Integumentary System Flashcards
What are the functions of the integumentary system?
Protection, Temperature regulation (sweat) , Sensation and metabolism (vit D synthesis)
Epidermis
superficial keratinized stratified squamous epithelium facing the exterior of the body
Dermis
CT deep to the epidermis that provides structural support and a route for blood vessels that provide nutritional support to the epidermis. Two layers- Papillary layer and reticular layer
Papillary layer of the dermis
most superficial layer of the dermis consists of areolar CT adjacent to the epidermis
Reticular layer of the dermis
Dense irregular CT forming the majority of the dermis
Hypodermis
layer of adipose CT deep to the dermis (aka superficial fascia or subcutaneous adipose tissue)
What are the major cell types found in the epidermis?
Keratinocyte, Melanocyte, Langherhan’s cells and Merkel cells
Keratinocyte
Most common cells in the epidermis, produce the fibrous intermediate filament protein keratin that provides strength to the epidermis and helps make a water-resistant barrier
Melanocyte
Cells that produce a brown pigment called melanin that absorbs UV radiation to protect from the damaging effects of the sun
Langherhan’s Cells
Type of leukocyte found in the epidermis where they can monitor the skin for infections
Merkel Cells
Specialized neuroepithelial somatosensory receptor cells that detect changes in the shape of the skin that contribute to our sense of touch
What are the five layers of the epidermis?
Stratum basale, Stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
Stratum basale
basal layer, deepest layer of the epidermis forms firm attachments to the basal lamina, stem cells in this layer undergo rapid division to produce keratinocytes, melanocytes and merkel cells also found at the border
Stratum spinosum
spiny layer, 8-10 layers of cells superficial to the stratum basale, keratinocytes in this layer contain a web-like system of intermediate filaments of the pre-keratin protein attached to desmosomes, melanin granules and langerhan’s cells are abundant in this layer
Stratum granulosum
granular layer, 3-4 cells thick, contains keratinocytes that are becoming flattened and disintegrating their organelles, and preparing to go through programmed cell death as they excrete lipid granules, the cytoplasm fills with keratin and the cell becomes flat and the plasma membrane thickens
Stratum lucidum
clear layer, thin layer only a few cells thick, does not stain when prepared for light microscopy giving it a clear appearance, superficial to the stratum granulosum and deep to the stratum corneum in thick skin, this layer is not present in thin skin covering most of the body
Stratum corneum
horny layer, superficial layer of dead kertainocytes filled w keratin and surrounded by glycolipids filling the extracellular space to create a water resistant barrier, thickest layer of the epidermis (about 2/3 of the epidermis), cells are constantly being shed from this layer, dead keratinocytes stay attached to the epidermis for about 2 weeks before they are normally shed
Melanin
produced by melanocytes. gives skin a brown color
Hemoglobin
Red pigment found in erythroctyes, increased blood flow can turn skin red, binding of oxygen to hemoglobin effects color, bright red when saturated w oxygen, when it becomes deoxygenated it turns dark red and appears blue though the skin
Cyanosis
Blue coloring of the skin that indicates a lack of oxygen as occurs when a person is suffocating
Bilirubin
A breakdown product of hemoglobin
Jaundice
A yellow pigmentation of the skin and whites of the eyes due to high bilirubin levels, may indicate impaired liver function
Carotenosis
Gives skin an orange color
Hair follicle
small accessory organs that produce hair, made of keratin
Hair root
deep into the dermis, grows out of the hair follicle and becomes the hair shaft as it grows superficially out of the epidermis
Hair bulb
large bulge in the region surrounding the deep end of the hair root, papilla at the base of the hair bulb contain blood vessels that provide nutrients to the growing epithelial cells hair follicle
Arrector pili
smooth muscle that pulls on the hair follicle to make the hair stand out causing goosebumps
Hair follicle receptor
Consists of specialized endings of neurons that detect movement of hair
Functions of hair
Protection, sensory input, thermoregulation and communication
Free nerve endings
extend through the dermis and epidermis contribute to the sense of pain
Pacinian corpuscle
found deep in the reticular layer of the dermis, is another somatosensory receptor that contributes to the sense of touch by detecting deep pressure and vibration
Meissner corpuscle
A somatosensory receptor common in the skin on tips of the fingers that are very sensitive to detect light touch, found in the superficial portion of the dermis in Dermal papillae where areolar CT forms the superficial layer of the dermis called the papillary layer
Merkel Cells
Specialized sensory receptor cells found in the deepest layer of the epidermis that are sensitive to the movement of the epidermis
Sebaceous glands
Produce an oily secretion that protects and lubricates the hair and skin, composed of stratified cubpidal epithelium that uses the holocrine secretion mode to produce oily sebum
Sudoriferous (sweat) glands
Coiled tubular glands that consist of stratified cuboidal epithelium that produces watery merocrine secretion to cool the body
Eccrine glands
All over the body, more in palmar and plantar regions
Appocrine glands
Located in the axilla, groin, face and nipples, function at puberty made of stratified cuboidal epithelial tissue
Nail
An accessory structure produced by modified epidermal tissue, functions in protection, scratching and grasping small objects
