Human A&PBIO 304 · American River College ← Week 2 pre-work

BIO 304 · Week 2 · Interactive Workbook

Skin Functions and Accessory Structures

Type your answers, draw in the boxes or upload a photo of your hand drawing, then use Save as PDF to submit. Your work saves on this device as you go.

Paste attempts0

Your work autosaves on this device.

Open the full notes →

Part 1 of 4 · Recall

Fill in the blanks

Type the term that completes each statement, using the word bank. Pull it from memory first.

Word bank

Barrier (physical, chemical, biological)ThermoregulationSensationVitamin D synthesisLimited excretionHair follicleSebaceous glandEccrine sweat glandApocrine sweat glandNail

  1. Keratin and lipids in the epidermis block water loss and pathogen entry. · Acid mantle (pH 4 to 6) discourages microbial growth.
  2. Sweat glands: evaporation cools the body. · Dermal vessels dilate or constrict: dump heat or conserve it.
  3. Meissner (light touch), Pacinian (pressure), Ruffini (stretch), free nerve endings (pain, temperature).
  4. UV-B converts 7-dehydrocholesterol in the epidermis to cholecalciferol (D3).
  5. Sweat carries small amounts of urea, salts, and water.
  6. Anchored in dermis. Arrector pili muscle pulls hair upright (goosebumps). Sensory function via root hair plexus.
  7. Connected to hair follicle. Secretes sebum (oily, antimicrobial). Acne starts when these clog.
  8. Throughout body surface. Watery sweat for thermoregulation. Independent of hair follicles.
  9. Axillae, groin, areolae. Develops at puberty. Thicker secretion, bacterially modified to produce body odor.
  10. Hard keratin plate over the nail bed. Protects the distal phalanx and improves fine motor function.

Define it: high-yield vocabulary

Write a clear definition in your own words for each term.

  1. Thermoregulation
  2. Barrier (protection)
  3. Cutaneous sensation
  4. Vitamin D synthesis
  5. Sudoriferous (sweat) gland
  6. Sebaceous gland
  7. Hair follicle
  8. Arrector pili muscle
  9. Nail

Part 2 of 4 · Anatomy lab

Draw and label

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.
Color Size Tool
Your uploaded drawing for Box A. Hair follicle and associated glands

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.
Color Size Tool
Your uploaded drawing for Box B. Sweat glands and nail

Structures to label

Label each on your drawing.

  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 3 of 4 · Physiology lab

Reason it through

A. Trace: cold exposure to warming response

Explain the main idea of this topic.

B. Synthesis

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.

Submit

Save as PDF, then upload to Canvas.

The exported PDF stamps your name and paste-attempt count. Drawn-here or hand-drawn diagrams only; typed or AI-generated diagrams are not accepted.

Submit on Canvas →