Ch. 23-1 Digestive System Flashcards
What is the primary function of the digestive system?
The digestive system takes in food, breaks it down into nutrient molecules, absorbs these molecules into the bloodstream, and rids the body of indigestible remains.
List the six major activities involved in the processing of food.
- Ingestion
- Mechanical Breakdown
- Propulsion
- Digestion
- Absorption
- Defecation
What are the two major categories of digestive system organs?
- Alimentary Canal/Gastrointestinal Tract (GI)
- Accessory Digestive Organs
What organs are part of the alimentary canal?
- Mouth
- Pharynx
- Esophagus
- Stomach
- Large and Small Intestines
- Anus
What organs are classified as accessory digestive organs?
- Mouth
- Tongue
- Gall Bladder
- Salivary Glands
- Pancreas
- Liver
What are the four layers (tunics) of the alimentary canal?
- Mucosa
- Submucosa
- Muscularis externa
- Serosa
What are the functions of the mucosal layer?
- Secrete mucous, enzymes, hormones
- Absorb digestion end products
- Protect against infectious disease
What is the composition of the mucosal layer?
- Epithelial lining
- Lamina propria
- Muscularis mucosae
What is the main characteristic of the submucosa layer?
Highly vascular with lots of blood and lymph vessels, elastic fibers, and many lymph follicles.
What is the primary function of the muscularis externa?
Functions in peristalsis and segmentation.
What is the serosa layer also known as?
Visceral peritoneum.
What is the structure of the mouth’s walls?
Thick stratified squamous epithelium.
What are the two parts of the palate?
- Hard palate
- Soft palate
What is the primary role of the tongue in digestion?
Grips food, mixes it with saliva, and initiates swallowing.
What types of papillae are found on the tongue?
- Filiform
- Fungiform
- Vallate
- Foliate
What is the composition of saliva?
About 97-99.5% water, with solutes including electrolytes, enzymes, proteins, and wastes.
What are the functions of saliva?
- Clean mouth
- Dissolve food for tasting
- Moisten food
- Digestive enzymes to break down starch and lipids
What are the three sections of the pharynx?
- Nasopharynx
- Oropharynx
- Laryngopharynx
What is the length of the esophagus?
About 25 cm long.
What prevents backflow in the esophagus?
Lower esophageal (cardiac) sphincter.
What type of epithelium is found in the esophageal mucosa?
Nonkeratinized stratified squamous epithelium.
What is the stomach’s primary role in digestion?
Temporary storage tank where chemical breakdown of proteins begins and food is converted into chyme.
What are the regions of the stomach?
- Cardiac region
- Fundus
- Body
- Pylorus
What are rugae?
Large folds that allow the stomach to expand and contract.
What are the three types of gastric glands in the stomach?
- Mucous neck cells
- Parietal cells
- Chief cells
What does the mucosal barrier in the stomach protect against?
It protects against the corrosive nature of gastric acid and protein digesting enzymes.
Fill in the blank: The stomach produces a layer of _______ that traps a layer of bicarbonate-rich fluid beneath it.
alkaline mucous
True or False: The stomach surface epithelium is completely renewed every three to six days.
True
