Integumentary System Review Worksheet KEY ( Physio) 2013-2014 ... - Free Printable

The image you've uploaded is a completed review worksheet for the integumentary system, which includes answers and explanations. Below is a detailed breakdown and explanation of each section to help reinforce understanding:

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🔹 Objective: Describe the structure and functions of the skin

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✔ 1. List the 5 functions of the integumentary system:

A. Body temperature regulation
- The skin helps regulate body temperature through sweat glands (cooling via evaporation) and blood vessels in the dermis (vasoconstriction/vasodilation).

B. Protection
- Acts as a physical barrier against pathogens, UV radiation, chemicals, and mechanical injury.

C. Cutaneous Sensations
- Contains sensory receptors (e.g., touch, pressure, pain, temperature) that detect external stimuli.

D. Excretion and absorption
- Sweat glands excrete small amounts of waste (like urea and salts).
- Skin can absorb certain substances (e.g., topical medications, some toxins).

E. Synthesis of Vitamin D
- When exposed to sunlight (UVB rays), the epidermis converts cholesterol into vitamin D₃, essential for calcium absorption.

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✔ 2. True or False: "The dermis is superficial to the epidermis."

Answer: False

Explanation:
- Superficial means closer to the surface.
- The epidermis is the outermost layer, so it is superficial to the dermis.
- The dermis lies beneath (deep to) the epidermis.
- Therefore, saying the dermis is superficial to the epidermis is incorrect.

> ✔️ Correct statement: *The epidermis is superficial to the dermis* OR *The dermis is deep to the epidermis.*

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✔ 3–5. Match the skin structure to its tissue type:

#### 3. Epidermis: D → Stratified Squamous Epithelial
- The epidermis is composed of stratified squamous epithelium (keratinized in thick skin).
- This tissue provides durability and protection.

#### 4. Dermis: F & I → Areolar Connective Tissue & Dense Irregular Connective Tissue
- The dermis has two layers:
- Papillary layer: Made of areolar connective tissue (loose, flexible).
- Reticular layer: Made of dense irregular connective tissue (strong, supports skin).
- So both F and I are correct.

#### 5. Subcutaneous: F & G → Areolar Connective Tissue & Adipose Connective Tissue
- The subcutaneous layer (hypodermis) consists of:
- Adipose tissue (G) – stores fat, insulates, cushions.
- Areolar connective tissue (F) – connects skin to underlying tissues.

> ⚠️ Note: It’s not always dense regular (H) or simple epithelia (A–E); those don’t apply here.

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✔ 6. Label the following view of the skin:

This diagram shows a cross-section of the skin with labeled structures. Here's what each label refers to:

| Structure | Description |
|---------|-------------|
| Epidermis | Outermost layer; stratified squamous epithelium; no blood vessels. |
| Dermis | Middle layer; contains blood vessels, nerves, hair follicles, glands. |
| Subcutaneous Layer | Deepest layer; adipose and loose connective tissue; anchors skin to muscles. |
| Free Nerve Ending | Sensory receptor detecting pain, temperature, light touch. Found in epidermis and dermis. |
| Arrector Pili Muscle | Smooth muscle attached to hair follicle; causes "goosebumps" when contracted. |
| Eccrine Sweat Gland | Coiled tubular gland in dermis; produces sweat for thermoregulation (all over body). |
| Apocrine Sweat Gland | Larger gland near hair follicles; found in axillae, groin; secretes viscous fluid (odor-related). |

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🧠 Summary of Key Concepts

| Layer | Tissue Type | Function |
|------|-------------|--------|
| Epidermis | Stratified Squamous Epithelium | Protection, keratin production |
| Dermis | Areolar + Dense Irregular CT | Support, blood supply, sensation, glands |
| Subcutaneous | Adipose + Areolar CT | Insulation, cushioning, energy storage |

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💡 Final Notes:

- Skin layers from superficial to deep: Epidermis → Dermis → Subcutaneous (hypodermis)
- Tissue types vary by layer — epithelial in epidermis, connective in dermis/subcutaneous.
- Sweat glands differ: eccrine (thermoregulation), apocrine (pheromones, scent).
- Hair follicles have associated arrector pili muscles and sebaceous glands.

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✔ This worksheet effectively reviews anatomy, histology, and physiology of the integumentary system. The provided key is accurate and well-explained.

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