A&P Lab Seven
underlying connective tissue of skin is
dermis
all following are functions of skin except
a. excretion of body wastes b. insulation c. protection from mechanical damage d. sit of vitamin a synthesis****
sweat (sudoriferous) glands
all over skin; outlets called pores; categorized by composition of secretions
___ are found primarily in the genital and axillary areas
apocrine
stratum basale
basal layer; #5; immediately adjacent to dermis; constantly undergoing cell division; 10%-25% of its cell are melanocytes
stratum lucidum
clear layer; #2; thin translucent flattened dead keratinocytes; not present in regions of thin skin
reticular layer
deepest layer; dense irregular connective tissue and contains arteries, veins, sweat, sebaceous glands, pressure receptors
superficial layer of skin is the
epidermis
stratum granulosum
granular layer; #3; thin layer & two types: 1. lamellated granules:waterproof glycolipid secreted into extracellular space 2. keratohyaline granules: combine w/ intermed. filaments in more superficial layers to form keratin fibrils
keratinocytes
keratin cells; part of epidermis; most abundant epidermal cells, function mainly to produce keratin:fibrous protein gives epidermis its durability and protective capabilities; tightly connected to each other by desmosomes
epidermis dendritic cells
langerhans cells; role in immunity; part of epidermis
these cells produce a brown-to-black pigment that colors the skin and protects DNA from the damaging effect of UV radiation
melanocytes
eccrine
merocrine sweat glands; clear perspiration; heat-regulation
pacinian corpuscle
nerve endings in the skin, responsible for sensitivity to pain and pressure
sebaceous glands
oil; all over except palms of hand and soles of feet; usually empty into hair follicles, some onto skin; sebum: keep skin soft/moist
tactile (Merkel) cells
part of epidermis; occasional spiky hemispheres; conjunction with sensory nerve endings, form sensory touch receptors called tactile or merkel discs located at epidermal-dermal junction
apocrine
predominantly in axillary and genital areas, milky protein- and fat- rich substance nutrient medium for microorganisms found on skin
melanocytes
produce melanin(brown-to-black); part of epidermis; connection of melanin in one spot is freckle
the ducts of ____ usually empty into a hair follicle but may also open directly on the skin surface
sebaceous (oil)
cutaneous glands
sebaceous and sweat glands
portion of hair that you see that projects from the scalp surface known as the
shaft
stratum spinosum
spiny layer; #4; several cell layers; thick, weblike bundles of intermediate filaments made of pre-keratin protein; spiky because as skin tissue prepared for exam, shrink but desmosomes hold tight; cells divide fairly rapidly; adequate nutrition from dermis
papillary layer
superficial dermis layer; composed of areolar connective tissue; uneven with fingerlike projections from superior surface called dermal papillae that attach to epidermis--produce fingerprints; allow heat to radiate from skin surface; pain and touch receptors found here
(t/f)nails are hornlike derivatives of the epidermis
true
stratum corneum
horny layer; #1; 20-30 layers; consists of dead flattened scalelike remnants that are fully keratinized
arrector pili muscle
microscopic band of muscle tissue which connects a hair follicle to the dermis; stimulated, will contract and cause the hair stand on end
hypodermis
superficial fascia (primarily adipose tissue) immediately deep to the dermis; not considered part of skin