A&P Lab 2, Integuments and Glands Flashcards
What are the functions of the integumentary system?
Protection (physical and physiological)
Regulation of body temperature
Sensory perception
Excretion
Blood reservoir
Initiation of vitamin D formation
Fat storage
What is the epidermis?
The outermost layer of the skin
Made of keratinized stratified squamous epithelium
Avascular
What cells make up the epidermis?
Keratinocyte (90%) synthesize protein that adds strength and waterproofing to cells.
Melanocytes (8%) produce pigment called melanin, restricted to the stratum basale.
Langerhan’s cells (<2%) immune cells of the skin.
Merkle’s cells (<2%) attached to sensory neuron (Merkle’s disk) involved in sensory perception.
What are the sublayers of the epidermis?
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
What is the stratum basale?
The deepest sublayer of the epidermis. It is made of living cuboidal cells. You can find melanocytes, Merkle’s disks, and keratinocytes in this layer.
What is the stratum spinosum?
The larger layer of the epidermis. The cells in this layer are alive until they get near the next level. They have a spiny or prickly appearance.
What is the stratum granulosum
The transition zone for skin cells. It has 3-5 layers. It appears granular or darker in color. It looks grainy. Keratinocytes begin to die and start to fill with keratin.
What is the stratum lucidum?
This layer is not found in all skin. It is only found in thick skin such as the bottom of your foot. It has 2-4 layers of dead cells filled with keratin.
What is the stratum corneum?
The most superficial layer of the epidermis. It is made up of 20-30 sublayers of dead keratinocytes filled with keratin. They look like shingles on a house.
What is the dermis?
True skin
All metabolic activity of the skin occurs here
Contains blood, nerve endings, hair, and glands
What are the layers of the dermis?
The reticular layer
The papillary layer
What is the reticular layer?
The inner layer of the dermis
Composed of dense irregular connective tissue
Contains tiny reticular fibers and has a netlike appearance
What is the papillary layer?
Superficial to the reticular layer
Composed of areolar connective tissue
(collagen fibers, elastic fibers, etc.)
This layer also forms nipple-like extensions into the epidermis. The order of these is genetically determined and different for each individual.
What creates a person’s fingerprint?
Dermal papilla
What is the hypodermis?
This is not a true skin layer
It is a subcutaneous layer that lies below the dermis
Made entirely of adipose tissue
Insulin is injected in this layer
