Twelve things to know about… HUMAN ORGAN SYSTEMS 12T2K! Twelve things to know about… HUMAN ORGAN SYSTEMS

Thing 1: Systems are made of organs Every system in our body is made up of some number of organs. Each organ in a system is made up of some number of tissues. Tissues  Organs System Some organs belong to more than one system.

Thing 2: Integumentary system Covers and protects the body. Skin is the main organ of the integumentary system. Skin has several functions: Regulates body temperature Produces vitamin D Protects our body Helps us sense our surroundings

Thing 3: Skeletal system There are 206 bones in a normal adult. Functions of the skeletal system include: Support of body shape Protection Skull protects brain Ribs protect heart and lungs Vertebrae protect spinal cord Bone marrow makes blood cells and stores fat Mineral storage (calcium)

Thing 4: Muscular system There are three types of muscle Smooth muscle lines inside of hollow organs (stomach, blood vessels, bladder) and is involuntary. Cardiac muscle is in the heart and is involuntary. Skeletal muscle are attached to bones by tendons. These are voluntary muscles.

Thing 5: Nervous system The central nervous system is made up of the brain and spinal cord. The CNS has many functions, including: Sending messages Processing information Storing information Analyzing responses

The peripheral nervous system has two kinds of neurons (nerve cells). Sensory neurons send information about the environment to the CNS. Motor neurons send signals from the CNS to other body parts (muscles, etc.)

Thing 6: Circulatory system The body’s transport system. Delivers oxygen and nutrients to cells Removes waste products Main parts: Blood Blood vessels Heart

Two types of large blood vessels: Arteries carry blood away from the heart. Veins carry blood to the heart.

Thing 7: Respiratory system Allows for gas exchange (O2, CO2). Lungs are the main organs. Breathing is the movement of air in and out of lungs. Respiration is the exchange of gases.

Thing 8: Excretory system Remove wastes from blood. Kidneys are the main organs. Skin and lungs are part of excretory system, too.

Thing 9: Digestive system Three main functions: Take in food Break down food Gets rid of undigested material Many organs involved, including: Stomach Liver Intestines (large and small) Pancreas Gall bladder Esophagus

Thing 10: Endocrine system Endocrine organs produce hormones, chemical messengers that act on target cells and tissues. Organs (glands) include: Pituitary gland Thyroid gland Adrenal gland Many others

Thing 11: Reproductive system Main organs in males: Penis Testicles Main organs in females: Ovary Uterus Vagina

Thing 12: Immune system Protects against infection Skin, tears, and mucus membranes help prevent infectious particles from entering our body. White blood cells called B cells and T cells fight infection inside our body. B cells make antibodies. Anything that an antibody binds to is called an antigen.