RMA Exam

The chapters move from the way the body is organized, through each organ system, to wellness and prevention. Each system follows the same pattern: structures, main functions, then common disorders with key signs and typical office tests. Remember throughout that the medical assistant observes, measures, documents and educates; the provider diagnoses and prescribes.

This chapter covers the levels of organization in the body, anatomical position, directional terms, body planes, body cavities, and the two systems used to divide the abdomen into areas. These terms appear in charting, in provider orders and in many exam stems, so learn them until they are automatic.

The body is built in layers, from the smallest unit to the whole person. A cell is the smallest living unit of the body. A tissue is a group of similar cells that work together. An organ is made of two or more tissue types that perform a specific job. An organ system is a group of organs that work together for a major body function. The organism is the complete living person.

Key cell parts appear on the exam. The cell membrane controls what enters and leaves the cell. The nucleus holds DNA, the genetic material, and directs cell activity. Mitochondria produce energy in the form of ATP and are often called the powerhouse of the cell. Ribosomes make proteins. The cytoplasm is the gel-like fluid that fills the cell and holds the organelles.

The four basic tissue types are epithelial tissue (covers surfaces and lines cavities, such as skin and the lining of the stomach), connective tissue (supports and binds, such as bone, cartilage, fat and blood), muscle tissue (contracts to produce movement) and nervous tissue (carries electrical signals).

Homeostasis is the body's ability to keep a stable internal environment, such as a steady temperature, blood pressure and blood glucose. Most body controls use negative feedback, in which a change triggers a response that reverses the change. Sweating when body temperature rises is a classic example.

Anatomical position is the standard reference position: the body stands upright, faces forward, arms at the sides with palms facing forward, feet flat and slightly apart. All directional terms assume the patient is in anatomical position, even if the patient is lying down. Left and right always mean the patient's left and right, not yours. Supine means lying face up and prone means lying face down; bilateral means both sides.

A plane is an imaginary flat surface that divides the body into sections. Planes are used in imaging reports such as CT and MRI.

Body cavities are spaces that hold and protect organs. The two main groups are the dorsal cavity and the ventral cavity.

The diaphragm, a dome-shaped muscle, separates the thoracic cavity from the abdominopelvic cavity. Inside the thoracic cavity, the mediastinum is the central space that holds the heart, great vessels, esophagus and trachea. Each lung sits in its own pleural cavity, and the heart sits in the pericardial cavity. The kidneys are retroperitoneal, meaning they lie behind the peritoneum, the membrane that lines the abdominal cavity.

Providers describe abdominal pain and findings using either four quadrants or nine regions. Quadrants are drawn with one vertical and one horizontal line crossing at the umbilicus (navel).

The nine-region system uses two vertical and two horizontal lines, like a tic-tac-toe grid.

Clinic Scenario: A patient calls and says she has sharp pain "in the lower right side of my belly" that began near her navel and is getting worse, with nausea and a low fever. The medical assistant recognizes that pain migrating from the umbilical area to the right lower quadrant is a classic warning sign of appendicitis. The MA does not diagnose or give advice, but follows the office triage protocol, notifies the provider immediately and documents the call, since this patient likely needs same-day evaluation or emergency care.

• The body is organized from cells to tissues, organs, systems and the whole organism; homeostasis keeps the internal environment stable.
• All directional terms assume anatomical position and refer to the patient's own left and right.
• Proximal and distal apply to limbs; superior and inferior apply to the trunk.
• Sagittal planes divide right and left, frontal (coronal) planes divide front and back, and transverse planes divide top and bottom.
• The appendix lies in the right lower quadrant (right iliac region), and the liver and gallbladder lie in the right upper quadrant.