5 Levels of Organization Pages 524-525

5 Levels of Organization Cells Tissues Organs Organ Systems Organism

Cells Cells are the smallest level of organization in living things.

Tissue Cells + Cells = Tissue There are 4 types of tissue in your body: Connective (bone, blood) Nerve Epithelial (skin, linings) Muscle

Organ Tissue + Tissue = Organ Organs are what we usually think about when we think about parts of the body

Organ Connective tissue makes up organs like the bones, blood vessels, tendons, ligaments, etc…

Organ Nerve Tissue Makes up organs like the brain, spinal cord, and nerves.

Organ Epithelial Tissue makes up organs like the skin, hair, and fingernails

Organ Muscle tissue makes up organs like the heart, stomach, kidneys, lungs, biceps, etc…

Organ System Organ + Organ = Organ System You have 11 organ systems in your body.

11 organ systems of the body

Organ Systems 1- Integumentary System The integumentary system is a temperature regulator, sensory system, and protects the organism. (first line of defense.) Skin, hair, and fingernails are some organs that make up the integumentary system.

Organ Systems Integumentary system facts: Skin is the largest organ in your body. Skin is 16% of your body weight You completely replace your skin cells about once per month. About 90% of dust in your house is dead skin cells. Hair is the fastest growing organ in the body Average #s of hairs: redheads= 80,000 Brown/black = 100,000 Blondes = 120,000 Fingernails grow faster during the summer and on your dominant hand.

Organ Systems 4- Nervous system The nervous system sends messages that control body functions The brain, spinal cord, and nerves are some organs in the nervous system.

Organ Systems Nervous system facts: Your nervous system functions using electricity. Messages can travel through your neurons at speeds of 250 mph! The avg. # of neurons in a human brain is 100 billion. The longest neuron (nerve cell) known to man is 15 feet long (in a giraffe leg). If you lined up all the neurons in your body, it would stretch 600 miles! An adult human brain weighs about 3 pounds.

Organ Systems How would your life be different without your nervous system? How long do you think you could survive?

Organ Systems 6- Cardiovascular system (circulatory) The cardiovascular system carries food and oxygen to the cells, and carries carbon dioxide away from the cells. Your heart, arteries, veins, and capillaries, are organs in the cardiovascular system.

Organ Systems Cardiovascular system facts: The heart beats about 3,000,000,000 times during an average lifetime. You have thousands of miles of blood vessels and arteries in your body. (you could wrap them around the world twice. You have about 5 million red blood cells, 10,000 white blood cells, and 250,000 platelets in 1 drop of blood. Arteries take blood away from the heart, and veins return it to the heart. Moving helps return blood to your heart You do NOT have blue blood!

Organ Systems 8- Respiratory system The respiratory system exchanges oxygen for carbon dioxide. (O2 in and CO2 out). Lungs, Bronchi, trachea, and diaphragm are all organs in the respiratory system.

Organ Systems Respiratory system facts: You breathe in 21% oxygen and .4% Carbon dioxide, you breathe out 16% oxygen and 4% carbon dioxide. You have the same surface area on you lungs as a tennis court. You breathe out about ½ of a liter of water per day. Your right lung is slightly larger than your left.

Organ Systems 9- Digestive System The digestive system breaks food down into nutrients that can be absorbed by the body. The mouth, liver, stomach, and intestines are some of the organs in the digestive system.

Organ Systems Digestive system facts: The average stomach can hold about 1.5 liters of food. Your intestines are lined with tiny projections called villi. They increase the surface area of your intestines so you can absorb as much as possible. Your intestines are about 15 meters long! Food stays in your stomach for 2-4 hours.

Organ Systems Which organ system do you think is most important? Which organ systems couldn’t function without other organ systems?