Digestive System Flashcards
The __________ system is the conduit
for delivery and removal of what is
necessary to support cells and tissues of
the body
cardiovascular
A ________ is a double sheet of peritoneal
membrane; the peritoneal membrane lines
the abdominal cavity. Mesenteries stabilize
the position of organs attached to the
abdominal wall and prevent tangling of
intestines during movement of the tract or
sudden changes in body position.
mesentery
What does the mesentery consist of
Mesothelium, areolar tissue, mesothelium
What are the major layers of the digestive tract
Mucosa, submucosa, muscularis Externa, serosa
Mucosa
epithelial lining and underlying connective tissue
Submucosa
connective tissue containing blood vessels and
glands
Muscularis externa
smooth muscle in two layers – inner circular
layer and outer longitudinal layer
Serosa/adventitia
the serosa is a peritoneal membrane covering;
it is not present in oral cavity, pharynx, esophagus and rectum – instead they have an adventitia
The ________ is especially constructed to
facilitate absorption of nutrients from the
lumen of the tract
mucosa
The _________ in the upper part of the tract
(oral cavity, pharynx and esophagus) is
stratified squamous where the rest of the
tract is simple columnar
epithelium
_________ and ________ increase
surface area for absorption
Circular folds, intestinal villi
__________ in the mucosa and
submucosa produce secretions that are
carried through ducts to epithelial surfaces.
Secretory glands
The ___________ has smooth muscle
within it that change the shape of the lumen
and move the circular folds and villi.
muscularis mucosa
What are the 2 secretory glands of the digestive tract?
Mucosal gland, submucosal gland
What are the 4 components of the mucosa
Epithelial layer, Villi, lamina propia, muscularis mucosae
Describe the movement of food through the digestive tract
1) Bolus of food arrives in the digestive system
2) Circular muscles contract behind bolus
3) Longitudinal muscles ahead of bolus contract
4) Contraction in circular muscle layer forces bolus forward.
\_\_\_\_\_\_\_\_ is the process of smooth muscle contraction by which materials are moved from one portion of the digestive tract to another. Longitudinally oriented smooth muscle contracts and shortens the segment of gut ahead of the food bolus, then circularly-oriented smooth muscle contracts to push it forward
Peristalsis
________ is the process of smooth muscle contraction by which materials are churned and fragmented, mixing the contents of the tract with secretions. These muscle contractions don’t happen in any set pattern so contents are not propelled in any particular direction
Segmentation
All movements of the gut are under the control of three primary mechanisms:
• Autonomic nervous system • Hormones produced by the digestive tract itself • Local factors such as changes in pH, mechanical distortion of the gut wall, or chemical signals released from the mucosa and/or specific nutrients
What are the major organs of the digestive tract?
Oral cavity(mouth), Pharynx, Esophagus, Stomach, Small/Large Intestine
What are the accessory organs of the digestive tract
Teeth, tongue, salivary glands, liver, gallbladder, pancreas
What is the function of the oral cavity for digestive purposes?
Mechanical processing with accessory organs (teeth and tongue), moistening, mixing with salivary secretions
What is the function of the pharynx for digestive purposes?
Muscular propulsion of materials into the esophagus
What is the function of the esophagus for digestive purposes?
transport of materials to the stomach
What is the function of the stomach for digestive purposes?
Chemical breakdown of materials by acid and enzymes; mechanical processing through muscular contractions
What is the function of the small intestine for digestive purposes?
Enzymatic digestion and absorption of water, organic substrates, vitamins, and ions
What is the function of the large intestine for digestive purposes?
Dehydration and compaction of indigestible materials in preparation for elimination
What are the functions of the digestive tract?
Ingestion, digestion, absorption.
What is the compact material created from digestion?
feces
The discharge of feces from the body is called what
defecation
What makes up the superior boundary of the oral cavity?
Hard and soft palate
What makes up the posterior boundary of the oral cavity?
uvula, palatine tonsil, root of the tongue, pair of lingual tonsils
What makes up the anterior and lateral boundary of the oral cavity?
Labia, cheeks
What makes up the inferior boundary of the oral cavity?
Floor of the mouth inferior to the tongue
______ is the matrix of the tooth, similar in construction to the matrix of bone
Dentin
The _____ of the tooth projects into the oral cavity from the surface of the gums
Crown
The _____ of each tooth sits in a bony cavity called an alveolus, or tooth socket
root
What is the hardest biologically manufactured substance
Enamel, it contains calcium phosphate in a crystal line form
What are the 4 types of teeth
Incisors, cuspids, bicuspids, molars
Incisors
blade-shaped teeth located at the front of the mouth. They are useful for clipping or cutting. Have a single root.
Cuspids
or canine teeth, are conical with a sharp ridgeline and a pointed tip. They are used for tearing or slashing. Cuspids have a single root
Bicuspids
or premolars, have flattened crowns with prominent ridges. They crush, mash, and grind. Bicuspids have one or two roots.
Molars
have very large, flattened crowns with prominent ridges adapted for crushing and grinding. Molars in the upper jaw typically have 3 roots, while those in the lower jaw usually have 2 roots.
The alveolar processes of the maxillae and the mandible form the ________
dental arcades
What is the correct name for baby teeth
deciduous teeth
Deciduous teeth or “baby teeth” are teeth of ________ ________ By the time children are 2 years old, they have 20 deciduous teeth.
primary dentition
Permanent teeth replace deciduous teeth and are considered _______________
Secondary dentition
Additional molars are included in the secondary dentition and the number of permanent teeth is brought to
32
The _______ is the space common to both the respiratory and digestive tracts. It is divided into three regions based on its association with portions of either the respiratory or digestive tract
pharynx
The ________ is a muscular tube extending from the pharynx to the stomach. It contains the layers in its wall typical of portions of the digestive tract, including the mucosa, submucosa, muscularis externa and adventitia. The esophagus passes through the diaphragm as it moves from the thoracic cavity into the abdominal cavity
esophagus
Another term for swallowing
deglutition
What are 3 phases of swallowing
- Buccal phase – a voluntary phase in which a bolus of food is moved into the oropharynx by movement of the tongue
- Pharyngeal phase – contraction of pharyngeal constrictors move the bolus through the pharynx
- Esophageal phase – in the esophagus, the bolus is moved toward the stomach by peristalsis
What is the function of the lesser omentum
Stabilizes the position of the stomach and provides an access route for blood vessels and other structures entering or leaving the liver.
What is the function of the greater omentum
forms an enormous pouch that extends inferiorly between the body wall and the anterior surface of the small intestine.
The _______ _______ is lined by the parietal peritoneum, which lines the inner abdominal wall, and the visceral peritoneum, which covers the organs
peritoneal cavity
The relationship of the organs to the ________ ________ are similar to that of the heart in the pericardial cavity and the lungs in the pleural cavities.
peritoneal cavity
What is the fundus?
portion of the stomach that is superior to the junction between the stomach and the esophagus. The fundus contacts the inferior, posterior surfaces of the diaphragm.
What is the cardia?
Cardia is the superior, medial portion of the stomach within 3 cm of the junction between the stomach and the esophagus
What is the pylorus
The pylorus forms the sharp curve of the J. As mixing movements occur during digestion, the pylorus frequently changes shape
What are rugae?
Prominent but temporary mucosal folds that allow the gastric lumen to expand
What are the functions of the stomach
- store and mechanically break down ingested food
- chemically breakdown food through the action of acid and enzymes
- produce intrinsic factor, a molecule necessary for the proper absorption and handling of vitamin B12, which is required for red blood cell production
What are the 3 segments of the small intestine?
Duodenum, jejunum, ileum
What is the duodenum?
Segment closest to the stomach. This portion of the small intestine is the “mixing bowl”.
What is the jejunum?
The segment between the duodenum and the ileum and is marked by a sharp bend at its beginning
What is the ileum?
The final segment of the small intestine, also the longest, averaging 11.5 feet in length. It ends at the ileocecal valve.
Where does 90% of nutrient absorption occur?
small intestine
What are the functions of the large intestine?
- absorbs water and compacts intestinal contents into feces
- absorbs vitamins
- stores fecal material prior to defecation
Function of salivary glands?
produce mucous and enzyme secretions
______ stores and concentrates bile produced by
the liver
gallbladder
________ has exocrine cells that produce digestive enzymes and endocrine cells that produce insulin, glucagon and other hormones
pancreas
_______ has many digestive and metabolic functions
liver
Which 3 pairs of salivary glands produce saliva
Parotid glands
Submandibular glands
Sublingual glands
The _______ lie under either side of the tongue, covered by the mucous membrane of the floor of the mouth. These glands produce a mucous secretion that acts as a buffer and lubricant
Sublingual salivary glands
The _____ lie along the inner surface of the mandible within the mandibular groove.
submandibular salivary glands
The large _______ lie inferior to the zygomatic arch deep to the skin covering the lateral and posterior surface of the mandible.
parotid salivary glands
What is the largest viseral organ?
Liver
Where is the liver located?
It is located underneath the diaphragm predominantly on the right side of the abdominal cavity.
What marks the division between right and left lobes in the liver?
Falciform ligament
The porta hepatis includes _______
- Hepatic portal vein
- Hepatic artery proper
- Common bile duct
______ is caused by alcoholism, it damages the liver
cirrhosis
The ________ collect bile produced by the cells of the liver
right and left hepatic ducts
The hepatic ducts combine to form the _________
common hepatic duct
The __________ is formed by the union of the common hepatic duct and the cystic duct.
common bile duct
Where does the common bile duct empty into?
Small intestine
Bile salts in bile break apart fat droplets in a process called _________, aiding in the digestion of fat
emulsification
Why do gallstones form?
• Too much cholesterol and too little bile salts
• Incomplete and infrequent emptying of the gall
bladder
• Presence of proteins that promote crystallization
of cholesterol
The ________ produces pancreatic juice that is a combination of water, ions and enzymes that aid in digestion
pancreas
The pancreatic duct meets the common bile duct and delivers _______ secretions to the small intestine
exocrine
What are the major pancreatic enzymes
Pancreatic amylase
Pancreatic lipase
Pancreatic nucleases
Pancreatic proteolytic enzymes
What is the function of pancreatic amylase
breaks down carbohydrates
What is the function of pancreatic lipase
breaks down fats
What is the function of pancreatic nucleases
breaks down RNA and DNA
What is the function of pancreatic proteolytic enzymes
breaks down proteins
