Digestive System Flashcards
Ingestion
Intake of food via the mouth
Name the five steps of the digestive process.
Ingestion Digestion Movement Absorption Elimination
Digestion
Mechanically or chemically breaking down foods into their subunits.
Movement
Food must be moved along the GI tract in order to fulfill all functions.
Absorption
Movement of nutrients across the GI tract wall to be delivered to cells via the blood.
Elimination
Removal of indigestible molecules.
What are the 4 major layers that make up the wall of the GI tract?
Mucosa
Submucosa
Muscularis
Serosa
Mucosa
Innermost layer of the GI tract that produces mucus to protect the lining and also produces digestive enzymes.
Submucosa
2nd layer of the GI tract, made of loose connective tissue that contains blood vessels, lymphatic vessels, and nerves.
Muscularis
3rd layer of the GI tract made of 2 layers of smooth muslce that moves food along the tract.
Serosa
Outer lining of the GI tract that is part of the peritoneum
Lumen
Central space in the GI tract containing the food being digested.
What does the mouth do?
The mouth contains teeth that begin the mechanical breakdown of food (chewing).
What begins carbohydrate digestion, and where does this reside?
3 pairs of salivary glands in the mouth secrete salivary amylase which begins carbohydrate digestion.
What are the tonsils made of, and what do they do?
Tonsils are made of lymphatic tissues, which are important in fighting disease.
What does the tongue have, and what does it do?
The tongue is covered in taste buds, and it assists in the mechanical breakdown and movement of food, forming a bolus and moving it towards the phalynx.
Bolus
A mass of chewed food
Pharynx
A cavity between the mouth and esophagus that serves as a passageway for food and air.
Esophagus
A long, muscular tube that carries food to the stomach.
Name the two phases of swallowing food.
Voluntary Phase
Involuntary Phase
What occurs during the voluntary phase of swallowing food?
Food being swallowed from the mouth into the pharynx is a voluntary act.
Describe the involuntary phase of swallowing food.
Once the food is in the pharynx, swallowing becomes a reflex. The epiglottis covers the voice box to make sure food is routed into the esophagus, and food moves down the esophagus through peristalsis.
Peristalsis
Peristalsis is the rhythmic contraction that ensures food moves down the esophagus.
When does heartburn occur?
Heartburn occurs when acids from the stomach pass into the esophagus.
What does heartburn feel like?
Heartburn feels like a burning sensation in the esophagus.