Lesson 7 Integumentary System Flashcards
Lessons 7-11
How does vitamin D synthesis occur in the skin?
UV radiation causes epidermal cells to produce cholecalciferol (vitamin D3), converted to calcitriol
what are the 5 functions of the skin?
- protection
- vitamin d synthesis
- sensation
- thermoregulation
- nonverbal communication
what type of tissue is the epidermis?
keratinized stratified squamous epithelium
what are the 5 epidermal cells types?
- keratinocytes
- stem cells
- melanocytes
- tactile cells
- dendritic cells
what are the 5 layers of the epidermis? (superficial to deep)
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
which layer of the epidermis contains dead keratinized cells?
stratum corneum
at which layer of the epidermis do keratinocytes begin to dehydrate and die?
stratum granulosum
what are the 2 layers of the dermis?
- papillary layer
- reticular layer
what type of tissue is the papillary layer composed of?
areolar tissue
what type of tissue is the reticular layer composed of?
dense irregular connective tissue
what are the 2 types of fibers in the dermis? list a function from each.
- collagen fibers
- provides flexibility, bends but resists stretching - elastic fibers
- provides flexibility and stretching, allows for recoil
what is dermatitis and what causes it?
inflammation of the papillary layer. can be caused by infection or radiation
what are decubitus ulcers and what causes them?
bedsores caused by the compression of superficial blood vessels
what are friction ridges?
they are formed by dermal papillae. fingerprints!!
what are flextion lines?
creases on the surfaces of the fingers, palms, wrists, and elbows from where skin folds during flexion of joints
what are hemangiomas?
birthmarks
what is a nevus?
a mole; elevated, melanized patch
what is subcutaneous fat and what are its functions?
subcutaneous tissue mostly composed of adipose tissue; insulates and reserves energy
what is a pilus?
hair
what are the 3 types of hair? name some characteristics of each
- downy hair (lanugo)
- fine, unpigmented hair (fetus) - vellus hair
- fine, pale hair that replaces lanugo by time of birth - terminal hair
- longer and coarser hair; more pigment
what are the 3 layers of hair? (deep to superficial)
- medulla (core)
- cortex (bulk of hair)
- cuticle (outermost region)
what are the 2 principle layers of a follicle?
- epithelial root sheath
- extension of the epidermis - connective tissue root sheath
- derived from the dermis (surrounds the epithelial root sheath)
what connects the follicle to the dermis?
arrector muscle (also makes the hair contract upwards)
what do myoepithelial cells do?
they have contracting properties that squeeze perspiration up the duct
what are the 2 types of perspiration and how does it occur?
- insensible perspiration
- water loss by evaporation from skin (you can’t see it) - diaphoresis
- visible sweating from skin
how do eccrine, apocrine, and holocrine glands release their secretions? what is the difference between them?
exocytosis. eccrine glands release their secretions directly onto the skin, while apocrine glands release secretions into hair follicles. holocrine glands accumulate a product and then the entire cell disintegrates.
what type of gland is a sebaceous gland?
holocrine gland
what are ceruminous glands?
modifed versions of apocrine glands. produces cerumen (earwax)
what are the 3 types of skin cancer? where and how does it occur?
- basal cell carcinoma
- cells in the stratum basale - squamous cell carcinoma
- keratinocytes in the stratum spinosum - melanoma
- melanocytes
what are characteristics of a first degree burn?
only involves the epidermis, and is painful
what are characteristics of a second degree burn?
involves part of the dermis, and can be painful. takes longer to heal
what are characteristics of a third degree burn?
involves all of the dermis and sometimes deeper tissues. painless because nerve endings are destroyed
