2.1 Body Organization & Integumentary System
Key Takeaways
- The body is organized hierarchically: atoms → molecules → cells → tissues → organs → organ systems → organism
- Four basic tissue types are epithelial (covers/lines), connective (supports/connects), muscle (movement), and nervous (transmits signals)
- Body planes include sagittal (left/right), coronal/frontal (front/back), and transverse/horizontal (top/bottom)
- Directional terms like anterior/posterior, superior/inferior, medial/lateral, and proximal/distal are essential for accurate medical documentation
- The integumentary system has three layers: epidermis (outer), dermis (middle with blood vessels and nerves), and subcutaneous/hypodermis (fat layer)
- Skin functions include protection, temperature regulation, sensation, vitamin D synthesis, and excretion through sweat glands
Last updated: March 2026
Body Organization & Integumentary System
Understanding the structural organization of the human body and the integumentary system is foundational to all clinical practice. The CCMA exam tests your ability to identify body structures, apply directional terminology, and understand how the skin protects the body.
Levels of Body Organization
| Level | Description | Examples |
|---|---|---|
| Chemical | Atoms and molecules | Water, glucose, DNA, electrolytes |
| Cellular | Basic unit of life | Red blood cells, neurons, white blood cells |
| Tissue | Groups of similar cells working together | Epithelial, connective, muscle, nervous |
| Organ | Two or more tissue types working together | Heart (muscle + connective + nervous tissue) |
| Organ System | Group of organs with a common function | Cardiovascular system (heart + blood vessels) |
| Organism | All organ systems functioning together | The human body |
Four Basic Tissue Types
| Type | Function | Examples | Locations |
|---|---|---|---|
| Epithelial | Covers surfaces, lines cavities, forms glands | Skin, mucous membranes, glands | Skin surface, GI tract lining, blood vessel lining |
| Connective | Supports, protects, binds structures | Bone, cartilage, blood, adipose, tendons | Throughout the body |
| Muscle | Produces movement through contraction | Skeletal, smooth, cardiac | Attached to bones, organ walls, heart |
| Nervous | Transmits electrical impulses | Neurons, neuroglia | Brain, spinal cord, nerves |
Muscle tissue subtypes:
- Skeletal — Voluntary, striated, attached to bones (you control it)
- Smooth — Involuntary, non-striated, found in organ walls (GI tract, blood vessels, bladder)
- Cardiac — Involuntary, striated, found only in the heart (self-excitatory)
Body Planes
| Plane | Orientation | Divides Body Into |
|---|---|---|
| Sagittal | Vertical, lengthwise | Left and right portions |
| Midsagittal (median) | Sagittal through the exact center | Equal left and right halves |
| Coronal (frontal) | Vertical, side to side | Anterior (front) and posterior (back) |
| Transverse (horizontal) | Horizontal | Superior (upper) and inferior (lower) |
Directional Terms
| Term | Meaning | Opposite | Example |
|---|---|---|---|
| Anterior (ventral) | Front | Posterior (dorsal) | The sternum is anterior to the spine |
| Posterior (dorsal) | Back | Anterior (ventral) | The spine is posterior to the sternum |
| Superior (cranial) | Toward the head | Inferior (caudal) | The heart is superior to the stomach |
| Inferior (caudal) | Toward the feet | Superior (cranial) | The stomach is inferior to the heart |
| Medial | Toward the midline | Lateral | The nose is medial to the ears |
| Lateral | Away from the midline | Medial | The ears are lateral to the nose |
| Proximal | Closer to the trunk | Distal | The elbow is proximal to the wrist |
| Distal | Farther from the trunk | Proximal | The fingers are distal to the wrist |
| Superficial | Near the surface | Deep | The skin is superficial to the muscle |
| Supine | Lying face up | Prone | Patient is supine for an abdominal exam |
| Prone | Lying face down | Supine | Patient is prone for a back examination |
Body Cavities
| Cavity | Location | Contents |
|---|---|---|
| Cranial | Skull | Brain |
| Spinal (vertebral) | Vertebral column | Spinal cord |
| Thoracic | Chest | Heart, lungs, esophagus, trachea, great vessels |
| Abdominal | Abdomen | Stomach, intestines, liver, gallbladder, spleen, kidneys, pancreas |
| Pelvic | Below abdominal | Bladder, reproductive organs, rectum |
Integumentary System
Three Layers of Skin:
| Layer | Depth | Key Structures | Function |
|---|---|---|---|
| Epidermis | Outermost | Keratinocytes, melanocytes, Langerhans cells | Protection, waterproofing, UV protection |
| Dermis | Middle | Blood vessels, nerve endings, hair follicles, sweat/sebaceous glands | Sensation, thermoregulation, nutrition |
| Subcutaneous (Hypodermis) | Deepest | Adipose tissue (fat), larger blood vessels | Insulation, energy storage, cushioning |
Skin Functions:
- Protection — Barrier against pathogens, UV radiation, chemical exposure, and physical trauma
- Temperature regulation — Sweating (cools), vasoconstriction (conserves heat), vasodilation (releases heat)
- Sensation — Touch, pressure, pain, temperature detected by nerve receptors
- Vitamin D synthesis — UV light converts cholesterol in the skin to vitamin D
- Excretion — Sweat removes small amounts of waste (urea, salts)
Common Skin Conditions:
- Eczema (dermatitis) — Itchy, inflamed skin patches
- Psoriasis — Thick, scaly, red patches with silvery scales
- Burns — First degree (epidermis), second degree (epidermis + dermis), third degree (all layers)
- Skin cancer — Basal cell carcinoma (most common), squamous cell carcinoma, melanoma (most dangerous)
- Cyanosis — Bluish skin from low oxygen
- Jaundice — Yellowish skin from elevated bilirubin
- Erythema — Redness of the skin
- Urticaria (hives) — Raised, itchy welts from allergic reaction
Test Your Knowledge
Which body plane divides the body into anterior and posterior portions?
A
B
C
D
Test Your Knowledge
A second-degree burn involves damage to which skin layers?
A
B
C
D
Test Your Knowledge
The term "proximal" in anatomy means:
A
B
C
D