Lesson 4: Digestive And Excretory Systems Flashcards
Define esophagus.
A long, straight tube that connects the pharynx to the stomach.
Define the digestive system.
The organs that break down food so it can be used by the body.
Define stomach.
The saclike, digestive organ that is between the esophagus and the small intestine and that breaks down food by the action of muscles, enzymes, and acids.
Define small intestine.
The organ between the stomach and the large intestine where most of the breakdown of food happens and most nutrients are absorbed.
Define large intestine.
The broader and shorter portion of the intestine, where water is removed from the mostly digested food to turn the waste into semisolid feces, or stool.
Define pancreas.
The organ that lies behind the stomach and that makes digestive enzymes and hormones that regulate sugar levels.
Define liver.
The largest organ in the body; it makes bile, stores and filters blood, and stores excess water as glycogen.
Define excretory system.
The system that collects and excretes nitrogenous wastes and excess water in the form of urine.
Define kidney.
One of the organs that filters wastes from the blood, excrete products as urine, and regulate the concentration of certain substances in the blood.
Define nephrons.
The unit in the kidneys that filters blood.
Define urine.
The liquid excreted by the kidneys, stored in the bladder, and passed through the urethra to the outside of the body.
Define enzyme.
A type of protein that speeds up metabolic reactions in plants or animals without being permanently changed or destroyed.
What is the digestive system?
The digestive system breaks down food you eat into nutrients to provide energy for cells.
What are the two types of digestion?
Chemical and mechanical digestion.
What is chemical digestion?
The process in which large molecules of food are broken down into smaller molecules so that they can pass in the bloodstream.
What is mechanical digestion?
The breaking, crushing, and mashing of food.
What are the parts of the digestive system?
The mouth, the esophagus, the stomach, the small intestine, and the large intestine.
Explain what the mouth does to help digestion.
Mechanical and chemical digestion begins in the mouth. The food is moistened by saliva and moves down the esophagus.
Explain what the esophagus does to help digestion.
Waves of muscle contractions called peristalsis move the food from the esophagus to the stomach.
Explain what the stomach does to help digestion.
The stomach is a muscular bag that crushes food and contains acids and enzymes for killing bacteria and breaking down proteins.
Explain what the small intestine does to help digestion.
The food travels to the small intestine after it has been reduced to a soupy mixture called chyme. The small intestine is where most chemical digestion takes place and most nutrients are absorbed.
Explain what the large intestine does to help digestion.
The food’s nutrients are absorbed and the remaining waste is removed from the body in the form of feces.
Where are nutrients absorbed?
In the small and large intestines.
Explain how nutrients are absorbed in the small intestine.
The small intestine contains folds, villi, and microvilli which help it absorb nutrients. The folds create more surface area for nutrients to be absorbed. Each fold is covered with villi and microvilli. Villi absorb nutrients and microvilli increase surface area of the villi.
