Chapter 6 Flashcards
What is the largest organ in the body?
Skin
What is the epidermis?
keratinized straitified squamous epithelium
What is the dermis?
connective tissue layer
What is the hypodermis?
Fat layer
What are the 6 functions of the skin?
Resistance to trauma, barrier to ultraviolet, vitamin d synthesis, sensory receptors, thermoreceptors, nonverbal communication
What are stem cells?
cells in deepest layer
What are keratinocytes?
most skin cells
What are melanocytes?
Shield UV
What are tactile/merkel cells?
nerve cells
What are dendritic cells?
guard against pathogens
What is the single layer of cells on the basement membrane?
stratum basale
What is the stratum spinosum?
layers of keratinocytes
What is the stratum granulosum?
3 to 5 layers of keratinocytes
What is the stratum lucidum?
translucent zone in thick skin
What is th stratum corneum?
up to 30 layers of dead, scaly, keratinized cells
What is the life cycle of keratinocytes? (4)
- produced by stem cells
- new cells push older towards surface
- cells fill with keratin
- cells die
What is the dermis composed of?
Collagen, elastic and reticular fibers, and fibroblasts
What is the dermal papillae?
extensions of dermis into epidermis
What are the layers of the dermis?
papillary layer and reticular layer
What is the most superficial layer of the skin?
They hypodermis
What is hemoglobin?
Red pigment of red blood cells
What is carotene?
yellow pigment
What is melanin?
brown pigment
What is cyanosis?
blue color from lack of oxygen
what is erythema?
redness due to dilated cutaneous vessels
What is jaundice?
yellowing of skin due to excess bilirubin in blood
What is bronzing?
golden-brown color skin
what is pallor?
pale skin from lack of blood flow
what is albinism?
genetic lack of melanin
what is a hematoma?
a bruise
What are freckles and moles composed of?
excessive melanocytes
What are flexion creases?
creases in skin by repeated closing of hand
what are flexion lines?
form in wrist and elbow areas
what is hair composed of?
hard keratin
what are the 3 different hair types?
lanugo, vellus, and terminal
What is the hair shaft?
above the skin
what is the hair follicle?
oblique tube within the skin
What are the 3 stages of the hair cycle?
anagen (growth)
catagen (shrinking)
telogen (resting)
What is the term for thinning or baldness?
alopecia
What is hirsutism?
excessive hair growth
What are guard hairs?
prevent foreign objects from getting into nose, eyes, or ears
What are merocrine glands?
simple tubular gland
what are apocrine glands?
produce sweat
What are sebaceous glands?
oily secretion glands
What are ceruminous glands?
only in external ear canal
What are mammary glands?
found only during lactation and pregnancy
What is polythelia?
additional nipples
What is basal cell carcinoma?
least dangerous skin cancer
what is squamous cell carcinoma?
medium dangerous skin cancer
What is malignant melanoma?
most deadly skin cancer
What does 1st degree burn?
only epidermis
What does 2nd degree burn?
epidermis and some dermis
What does 3rd degree burn?
epidermis and dermis
What is an autograft?
tissue from person needing graft
what is an isograft?
tissue from identical twin
what is a homograft?
tissue from unrelated person
what is a heterograft?
tissue from another species, mostly pig
