Skeletal and Muscle Systems Skeletal System Made up of bones, tendons and ligaments Bones provide protection ex. Rib cage for lungs and skull for brain Bones give the body structure and allow it to move. Muscle System Provides power for movement Muscles work in pairs to produce movement Movement starts with a nerve signal arriving at the muscle causing the muscle to contract

Digestive System Breaks down food into nutrients the organism can use Organs in contact with food – mouth, esophagus, stomach, small intestine, large intestine Digestion continues in the stomach and then the small intestine Nutrients absorbed into the blood at the small intestine Liver and pancreas provide chemicals for the breakdown of food. Water reabsorbed in the large intestine from the undigested food

Excretory System Removes wastes (salt, excess water, and nitrogen ) from the body Excess water, salt and other wastes are removed through the skin as sweat. Kidneys filter wastes from the blood to produce urine The tiny filters in the kidney are called nephrons. Urine flows from the kidneys to the bladder

Respiratory System Provide oxygen for the cells Removes carbon dioxide (waste) from the blood. Made up of lungs and the passageways that lead to them Air from nose and mouth travel through a series of tubes In the lungs these tubes branch into bronchi The bronchi branch eventually into alveoli (thin-walled air sacs) Oxygen and carbon dioxide are exchanged here through capillaries Fish have gills for gas exchange

Circulatory system Vertebrates have a closed circulatory system. Blood moves through vessels Arthropods, most mollusks and some other invertebrates have an open circulatory system-blood washes over the organs. Consists of heart and blood vessels Heart pumps O 2 -rich blood to the cells Cells return CO 2 –blood to the heart and then the lungs blood picks up O 2 O 2 -rich blood returns to the heart and is pumped back to the cells. Nutrients from the small intestine are picked up by the blood vessels and sent to the cells. O2. and nutrients pass in and CO2 pass out of cells into the blood through capillaries.

Nervous and Endocrine Systems Vertebrate nervous system –brain, nerve cord, nerves, and sense organs. Endocrine system has glands that produce hormones. Hormones –chemicals released into bloodstream, that change body activity. Adrenaline is an example of a hormone that helps the body to adjust to stress.

Nervous and Endocrine Systems Example of nervous (NS) and endocrine (ES) systems working together. Fight or Flight Response. Rabbit sees a fox. Nerve cells in rabbit’s eyes send message to brain. Brain sends message back through the nerves to the spinal cord. Nerve cells here send message to leg muscles to start moving. At the same time, ES sends out adrenaline that increases heart rate and which in turn sends extra blood to the muscles. Rabbit is now ready to fight or run.