Structure of the Skin

Question 1

describe thin skin

Answer 1

4 thinner epidermal layers that covers all remaining parts of the body. Not palm, soles, fingers, toes,

Question 2

describe thick skin

Answer 2

5 epidermal layers and covers palm, soles, fingers, toes, surface layer has dead cells and lacks hair follicles.

Question 3

Epidermis organization

Answer 3

keratinized stratified squamous epithelium organized into several distinct strata.

Question 4

Structure of stratum basale

Answer 4

single layer of cuboidal or columnar cells. (Keratinocytes, melanocytes, merkel cells)

Question 5

Function of stratum basale

Answer 5

continuously undergo mitotic cell division to produce new skin cells.

Question 6

keratinocytes

Answer 6

most abundant cells, are held together by desmosomes. tough, fibrous keratin protects skin from heat, microbes, chemicals, helps to waterproof skin.

Question 7

melanocytes

Answer 7

synthesize melanin; responsible for skin color; absorbs ultraviolet radiation to protect skin from damaging effects of sunlight.

Question 8

merkel cells

Answer 8

tough receptors that join with sensory neurons to form merkel discs.

Question 9

structure of Stratum spinosum

Answer 9

several layers of keratinocytes; that can change shape. (dendritic cells)

Question 10

Function of Stratum spinosum

Answer 10

skin preparations for microscope slides where keratinocytes shrink and pull apart, except where attached by desmosomes gives the layer “spiny” appearance.

Question 11

dendritic (Langerhans) cells

Answer 11

macrophages that arise in bone marrow and migrate to epidermis to protect body against microbes that invade skin; source of nutrients.

Question 12

Structure of Stratum ganulosum.

Answer 12

keratinocytes that contain dark-staining granules of protein that eventually become keratin.

Question 13

Function of Stratum Ganulosum.

Answer 13

The keratinocytes flatten, then nucleus and organelles disintegrate and granules of keratin accumulate in cytoplasm. keratinocytes die and release waterproofing glycolipids that form barrier between stratum spinosum and stratum granulosum. outer limit for diffusion of substances.

Question 14

Structure of stratum lucidum

Answer 14

thin, translucent layer of dead cells found only in thick skin.

Question 15

Structure of stratum corneum

Answer 15

up to 30 layers of dead, scaly keratinized cells and makes up about 75% of thickness of epidermis.

Question 16

Function of stratum corneum

Answer 16

30-40 days to migrate to skin surface and exfoliate as dander; most household dust is dander that does not get eliminated; provides food for dust mites; can cause thickened callus to form.

Question 17

Composition of Dermis layer

Answer 17

connective tissue comprised mainly of collagen fibers, elastic fiber, reticular fibers, fibroblasts, macrophages are also present.

Question 18

Papillary layer

Answer 18

superficial zone of areolar connective tissue containing elastic fibers. contains capillaries, touch receptors numerous free nerve endings.

Question 19

Reticular layer

Answer 19

deep zone of dense irregular connective tissue containing collagen bundles. Adipocytes, hair follicles, nerves, oil glands ducts of sweat glands.

Question 20

Functions of reticular layer

Answer 20

the collagen and elastic fibers provide strength, extensible and elasticity.

Question 21

Structure of Hypodermis

Answer 21

areolar connective and adipose tissue.

Question 22

Function of Hypodermis

Answer 22

binds skin to under lying tissue cushions body, provides thermal insulation, stores energy.

Question 23

How is the blood supply involved in the hypodermis?

Answer 23

numerous blood vessels supply skin with oxygen and nutrients and provides pathway for rapid absorption of drugs and/or medicines in the blood stream.

Question 24

How is skin color determined?

Answer 24

by genes that control the interaction of melanin, carotene, hemoglobin.

Question 25

Melanin

Answer 25

produces variations in skin color that range from pale yellow to black. if exposure to UV radiation in sunlight melanocytes stimuli the increase in melanin.

Question 26

Carotene

Answer 26

yellow-orange pigment that accumulates in the stratum corneum or sub-cutaneous fat, which gives the skin a yellowish tint. (asian decent)

Question 27

Hemoglobin

Answer 27

small amounts of melanin and carotene make epidermis become translucent. blood becomes visible, which produces the pinkish flesh that are typical in Caucasians.

Question 28

Erythema

Answer 28

abnormal redness due to the dilation of dermal blood vessels during strenuous exercise or heat or anger or embarrassment.

Question 29

Cyanosis

Answer 29

blueness of the skin due to insufficient oxygen in the blood because of airway obstructions or lung disease or cold weather.

Question 30

Jaundice

Answer 30

yellowing of the skin and whites of the eyes due to elevated levels of bilirubin in the blood because the liver is unable to dipose of the excess bilirubin.

Question 31

Pallor

Answer 31

pale skin due to reduced dermal blood flow because of low blood pressure or shock or anemia or emotional stress.

Question 32

Albinism

Answer 32

genetic defect that results in a lack of the amino acid tyrosine, which blocks the synthesis of melanin and produces pale skin, white hair, and pink eyes.

Question 33

Hematoma

Answer 33

visible blood clot caused by trauma to the skin produces a bruise. Hemangiomas= “birthmarks”