Digestive System Flashcards
What is the digestive tract (aka alimentary tube)?
A muscular tube that runs from mouth to anus. It is a complex system with many layers.
What are the two different types of lining in the digestive tract?
1.Mucosa
- Epithelial lining
- Consists of secretion, absorption,
endocrine cells
2. Submucosa
- Layer of connective tissue
- Supports blood vessels, lymphatic
vessels, and nerves
What are the two different types of lining in the digestive tract?
1.Mucosa
- Epithelial lining (protective layer)
- Consists of secretion, absorption,
endocrine cells
2. Submucosa
- Layer of connective tissue (glue)
- Supports blood vessels, lymphatic
vessels, and nerves (holds them
together)
What are three smooth muscle layers in the digestive tract?
Longitudinal layer
- Arranged along length of tract
- Shortens and lengthens
Circular layer
- Ring around lumen (lumen means
inside space)
- Constricts lumen
Oblique layer
- Twists and turns
- Only located in stomach
- Rumbles
Explain the longitudinal layer of smooth muscle
It is a layer of muscle arranged along the length of tract, which shortens and lengthens.
Explain the circular layer of smooth muscle
It is a ring around the lumen (which means empty space), that constricts it.
Explain the oblique layer of smooth muscle
This is a layer of muscle only found in the stomach, which twists and turns. This causes the rumbling sound.
What are the four steps of digestion?
- Ingestion
- Digestion
- Absorpion
- Egestion/Elimination
What is mechanical digestion?
The physical breaking down of solid food masses, which mostly occurs in the mouth and stomach
What is chemical digestion?
The chemical breaking down of mechanically digested food, through various juices. These juices contain enzymes that break food down to molecules.
What is ingestion?
The intake of food.
What is digestion?
The preparation of food for absorption, which occurs in the alimentary canal
What is absorption?
The removal and storage of valuable nutrients, which occurs primarily in small intestine.
What is egestion/elimination?
The excretion of waste through the rectum and anus
What is the purpose of the mouth?
The mouth is where ingestion occurs and where the digestive process begins. Teeth aid in the mechanical digestion of food.
What is the purpose of the salivary glands?
The salivary glands are an accessory organ which secretes saliva, mucous, and salivary amylasse. These begin the chemical breakdown of carbohydrates.
What is the purpose of the pharynx?
The pharynx is a pipe where you’re still both eating and breathing through. Logitudinal and circular muscles ensure that the food moves down (peristalsis).
What is peristalsis?
It is the operation of circular and logitudinal muscles which help move food along the digestive tract. They are so strong that we can digest food even upside down!
What is the esophagus?
The pipe that connects the pharynx to the stomach.
What is bolus?
Bolus is the name for ood that has already passed through the mouth, and thus the chemical and mechanical digestion that occurs there.
What are sphincters?
Sphincters are ring-shaped muscles that contract and dilate, effectively regulating the flow of materials through the digestive system
What is the stomach?
A j-shaped organ that both mechanically and chemically digests. It also aborbs select things, such as water, medicine, and alcohol.
What causes stomach ulcers?
When bacteria prevent the stomach from secreting mucus, which exposes the stomach lining to HCl
How does the stomach mechanically digest food?
It twists and turns using longitudinal, circular, and oblique muscles in order to mechanically digest.
How does the stomach chemically digest?
Cells in stomach secrete gastric juice (mixture of enzymes and HCl).
What are the two stomach sphincters?
The one at the entrance is the cardiac/esophogeal sphincter and the one at the exit is the pyloric sphincter.
What is the epiglottis?
The epiglottis in it is a flaplike structure that ensures food does not travel down the trachea.