Biology 35.1 Cheet Sheet
Main function of the digestive system is to disassemble the food you eat into its component molecules so your body can use it for energy
Your mouth breaks food down into smaller pieces for digestion
Chewing is mechanical digestion
Chemical digestion also occurs in the mouth, with the release of the enzyme amylase to break down polysaccharides into smaller molecules.
Swallowing your food sends it into the esophagus, which connects the mouth to the stomach.
The esophagus uses peristalsis to move the food down into the stomach
Contractions occur in waves
circular muscles relax and longitudinal muscles contract, then vice versa
Epiglottis prevents food from going into respiratory system
The stomach is a muscular, pouchlike enlargement of the digestive tract
Muscles work to break down the food in the stomach and chemical cocktails work to break the molecules of food into usable substances .
The cocktail is called “gastric juice”
It includes pepsin and hydrochloric acid
Pepsin processes proteins in food.
Pepsin works best in an acidic environment
Stomach does not dissolve itself with gastric juices due to the mucus lining of the inner stomach
Food remains the the stomach for two to four hours
The small intestine is a muscular tube about 6 m long and 2.5 cm wide.
Muscle and chemical reactions further break down the food in the SI
Carbohydrates and proteins are also changed by enzymes produced by the pancreas and liver.
The first 25 cm of the SI is called the duodenum.
Most enzymes and chemicals in the duodenum are produced from the pancreas, liver, and gallbladder.
The pancreas is a soft, flattened gland that secrets digestive enzymes and hormones.
It helps to break down carbs, proteins, and fats.
Alkaline pancreatic juices help to neutralize the acidic food's pH, stopping pepsin as well.
The liver is a large, complex organ that produces bile.
Bile is a chemical substance that helps to break down fats.
The gallbladder stores bile
Bile breaks apart fats into smaller droplets
If the bile concentration is too high, or there is too much cholesterol in the person's diet, or if the gallbladder becomes inflamed, gallstones can form.
Villus absorb food
A villus is a small projection on the lining of the small intestine.
The allow for a higher absorption rate and small enough molecules are absorbed directly into the cells of the villi.
The large intestine is a muscular tube that is also known as a colon.
It is 1.5 m long and 6.5 cm wide.
The appendix is attached to the large intestine.
The large intestine absorbs and recycles water.
The rectum is the last stop in the digestive system. Here, waste is eliminated from the organism.
