Presentation on theme: "Choose one food that you ate today, where do you think digestion and absorption are taking place?"— Presentation transcript:
Choose one food that you ate today, where do you think digestion and absorption are taking place?
Before the food you eat can be used it must be digested. Your digestive system has 3 main functions- digestion, absorption, and elimination.
The process by which the digestive system breaks down food into molecules that the body can use. Mechanical digestion Foods are physically broken apart into smaller pieces Chemical digestion Chemicals produced by your body break large molecules into smaller ones that your body uses.
Mechanical digestion allows food to be digested faster and used sooner. Most of the chemicals involved in digestion are enzymes, substances that speed up chemical reactions.
Absorption is the process by which nutrients pass through the lining of your digestive system into your blood. Blood transports the nutrients Anything not used is eliminated
Mouth Pharynx Esophagus Stomach Small Intestine Large Intestine Liver, gallbladder, and pancreas are slightly involved in the digestion process
Mechanical digestion Teeth tear, crush, and grind food Tongue pushes the food around Chemical digestion occurs with saliva Saliva moistens food so it can be swallowed
The junction between the digestive tract and the respiratory system. Epiglottis opens and closes to allow air into the respiratory system and food into the digestive system.
Muscular tube that connects the pharynx to the stomach. Peristalsis occurs when muscle contractions push food through the esophagus, toward the stomach.
Muscular pouch located in the abdomen Able to contract and expand Can hold about one gallon of food and liquid Most mechanical digestion and some chemical digestion occurs here Mechanical digestion occurs as 3 layers of muscle produce a churning motion Mixes the food with fluids.
Chemical digestion occurs as cells lining the stomach release gastric juice, which breaks down proteins. Hydrochloric acid in gastric juice kills many bacteria that may be swallowed with food. Mucus coats the lining of the stomach and gives it protection from the acidic gastric juice.