Integumentary system Part 1 Flashcards
SKIN IS DIVIDED INTO 3 LAYERS. name those layers.
- Epidermis
- Dermis
- Hypodermis/ Subcutic
The largest organ in the human body
Skin
Skin is divided into two categories based on the thickness of the epidermis
Name those two categories
Thin and Thick skin
What does the thick skin compromised of?
Thicker keratin layer
Where do you find the thick skin and thin skin
Thick: Soles of the feet
Palms of the hands
Thin: covers the rest of the body
Name the layers of the thin and thick skin
Thick- stratum basal
Stratum spinosum
Stratum granulosum
Stratum lucidum
Stratum corneum
Thin- all of the above layers except Stratum lucidum
Between thick and thin skin, which one has hair follicles which one does not have Hair follicles
- Thin skin has hair follicles
- Thick skin does not have hair follicles
Functions of the skin
- Protection
- Moisture control
- Metabolic
- Immunological
- Themoregulation
- Sensory
Characteristics of Epidermis
- High proliferative stratified squamous epithelial layer
- Produces non-living layer of keratin
- Non- epithelial cells (langerhans cells, Melanocytes and Merkel cells)
Characteristics of Dermis
Fibrous and fribroadipose tissue layer that supports epidermis
Consists of blood vessels nerve and sensory receptors
.Responsible for tone and texture of skin
Connective tissue layer
Has 2 layers
Hypodermic characteristics
Contain adipose tissue with supporting fibrous bands called septa
Contain large vessels
Stratum Basale
1. Name the cells that make Stratum basala
2. Name the junction and the role
3. Stratum basale is highly mitotic and contains which cells, and what does this cells do
4. Specialized cells and the function
5. The basal cells form
6. Superficial progenitor basal cells mature
- Cuboidal or columnar cells which rest on the basement membrane
- Dermo-epidermal junction that binds the epidermis to the dermis
- Progenitor cells that gives rise to the other layers of the epidermis
- Melanocytes which is responsible for melanin production
- The basal cells form an irregular basal surface and have an indented cell membrane with hemidesmosomes
- Matures into cells of the stratum spinosum
Stratum spinosum
1. Layers of spinosum
2. Explain the organelles
3. Other name?
4. Specialized cells
5. Keratinocytes matures into?
- Multiple layers of polyhedral shaped keratinocytes
- Round shaped nuclei, prominent nucleoli and cytoplasm
- Prickle cell layer
- Keratinocytes which is actively synthesize keratin
- Matures stratum granulousm
Stratum granulosum
1. Characteristics of cells
2. This cells undergoes which processes, and explain
- 1-5 layers of flattened cells
- Keratinization, filling cytoplasm with basophilic keratohyaline granules
Stratum lucidum
1. Characteristics
Found only in the thick skin
Very thin single layer of translucent flattened cells which lack nuclei and organelles and are packed with mostly keratin filaments
Stratum corneum
1. Explain the cells that make up stratum corneum
2. Name the basket weave pattern that the cells form
3. This cells are continuously shed at the?
4. Characteristics of this cells based on water.
- The cells progress toward the surface lose their nuclei and cytoplasm and become keratinised squamous epithelial cells which then comprises the surface coating of the stratum corneum
- Orthokeratosis
- Epidermal surface
- Are water repellent since they are coated with lipid containing anti wetting agents that were synthesized during maturation in the granular layer.
The intra-epidermal antigen presenting cells (Histocytes)
Langerhans cells
Where do we find langerhans cells
Presents in all layers of epidermis but easily noticed in stratum spinosum
When the langerhans cells are stimulated what they do
They migrate from the dermis and then ti lymphatic system
Explain the organelles in langerhans cells
Irregularly lobulated nuclei and almost clear cytoplasm
The cytoplasm processes extend from the cells and insinuate between keratinocytes
The cell of the epidermis with a rod-like structure with cross striations
Birbeck granules
The cytoplasmic organelle of Langerhans cells
Birbeck granules
one end of Birbeck granules what it does?
One end distends into a vesicle, resembles a tennis cricket.
Cells that produce melanin
melanocytes
function of melanin
skin and hair colour
True or False based on melanocytes
1.The numbers of melanocytes do not really vary; however, these cells are more active in dark-skinned people.
2. Has several branched dendritic process (easily seen on H&E stain).
3. Rounded cell bodies with clear cytoplasm appearance
1.True
2. False
3. True
Melanocytes antigens shows what?
Melanocyte antigen shows globular cell-bodies situated in the basal layer with branching dendritic processes, seen under an immunohistochemical stain.
In which area do we find more melanocytes?
Usually presented as separated individual cells in the basal layer, numerous in areas that are exposed to light
In which form are the sensory nerve ending in the skin?
Sensory nerve endings in the skin are in the form of free-nerve endings and specialised encapsulated nerve endings (with the capsules being Schwann cells)
Is sensory nerve ending in the skin myelinated or unmyelinated?
The sensory nerve ending in the skin can either be myelinated or unmyelinated..
Free nerve endings are responsible for what?
Mainly responsible for Pain and Itch sensations and detecting Temperature
Where do we find free nerve endings?
Occupy the papillary dermis and associate with Merkel cells in the epidermis to act as a slow-adapting mechanoreceptor
Ramify around hair follicles
small, encapsulated receptors that are found in the papillary dermis of the fingertips, soles of the feet, eyelids, lips and genitalia.
Meissner corpuscles
These are fast-adapting mechanoreceptors which detect changes in texture and vibration
Meissner corpuscles
Explain the structure of Meissner corpuscles.
Meissner corpuscles are ovoid with a collagenous tissue capsule that surrounds a mass of plump oval cells arranged transversely.
Large, encapsulated sensory receptors that are responsive to pressure, coarse touch and rapid vibration
Pacinian Corpuscles
Where do we find Pacinian corpuscles?
Located in the deeper layers of the hypodermis, singularly or in small clusters, numerous in palms and soles
What do Pacinian corpuscles have?
Have a delicate capsule that contains concentric lamellae of flattened cells separated by interstitial fluid spaces and collagen fibres
Intra-epidermal touch receptors
Merkel cells
What does the Merkel cells contain?
Contain neuro-endocrine type membrane-bound vesicles in cytoplasm
Where do we find the Merkel cells
Particularly near junctions with myelinated nerve endings in the upper dermis
True or False based on Merkel cells.
1. Not easily seen on H&E stain, immunohistochemical stain sometimes used
2. Rounded cell with pale-staining cytoplasm
- True
- True
Where are each free nerve ending receptors found?
Meisnner- (papillary) epidermis
Pacinian-hypodermis
Merkel-(intra-epidermal) epidermis
Types of dermis
Papillary
Reticular
What structure runs vertically from deep reticular dermis to fascial fibrous tissue that underlies subcutaneous
Fibrous septa
