Chapter 1 - Structure And Function Of The Skin Flashcards
True or false. The skin is the largest organ of the human body. It accounts for 15-20% of total body weight.
True.
What other name is the skin given ?
The Integument
What are the two broad categories of the layers of the skin ?
- Epidermis
2. Dermis
What strengthens the bond between the Epidermis and Dermis ?
- Dermal papillae(projections)
2. Epidermal ridges (Invaginations)
Beneath the Dermis is the….
Hypodermis or Subcutaneous layer (superficial fascia)
What are the 5 main broad categories of skin functions ?
- Protection
- Sensory
- Metabolic
- Thermoregulation
- Sexual signalling
How is the skin a sexual signalling organ ?
- Factors such as pigmentation and appendages such as hair and nail serve as health indicators for attracting the opposite sex in many vertebrate species including man.
- Pheromones such as sweat and oil also play a role in this area
How is the skin active in metabolism?
The cells of the skin play a role in the formation of Vitamin D.
Excess electrolytes and water can be expelled via sweat generated by the skin.
Subcutaneous tissue (Hypodermis) stores a lot of fat as a source of extra energy.
How does the skin play a role in thermoregulation ?
- Insulation (reduce heat loss) : subcutaneous fat, hair (especially on the head)
- Heat loss : numerous superficial blood vessels, sweat production
How is the skin a protective organ ?
- Physical barrier against : microbes, friction, chemicals, excess uptake of water or loss
- Melanin : protects cell nuclei from UV light
What forms dermatoglyphs? (Finger prints)
The well formed ridges between the epidermis and dermis in thick skin.
The main cells of the epidermis are the Keratonocytes ?
True.
Melanocytes produce the pigment melanin.
True
Langerhan cells are antigen presenting cells ?
True.
Thick skin ranges in thickness of the epidermis from about 0.4to 1.4mm while thin skin can range from 0.07 to about 0.15mm.
True
Cells in the epidermis lack microvasculature and receive nutrients by diffusion from the dermis.
True.
What are the layers of the keratinocytes in the epidermis from dermis upwards.
- Stratum basal
- Startum spinosum
- Stratum granulosum
- S. Lucidum
- S. Corneum
In which layer of the epidermis do we note a niche for progenitor cells ?
- The stratum basal
2. Deep parts of the stratum spinosum
Describe the stratum basal .
A single layer of basophilic cuboidal or columnar cells on the basement membrane at the dermal- epidermal junction.
What kinds of cell junctions occur at the S. Basal layers.
Hemidesmosomes adhere the keratinocytes of this layer with the basal membranes.
Desmosomes adhere the keratinocytes together.
Which layer of the epidermis is usually the thickest?
The spinous layer
The cells of the spinous layer are polyhedral with central nuclei and actively synthesis keratins.
True.
The stratum lucidum is found only in thick skin ?
True.
The color of skin is due to many factors. The most important is the keratinocytes content of melanin and Carotene.
True.
