Anatomy and Physiology Foundations

Anatomy describes structure; physiology describes function. Homeostasis is the body’s effort to maintain stable internal conditions. Illness and injury disturb that stability, and the body compensates through changes in heart rate, breathing, vascular tone, hormones, movement, and behavior. EMT students do not need to master every cell before class, but they should understand how systems depend on one another.

Air moves through the upper airway, trachea, bronchi, and smaller passages toward alveoli. Ventilation is movement of air; oxygenation involves loading oxygen into blood; gas exchange moves oxygen and carbon dioxide across membranes. The diaphragm is a major breathing muscle. Work of breathing, chest movement, speech, skin signs, and mental status help reveal whether the system is meeting the body’s needs.

The heart pumps through pulmonary and systemic circulation. Arteries carry blood away from the heart, veins return it, and capillaries support exchange with tissues. Pulse reflects a pressure wave, blood pressure reflects forces within the arterial system, and perfusion means delivering oxygenated blood to tissues. A normal-looking number does not guarantee adequate perfusion.

The brain, spinal cord, and peripheral nerves coordinate sensation, movement, consciousness, breathing, and automatic responses. The endocrine system uses hormones to regulate functions over time. Glucose regulation involves insulin and other hormones; stress responses can change pulse, breathing, skin, and mental status.

Bones provide structure and protection, joints permit movement, and muscles create force. Skin protects, senses, and regulates temperature. Digestive organs process nutrients and include the stomach, intestines, liver, gallbladder, and pancreas. Kidneys regulate fluid and waste. Symptoms frequently cross systems, so assessment should avoid tunnel vision.