Digestion 1 Flashcards
What is the sole purpose of the digestive system?
Extract useful nutrients from ingested food and fluids
The digestive system is simply a “long tube” going through the body. What is the name given to this “tube”?
Alimentary canal
The ‘alimentary canal’ consists of 6 parts. What are they?
- Oral cavity
- Pharynx
- Esophagus
- Stomach
- Small intestine
- Large intestine
The digestive system has organs which are not part of the alimentary canal, but aid in digestion. What is the general name of all of these organs?
Accessory organs
There are 6 accessory organs that aid in digestion. What are they?
- Pancreas
- Gallbladder
- Liver
- Salivary glands
- Teeth
- Tongue
What is ‘enteritis’, and what is it commonly called and caused by?
Inflammation of the intestinal mucosal lining.
Commonly called intestinal flu.
Caused by viruses, bacteria, or certain foods.
What is the common meaning for ‘deglutition’?
Swallowing
What are some of the characteristics of the ‘oral cavity’? (There are 6 of them)
- Ingest food
- Receive saliva
- Mastication
- Digestion of carbohydrates
- Formation of ‘bolus’ (food mass)
- Deglutition (swallowing)
What are some of the characteristics of the ‘pharynx’? (There are 3 of them)
- Receive bolus from oral cavity
- Autonomically continues deglutition of bolus
- Passes to ‘esophagus’
What are some of the characteristics of the ‘esophagus’? (There are 2 of them)
- Moves bolus to stomach via peristalsis (muscle moving waves)
- Esophageal sphincter restricts back-flow of food
Which sphincter restricts the back-flow of food from the esophagus to the pharynx?
Esophageal sphincter
What is ‘peristalsis’?
The movement of a bolus via the muscles in the esophagus/intestines.
What are some of the characteristics of the ‘stomach’? (There are 7 of them)
- Receives bolus from esophagus
- Churns bolus w/ gastric juice and forms chyme
- Digestion of proteins
- Limited absorption
- Chyme moves to duodenum
- Back-flow of chyme prohibited
- Can vomit
What is ‘chyme’?
Chemical breakdown of a bolus when mixed with gastric juices
What are some of the characteristics of the ‘small intestine’? (There are 5 of them)
- Receives chyme from stomach
- Chemically/Mechanically breaks down chyme
- Absorbs nutrients
- Transports wastes via peristalsis to large intestine
- Prohibits back-flow of intestinal wastes from large intestine
What are some of the characteristics of the ‘large intestine’? (There are 4 of them)
- Receives undigested waste from small intestine
- Absorbs water and electrolytes
- Forms and stores feces
- Expels waste via defecation reflex
Where does digestion start and how?
Starts in the mouth with saliva and is broken down into smaller particles
Mastication (chewing) is important because it does what to the food? Why is this important?
Increases the surface area of the food
Rate of digestion depends on the total surface area exposed
There are 3 processed involved with digestion that start in the mouth. What are they?
- Mastication (chewing)
- Food is lubricated w/saliva
- Digestion starts w/amylase
What does ‘amylase’ do?
ONLY breaks down starch/carbohydrates
What do the salivary glands secrete, and where do they secrete?
- Saliva
2. Buccal cavity
Saliva contains a substance that acts as an antibiotic. What is it?
Lysozyme
Saliva secretion is stimulated by 3 things. What are they?
- Taste
- Smell
- Tactile stimuli w/tongue
What is the daily amount of saliva secretion?
800-1500 ml
What is the pH of saliva?
7-Jun
What is the percentage of H2O and solutes in saliva?
H2O = 99.5% Solutes = 0.5%
True of False:
The salivary glands are under sympathetic control.
FALSE
Salivary glands are under PARASYMPATHETIC control
(Rest/Digest)
There are 3 paired glands involved in saliva secretion. What are the 3 paired glands?
- Large parotid
- Submandibular gland
- Sublingual gland
Which two salivary glands secrete both serous and mucous enzymes?
- Submandibular gland
2. Sublingual gland
What salivary gland secretes only serous fluid-enzymes?
Large Parotid
What are the characteristics of ‘mumps’?
Viral disease of the parotid salivary gland
What are the characteristics of ‘parotitis’ disease?
Inflammation of parotid gland
What are the characteristics of ‘ptyalocele’ disease?
Cystic tumor of a salivary gland
How many taste buds do humans have? How many taste cells are there per bud?
4000 Taste buds
30-100 Taste cells/bud
What type of receptors are involved in taste?
Chemoreceptors
The esophagus is a ‘thin’ muscular tube that moves food from the ________ to the _______.
Pharynx to the Stomach
How long is the ‘esophagus’?
10-12 inches long
Where is the ‘esophagus’ located behind?
the trachea
The lower end of the esophagus has a sphincter that is called by two names. What are they?
- Cardiac sphincter
2. Gastroesophageal sphincter
The esophageal sphincters prevent what from entering into the esophagus?
Stomach acid
What are some of the characteristics of ‘heartburn’?
Regurgitation of gastric contents into esophagus
Epithelial layer is ‘burned’ away
(G.E.R.D) - Gastro Esophagial Reflux Disorder
What is the definition of ‘achalasia’?
Lower esophageal sphincter (cardiac sphincter) fails to relax.