephalic phase.
1. Taste or smell of food 2. Stimulation of medulla oblongata 3. Parasympathetic impulses carried by vagus nerve to neurons of enteric plexus. 4. Postganglionic neurons stimulate secretion of gastrin and histamine. 5. Gastric secretions are released.
The muscularis of the stomach consists of ______ layers.
3
The hepatic lobule is a _____ -sided structure with a(n) _____ triad at each corner and a central vein located in the center of each lobule
6, portal
Describe a hepatic lobule.
A hexagon-shaped tissue with a portal triad at each corner
Describe the cecum.
A rounded pouch located at the proximal end of the large intestine
Pepsinogen
Active form aids in breaking proteins into smaller peptide chains.
Digestion
Breakdown of large organic molecules into their component parts
Identify the substances that aid in the chemical digestion of proteins.
Carboxypeptidase Pepsin Trypsin Peptidases
Submucosa
Consists of a thick layer of connective tissue containing nerves, blood vessels, lymphatics and glands
Serosa
Consists of a thin layer of connective tissue and simple squamous epithelium
Mucosa
Consists of an epithelial lining, a layer of connective tissue referred to as lamina propria and a thin layer of muscle
Pyloric sphincter
Controls passage of food from stomach to small intestine
Hydrochloric acid
Destroys ingested bacteria and activates pepsin
Identify the secretions of the small intestine.
Disaccharidases Mucus Secretin Cholecystokinin Peptidases
Identify the components of pancreatic juice
Enzymes to digest nucleic acids Enzymes to digest proteins Enzymes to digest carbohydrates Enzymes to digest lipids Bicarbonate ions
Identify the functions of hydrochloric acid in the stomach.
Inactivates salivary amylase Activates pepsin Destroys ingested bacteria
Identify the functions of the liver.
Interconversion of nutrients Storage of glycogen, lipids, vitamins and minerals Phagocytosis Synthesis of new molecules Production of bile
What is the function of HCO3- when it is secreted by the large intestine?
It increases the pH of the feces, which are acidic because of bacterial secretions.
Identify the organs of the digestive system that are considered accessory organs.
Liver Gall bladder Pancreas Salivary glands
Identify the structures of the digestive tract that are lined with stratified squamous epithelium.
Mouth Anal canal Esophagus Oropharynx
Propulsion
Movement of food from one end of the digestive tract to the other
Absorption
Movement of molecules from the digestive tract into the circulation or lymphatic system
Secretions of the stomach
Pepsinogen Gastrin Hydrochloric acid Mucus Intrinsic factor
Mastication
Process by which teeth break food into smaller particles to increase the total surface area
Identify the functions of mucus secretion in the large intestine.
Protects intestinal lining Helps fecal matter stick together Lubricates colon wall
Identify the effects of aging on the digestive system.
Reduction in motility Thinning of tooth enamel Decrease in mucus production
Stimulation of pancreatic juice
Secretin Vagus nerve Cholecystokinin
Name the outermost or most superficial layer of the organs in the digestive tract
Serosa Adventitia
Gastrin
Stimulates gastric secretions
Identify the structures of the digestive tract that are lined with simple columnar epithelium.
Stomach Large intestines Small intestines
True or false: Both nervous and chemical mechanisms play an important role in regulating the digestive system.
TRUE The movement, secretion, absorption and elimination of food is determined by both nervous and chemical mechanisms.
True or False: Villi and microvilli of the small intestine serve to increase surface area to allow for greater digestion and absorption.
TRUE villi and microvilli always increase surface area
Ingestion
The intake of solid or liquid food into the stomach
How does the muscularis of the stomach differ from the muscularis of the majority of the alimentary canal?
The stomach has 3 layers of muscle in the muscularis and the majority of the digestive tract only has 2 layers of muscle.
Muscularis
Throughout most of the digestive tract, this tunic consists of two layers of smooth muscle: an inner circular layer, and an outer longitudinal layer
The salivary glands, tonsils, liver, gall bladder, and pancreas are _________ _________ of the digestive system
accessory organs
Identify the major neurotransmitters that regulate the digestive system.
acetylcholine norepinephrine serotonin
The majority of ion absorption occurs as a result of _____.
active transport
Intrinsic factor
aids in the absorption of vitamin B12
Largest part of stomach
body
The large intestine consists of the _____, and the anal canal.
cecum, colon, rectum
The taste, smell, or thought of food stimulates gastric secretions by activating the ______ phase of gastric regulation.
cephalic
nuclease
chemical digestion of DNA and RNA
lipase
chemical digestion of fats
amylase
chemical digestion of polysaccharides
proteolytic enzymes
chemical digestion of proteins
The semi-fluid material within the stomach that is a mixture of ingested food and gastric secretions is called
chyme
The submucosa consists of ______ tissue.
connective
Identify the duct leading from the gallbladder.
cystic duct
Feces are eliminated from the body by the process of
defecation or elimination
The tongue, oropharynx and mouth are all involved with swallowing or
deglutition
Place the segments of the small intestine in the order of which food travels.
duodenum Jejunum ileum
The process by which bile salts transform large lipid droplets into much smaller lipid droplets is called
emulsification
The majority of nervous stimulation of the digestive system comes from the _______.
enteric nervous system
The ____________ sphincter is between the esophagus and the stomach and the _____________ sphincter is between the stomach and the small intestine.
esophageal/cardiac, pyloric
The structure within the mediastinum, anterior to the vertebrae and posterior to the trachea is the
esophagus
During stomach filling the rugae _______.
flatten and allow the stomach to increase in volume
Rounded superior portion of stomach
fundus
The saclike structure on the inferior surface of the liver is the
gallbladder
Identify the parts of the pharynx that function in digestion
laryngopharynx oropharynx
The largest internal organ of the body is the
liver
Identify the strong and infrequent peristaltic contractions that move contents longer distances within the large intestine.
mass movements
The esophagus is in the ______.
mediastinum
The movements of the small intestine include segmental contractions which ______ intestinal contents and peristaltic contractions which ______ intestinal contents.
mix, propel
Identify the primary products of the chemical digestion of lipids.
monoglycerides fatty acids
Chemical digestion of starch due to secretion of enzymes occurs in the ______.
mouth small intestine
Identify the part of the pharynx that does not typically function in digestion.
nasopharynx
Select the mechanisms that regulate the digestive system.
nervous mechanisms chemical signals
Acetylcholine, norepinephrine and serotonin are ______ that affect digestive tract ______.
neurotransmitters; motility
Cardiac sphincter
opening from the esophagus to the stomach
Identify the structures that are involved in deglutition.
oropharynx tongue esophagus
Identify the organ that consists of a head located within the curvature of the duodenum and a tail that extends to the spleen
pancreas
Lipases are secreted by
pancreas
The majority of lipase is secreted by the _____.
pancreas
Identify the structures that secrete lipase
pancreas lingual glands
Identify the types of movements that occur within the small intestine.
peristalic contractions segmental contractions
Mucous
protects stomach lining
Funnel shaped part of stomach
pyloric part
The adventitia or ____________ is the outermost layer of structures in the digestive system.
serosa
The abdominal cavity is lined by ______________ which produce a thin, lubricating film.
serous membranes
Secretin, cholecystokinin, and peptidases are secretions of the ______.
small intestine
The majority of lipid digestion occurs in the ______.
small intestine
The chemical digestion of the disaccharides occurs in the ______.
small intestine Reason: Starch is broken down into disaccharides in the mouth, but the chemical digestion of disaccharides does NOT occur until the disaccharides reach the small intestine.
Cholecystokinin, secretin and the vagus nerve all ______ the release of pancreatic juices.
stimulate
Identify the organ of the digestive system that primarily functions as a storage and mixing chamber.
stomach
Intrinsic factor is secreted by the organ called the
stomach
Identify the structures where lipid digestion occurs.
stomach small intestine
The layer of the digestive tract that consists of connective tissue containing nerves, blood vessels, lymphatic vessels, small glands, and a network of nerve cells is the
submucosa
Bicarbonate ion
to raise pH of small intestine
True or False: Throughout the digestive tract, the muscularis consists of 2 layers of muscles, except the stomach, which has 3 layers.
true
True or False: Water absorption in the small intestine occurs as a result of osmosis.
true
Identify the features of the small intestine that function to increase surface area and thus enhance digestion and absorption.
villi microvilli circular folds