Lab 3- Tissues and Integumentary Sys.

Question 1

What are the two distinct regions of the skin?

Answer 1

epidermis: composed of epithelium and an underlying connective tissue; and the dermis

Question 2

What part is deep to the dermis?

Answer 2

subcutaneous layer or hypodermis; which is not considered part of the skin; consists primarily of adipose tissue

Question 3

Epidermis

Answer 3

avascular; keratinized stratified squamous epithelium; consits of four distinct cells types and four or five distinct layers

Question 4

What are the cells of the epidermis?

Answer 4

keratinocytes, melanocytes, dendritic cells, and tactile epithelial cells

Question 5

Keratinocytes

Answer 5

most abundant epidermial cells; produce keratin fibrils; keratin is a fibrous protein that gives the epidermis its durability and protective capabilites; keratinocytes are tightly connected by desmoses

Question 6

Melanocytes

Answer 6

spidery balck cells that produce the brown to black pigment called melanin; melanin protects against ultraviolet radiation (UVR)

Question 7

Dendritic Cells

Answer 7

aka Langerhans cells; arise form the bone marrow and migrate to the epidermis; they ingest foreign sibstances and play a key role in activating the immune response

Question 8

Tactile Epithelial Cells

Answer 8

occasional spiky hemispheres that, in combination with sensory nerve endings, form sensitive touch receptors located at the epidermal-dermal junction

Question 9

How many layers are in thin skin?

Answer 9

4

Question 10

How many layers are found in thick skin?

Answer 10

5; added stratum lucidum

Question 11

What are the layers of the epidermis from deep to superficial?

Answer 11

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum

Question 12

Stratum Corneum

Answer 12

horny layer; the outermost layer consisting of 20-30 layers of dead, scalelike keratinocytes; they are constantly being exfoliated and replaced by the division of deeper cells

Question 13

Stratum Lucidum

Answer 13

clear layer; present only in thick skin; a very thing transparent band of falttened, dead keratinocytes with indistinct boundaries

Question 14

Stratum Granulosum

Answer 14

granular layer; a think layer named for the abundant granules its cells contain; these granules are 1) lamellar granules, which contain a waterproofing glycolipid that is secreted in the extracellular space; and 2) keratohylaine granules, which help to form keratin in the more superficial layers; at the upper border of this layer, the cells are beginning to die

Question 15

Stratum Spinosum

Answer 15

spiny layer; serveral layers of cells that contain thick, weblike bundles of intermediate filaments made of a pre-keratin protein; the cells in this layer appear spiky because when tissue is prepared, the cells shrink, but their desmosomes hold tight to adjacent cells; cells in this layer and the basal layer are the only ones to receive adequate nourishment from diffusion of nutrients from the dermis

Question 16

Stratum Basale

Answer 16

basal layer; a single row of cells immediately above the dermis; its cells are constantly undergoing mitosis to form new cells, hence it alternate name stratum germinativum; some 10-25% of the cells in this layer are melanocytes, which thread their processes through this and adjacent layers of keratinocytes; occasional tactile epithelial cells are also present in this layer

Question 17

What are the two regions of the dermis?

Answer 17

papillary and reticular areas

Question 18

Papillary Dermis

Answer 18

more superficial dermal region composed of areolar tissue; uneven and has fingerlike projections from it superior surface; abundant capillary networks allow nutrients and allow heat to radiate to the skin surface; pain receptors (free nerve ending) and touch receptors (tactile corpuscles) found here

Question 19

Dermal Papillae

Answer 19

attach papillary dermis to the epidermis above; uneven fingerlike projections ; these projections lie on top of the larger dermal ridges; they produce fingerpronts

Question 20

Reticular Dermis

Answer 20

deepest skin layer; composed of dense irregular connective tissue and contains many arteries and veins, sweat and sebaceous glands, and pressure receptors (lamellar corpuscles)

Question 21

What results in skin color?

Answer 21

relative amount of melanin and carotene in the skin; degree of oxygenation of the blood

Question 22

Carotene

Answer 22

yellow orange pigment present primarily in the stratum corneum and in the adipose tissue of the hypodermis

Question 23

What are the accessory organs of the skin?

Answer 23

cutaneous glands, hair, and nails ; they originate from the stratum basale and extend into the dermis

Question 24

Nails and their Parts

Answer 24

are hornlike derivatives of the epidermis; nail plate, free edge, hyponychium, nail root, nail folds, eponychium, nail bed, nail amtrix, lunule

Question 25

Nail Plate

Answer 25

the visible attached portion

Question 26

Free Edge

Answer 26

the port of the nail that grow out away from the body

Question 27

Hyponychium

Answer 27

the region beneath the free edge of the nail

Question 28

Nail Root

Answer 28

part that is embedded in the skin and adheres to an epithelial nail bed

Question 29

Nail Folds

Answer 29

skin folds that overlap the borders of the nail

Question 30

Eponychium

Answer 30

projection of the thick proximal nail fold commonly called the cuticle

Question 31

Nail Bed

Answer 31

extension of the stratum basal beneath the nailN

Question 32

Nail Matrix

Answer 32

thickened proximal part of the nail bed containing germinal cells responsible for nail growth; as the matrix produces the nail cells, they become heavily keratinized an die

Question 33

Lunule

Answer 33

proximal region of the thickened nail matrix (appears as a white crescent moon)

Question 34

What are the color of nails and why do they appear that way?

Answer 34

nails are transparent and nearly colorless but they appear pink because of the blood supply in the underlying dermis

Question 35

Where is hair not found?

Answer 35

thick skinned areas (palms of the hands and soles of the feet) and parts of the external genitalia, nipple, and lips

Question 36

What are the two primary regions of hair?

Answer 36

hair shaft: the region projecting from the surface of the skin; and the hair root: which is beneath the ruface of the skin and is embedded within the hair follicle

Question 37

Hair Bulb

Answer 37

collection of well-nourished epithelial cells at the base of the hair follicle

Question 38

Hair Follicle

Answer 38

structure formed from both epidermal and ermal cells; epithelial sheath is enclosed by a thickened basement membrane, the glassy membrane and by a peripheral connective tissue or fibrous sheath

Question 39

Hair Papilla

Answer 39

snall nipple of dermal tissue protruding into the ahir from the peripheral connective tissue sheath and provides nutrients to the growing hair

Question 40

Hair Matrix

Answer 40

layer of acitvely dividing epithelial cells located on top of the hair papilla

Question 41

Arrector Pili Muscle

Answer 41

small bands of smooth muscle cells connect eahc hair follicle to the papillary layer of the dermis; when theu contract the slanted hair follice is pulled up right causing coose bumbs

Question 42

What are the two categories of cutaneous glands?

Answer 42

sebaceous and sweat glans

Question 43

Sebaceous Glands

Answer 43

oil glands; found nearly all over the skin (except for the palms of the hands and soles of the feet); ducts usually empty into a hair follicle but some open directly on the skin surface; become particulary active during puberty, when more male hormones (androgens) begin to be produced for both genders; this the skin becomes oilier during this period

Question 44

Sebum

Answer 44

product of sebaceous glands; mixture of oily substance and fragmented cells that acts as a lubricant to keep the skin soft and moist (natural skin cream) and keeps the hair from becoming brittle

Question 45

Sudoriferous Glands

Answer 45

sweat glands; exocrine glands that are widely distributed all over the skin; outlets for the glands are epithelial openings called pores; sweat glands are caegorized by the compostition of their secretions

Question 46

Eccrine Sweat Glands

Answer 46

aka merocrine sweat glands; these are distributed all over the body; produce a clear secretion consisting primarily of water, salts, and urea; important part of bodys heat regulating apparatus (which is controlled by the nervous sys)

Question 47

Apocrine Sweat Glands

Answer 47

found predominantly in the axillary and genital area; these secrete the basic components of eccrine sweat plus proteins and fat-rich substances; excellent nutrient medium for the microorganisms typically found on the skin; initially odorless but when bacteria break down its organic components it begins to smell