Chapter 5: Integumentary System Flashcards
What are the two main parts of the skin?
Epidermis and dermis
What is the epidermis composed of?
Keratinized stratified squamous epithelium containing four main types of cells:
Keratinocytes
Melanocytes
Intraepidermal macrophages
Tactile epithelial cells
What is the dermis composed of?
Dense, irregular connective tissue containing collagen and elastic fibers
Where are lamellar granules located, and what is their function?
They are located in keratinocytes
They release lipid-rich secretions acting as a sealant, preventing the loss of body fluids and entry of foreign materials
What are the layers of the epidermis?
Four strata or layers:
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum
What is the function of stratum spinosum?
It provides strength and flexibility
What is the function of stratum granulosum?
This is where keratinocytes undergo apoptosis
What is the stratum lucidum?
This is the fifth layer of skin in thick skin (on palms and soles). It is located between the granulosum and the corneum
Describe the superficial part of the dermis?
Makes up 1/5 of the thickness of the layer
Made of areolar connective tissue containing fine elastic fibers
Surface area is increased by dermal papillae, touch receptors, and free nerve endings
What is another term for touch receptors?
Meissner corpuscles
Describe the deeper part of the dermis
Attached to subcutaneous layer
Made of dense irregular connective tissue containing bundles of collagen and coarse elastic fibers
Adipose cells, hair follicles, nerves, oil glands, and sweat glands are found between the fibers.
What are striae?
These are permanent stretch marks that are visible at the skin surface
Created from extreme stretching that causes tears in course elastic fibers in the deep layer of the dermis
What is vitiligo?
This is a loss of melanocytes in a skin region and leads to patches of lighter or pale skin
Where does tattooing deposit pigmentation?
Pigment is deposited into the dermis with a needle. Because the dermis is stable, tattoos are permanent
Describe the layering of a hair follicle
It has an internal and external layer of epidermal cells, and then together are surrounded by a connective tissue sheath
What are hair root plexuses?
These are nerve ending surrounding each hair follicle that are sensitive to touch
What is the hair bulb?
This is the base of each hair follicle.
it contains the papilla of the hair, which are the blood vessels that provide nourishment for growing hair
What are arrector pili?
These are bundles of smooth muscle associated with hairs that contract under stress like cold or fright that make the hairs stand perpendicularly
What stimulates hair growth during puberty?
Androgens
What is Hirsutism?
This is the excessive hair growth due to androgens
What is androgenic alopecia?
This is genetically inhibited growth of scalp hair
What are ceruminous glands?
These are glands in the outer ear canal and produce a yellowish secretion called cerumen or earwax
What are sebaceous glands?
These are glands that secrete sebum (oily substance) that keeps hair from drying out, prevents excessive evaporation, softens skin, and inhibits certain bacteria
What are the two types of sudoriferous glands?
Apocrine sweat glands
Eccrine sweat glands