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.