Anatomy and Physiology for First Aid

Circulatory system

Circulatory system (click to view)

Nervous system

Nervous system (click to view)

First aid responders should have at least a passing understanding of the structures (anatomy) and functions (physiology) of the human body. This knowledge can assist you with patient assessment, patient care, and emergency communication and reporting.

Medical Terminology

Having a grasp of medical terminology gives you a common language to use when completing incident reports and communicating with other emergency workers.

  • Other notable terms
    • Acute vs. chronic (
    • Adult vs. child for first aid/CPR - An infant is under 1 year old; a child is 1 to about 12; an adult is older than 12. For AED use, a child is under 8 and/or weighing less than 55 pounds.
    • Basic life support (BLS) vs. advanced life support (ALS) (Health Ed Solutions) - Although most lifeguards are not certified BLS providers, they are trained to administer many BLS first aid/CPR techniques. ALS is sometimes referred to as advanced cardiac life support (ACLS).
    • Casualty vs. patient vs. victim
      • casualty is a person or thing injured, lost, or destroyed. This term is used in military or disaster contexts to report the number of dead or wounded victims. Casualty is also often used in British English to describe the victim of an illness or injury.
      • victim is one who suffers adverse effects of a force, agent, or circumstance; one who is tricked, injured, or destroyed. A victim of an illness or injury can be recognized, rescued, and approached if safe to do so. The victim becomes a patient when assessment, first aid care, or medical treatment begin.
      • patient is one who receives medical care. The victim becomes a patient when assessment and first aid care begin; the patient becomes a victim or casualty if conditions do not improve and his or her life is lost.
    • Signs vs. symptoms (MedicalNewsToday)

The Human Organism

The human body consists of trillions of cells that contribute to body functioning. A cell is the smallest structural unit of living matter capable of independence and specialization. Groups of similar cells form tissues, the basic structures of the body. Body tissues include skin, hair, fat, muscle, nerves, and bone. Tissues make up organs, including vital organs like the brain, heart, and lungs.

Body Systems

Body systems are collections of organs and other tissues that work together to perform a function needed for life. They include the circulatory, digestive, endocrine, genitourinary, immune,  integumentary, musculoskeletal, nervous, and respiratory systems.