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