integument ppt

Physical and Chemical Injury Protection: The integument serves as a barrier against various physical and chemical agents.
UV Radiation Protection: The skin protects underlying tissues from ultraviolet radiation.
Bacterial Invasion Prevention: Functions as a barrier to prevent pathogens from entering the body.
Trauma Protection: Absorbs impact and reduces the risk of injury to underlying tissues.
Dehydration Prevention and Water Penetration Control: Maintains water balance by preventing excess water loss.

Thermoregulation:
- Involves the regulation of body temperature through vascular changes and sweat gland activity.

Capable of detecting various sensations such as touch, pain, and temperature through specialized nerve endings.

Epidermis: The outermost layer of skin.
Dermis: Connective tissue that supports the epidermis.
Glands:
- Sweat Glands: Involved in water regulation and thermoregulation.
- Sebaceous Glands: Produce oil to lubricate the skin.
Hair: Contributes to protection and sensory functions.
Nails: Protect the tips of fingers and toes.
Hypodermis: Also known as subcutaneous tissue or superficial fascia; not technically part of the skin but typically considered alongside it.

Stratum Basale:
- Composed of a single layer of cuboidal to columnar cells.
- Rests on the basement membrane and is mitotic, renewing epithelial cells every 15 to 30 days.
Stratum Spinosum:
- Contains 2 to 10 layers of cuboidal and polygonal cells.
- Features cytoplasmic processes formed by shrinkage that are filled with desmosomal filaments, providing cohesion between cells.
Stratum Granulosum:
- Composed of 3 to 5 layers of polygonal or spindle-shaped cells.
- Contains two types of granules:
  - Keratinohyalin: Coats keratin filaments inside the cell.
  - Membrane Coating: Serves as intercellular cement, secreted by cells.
Stratum Lucidum:
- Present only in thick skin, consists of 1 to 2 layers of water-proof translucent, flat cells without nuclei, filled with keratin filaments and keratinohyalin.
- The extracellular space is filled with intercellular cement.
Stratum Corneum:
- Composed of flat, dead cells without nuclei.
- Fully keratinized, lacking cytoplasm.
- Cells shed at the surface, providing waterproofing properties.

Thick Skin:
- Contains hundreds of layers in the stratum corneum.
- Notable for the presence of the stratum lucidum.
Thin Skin:
- Contains only 2 to 3 layers in the stratum corneum.

Keratinocytes: Epithelial cells that produce keratin.
Melanocytes: Synthesize pigment, located between cells of the stratum basale, with processes interdigiting between epidermal cells to transfer melanin granules.
Langerhans Cells: Function in immune response within the skin.
Merkel Cells: Serve as sensory receptors for touch.

Found in the stratum basale.
Synthesize and transfer melanin granules to nearby epidermal cells, providing pigmentation to the skin.

Melanin: The primary pigment in epidermal cells.
Blood Vessel Count: Blood volume and oxygenation influence skin color, particularly hemoglobin's red or blue tint.
Carotene: A dietary pigment contributing to skin coloration.

Tanning:
- Melanin production increases in response to ultraviolet (UV) exposure, leading to darkened skin.

Papillary Layer:
- Thin layer of loose connective tissue featuring dermal papillae that increase surface area for adhesion with the epidermis.
Reticular Layer:
- Thick layer of dense connective tissue that underlies the papillary layer.

Composed of networks in the hypodermis, reticular, and papillary layers of the dermis.
Features arteriovenous (AV) shunts that connect the two vascular networks in the lower dermis.

Blood flow to the papillary layer of the dermis increases or decreases to regulate heat loss or retention.
Altered blood flow is regulated by the opening and closing of arteriovenous shunts.

Purpose: Temperature regulation.
Classification:
- Eccrine Sweat Glands:
- Simple, coiled, tubular glands generally found in the deep dermis and hypodermis, lined with simple columnar and cuboidal epithelium, secreting mainly water.
- Apocrine Sweat Glands:
- Partially involve the shedding of cell cytoplasm in their secretion process.

Structure: Alveolar glands responsible for producing sebum, an oily lubricant for the skin.
Location: Reside within the dermis and are usually associated with hair follicles.
Secretion Method: Secrete sebum by sloughing off the entire cell.

Hair Components:
- Shaft: The visible part of the hair.
- Root: The part of the hair embedded in the follicle.
- Medulla, Cortex, and Cuticle: Structural layers of the hair.
- Hair Follicle: A downgrowth of the epidermis encompassing the hair root.
- Cuticle: Outermost protective layer.
- Inner Root Sheath: Encases the hair root.
- Outer Root Sheath: Provides structural support.
- Arrector Pili Muscle: Responsible for hair standing on end (goosebumps).
- Sebaceous Glands: Associated with hair follicles.