Chapter 5 - Integumentary System Flashcards
What does the skin include?
Epidermis & Dermis
What 2 structures does the integumentary system include?
- Skin/Cutaneous Membrane
2. Accessory Structures
What are the 5 Accessory Structures?
- Hair
- Oil glands
- Sweat glands
- Nails
- Sensory receptors
The skin is a large organ composed of 4 tissue types. What are these 4 tissue types?
- Nerve
- Epithelial
- Connective
- Muscular
How thick is the skin on most of the body?
1-2mm thick
What are the 6 functions of the skin?
- Regulates/maintains body temperature
- Stores blood
- Protection from external environment
- Detects cutaneous sensations/provides sensory information about the surrounding environment
- Excretes & absorbs substances
- Synthesizes Vit. D
What’s the difference between the Epidermis & the Dermis?
EPIDERMIS:
- superficial, thinner
- contains epithelial tissue
- avascular
DERMIS:
- deep, thicker
- contains connective tissue
- vascular
What is deep to the dermis & NOT part of the skin?
Subcutaneous layer/Hypodermis
What does the subcutaneous layer/hypodermis consist of?
Areolar & Adipose tissue
What is the function of the subcutaneous layer/hypodermis?
- fat storage
- area for blood vessel passage
- area of pressure-sensing nerve endings
What is the epidermis primarily composed of?
Stratified squamous epithelium
What are the 4 Principle Cells of the Epidermis?
- Keratinocytes
- Melanocytes
- Langerhans cells (small fraction of epidermal cells)
- Merkel cells (least numerous of epidermal cells)
What are the 2 functions of Keratinocytes?
- produce KERATIN (w/c protects skin & underlying tissue from heat, microbes & chemicals)
- produce LAMELLAR GRANULES (w/c act as a waterproof sealant)
What is the function of Melanocytes?
-produce the pigment MELANIN (skin colour & absorbs UV light)
Where do Langerhan Cells derive from & what is the function?
- derived from RBM
- participate in immune response
What are the 2 functions of Merkel Cells?
- Contact a tactile Merkel disc (sensory structure)
2. Detect touch sensations
What are the 5 layers of the Epidermis (deep to superficial)?
- Stratum Basale/Germinativum
- Stratum Spinosum
- Stratum Granulosum
- Stratum Lucidum
- Stratum Corneum
What is the Stratum Basale/Germinativum?
- deepest layer
- single row of Cuboidal/Columnar Keratinocytes
- contains Merkel cells, Melanocytes, Keratinocytes & continuously dividing Stem cells (produce keratinocytes)
In the Statum Basale/Germinativum, Keratinocytes have a cytoskeleton called what? What does it form?
- Tonafilaments/Keratin Intermediate Filaments
- form the protein Keratin in most superficial layers
How do cells attach in the Stratum Basale/Germinativum?
-attach to each other & basement membrane via Desmosomes & Hemidesmosomes
When the germinal portion of the epidermis is destroyed, new skin can’t regenerate. What is required for healing?
Skin graft
What is the Stratum Spinosum? How do cells attach?
8-10 cell layers held together
-via Desmosomes (provides skin strength & flexibility)
What happens to the cells & what is the appearance of Stratum Spinosum during slide preparation?
cells SHRINK & appear SPINY
In the Stratum Spinosum, what is taken in by keratinocytes via phagocytosis?
Melanin