Digestive System Flashcards
Its purpose is to break down or digest the food into particles that are small and simple enough to be absorbed.
Digestive system
Ingests food, digests it, absorbs the end products, and eliminates the waste.
Digestive system
The study of the digestive tract.
Gastroenterology (gastr/o, stomach; enter/o, intestines).
The digestive ___ and the accessory ___ of digestion make up the digestive system.
tract
organs
Also called the alimentary canal or the gastrointestinal (GI) tract.
Digestive tract
A hollow tube extending from the mouth to the anus.
Digestive tract
The structures of the ___ ___ include the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.
Digestive tract
The ___ ___ of digestion include the salivary glands, teeth, liver, gallbladder, and pancreas.
accessory organs
Empty their secretions into the mouth.
Salivary glands
The liver, gallbladder, and pancreas empty their secretions into the ___ ___.
small intestine
The process by which food is broken down into smaller particles suitable for absorption.
Disgestion
Takes place within the digestive tract.
Disgestion
The process whereby the end products of digestion move across the walls of the digestive tract into the blood and lymph for distribution throughout the body.
Absorption
The two forms of digestion are ___ and ___.
mechanical
chemical
There are ___ forms of digestion.
2
The breakdown of large food particles into smaller pieces by physical means.
Mechanical digestion
This process is usually achieved by chewing and by the mashing actions of the muscles in the digestive tract.
Mechanical digestion
The chemical alteration of food.
Chemical digestion
A protein is chemically digested into amino acids.
Chemical digestion
Digestive enzymes, stomach acid, and bile accomplish ___ digestion.
chemical
The end products of digestion are absorbed as they move across the lining of the digestive tract into the ___ and ___ and eventually reach every cell in the body.
blood
lymph
Food that cannot be digested and absorbed is eliminated from the body as ___.
feces
The last stage of the digestive process.
Elimination of waste
The Digestive System.( A) Hollow tube from mouth to anus. (B) Anatomical arrangement of organs of the digestive system.
True or false: although modified for specific functions in different organs, the wall of the digestive tract has a similar structure throughout its length.
True
The wall of the digestive tract has ___ layers.
4
The wall of the digestive tract has four layers: the ___, the ___, the ___ layer, and the ___.
mucosa
submucosa
muscle
serosa
The innermost layer of the digestive tract.
Mucosa
Consists of the mucous membrane, a small amount of connective tissue, and smooth muscle.
Mucosa
In parts of the digestive tract, especially the small intestine, the ___ is folded to increase the surface area for absorption.
mucosa
Glands of the ___ secrete mucus, digestive enzymes, and hormones.
mucosa
In general, the ___ is concerned with digestion and absorption.
mucosa
A thick layer of loose connective tissue.
Submucosa
Lies beneath the mucosa.
Submucosa
Contains blood vessels, nerves, glands, and lymphatic vessels.
Submucosa
The third layer of the digestive tract.
Muscle layer
___ layers of ___ muscles make up the muscle layer of the digestive tract.
2
smooth
Two layers of smooth muscles are an ___ ___ layer and an ___ ___ layer.
inner circular
outer longitudinal
True or false: the muscle layer is responsible for several types of movements in the digestive tract.
True
An activity where the stomach muscles alternate between contraction and relaxation so that digestion of food occurs mechanically, mixing the particles with digestive juices.
Segmentation
A rhythmic alternating contraction and relaxation of the muscles that pushes the food in a forward direction through the digestive tract.
Peristalsis (pair-i-stal-sis)
The two muscle movements are:
peristalsis and segmentation.
Moves food in the same way that toothpaste squirts from a tube.
Peristalsis
Peristaltic ___ squeeze the food from behind and push it forward. Peristaltic ___ are stimulated by the presence of food.
waves x2
The outermost lining of the digestive tract.
Serosa
It extends as peritoneal membranes: the mesentery, mesocolon, and omentum.
Serosa
These three form large, flat, folded structures that perform several important functions. They help anchor the digestive organs in place; carry blood vessels, lymph vessels, and nerves to the abdominal organs; and help restrict the spread of infection in the abdominal cavity.
Mesentery, mesocolon, and omentum
The peritoneal membranes, located behind the digestive organs, are called the ___ and ___. When they are located in front of the organs, they are called the greater and lesser ___.
mesentery
mesocolon
omentum
The greater ___ is a double layer of peritoneum that contains a considerable amount of fat and resembles an apron draped over the abdominal organs.
omentum
The digestive tract has a unique nervous network called the ___ nervous system (___NS).
enteric
Regulates GI (gut) motility and secretion; its activity is modulated by autonomic nerves, especially the parasympathetic (vagal) fibers.
Enteric nervous system (ENS)
The enteric nervous system (ENS) regulates GI (gut) motility and secretion; its activity is modulated by autonomic nerves, especially the ___ (___) fibres.
parasympathetic (vagal)
Layers of the Digestive Tract.
Also known as the oral cavity.
Mouth
The digestive tract begins with this.
Mouth
Food is ingested into the this, where digestion begins immediately.
mouth
Lined with mucous membrane and contains structures that assist in the digestive process. These include the teeth, tongue, salivary glands, and several other structures.
Mouth
Part of the oral cavity and refers to the area between the gums and the cheek or lips.
Buccal cavity
Their purpose is to chew food and begin mechanical digestion.
Teeth
The teeth breaking down large pieces of food into smaller pieces.
Mastication (mass-ti-kay-shun) / chewing
Chewing =
mastication (mass-ti-kay-shun).
Once moistened by the ___ in the mouth, the small pieces of food are easily swallowed.
secretions
True or false: the shape and location of each tooth determine its function.
True
The sharp, chisel-shaped teeth.
Incisors
Cone-shaped teeth used to tear or grasp food.
Cuspids
The larger, flatter teeth suited for grinding food.
Molars
Note the positions and names of the teeth: the incisors, cuspids (___), premolars (___), and molars, including the wisdom teeth.
canines
bicuspids
Baby teeth =
deciduous (deh-sid-yoo-us)
A tooth has ___ parts.
3
A tooth has 3 parts: the ___, the ___, and the ___.
crown
neck
root
Above the level of the gum or gingiva (jin-ji-vah) and is covered with hard, brittle enamel.
Crown
Connects the crown with the root of the tooth.
Neck
The part of the tooth embedded in the jawbone.
Root
The outer surface of this is anchored to the periodontal membrane by cementum.
Root
The bulk of the tooth consists of this bone-like material.
Dentin
Nerves, blood vessels, and connective tissue, called pulp, penetrate this.
Detin
Supplies the tooth with sensation and nutrients.
Pulp cavity
As the pulp cavity extends into the root, it is called the ___ ___.
root canal
The ___ is the name given to the tissues that surround the teeth; it includes the gums, soft tissue, and bone.
periodontium (perio-daunt-tee-um)
A muscular organ that occupies the floor of the mouth and serves two major roles in the digestive process.
Tongue
Facilitates chewing and swallowing by continuously repositioning the food in the mouth.
Tongue
The tongue serves ___ major roles in the digestive process.
2
As swallowing begins, the tongue pushes the food, which it has molded into a ball-like mass called a ___, toward the ___.
bolus (boh-luss)
pharynx
Contains the taste buds and allows you to taste food.
Tongue
Small piece of mucous membrane which anchors the tongue to the floor of the mouth.
Frenulum
An extensive ___ network that provides the sublingual (under the tongue) area with a rich supply of blood.
capillary
True or false: the blood supply under the tongue is so good that medications that are administered sublingually are absorbed rapidly.
True
___ pairs of salivary glands secrete their contents into the mouth.
3
Three pairs of salivary glands secrete their contents into the mouth: the ___, ___, and ___ glands.
parotid
submandibular
sublingual
The largest of the three glands that lies below and anterior to the ears.
Parotid glands
Parotid, submandibular, and sublingual glands.
Salivary glands
These are the glands that may be infected by the mumps virus, which results in a chipmunk-like appearance.
Parotid glands
Located on the floor of the mouth. They are located under the tongue and are the smallest of the salivary glands.
Submandibular glands
The salivary glands are exocrine glands that secrete ___ (from a Greek word meaning “spittle”), a watery fluid that contains mucus and a digestive enzyme called salivary amylase or ptyalin.
saliva
True or false: approximately 1 L of saliva is secreted each day.
True
Saliva reaches the mouth by way of tiny ___.
ducts
True or false: the most important function of saliva is to soften and moisten food and thereby facilitate swallowing.
True
The ___ and ___ palates form the roof of the mouth.
hard
soft
The anterior hard palate separates the ___ cavity from the ___ passages and the posterior soft palate separates the ___ cavity from the ___.
oral
nasal
oral
nasopharynx
The ___ palate extends toward the back of the oral cavity as the uvula (yoo-vyoo-lah).
soft
The V-shaped piece of soft tissue that hangs down from the upper back region of the mouth.
Uvula (yoo-vyoo-lah)
Prevents food and water from entering the nasal passages during the act of swallowing.
Uvula
Masses of lymphatic tissue located along the sides of the posterior oral cavity.
Palatine tonsils
Oral Cavity. (A) Structures in the mouth. (B) Longitudinal view of a tooth. (C) Location of the salivary glands.
The tongue pushes the food from the mouth into this.
Pharynx (throat)
Involved in swallowing and has three parts.
Pharynx
Swallowing =
deglutition (dee-gloo-tih-shin)
The three parts of the pharynx are the ___, ___, and ___.
nasopharynx
oropharynx
laryngopharynx
True or false: only the oropharynx and laryngopharynx are part of the digestive tract.
True
Eating and Swallowing Structures From Mouth to Pharynx to Esophagus.
The act of swallowing normally directs food from the pharynx (throat) into the ___, a long tube that empties into the stomach.
esophagus
Food does not normally enter the nasal or respiratory passages because swallowing temporarily closes off the openings to both. For example, during swallowing, the soft palate moves toward the opening to the ___. Similarly, the laryngeal opening is closed when the trachea moves upward and allows the ___ to cover the entrance to the respiratory passages. You can see this process as the up-and-down movement of the Adam’s apple, part of the larynx or voicebox.
nasopharynx
epiglottis
The food tube that carries food from the pharynx to the stomach.
Esophagus (eh-sof-ah-gus)
Approximately 10 inches (25 cm) long, descends through the chest cavity, and penetrates the diaphragm.
Esophagus
The act of swallowing pushes the ___ of food into the esophagus.
bolus
The presence of food in the esophagus stimulates ___ activity and causes the food to move through the esophagus into the stomach.
peristaltic
Glands within the ___ of the esophagus secrete mucus, which lubricates the bolus and facilitates its passage along the esophagus.
mucosa
There are ___ esophageal sphincters.
2
The two esophageal sphincters are the ___ sphincter, located at the top of the esophagus, and the ___ or ___ ___ ___ (___), located at the base of the esophagus.
pharyngoesophageal
gastroesophageal / lower esophageal sphincter (LES)
Swallowing pushes food past the ___ sphincter into the esophagus.
pharyngoesophageal
Relaxation of the ___ ___ ___ (___) keeps the base of the esophagus open, thereby allowing the passage of food into the stomach.
lower esophageal sphincter (LES) / gastroesophageal
When it is contracted, it closes the base of the esophagus, thereby preventing reflux or regurgitation of acidic stomach contents back into the esophagus.
lower esophageal sphincter (LES) / gastroesophageal
A pouchlike organ that lies in the upper left part of the abdominal cavity under the diaphragm and receives food from the esophagus.
Stomach
It performs five important digestive functions.
Stomach
Regulates the rate at which the partially digested food is delivered to the small intestine (this is the most important function).
Stomach
Secretes gastric juice, which includes digestive enzymes, hydrochloric acid (HCl), and intrinsic factor.
Stomach
Plays an important role in the mechanical digestion (mixing and mashing) of food.
Stomach
Limited to the stomach.
Chemical digestion
Absorbs small quantities of water and dissolved substances.
Stomach
True or false: the stomach is not well suited for an absorptive role, so absorption is limited. It can, however, absorb alcohol efficiently.
True
Secretes gastric hormones.
Stomach
The major regions of the stomach include the ___, the ___, and the ___.
fundus
body
pylorus
There are ___ major regions of the stomach.
3
Literally means “gatekeeper” and continues as the pyloric canal.
Pylorus
Located at the end of the pyloric canal and performs two functions.
Pyloric sphincter
A pyloric sphincter is located at the end of the pyloric canal and performs ___ functions.
2
Remains closed most of the time and therefore holds the food in the stomach long enough to allow the stomach to mix and mash its contents into a paste.
Pyloric sphincter
Helps regulate the rate at which the gastric contents are delivered to the small intestine.
Pyloric sphincter
Other landmarks of the stomach include the greater and lesser ___.
curvatures
The empty stomach lies in thick accordion-like folds called ___.
rugae (roo-gay)
Allows the stomach to expand.
Rugae
The stomach has ___ layers of muscles that lie in three directions.
3
The stomach has three layers of muscles that lie in three directions: ___, ___, and ___.
longitudinal
oblique
circular
This arrangement allows the stomach to churn and mix the food with gastric juice to create a thick, pastelike mixture called chyme (kime).
Stomach muscle layers
Food and gastric juices mixed to create this thick, paste-like mixture.
Chyme (kime)
The muscles of the stomach also generate peristaltic waves that squeeze the food toward the ___.
pylorus
The mucous membranes of the stomach contain ___ types of glands.
2
The mucous membranes of the stomach contain two types of glands: ___ and ___.
exocrine
neuroendocrine
The exocrine glands contain ___ types of secretory cells.
3
The exocrine glands contain three types of secretory cells: (1) the ___ cells, which secrete mucus; (2) the ___ cells, which secrete digestive ___; and (3) the parietal cells, which secrete HCl and ___ factor.
mucous
chief
enzymes
intrinsic
The secretions of the gastric glands.
Gastric juice
True or false: in addition to the gastric juice, other cells secrete thicker mucus and bicarbonate that adheres closely to the stomach lining. This secretion forms a protective coating for the stomach lining and prevents the acidic gastric juices from digesting the stomach itself.
True
Stomach. (A) Regions of the stomach: fundus, body, and pylorus; landmarks: greater curvature, lesser curvature. (B) Three muscle layers of the stomach. (C) Mucosa of the stomach, showing the mucous, parietal, and chief cells.
Small Intestine. (A) Folds of the intestinal wall. (B) Single villus showing the blood capillaries and the lacteal.
Large Intestine: Cecum with Appendix; Ascending Colon, Transverse Colon, Descending Colon, and Sigmoid Colon; Rectum and Anal Canal.
(A) Liver, gallbladder, bile ducts, and pancreas. (B) Liver lobule. (C) The entrance of the common bile duct into the duodenum (ampulla of Vater and sphincter of Oddi).
Carbohydrate Digestion.
Protein Digestion.
Fat Digestion: Emulsification and Digestion.
Summary: Digestion and Absorption of the Turkey Meal.
