Chapter 5 - Integumentary System Flashcards Preview

skin & accessory structures including hair, nails, glands, blood vessels, muscles and nerves 
 

medical specialty for the diagnosis and treatment of disorders of the integumentary system. 

subcutaneous membrane

covers body 

largest organ of body by surface area & weight

2 square metres (22 sq. feet)

4.5-5 kg (10-11 lb)

7% 

0.5-4.0 mm thick

thinnest on eyelids

thickest on heels 

average = 1-2 mm

1) epidermis - outer, thinner layer; consists of epithelial tissue

2) dermis - inner, thicker layer

a subcutaneous (subQ) layer (also called hypodermis)

which attaches the skin to underlying tissues & organs. 

- composed of keratinized stratified squamous epithelium 

contains 4 major types of cels 

1) keratinocytes

2) melanocytes

3) Langerhans cells

4) Merkel cells 

(90% of the cells)

- produce keratin (a tough fibrous protein that provides protection)

produce the pigment melanin that protects against damage by UV radiation

involved in immune responses, arise from red bone marrow

 function in sensation of touch along with adjacent tactile discs

 four major layers (thin skin)

five major layers (thick skin) 

1) stratum corneum

2) stratum lucidum

3) stratum granulosum

4) stratum spinosum

5) stratum basale

aka stratum germinativum

deepest layer

continuous cell division occurs which produces all other layers 

8-10 layers of keratinocytes 

Langerham cells & projections of melanocytes present 

present only in thick skin 

(the skin of the fingertips, palms, and soles) 

includes keratohyalin and lamellar granules 

consists of 3 to 5 layers of flattened keratinocytes undergoing apoptosis

marks transition between deeper metabolically active strata & dead cells of superficial strata

composed of many sublayers of flat, dead keratinocytes called corneocytes or squames that are continuously shed and replaced by cells from deeper strata;

constant friction can stimulate formation of a callus. 

constant friction 

the accumulation of more and more protective keratin, occurs as cells move from the deepest layer to surface layer 

- an excess of keratinized cells shed from the scalp 

composed of connective tissue containing collagen & elastic fibers

contains 2 layers 

1) Papillary region

2) Reticular region 

outer region, consists of areolar (soft) connective tissue containing thin collagen, elastic fibers, dermal papillae (including capillary loops), corpuscles of touch & free nerve endings 

deeper region, 

consists of dense irregular connective tissue

containing collagen and elastic fibers, adipose cells, hair follicles, nerves, sebaceous (oil) glands, & sudoriferous (sweat) glands 

stretch marks 

- appear if the skin is stretched too much 

tension lines” in the skin indicate the predominant direction of underlying collagen fibers 

reflect contours of the underlying dermal papillae & form the basis for fingerprints (and footprints);

function: to increase firmness of grip by increasing friction.