Flashcards in Chapter 5:The Integumentary System Deck (106)
How many regions make up the skin?
What is the epidermis?
outermost superficial region of skin
What is the dermis?
the middle region of the skin
What is the hypodermis?
the deepest region of the skin
what is another name for the hypodermis?
what is superficial fascia?
What is the epidermis comprised of?
keratinized stratified squamous epithelium, with 4 cell types and 4 to 5 layers
What cell types are found int the epidermis?
What is the function of the epidermis?
it is the outer portion of the skin, is exposed to the external environment and functions in protection
– produce the fibrous protein keratin.
– produce the brown pigment melanin.
epidermal macrophages that help activate the immune system.
function as touch receptors in association with sensory nerve endings.
What are the layers of the epidermis?
What is the stratum basale?
the basal layer of the epidermis. the deepest layer, firmly attached to the dermis
What is the stratum basale made of?
a single row of the youngest keratinocytes
what happens in the stratum basale?
cells undergo rapid division, hence its alternate name, stratum germinativum
What is the stratum spinosum?
the prickly layer of the epidermis. 2nd from the bottom
What is the stratum spinosum made of?
1. cells contain weblike system of intermediate filaments attached to desmosomes.
2. melanin granules and Langerhans' cells are abundant in this layer
What is the stratum granulosum?
the granular layer, 2nd from the top
what does the stratum granulosum look like?
thin; three to five cell layers in which drastic changes in keratinocyte appearance occurs
What accumulates in the stratum granulosum?
Keratohyaline and lamellated granules
What is the stratum lucidum?
a clear layer, found only in thick skin. superficial to the stratum granulosum
What is the stratum lucidum made of?
a few rows of flat, dead keratinocytes
What is the stratum corneum?
the horny layer, the outermost layer
What percent of the epidermis is made of the stratum corneum?
What are the functions of the stratum corneum?
2. Protection from abrasion and penetration
3. Rendering the body relatively insensitive to biological, chemical, and physical assaults
What is the dermis?
the second major skin region containing strong, flexible connective tissue
What cell types are in the dermis?
fibroblasts, macrophages, and occasionally mast cells and white blood cells