Digestive System Flashcards
What is the mouth
Purpose is mechanical digestion
Teeth break down the physical food into smaller pieces to flow easier through the rest of the system
Saliva contains enzymes (biological catalysts)
Enzymes breaks down food through chemical digestion
Breaks down complex molecules in the food
Saliva contains mucus which acts as a lubricant to help us swallow food
Tongue helps to move and shape the food
Instinctual chewing allows us to shape our food into a ball
What is the digestive system
Digestive system creates the essential component of glucose when it breaks down food to conduct cellular respiration (glucose + oxygen gas -> carbon dioxide + water + energy)
- Ingestion
- Digestion
- Absorption
- Egestion/Excretion
What is the gastrointestinal tract and accessory organs
“Tract” refers to the pathway in the digestive system
All organs that touch food are a part of the gastrointestinal tract
Accessory organs are organs which do not touch food
What is the esophagus
Composed of smooth muscle
Connects the mouth to the stomach
Uses peristalsis - wave-like muscle contraction used to move the food downwards
Muscles contract in to push it down
What is the stomach
Purpose: storage of food and chemical digestion
2 sphincters
Top: Cardiac sphincter/Gastroesophageal sphincter
Bottom: Pyloric sphincter
Close and open
Regulates food passing from the esophagus into the stomach, and prevents the contents of the stomach from reentering the esophagus
Stomach acid contains HCL (Hydrochloric Acid)
Performs chemical digestion to break down food
Stomach has muscular walls; moves around and churns
Helps with mechanical digestion
What is the small intestine
Purpose: mechanical and chemical digestion, and absorption
Chemical digestion and absorption are most prevalent
Mechanical digestion occurs with muscular walls
Chemical digestion through enzymes
What are villi
Villi are located in the small intestine as finger like walls
Villi contain veins and arteries
Veins and arteries are used to transport nutrients
More villi = more surface area = more efficiency
Villi have finger like projections around them as well; referred to as microvilli
Increases surface area for more efficient absorption
There is 500x microvilli for each villi
What are the three accessory organs
Pancreas: Secretes enzymes to break down nutrients
Liver: Secretes bile, emulsifies fat
Bile breaks down large molecules of fat into smaller ones
Gallbladder: Storage of bile
What are the Large Intestine, Rectum, Anus
Purpose: storage, reabsorption of water, and excretion
Without reabsorption of water, it would lead to dehydration, and watery stool (diarrhea)
Rectum: used for storage
Large intestine: reabsorption of water
Anus: excretion
Anus is another circular set of tissue which can control the exit of waste
Sometimes referred to as anal sphincter
