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.

Digestive System

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.