Integumentary system

Nursing2nature notes

The Functions of the skin are these, describe what they each do:

1. Protection

2. Excretion

3. Thermoregulation

4. Sensation

5. Vitamin D synthesis

Epidermis (epi-on top, dermis-skin)

• Keratinized stratified epithelium

Dermis

• Loose connective tissue and dense irregular tissue

Hypodermis (hypo-below)

• KNOWN as the subcutaneous tissue

• Loose connective tissue

• Anchors skin to the muscle

The Epidermis has cells called keratinocytes which are:

Keratinocytes:

• Makes up 95% of the cells in the Epidermis

• Strengthens the EPI + makes it resistant to mechanical trauma

• Joined by desmosomes

• Arranged into “strata (layers)”

Name the layers of the epidermis—> Hint: CLGSBD

• Stratum Corneum

• Stratum Lucidum

• Stratum Granulosum

• Stratum Spinosum

• Stratum Basale

Presenting the 1st layer of the Epidermis STRATUM CORNEUM

Presenting the layer underneath the corneum of the Epidermis—> Stratum Lucidum

• Deep to the Stratum Corneum

• Found in THICC skin

• Clear layer of dead Keratinocytes

Presenting the layer underneath the Lucidum of the Epidermis—> Stratum Granulosum

• Middle layer of the epidermis

• Named for prominent granules

• 3-5 rows of cells

• Excretes a lipid-based substance

Presenting the layer underneath the Granulosum of the Epidermis—>Stratum Spinosum

• Thiccccest stratum

• Undergo mitosis

• Help to synthesize vitamin D

Presenting the layer underneath the Spinosum of the Epidermis—> Stratum Basale

• Consists of a single layer of stem cells

• Undergo mitosis

• Known as (Stratum Germinativum)

• Helps to synthesize vitamin D

Keratinocyte Life Cycle

• Begins in the Strum Spinosum

• Sheds in the Stratum Corneum

Other cells of the epidermis:

• Dendric Cells

• Merkel Cells

• Melanocytes

• Dendric Cells

  -Protects the skin and underlying tissue from pathogens (found in Stratum Spinosum)

• Merkel Cells

  -Oval cells found in the Stratum Basale (found in Stratum Basale)

• Melanocytes

  • Produces melanin, a protein (found in stratum Basale)

Thick Skin Vs Thin skin

THICK SKIN

• Consists of all five layers of the epidermis with a thick Stratum Corneum

• Lacks hair follicles+ contains sweat glands

• Found in palms of hand and soles of feet

• Subject to mechanical stress

Thick Skin Vs Thin skin

Thin skin

• Consist of only four layers of the epidermis, lacking the Stratum Lucidum

• Has hair follicles

• Subject to less mechanical stress

The Dermis Layer

• Dermis has Two Layer:

  -PALPILLARY LAYER

  -RECTICULAR LAYER

• House blood supply

Papillary Layer (dermis layer)

• Loose connective tissue

  • we can find phagocytes and fibroblast

• Superficial layer of the dermis

• Dermis Papillae:

  • Found on the surface of the papillary layer

  • Houses tiny blood vessels called capillaries

  • houses sensory receptors called Tactile corpuscles

Reticular Layer (Under Papillary layer)

• Deepest and thickets layer of the dermis

• Consist of dense irregular connective tissue

• Collagen fibers that allow skin to revert after stretching

• Proteoglycans that hydrate the skin

• Blood vessels and accessory structure (hair, sweat glands, sebaceous glands)

• Sensory receptors, such as Pacinian corpuscles that respond to changes in pressure and vibration ( 14:50)