Digestive, Integumentary, and Excretory System

The digestive system: ingestion, digestion, elimination. Digestion begins as soon as food enters the body. The saliva starts to break down the food in the mouth and it is further digested as it moves down the esophagus into the stomach. After the stomach food moves into the  small intestines where nutrients are absorbed and then to the large intestine where water is absorbed. After that it comes out the anus.

The integumentary system protects the body. The skin is the largest organ in the body. There are 3 layers of skin: epidermis, dermis, and subcutaneous layer sometimes called the deep layer or fatty layer. The epidermis serves as a water repellent layer the is the bodies main defense. The dermis is where nerves and blood vessels are located so it responsible for our sensory response. It also is where the oil and sweat glands are located. It helps with controlling body temperature and releasing waste. The fatty layer helps us with insulation and attaches the skin to the muscles.

The excretory system removes liquid waste from our body in the form of urine. The main organs are the kidneys and bladder. There are 3 tubes that are part of the system: 2 ureters and the urethra. The kidneys work to clean the blood and make urine. The bladder is the storage system for the urine. The urine travels down the ureters and out through the urethra.