Histo - Skin Flashcards
1
Q
What are the 5 Functions of Skin?
A
-
Protection from…
- abrasion, water loss/gain, bacterial invasion, sunlight
- Sensory
-
Thermoregulatory
- Either insulation or mechanism for heat loss
-
Metabolic
- Vitamin D
-
Sexual signaling
- Visual or pheromones
2
Q
What are the 3 Layers of Skin (Integument)?
A
-
Epidermis
- Keratinized SS
- Epidermal ridges
- Keratinized SS
-
Dermis
- Papillary dermis (loose CT)
- Reticular dermis (dense irregular CT)
- Dermal papillae
-
Hypodermis
- Loose CT
- Abundant fat
- Subcutaneous tissue = superficial fascia
3
Q
What are the 2 Types of Skin?
A
-
Thick skin
- Example: palm/foot
- thicker keratin
- no hair follicles
- Example: palm/foot
-
Thin skin
- Example: arms/legs
- thinner keratin
- hair follicles
- Example: arms/legs
4
Q
What type of skin is this?
A
Thin skin
5
Q
What type of skin is this?
A
Thick skin
6
Q
Identify the 3 layers of skin
A
7
Q
What are the 5 Layers of Epidermis?
A
Basics:
- Main cells = keratinocytes
Layers:
-
Stratum Basale = cuboidal or columnar cells
- Proliferative
- Binds BL via hemidesmosomes & integrins
- Binds BL vs anchoring fibrils of Type VII collagen
-
Stratum Spinosum
- Lower layer = proliferative
- Numerous desmosomes & tight junctions
-
Stratum Granulosum
- Filled w/ keratohyline granules
- Filaggin/cytokeratin
- Lamellar granules (exocytosed)
- Lipids/glycolipid
- Filled w/ keratohyline granules
-
Stratum Lucidum (Anucleated)
- only in THICK skin
-
Stratum Corneum (Anucleated)
- form the keratin layer
- dead squames filled w/ cytokeratin
- surrounded by protective layer
8
Q
What are the layers can you see in this image?
A
9
Q
What is this?
A
Keratinocytes in Stratum Spinosum
10
Q
What can we see in this picture?
A
- C = Stratum corneum
- L = Stratum lucidum
- G = Stratum granulosum
- S = Stratum spinosum
11
Q
What are the 5 Main Issues with the Skin that can arise?
A
-
Blisters
- Friction blisters
- Blistering diseases
- bullus pemphigoid (hemidesmosome disruption)
- pemphigus (autoimmune–> damage to keratinocyte jxns)
-
Cancers
- Basal cell carcinoma
- Squamous cell carcinoma
- Merkel cell (tactile) carcinoma
-
Psoriasis
- increased proliferation & differentiation
-
Pigment disorders
- albinism
- vitiligo (loss of pigment)
-
Moles or Nevi
- from melanocytes
12
Q
What are the 3 other cells found in the Epidermis?
A
-
Melanocytes
- Derivative: Neural crest
-
Location: Stratum Basale
- 1 per 5-6 keratinocytes
- Pale staining
-
Structure: Long Projections/granules
- Extend into invaginations of keratinocytes
-
Function: cytocrine secretion
- inject melanin –> keratinocytes
- cluster over nucleus & protect from UV
-
Langerhans Cells
- Derivative: Monoocytes
-
Location: Stratum Spinosum (mostly)
- Rare/difficult to see
- Structure: Dendritic cells
- Function: Ag presenting cell
-
Merkel Cells
- AKA: Epithelial tactile cells
- Location: Stratum Basale
-
Structure: look like keratinocytes (but no melanin)
- dense core granules
- mechanoreceptors
-
Fucnction: light touch/texture
- base interacts w/ unmyelinated sensory fibers
13
Q
What cell type is this?
A
Langerhans Cells
14
Q
What cell type is this?
A
Merkel Cells
15
Q
What cell type is this?
A
Melanocytes