Body Systems

Cell

Basic unit of all living things, e.g., blood cells, nerve cells, bone cells

Tissue

Made up of cells to perform a specific activity, e.g., muscles, nerves, epithelial and connective

Organ

Made up of tissues that work together to perform a specific activity, e.g., heart, brain, skin

Organ System

Groups of organs working together to maintain homeostasis, e.g., digestive, nervous, skeletal

Organism

Entire living things capable of carrying out basic life processes, e.g., bacteria, human

Muscle Tissue

Contracts and relaxes to move organs, found throughout the body, e.g., biceps, heart, veins

Nerve Tissue

Sends and receives signals to and from organs, e.g., brain, nerves, spinal cord

Connective Tissue

Supports organs, connects them, e.g., cartilage, bones, tendons

Epithelial Tissue

Lines internal and external organs, e.g., skin, hair, nails

Integumentary System

Protects organs, regulates temperature, includes skin, hair, nails

Skeletal System

Supports, moves, protects the body, produces blood cells, stores calcium

Muscular System

Moves the body, maintains posture, includes muscles and tendons

Nervous System

Transmits signals throughout the body, includes brain, spinal cord, nerves

Circulatory System

Carries gases and nutrients, regulates body temperature, includes heart, blood vessels

Respiratory System

Transfers oxygen to blood, expels carbon dioxide, includes lungs, trachea

Excretory System

Discharges waste, regulates water levels, includes kidneys, bladder

Digestive System

Converts food into energy, absorbs nutrients, eliminates waste, includes mouth, intestines

Endocrine System

Produces hormones for various functions, e.g., metabolism, growth, sexual function

Immune System

Protects against disease, includes lymph nodes, white blood cells, spleen