An overview of the basic concepts of anatomy and physiology, focusing on the structure and functions of the human body as they relate to medical imaging.
Introduction to Anatomy & Physiology
Key concepts, terminology, and organizational levels that form the foundation for studying the human body.
| Discipline | Focus | Typical Questions |
|---|---|---|
| Anatomy | Structure – the shape, location, and relationships of body parts. | Where is the heart? What are the layers of skin? |
| Physiology | Function – how those structures work and interact. | How does the heart pump blood? What triggers muscle contraction? |
Together they answer “what” and “how” the body operates as an integrated system.
| Level | Description | Example |
|---|---|---|
| Chemical | Atoms → molecules (e.g., water, proteins). | ATP, DNA |
| Cellular | Basic unit of life; specialized for tasks. | Neuron, erythrocyte |
| Tissue | Groups of similar cells + extracellular matrix. | Muscle tissue, epithelial tissue |
| Organ | Two or more tissue types performing a specific function. | Stomach, kidney |
| Organ System | Organs working together toward a common goal. | Digestive system |
| Organism | The complete human body, a functional whole. | Homo sapiens |
Mnemonic: Cells Teams Organize Systems Organisms → CTOSO.
| Term | Meaning | Example |
|---|---|---|
| Anterior / Ventral | Toward the front (belly side). | Chest is anterior to the spine. |
| Posterior / Dorsal | Toward the back. | Scapula is posterior to the ribs. |
| Superior / Cranial | Toward the head or upper part. | The nose is superior to the mouth. |
| Inferior / Caudal | Toward the feet or lower part. | The pelvis is inferior to the abdomen. |
| Medial | Toward the midline. | The big toe is medial to the little toe. |
| Lateral | Away from the midline. | The ears are lateral to the nose. |
| Proximal | Near the point of attachment (limbs). | The elbow is proximal to the wrist. |
| Distal | Far from the point of attachment. | The fingers are distal to the elbow. |
| Superficial | Near the surface. | Skin is superficial to muscle. |
| Deep | Farther from the surface. | Bones are deep to skin. |
| Planes | Imaginary cuts used to describe sections. | Sagittal, frontal (coronal), transverse. |
| Directions | Movements relative to joints. | Flexion, extension, abduction, adduction, rotation. |
| Cavity | Major Organs Inside | Protective Membrane |
|---|---|---|
| Dorsal (Posterior) Body Cavity | - Cranial cavity (brain) - Spinal (vertebral) cavity (spinal cord) |
Meninges (dura, arachnoid, pia) |
| Ventral (Anterior) Body Cavity | - Thoracic cavity (heart, lungs) - Abdominal cavity (stomach |