Sense Organ: The Skin worksheet - Free Printable

Let's solve this worksheet step by step.

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A. Identify the layers of the skin

The diagram shows a cross-section of the skin with three main layers, labeled by colored arrows:

1. Blue arrow (top layer) → Epidermis
- This is the outermost layer of the skin. It protects the body from pathogens and UV radiation. It contains keratinocytes and melanocytes.

2. Red arrow (middle layer) → Dermis
- This layer lies beneath the epidermis. It contains blood vessels, nerves, hair follicles, sweat glands, and sebaceous glands. It provides strength and elasticity.

3. Green arrow (bottom layer) → Hypodermis (or Subcutaneous layer)
- This is the deepest layer, made mostly of fat and connective tissue. It insulates the body and cushions internal organs.

✔ Answers:
- Blue → Epidermis
- Red → Dermis
- Green → Hypodermis

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B. Identify what your skin feels in contact with the objects or scenarios below

Now, we match each scenario to the appropriate sensation detected by the skin. The skin has receptors for:
- Touch/Pressure
- Pain
- Temperature (warm/cold)
- Itch
- Vibration

Let’s go through each one:

1. Touching a sandpaper
→ Rough texture → Touch / Pressure / Vibration
*(Sandpaper stimulates mechanoreceptors that detect pressure and texture)*

2. Bruise on the knee
→ Injury to underlying tissues → Pain
*(Pain receptors are activated due to tissue damage)*

3. A pat on the shoulder
→ Gentle touch → Touch / Pressure
*(Mechanoreceptors like Merkel cells and Pacinian corpuscles respond)*

4. Holding a glass of warm milk
→ Warm temperature → Warmth (Thermal sensation)
*(Thermoreceptors detect warmth)*

5. Touching the skin of pineapples
→ Rough, spiky surface → Touch / Pressure / Vibration
*(Similar to sandpaper – detects texture and pressure)*

6. Having an injection in the arm
→ Needle piercing skin → Pain
*(Needle activates nociceptors – pain receptors)*

7. Walking under the sun
→ Sunlight and heat → Warmth / Light (if UV is considered)
*(Thermoreceptors detect warmth; also, sunlight can trigger other sensory responses, but primarily warmth)*

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✔ Final Answers for Part B:

| Sensation | Scenario |
|---------|--------|
| Touch / Pressure / Vibration | touching a sandpaper |
| Pain | bruise on the knee |
| Touch / Pressure | a pat on the shoulder |
| Warmth | holding a glass of warm milk |
| Touch / Pressure / Vibration | touching the skin of pineapples |
| Pain | having an injection in the arm |
| Warmth | walking under the sun |

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Summary:

A. Layers of the Skin:
- Blue → Epidermis
- Red → Dermis
- Green → Hypodermis

B. Sensations:
1. Touching a sandpaper → Touch / Pressure / Vibration
2. Bruise on the knee → Pain
3. A pat on the shoulder → Touch / Pressure
4. Holding a glass of warm milk → Warmth
5. Touching the skin of pineapples → Touch / Pressure / Vibration
6. Having an injection in the arm → Pain
7. Walking under the sun → Warmth

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