Nurse Notes / Integument

Notes and writing by Billy Staggs Cahill 

Nursing – RN 

Fall 2017

Anatomy and Physiology

Instructor: Dr. Vera Mcilvain

     It’s important to note the Integumentary System:

The largest and heaviest of all systems, and there’s interesting concepts regarding our skin and its hidden secrets. There’s Melanocytes, which strangely look like some sea creature from ancient mythology. It has tentacles (dendrites), lives on TOP of Basement Membrane. It transports  via phagocytose through these dendrites, granules into Karitnocytes: Keratinocytes Phagocytose Melanosomes.  This is the explanation for skin color.  


UV Protection:

  • Melanin in Keratinocytes
  • Protect DNA
  • Melanin synthesis increases with UV exposure.

Melanomas – DNA damage in Melanocytes.

Other quick notes:


  • Synthesized by Melanocytes in Stratum Basale.
  • Keratinocytes Phagocytose Melanosomes.
  • All have Melanocytes, melanin production varies.

Let’s focus on the layers of the Epidermis itself. DO NOT confuse Dermis with Epidermis, as this is common. Many people / students recall highlights of learning the Integumentary System in high school. However, they had no interest in the medical field. This sets up a scenario of early learning confusion. 

The Epidermis consists of FIVE STRATUM LAYERS:

  1.  Stratum Corneum

The Stratum Corneum is the first layer, and it’s superficial. Exfoliation of dead skin cells flake off the top. We can note or insert, that mitosis (cell division) occurs in the Stratum Basale. It cycles its way up to the top, and as it cycles, the cells die. There’s more physiological mechanisms than this, but for the sake of simplicity — we’ll keep it short and sweet for now. 

With integumental respect, we can say that Stratum Basale is the mitosis factory that assembles our cells before they surface superficially and flake (exfoliation). 

Let’s look at a model I did of the function of how the Integument works. K1, K2, K3, . . . denotes each, individually numbered Keratinocyte.

Also note: Keratnocytes are bounded, cell – cell – cell by Desmosomes.

function stratum

The quick sketch above of how the integument functions is just summarizing; there’s much more complexity than this. 

Mitosis → Stratum Basale → (Upward Keratinization) → Upward to Stratum Spinosum (8 – 10 layered stratum) → Stratum Granulosum (grainy layered and no cell division occurs)→  Stratum Lucidum (clear layered and only in thickest parts) → Stratum Corneum (15 – 30 layers) → Exfoliation @ top of Epidermis. 

Given time, mitosis and escalation, building upward and keratinization → → →  function how the integument works.

Very simplex concept with so much complexity in between. 

(SB) A → → (SS) B → → (SG) C → → (SL) D → → (SC) E → → exfoliation 

Let us respectively use variables:

Let K = Keratinocyte, ⊕ = cell, ∴ = Desmosome

SS (Stratum Spinosum) → → K1⊕∴  K2⊕∴  K3⊕∴  K4⊕∴  K5⊕∴  K6⊕∴ . . . 

Downward, 8 – 10 layers

cell – cell – cell – cell – cell – cell

is SG (Stratum Granulosum) No cell division, transition into dying cells full of keratin. 

  • Spiny Layer
  • 8 – 10 layers of keratinocytes all bound by desmosomes, as shown in models above.
  • thickest layer
  • Formed / produced by division of stratum basale
  • deeper cells can continue dividing (going under mitosis)
  • Specialized cells: Langerhans (dendritic) cells: phagocytic
  • Immune response


(cell eating)


Picture by: European Respiratory Journal – ERS Publications

Langerhan (Dendritic) cells found integrated throughout SS:

Let +O+ represent Langerhans cell.

 → → K1⊕∴  K2⊕∴  K3⊕∴  K4⊕∴  K5⊕∴  K6⊕∴ . . . 

 → → K1⊕∴  K2⊕∴  K3⊕∴ +O+ K4⊕∴  K5⊕∴  K6⊕∴ . . . 

 → → K1⊕∴+O+  K2⊕∴  K3⊕∴  K4⊕∴  K5⊕∴  K6⊕∴ . . . 

 → → K1⊕∴  K2⊕∴  K3⊕∴  K4⊕∴ +O+ K5⊕∴  K6⊕∴ . . . 

 → → K1⊕∴ +O+ K2⊕∴  K3⊕∴  K4⊕∴+O+  K5⊕∴  K6⊕∴ . . . 

 → → K1⊕∴  K2⊕∴  K3⊕∴ +O+ K4⊕∴  K5⊕∴  K6⊕∴ . . . 

 → → K1⊕∴ +O+ K2⊕∴  K3⊕∴  K4⊕∴  K5⊕∴  K6⊕∴ . . . 

 → → K1⊕∴  K2⊕∴  K3⊕∴  K4⊕∴  K5⊕∴  K6⊕∴ . . . 


Stratum Granulosum (SG)

     Moving upward to the next layer, we arrive at Stratum Granulosum. This layer is above SS of course. It is known in the world of nursing as the “grainy layer”. Well, that’s because it does look grainy. It is 3 – 5 layers (not that many layers at all). The layers are composed of dying keratinocytes. Therefore, there is NO mitosis. Lots of ketanized cells — flattened and thinner. They’re almost dinner plate looking much like the description of Cisternae in the Golgi Apparatus. 

  • Keratinohyalin (protein) produced:
  • forms dense granules
  • cross – links keratin
  • Cells dehydrate (flatness) NO nutrients! Organelles disintegrate.


Stratum Lucidum (the clear layer)

  • covers stratum granulosum
  • flattened and packaged dead cells abundant in keratin
  • Only present in few locations of the body: palms, soles, fingertips, (areas that are treated harshly)

Note: This is the layer where cells are REALLY dead, they’re beyond granulosum!

We’re at the very, very, very, very top! Stratum Corneum.

We’ve made it to the top where exfoliation occurs (very top of epidermal body)

  • exposed surface of skin
    • 15 – 30 layers of dead, keratinized cells, no organelles! No mito, golgi, nucleus, nothing, NADA! ZERO! NULL!
    • Water resistant
    • shed and replaced EVERY TWO WEEKS
    • callous


Study sheets: Episheet 1, 2 and 3:

Billy Staggs (Nursing Student)








Side notes and overview:

     Functions of the skin and hypodermis:

  • protection (abrasion, infection, dehydration)
  • excretion by glands (salt, water, waste)
  • maintain body temp. (insulation, evaporation)
  • melanin production (UV protection)
  • keratin production (water repellent, abrasion prevention)
  • D3 synthesis (for Ca2 metabolism)
  • storage (lipids) — stores lipids!
  • detection (touch, pressure, pain, sensations, temp)



Epidermis – Epithelium tissue

Dermis – Connective tissue

Accessory structures:

hair, glands, nails

originate in dermis



connects integument to underlying muscle & bone.

Connections: Cardiovascular system and nervous system.

Epidermal ridges and Dermal papillae: 



top mattress and bottom mattress for memory


Skin Lesions

Skin Lesions 배너

hypodermic needle2

  • cells derivatives of stratum corneum
  • ========—————– (derivatives)
  • top epidermal layer with hardened keratin. Recall HARDENED KERATIN!
  • protects the end of fingers and toes
  • nail production starts @ nail root
  • Nail bed: layer of epidermis stratum basale ( bottom layer)
  • Hyponychium: thickened stratum corneum, fingertip

finger nail


finger nail 2