Anatomy explores the structures of the human body and how they fit together to keep us moving, breathing, thinking, and growing.
Human anatomy studies the body's structures, from individual bones and muscles to complete organ systems. Learning anatomy helps explain how different parts of the body are arranged and how those structures support important functions such as movement, circulation, breathing, digestion, sensation, and communication between organs.
The body is organized into interconnected systems that share jobs and resources.
Learn MoreBones support the body, protect organs, store minerals, and provide attachment points for muscles.
Learn MoreMuscle tissue creates movement, helps maintain posture, and powers actions inside the body.
Learn MoreThe cardiovascular system moves blood, oxygen, nutrients, hormones, and wastes through the body.
Learn MoreThe respiratory and digestive systems bring in oxygen and nutrients the body needs.
Learn MoreThe brain, spinal cord, and nerves help the body sense, process, and respond to information.
Learn MoreThe human body contains many organ systems, including the skeletal, muscular, cardiovascular, respiratory, digestive, nervous, endocrine, urinary, reproductive, immune, and integumentary systems. Each system has specialized structures, but none works entirely alone. For example, muscles need oxygen delivered by the cardiovascular system, while nerves help coordinate muscle movement. Anatomy focuses on where these structures are located and how they connect, while physiology focuses more on how they function.
The adult human skeleton usually contains 206 bones, although the exact count can vary because some small bones may fuse or differ among individuals. Bones provide a strong framework for the body, protect structures such as the brain and spinal cord, and work with joints and muscles to make movement possible. Bone is living tissue that can remodel itself over time. Bone marrow inside certain bones also helps produce blood cells.
Human muscle tissue occurs in three main types: skeletal, cardiac, and smooth muscle. Skeletal muscles attach to bones and produce most voluntary body movements. Cardiac muscle forms the heart and contracts rhythmically to pump blood. Smooth muscle is found in places such as the walls of the digestive tract and blood vessels, where it helps move materials and adjust the size of internal passageways without conscious control.
The heart is a muscular organ that pumps blood through a network of blood vessels. Arteries generally carry blood away from the heart, while veins generally return blood toward it, and tiny capillaries allow materials to move between blood and body tissues. The circulatory system distributes oxygen and nutrients, transports chemical signals such as hormones, and carries carbon dioxide and other wastes toward organs that remove or process them.
The respiratory system brings air into the lungs, where oxygen can move into the blood and carbon dioxide can move out. The digestive system breaks food into smaller molecules that can be absorbed and used by cells. Structures such as the mouth, stomach, intestines, liver, and pancreas all contribute to digestion. Together, these systems help supply the materials cells need to release energy and build or repair body tissues.
The nervous system includes the brain, spinal cord, and a vast network of nerves. Sensory receptors detect changes inside and outside the body, nerves carry signals, and the brain and spinal cord process much of that information. The nervous system can then help coordinate responses such as movement, changes in heart rate, reflexes, and attention. Different regions of the brain specialize in different tasks, but they work together as connected networks rather than as completely separate units.