Study Guide - Integumentary System Course
A comprehensive review of every topic covered in the integumentary system course. Use this guide for exam prep, quick revision, or as a reference while studying.
Test your knowledge with the Integumentary System Game.
| Term | Definition |
|---|---|
| Integumentary system | Organ system comprising the skin, hair, nails, and glands |
| Epidermis | Outermost skin layer - avascular stratified squamous epithelium |
| Dermis | Middle skin layer - connective tissue with blood vessels and nerves |
| Hypodermis | Subcutaneous layer - adipose tissue for insulation and energy storage |
| Keratinocytes | Most abundant epidermal cells - produce keratin for waterproofing |
| Melanocytes | Cells that produce melanin pigment for UV protection |
| Langerhans cells | Dendritic immune cells in epidermis - antigen presentation |
| Merkel cells | Touch receptors in stratum basale |
| Stratum basale | Deepest epidermal layer - stem cells undergoing constant mitosis |
| Stratum corneum | Outermost epidermal layer - dead, flat, keratinized cells that shed |
| Keratinization | Process of keratinocytes filling with keratin as they migrate to surface |
| Melanin | Pigment protecting DNA from UV damage |
| Collagen | Protein providing tensile strength to the dermis |
| Elastin | Protein providing elastic recoil to the dermis |
| Papillary dermis | Upper dermis - dermal papillae, capillaries, Meissner's corpuscles |
| Reticular dermis | Lower dermis - dense connective tissue, hair follicles, glands |
| Meissner's corpuscles | Light touch receptors in papillary dermis |
| Pacinian corpuscles | Deep pressure and vibration receptors in reticular dermis |
| Arrector pili | Smooth muscle causing goosebumps when contracted |
| Anagen | Active hair growth phase (2-7 years for scalp hair) |
| Catagen | Hair regression phase (2-3 weeks) |
| Telogen | Hair resting phase (~3 months) before shedding |
| Eccrine glands | Sweat glands for thermoregulation - watery secretion |
| Apocrine glands | Sweat glands in axillae/groin - thicker secretion, body odor |
| Sebaceous glands | Oil glands producing sebum to lubricate skin and hair |
| Sebum | Oily secretion that waterproofs and has antimicrobial properties |
| Lunula | White crescent at nail base - visible part of nail matrix |
| Rule of Nines | Method to estimate burn surface area in adults |
| Basal cell carcinoma | Most common skin cancer - from stratum basale, rarely metastasizes |
| Melanoma | Most dangerous skin cancer - from melanocytes, high metastatic potential |
| ABCDE rule | Asymmetry, Border, Color, Diameter, Evolving - melanoma screening |
| Hemostasis | First wound healing stage - clot formation |
| Granulation tissue | New connective tissue and blood vessels during wound proliferation |
Epidermis
Avascular, keratinocytes, melanocytes, 5 strata
Dermis
Collagen, elastin, blood vessels, nerves, glands, hair follicles
Hypodermis
Adipose tissue, insulation, energy storage, cushioning
| Degree | Depth | Pain | Healing |
|---|---|---|---|
| 1st (superficial) | Epidermis | Painful | 3-5 days, no scar |
| 2nd (partial) | Epidermis + upper dermis | Very painful, blisters | 2-3 weeks, possible scar |
| 3rd (full) | Epidermis + full dermis | Painless (nerves destroyed) | Grafting needed, scar |
| 4th | Through to muscle/bone | Painless | May require amputation |
Q1.List the five strata of the epidermis from deepest to most superficial. Which one is absent in thin skin?
From deepest to superficial: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum. The stratum lucidum is absent in thin skin and is found only in thick skin (palms and soles).
Q2.Compare and contrast the papillary and reticular layers of the dermis.
The papillary dermis is the thinner upper layer made of loose areolar connective tissue with dermal papillae, capillary loops, and Meissner's corpuscles. The reticular dermis is the thicker lower layer made of dense irregular connective tissue with thick collagen bundles, elastin fibers, hair follicles, glands, and Pacinian corpuscles.
Q3.Explain why 3rd-degree burns are painless while 2nd-degree burns are extremely painful.
Third-degree burns destroy the full thickness of the dermis, including all nerve endings (free nerve endings, Meissner's and Pacinian corpuscles) that transmit pain signals. Second-degree burns damage the upper dermis but leave many nerve endings intact and exposed, causing intense pain.
Q4.Describe the four stages of wound healing in order.
1) Hemostasis - platelets form a plug and fibrin mesh seals the wound. 2) Inflammation - neutrophils and macrophages clear debris and pathogens. 3) Proliferation - fibroblasts deposit collagen, angiogenesis forms new blood vessels, epithelial cells resurface the wound. 4) Remodeling - collagen is reorganized and cross-linked over months to years, reaching about 80% of original tensile strength.
Q5.Using the ABCDE rule, describe the warning signs of melanoma.
A = Asymmetry (one half does not match the other); B = Border irregularity (ragged, blurred edges); C = Color variation (uneven - brown, black, red, white, blue); D = Diameter larger than 6 mm (pencil eraser size); E = Evolving (changing in size, shape, or color over time).
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