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Review Notes #8 Human Systems Organization • Cells – basic unit of living things, each have specific function. • Tissue – small group of cells acting together. • Ex. Muscle, blood, skin. • Organ – large group of tissues working together • Ex. Heart has blood, muscle, and nerve tissue • Organ system – group of organs working together. • All body systems work together to maintain homeostasis Skeletal System • Supports and protects the body and organs. • Bones are hard strong material. • Cartilage is the flexible material between bones that acts as a cushion. • Joints are where bones are connected to other bones. • 3 types – see diagram Tendons and Ligaments • Tendons – Attach muscle to bone so that the muscle can move. • Ligaments attach bone to bone. Muscular System • Muscle tissues contract to move bones or organs. • Voluntary muscle – moved by your will. • Provide locomotion • Involuntary Muscle – called smooth muscles, move without us thinking about it. • Ex. Heart and blood vessels. The Nervous System • Brain – receives and interprets nerve impulses. • Controls voluntary and involuntary muscles. • Spinal Chord – channels impulses to and from brain • Controls reflexes. • Nerves – provides communication between all organs and tissues. The Endocrine System • Made up of glands • A gland is an organ that secretes hormones. • Ex. Adrenaline Gland. • Endocrine and nervous system allow the body to respond to stimuli. The Digestive System • Breaks down food that can be absorbed and carried to cells. • The digestive tract is the path through which food travel. • Mouth, esophagus, stomach, small intestine, large intestine. • Accessory organs produce digestive juices to help breakdown food. • Ex. Pancreas, liver, gallbladder Digestive System cont’d • Food is physically broken down by chewing and chemically broken down by digestive juices. • Most nutrients are absorbed in the small intestine. • Solid waste is passed through the large intestine. The Circulatory System • Transports materials via blood. • Carries oxygen, nutrients, and water to cells. • Carries carbon dioxide and waste away from the cells. The Blood • Blood contains plasma, red and white blood cells and platelets. • Red blood cells contain hemoglobin which carries oxygen to the cells. The Heart • The heart is a muscle which pumps blood through out the body. • In the lungs it receives oxygen and gets rid of carbon dioxide. • Oxygenated blood returns to the heart and is pumped to the rest of the body. Blood Vessels • Arteries – carry blood away from the heart. • Veins – returns blood to the heart. • Capillaries - connect veins and arteries. • Capillaries allow nutrients to pass through them into other cells of the body. The Respiratory System • This system takes in oxygen so that the cells may undergo respiration. • Oxygen is combined with digested food and is burned to produce energy. • This system gets rid of the carbon dioxide produced. Respiratory Path • When you inhale, air enters through the nose or mouth, through the trachea, into the bronchi, into tiny air sacs in the lungs that are surrounded by capillaries. • At these capillaries, gases are exchanged. The Excretory System • Removes waste from the body. • Lungs – rid the body of water vapor and carbon dioxide when exhaling. • The skin – Removes waste when you perspire through the pores in your skin. More Excretory System • Liver- removes harmful substances from the blood and produces urea. Urea is sent to the kidneys. • The Kidneys – filter out excess water, salt, and urea from the blood. • This makes up urine which is sent to the bladder and excreted.