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Human A&P BIO 304 · American River College ← Course home (Week 2)

BIO 304 . WEEK 2 . FRIDAY . LAB WORKBOOK

Skin Functions and Accessory Structures

Hair, glands, nails, and the integrated functions of the integumentary system.

Print this page. You will draw your own diagrams from the directions below, then hand-label the structures listed. Drawing by hand is the integrity mechanism for this course.

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Part 1 of 2

Anatomy Lab

1A. What you will draw

Skin is more than a barrier. Today you'll draw the accessory structures that give skin its full range of function: hair follicles, sebaceous glands, two kinds of sweat glands, and nails.

Box A. Hair follicle and associated glands

Directions

  1. Draw a hair follicle in cross-section, extending from the epidermal surface deep into the dermis. The shaft of the hair sticks up above the surface.
  2. Label the hair shaft (above the skin), the hair root (below the surface), the hair bulb (the rounded base, where the hair grows).
  3. Draw a sebaceous gland attached to the side of the follicle, with its duct opening into the follicle. Label.
  4. Draw the arrector pili muscle: a thin smooth muscle attached at an angle from the follicle to the underside of the epidermis. Label.
  5. Note: when arrector pili contracts, the hair stands up (goosebumps) and a small amount of sebum is squeezed from the gland.

Box B. Sweat glands and nail

Directions

  1. Left half: draw two sweat glands side by side, each deep in the dermis with a duct rising to the surface.
  2. Label the eccrine sweat gland (smaller, opens directly onto skin surface, found over most of the body) and the apocrine sweat gland (larger, opens into a hair follicle, found in axillae and groin).
  3. Right half: draw a nail in side view. Show the nail plate (the visible nail), the nail bed (skin beneath the nail), the nail root (under the proximal skin fold), and the lunula (white half-moon at the base).
  4. Label every structure.

1C. Structures to label (12)

After you finish each drawing, label every structure below directly on your sketch.

  1. Hair shaft
  2. Hair root
  3. Hair bulb
  4. Hair follicle
  5. Sebaceous gland
  6. Arrector pili muscle
  7. Eccrine sweat gland
  8. Apocrine sweat gland
  9. Nail plate
  10. Nail bed
  11. Nail root
  12. Lunula

Part 2 of 2

Physiology Lab

2A. Trace: cold exposure to warming response

A person steps outside into freezing air. Trace the integumentary system's response in numbered steps. Include receptors, control center, and effectors from this week. Aim for 6 to 8 steps.

2B. Synthesis questions

Answer each in 2 to 4 sentences. Use the language from this week's lecture and your drawings as evidence.

1. Eccrine sweat is mostly water and electrolytes. Apocrine sweat is rich in lipids and proteins. Predict (a) which type contributes most to body cooling during exercise, and (b) which is responsible for body odor when bacteria are present. Justify each.
2. A burn patient loses large patches of skin. Beyond fluid loss and infection risk, predict the consequences for thermoregulation in a cool hospital room, and explain why blankets and warmed IV fluids are routine in burn care.
3. Sebaceous glands secrete sebum, an oily mixture. People with acne often have overactive sebaceous glands. Explain mechanistically why blocked sebaceous ducts plus bacterial colonization produce inflamed pimples.

3. What to submit

Complete both the Anatomy Lab (your own drawings, hand-labeled, plus the structures list) and the Physiology Lab (activity and synthesis questions). Photograph or scan every page and upload to Canvas before the deadline listed on the schedule. Hand-drawn, hand-labeled work is the integrity mechanism for this course. Typed or AI-generated diagrams are not accepted.