2.29k likes | 2.5k Views
The Integumentary System. Bio 103 Martini Chapter 5. The integument (skin). It’s Large: 1.5 to 2.0 meters 2 16% of total body weight. The integument (skin). It’s Large: 1.5 to 2.0 meters 2 16% of total body weight 2 main parts. The integument (skin). It’s Large: 1.5 to 2.0 meters 2
E N D
The Integumentary System Bio 103 Martini Chapter 5
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight • 2 main parts
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight • 2 main parts • cutaneous membrane (epidermis and dermis) • accessory structures (hair, nails, exocrine glands)
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight • 2 main parts • cutaneous membrane (epidermis and dermis) • accessory structures (hair, nails, exocrine glands) • Functions:
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight • 2 main parts • cutaneous membrane (epidermis and dermis) • accessory structures (hair, nails, exocrine glands) • Functions: • Protect
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight • 2 main parts • cutaneous membrane (epidermis and dermis) • accessory structures (hair, nails, exocrine glands) • Functions: • Protect • Excrete salt, water and wastes
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight • 2 main parts • cutaneous membrane (epidermis and dermis) • accessory structures (hair, nails, exocrine glands) • Functions: • Protect • Excrete salt, water and wastes • maintain body temperature
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight • 2 main parts • cutaneous membrane (epidermis and dermis) • accessory structures (hair, nails, exocrine glands) • Functions: • Protect • Excrete salt, water and wastes • maintain body temperature • synthesize vitamin D
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight • 2 main parts • cutaneous membrane (epidermis and dermis) • accessory structures (hair, nails, exocrine glands) • Functions: • Protect • Excrete salt, water and wastes • maintain body temperature • synthesize vitamin D • Store energy (lipids)
The integument (skin) • It’s Large: 1.5 to 2.0 meters2 • 16% of total body weight • 2 main parts • cutaneous membrane (epidermis and dermis) • accessory structures (hair, nails, exocrine glands) • Functions: • Protect • Excrete salt, water and wastes • maintain body temperature • synthesize vitamin D • Store energy (lipids) • Detect changes in the environment (sensations)
Integument Cutaneous Membrane
Integument Cutaneous Membrane • Epidermis – epithelial cells • Dermis – fibrous connective tissue
Integument Cutaneous Membrane • Epidermis – epithelial cells • Dermis – fibrous connective tissue • Subcutaneous layer (i.e., hypodermis or superficial fascia: composed of adipose and loose areolar CT
Integument Cutaneous Membrane • Epidermis – epithelial cells • Dermis – fibrous connective tissue • Subcutaneous layer (i.e., hypodermis or superficial fascia: composed of adipose and loose areolar CT • not considered part of skin, but interwoven with dermis
Width of epidermis Thick skin: epidermis is thick 5 layered epidermis palms, fingertips, & soles
Width of epidermis Thick skin: epidermis is thick 5 layered epidermis palms, fingertips, & soles Thin skin: epidermis is thin 4 layered epidermis everywhere else
Cell types of Skin Epidermis • Cell types: • keratinocytes • make keratin
Cell types of Skin Epidermis • Cell types: • keratinocytes • make keratin • basal (germinative cells) • stem cells
Cell types of Skin Epidermis • Cell types: • keratinocytes • make keratin • basal (germinative cells) • stem cells • merkel cells • sensitive to touch
Cell types of Skin Epidermis • Cell types: • keratinocytes • make keratin • basal (germinative cells) • stem cells • merkel cells • sensitive to touch • melanocytes • pigment cells
Cell types of Skin Epidermis • Cell types: • keratinocytes • make keratin • basal (germinative cells) • stem cells • merkel cells • sensitive to touch • melanocytes • pigment cells • langerhans cells • immune response
Layers of the Epidermis • Stratum means layer:
Layers of the Epidermis • Stratum means layer: • stratum corneum
Layers of the Epidermis • Stratum means layer: • stratum corneum • stratum lucidum • absent in thin skin
Layers of the Epidermis • Stratum means layer: • stratum corneum • stratum lucidum • absent in thin skin • stratum granulosum
Layers of the Epidermis • Stratum means layer: • stratum corneum • stratum lucidum • absent in thin skin • stratum granulosum • stratum spinosum
Layers of the Epidermis • Stratum means layer: • stratum corneum • stratum lucidum • absent in thin skin • stratum granulosum • stratum spinosum • stratum germinativum
Stratum Germinativum (basale) • Deepest layer (usually single) – attached to dermis
Stratum Germinativum (basale) • Deepest layer (usually single) – attached to dermis • Basal cells most common, rapidly divide to make new keratinocytes:
Stratum Germinativum (basale) • Deepest layer (usually single) – attached to dermis • Basal cells most common, rapidly divide to make new keratinocytes: • basal cells constantly replacing lost keratinocytes • new cells make keratin & die as they approach free surface of the skin
Stratum Germinativum (basale) • Deepest layer (usually single) – attached to dermis • Basal cells most common, rapidly divide to make new keratinocytes: • basal cells constantly replacing lost keratinocytes • new cells make keratin & die as they approach free surface of the skin • 10-25% of cells are melanocytes
Stratum Germinativum (basale) • Deepest layer (usually single) – attached to dermis • Basal cells most common, rapidly divide to make new keratinocytes: • basal cells constantly replacing lost keratinocytes • new cells make keratin & die as they approach free surface of the skin • 10-25% of cells are melanocytes • some merkel cells
Stratum Germinativum (basale) • Deepest layer (usually single) – attached to dermis • Basal cells most common, rapidly divide to make new keratinocytes: • basal cells constantly replacing lost keratinocytes • new cells make keratin & die as they approach free surface of the skin • 10-25% of cells are melanocytes • some merkel cells • forms epidermal ridges
Stratum Spinosum (spiny layer) • 8-10 layers of keratinocytes bound together by desmosomes(see pg 110)
Stratum Spinosum (spiny layer) • 8-10 layers of keratinocytes bound together by desmosomes(see pg 110) • contains Langerhans’ cells • stimulate immune response
Stratum Spinosum (spiny layer) • 8-10 layers of keratinocytes bound together by desmosomes(see pg 110) • contains Langerhans’ cells • stimulate immune response • microorganisms • superficial skin cancers
Stratum Granulosum (grainy layer) • 3-5 layers of keratinocytes • cells have stopped dividing and making large amounts of keratin and keratohyalin
Stratum Granulosum (grainy layer) • 3-5 layers of keratinocytes • cells have stopped dividing and making large amounts of keratin and keratohyalin • As keratin fibers form, cells grow thinner and membranes are less permeable
Stratum Granulosum (grainy layer) • 3-5 layers of keratinocytes • cells have stopped dividing and making large amounts of keratin and keratohyalin • As keratin fibers form, cells grow thinner and membranes are less permeable • keratohyalin forms dense cytoplasmic granules: • promotes dehydration, aggregation, cross-linking of keratin fibers
Stratum Granulosum (grainy layer) • 3-5 layers of keratinocytes • cells have stopped dividing and making large amounts of keratin and keratohyalin • As keratin fibers form, cells grow thinner and membranes are less permeable • keratohyalin forms dense cytoplasmic granules: • promotes dehydration, aggregation, cross-linking of keratin fibers • eventually organelles disintegrate and cells die leaving keratin fibers surrounded by keratohyalin
Stratum Lucidum (clear layer) • Found only in thick skin
Stratum Lucidum (clear layer) • Found only in thick skin • Thin, translucent band consisting of a few rows of clear, flat, dead keratinocytes
Stratum Lucidum (clear layer) • Found only in thick skin • Thin, translucent band consisting of a few rows of clear, flat, dead keratinocytes • Keratohyalin granules begin to cling to keratin filaments in the cells causing them to aggregate in parallel fashion
Stratum Corneum (horn layer) • Largest layer:
Stratum Corneum (horn layer) • Largest layer: • 15-30 cell layers of keratinized cells (dead cells with keratin) • ¾ of epidermal thickness
Stratum Corneum (horn layer) • Largest layer: • 15-30 cell layers of keratinized cells (dead cells with keratin) • ¾ of epidermal thickness • keratinization: superficial layers of dead cells are filled with keratin on all exposed surfaces except eyes
Stratum Corneum (horn layer) • Largest layer: • 15-30 cell layers of keratinized cells (dead cells with keratin) • ¾ of epidermal thickness • keratinization: superficial layers of dead cells are filled with keratin on all exposed surfaces except eyes • cells remain tightly interlocked by desmosomes
Stratum Corneum (horn layer) • Largest layer: • 15-30 cell layers of keratinized cells (dead cells with keratin) • ¾ of epidermal thickness • keratinization: superficial layers of dead cells are filled with keratin on all exposed surfaces except eyes • cells remain tightly interlocked by desmosomes • skin cells are shed in sheets, instead of individually
Stratum Corneum (horn layer) • Largest layer: • 15-30 cell layers of keratinized cells (dead cells with keratin) • ¾ of epidermal thickness • keratinization: superficial layers of dead cells are filled with keratin on all exposed surfaces except eyes • cells remain tightly interlocked by desmosomes • skin cells are shed in sheets, instead of individually • Protects against abrasion & water loss