Organs & Systems 3.2 How do we look inside the body? There are a variety of medical imaging techniques. Can you name any? X ray Electromagnetic radiation is transmitted through the body to produce an image on photographic film. Best used for hard tissue like bone. CT or CAT Scan CAT = computer axial tomography X rays of very thin slices; computer puts together a 3-D image Ultrasound Also called medical sonography. Uses high frequency sound waves. Can observe movement of body parts, useful for watching organ (or fetal) function. MRI scan Magnetic resonance imaging Produced using radio signals in a magnetic field. Endoscopy A flexible tube with a camera and light attached are inserted in to the body. It is an alternative to barium X rays for detecting ulcers. Human Organ Systems Digestive System Physically & chemically breaks down food into smaller nutrient molecules which the bodys cells can absorb & use. Mouth to Stomach Teeth aid in physical digestion & saliva begins chemical digestion. Food is swallowed through the pharynx, moved by muscular contractions through the esophagus to the stomach. Stomach Gastric juices contain hydrochloric acid & pepsin (an enzyme) & mucus. Stomach mixes contents, continuing physical & chemical digestion, and contents are now liquid. Small Intestine In the duodenum, most of the chemical digestion takes place. Digestive enzymes & substances are released from the pancreas & gall bladder. Absorption occurs the rest of the length of the small intestine. Large Intestine Includes the colon, rectum, and anus. Main functions are to absorb water, vitamins, various salts, and eliminate waste. Bacteria are present, and help to digest food & produce nutrients such as vitamin K. Digestive System Recap This is a nice simple video from kidshealth.org. This Lets watch this episode of The Magic School Bus on the Digestive System.this episode Here is a fun drag & drop quiz on the structures in the digestive system. Here