Ch. 5 Integument
Terms
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- What is the largest organ system?
- Integument
- What are the two components of the Integument system?
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Cutaneous membrane (skin)
Accessory structures - What is the Cutaneous membrane?
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Epidermis- superficial epithelium
Dermis- underlying CT - What are Accessory structures?
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Hair, nails, multicellular exocrine glands
-Most located in dermis and protrude through epidermis - Subcutaneous layer
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hypodermis
-Deep to dermis (more towards inside)
-has a lot of the main vessels and subcutaneous fats - What are the functions of the Integument
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-Protection of the underlying tissues, locking in heat or letting it out
-Excretion- Salt water organics
-Maintenance- of the body temperatur
-Synthesis of vitamin D3
-Storage of lipids
-Detection of pain, pressure
-Social functions-communication - Epidermis is ...
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-Avascular- doesn't have any blood vessels
-Dominated by Keratinocytes
-made of 5 layers - Stratum Germinativum
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or Stratum basale
-interlocks with dermis
-Forms epidermal ridges (adajent to dermal papili)
-Basal cells dominate
-->replace keratinocytes - Stratum Spinosum
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-Superficial to S. Germinativum
-8-10 layers of keratinocytes
-Contain langerhans cells which stimulate defense against microorganisms and superficial skin cancers - Stratum Granulosum
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-3-5 layers of keratinocytes
-Cells stop dividing, are nearly dead
-Cells begin producing keratin and keratohyalin - Stratum Lucidum
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-Tick skin only (soles of feet, palms of hands)
-Glassy layer
-Cells packed with keratin and excess keratin - Stratum Corneum
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-15-20 layers of keratinized cells
-Dry-inhospitable environment
-Lipid secretions maintain the layer
-Water resistant (insensible perspiration and sensible perspiration) - Insensible perspiration
- Always loosing moisture, as you breathe, as air blows over you
- Sensible perspiration
- When yo're working out
- Skin color has to do with...
- Epidermal Pigmentation and Dermal Circulation
- Epidermal pigmentation
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-Carotene-most apparent in S. corneum, gives you a orange color
-Malnin-produced by melanocytes (larger in individuals with darker skin)
*Travels in vesicles to keratinocytes
*Pale skin occurs in S. germinativum and spinosum
*Darker Skin- granulosum
*Protects keratinocyes from UV - Dermal Circulation
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-Cutaneous Plxus
-Papillary plexus
-Contusions - Jaundice
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Liver unable to excrete bile, yellow pigment in body fluids
-results in yellow tint to skin - Vitiligo
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Loss of melanocytes in skin
-Splotches of color in skin (Michael Jackson) - Epidermis and Steroid Production
- -UV radiation- S. spinosum and germinativum convert cholesterol related steroid to vitamin D3 used in absorption of Ca and P
- Epidermal Growth Factor
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-Promotes division of germinative cells
-Accelerates production of keratin in keratinocytes
-Stimulates development and repair
-Stimulates synthetic activity and secretion -
Dermis
-Papillary (dermal papillae) -
Areolar TIssue
-Capillaries, lymphatics, sensory neurons
-Where you can sense pressure, pain, etc. -
Dermis
-Reticular - -Dense irregular tissue with collagen and elastic fibers
- Dermal Strength
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-Tolerant of stretching
-Skin Tugor- flexibility and resilience of skin - Stretch marks
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-Skin stretches beyond elastic capabilities
-They tend to go away - Lines of Cleavage
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-Collagen and elastic fibers arranged in parallel bundles
-Used a lot in surgery field
-Heal better if you cut with the lines - Cutaneous plexus
- network of arteries along reticular layer of dermis
- Papillary plexus
- provides blood to capillaries along epidermis-dermis layers
- Contustions
- Bruise, when you break the capillaries in the papillary plexus
- Ulcers
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-Decubitis ulcers (bedsores)
-Dead skin areas
-Circulation is difficult in areas
-Too much pressure from lying down on teh areas too long - Innervation of Skin
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Integument filled with sensory receptors
-Merkel cells monitored by Merkel discs
-Sensors to light touch (Meissner's corpuscles)
-Sensors to deep rpessure (Pacinian corpuscles) - Where is the Hair produced?
- In the dermis and epidermis
- Bulb (of hair)
- epithelial cells surrounding papilla
- Papilla (of hair)
- peg of CT with capillaries and nerves
- Root (of hair)
- base to 1/2 way to surface
- Shaft (of hair)
- root to tip
- Cuticle (of hair)
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outer surface of shaft
-dead keratinized cells - Cortex (of hair)
- intermediate layer
- Medulla (of hair)
- core (soft keratin)
- Vellus hairs
- "peach fuzz" all over body
- Terminal hairs
- Heavy, deeply pigmented (head, eyebrows)
- What is hair color caused by?
- Differences in pigment produced at papilla by mealnocytes
- Function of Hair
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-Protection (head, nose, ears)
*Acts as physical protection against mosquitos
*Hair in nose-helps slow down air so it can be warmed and helps filter air
*Hair in ears keeps foreign particles out
-Root hair plexus-sensory nerves
-Warning- Arrector pili - Sebaceous gland
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oil
-Holocrine, simple branched
-Arrector pili contract to sqeexe oil onto follicle and skin surface - Sebaceous follicles
- Glands not associated with hair follicles
- Seborrheic dermatitis
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Infection of sebaceous follicles
*commonly affect the ears and the T-zone - Apocrine
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sweat gland
-Produce sticky, cloudy secretion
*Armpits, around nipples and groin
*Myoepithelial cells contract - Merocrine
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Sweat Gland- sensible perspiration
-Cool surface of skin
-excrete water, electrolytes and drugs
-provide protection from environmental hazards
*Flushing-rinses chemicals off of skin
*Dermacidin- kind of an antibacterial- kills some of the microorganisms that might get on your skin -
Glandular Secretion Control
-Apocrine -
Turned on by autonomic nerous system
-If one is on, they are all on -
Glandular Secretion Control
-Merocrinee - more precisely controlled
- What are nails composed of?
- compressed cells packed with keratin
- What is the function of nails?
- Protect exposed tips
- What are the parts of the nail?
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-Nail body (exposed part) covers nail bed
-Production occurs at nail root
-Cuticle- stratum corneum extends over exposed nail - What happens with injury to integument?
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-cells of germinativum divide, surround wound
-Macrophages- keep wound clean
-Endothelial cells of blood vessels dived
-Franulation tissue- blod clot, fibroblasts, capillary network
-Lots of lood flow into wound area to bring in nutrients and white blood cells to fight off infection
-Clot dissolves, capillaries decline
-Collagen fibers and ground substance appear
-Fibrous (scar) tissue forms - What is a keloid scar?
- when tissue continues beyond what was needed, the scar is raised
- What is a first degree burn?
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(Superficial)
damage to epidermis only - What is a second degree burn?
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(partial thickness)
damage to entire epidermis, maybe some dermis - What is a third degree burn?
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(Full thickness)
destroy epidermisa nd dermis, extend into subcutaneous tissue - What are some problems with burns that cover greater than 20% of the body?
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-It is very difficult to maintain fluid and electrolyte balance
-Thermoregulation
-Loss of protection from attack - What is th eleading cause of death for burns that cover over 20% of the body?
- sepsis
- What happens with aging and the epidermis
- -epidermis thins as germinative layer slows down production
- What happens with aging and langerhans cells?
- they drop by 50%, (langerhans are involved in imunity)
- What happens with aging and the dermis?
- the dermis thins, and integument becomes weaker
- What happens with aging and skin repair?
- It proceeds slowly
- What happens with ging and hair and body fat?
- The distribution fades
- There are declines in what, with the aging of the integument?
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-D3
-Melanocyte activity
-Glandular activity
-Blood supply to dermis
-Hair follicle funciton