Definition: Cellular metabolism refers to the chemical processes in cells that break down nutrients and produce energy.

Highlight: The skeletal system not only provides structure but also produces both red and white blood cells in the bone marrow.

Example: The diaphragm, working with the respiratory system, contracts and relaxes to enable breathing.

Vocabulary: Alveoli are tiny air sacs in the lungs where gas exchange occurs.

Definition: Hormones are chemical messengers that regulate body functions and maintain homeostasis.

Highlight: The immune system uses specialized white blood cells called T cells and B cells to fight infections.

Example: When you exercise, your muscular system works with the skeletal system to enable movement while the endocrine system releases hormones to regulate energy use.

Vocabulary: Macrophages are large white blood cells that engulf and destroy harmful substances.

Definition: The integumentary system includes the skin, hair, nails, and associated glands.

Highlight: The lymphatic system acts as a secondary circulatory system, reaching areas between cells that blood vessels cannot access.

Example: When you get hot, sweat glands in your skin release moisture to cool you down through evaporation.

Vocabulary: Sebaceous glands produce oil that helps waterproof and protect the skin.

Definition: Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes.

Example: When blood sugar drops, the hypothalamus triggers hunger signals, making your stomach growl.

Highlight: The circulatory system interacts with nearly every other body system, making it crucial for survival.

Vocabulary: Neurons are specialized nerve cells that transmit information throughout the body.