Chapter 19: The Human Body Section 1: Body Systems
Bones provide structure; muscles allow movement! • All the bones in your body make up your skeletal system. The skeletal system gives shape and support to the body. • The place where two or more bones come together is called a joint. Joints make movement possible. • The skin forms a protective covering for the body, is a sense organ, helps control body temperature, and helps provide vitamin D. • A muscle is an organ that can relax, contract, and provide force to move body parts. • Muscles you CHOOSE to move are voluntary – those that you CANNOT control are involuntary.
Digestive System • Food is broken down in the digestive system; undigested food is eliminated. • Food travels through the mouth, esophagus, stomach, small intestine, and large intestine. • Most digestion and absorption of food occurs in the small intestine; water is absorbed in the large.
Nutrients!! • The six main kinds of nutrients are proteins, carbohydrates, lipids, vitamins, minerals, and water. • Proteins, carbohydrates, lipids, and vitamins are organic nutrients. • Minerals and water are inorganic nutrients. Your cells need water to carry out important chemical reactions.
Urinary System • The kidneys are the main organs of the urinary system. Their function is to filter the blood and to remove wastes.
Respiratory System • Works with circulatory system to supply oxygen to cells • Helps move oxygen into the body and waste gases out of the body • The bronchi of the lungs branch into bronchioles, which end in alveoli • Air leaves the alveoli and enters tiny blood vessels called capillaries
Circulatory System • Made up of the heart, blood vessels, and blood. The heart pumps blood to all the cells of the body. • Red blood cells carry oxygen. White blood cells fight infections and heal wounds. • The four major blood types are A, B, AB, O. • Lymphatic system collects tissue fluid and returns it to the blood.
Immune System • In specific immunity, the body makes antibodies that destroy disease-causing organisms • The skin and respiratory, digestive, and circulatory systems block or destroy many disease-causing organisms
Nervous and Endocrine Systems • The brain, spinal cord, and nerve receptors make up the nervous system. • The nervous system sends messages to and from the brain to all parts of the body. • A reflex is an involuntary, automatic response to a stimulus. Reflexes help protect your body by allowing your body to respond without your having to think about what to do. • In the endocrine system, chemicals called hormones carry messages throughout the body.
Human Reproduction • The male reproductive system has both internal and external organs. • The testes produce the male hormone testosterone and sperm, the male reproductive cells. • Fluid from seminal vesicles mixes with sperm to form semen. • Semen leaves the body through the urethra.
Human Reproduction • The organs of the female reproductive system are internal. • Ovaries are the female sex organs that produce eggs and the hormone estrogen. • An egg is released from an ovary roughly every 28 days – a process called ovulation. • The monthly cycle of changes in the sexually mature female reproductive system in the menstrual cycle. • The menstrual cycle has three phases. Ovulation occurs at the end of phase two.
Human Reproduction • Human development goes through many stages. • Development begins with fertilization – joining of a sperm and an egg. • During childhood growth is rapid and the child learns many new skills. • Adolescence includes puberty and a final growth spurt. • During adulthood the muscular and skeletal systems stop growing.