Integument

Question 1

Integument

Answer 1

barrier for protection, sensation, excretion, thermoregulation, and synthesis of Vitamin D3

composed of epidermis and dermis

epidermis=ectoderm
dermis=mesoderm

Question 2

Hypodermis

Answer 2

a loose CT layer that binds skin to underlying tissues and corresponds to the superficial fascia

Question 3

Epidermis

Answer 3

stratified squamous keratinized epithelium composed of keratinocytes
-also contains melanocytes, langerhans cells, and merkel cells

Question 4

Dermal papillae

Answer 4

irregular projections at epidermal-dermal junction

has epidermal ridges to strengthen adhesion

Question 5

Thick skin

Answer 5

palms and soles
has five layers
fingerprints

Question 6

Thin skin

Answer 6

widespread on body
four layers
glands and hair follicles

Question 7

THe layers of the epidermis

Answer 7

Stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum basale

Question 8

Keratinocytes

Answer 8

predominant cell typer of the epidermis

makes keratin

participate in the epidermal water barrier

cornified cells that undergo keratinization and desquamation

Question 9

Strtum basale

Answer 9

single layer of keratinocytes with some stem cells

mitotically active, cuboidal and low columnar cells

contain melanin

bound apically via demosomes
bound basally by hemidesmosomes

Question 10

Stratum spinosum

Answer 10

The thickest layer

polyhedral cells with central nuclei and spiny processes

keratin filaments assemble here into microscopically visable bundles called tonofibrils

Question 11

Stratum Granulosum

Answer 11

three to five layers of flattened cells

filled with keratohyaline granules
these stain intensely basophilic

lamellar granules which are small ovoid structures containing lipids and glycolipids which will exocytosis and produce lipid rich impermeable layer that protects against water lass

keratinization and lipid rich layer make up an almost impentetrable skin barrier

Question 12

Stratum corneum

Answer 12

15-20 layers of squamous keratinized cells filled with filamentous keratins

anucleate and coated by an extracellular layer of lipids

fully keratinized cornified cells squames

Question 13

Stratum Lucidum

Answer 13

found only in thick skin

thin translucent layer of flattened eosinophilic keratinocytes

nuclei and organelles haave been lost

cytoplasm is almost exclusively keratin filaments

Question 14

Melanocytes

Answer 14

produce melanin and transfers it to keratinocytes
melanin=pigment protein that protects nuclei from UV radiation
neural crest derived

Question 15

Epidermal-melanin unit

Answer 15

one melanocyte maintains an association with a specific number of keratinocytes (1:10)

Question 16

Melanin production

Answer 16

Tyrosinase converts tyrosine to DOPA and that is polymerized to produce melanin

this occurs in membrane bound organelles called premelanosome

as the melanin increases the premelanosome will turn into melanosome which will be transfered to keratinocytes as a pigment donation

Question 17

Langerhans cells

Answer 17

Antigen presenting cells
develop from monocyte

found in the stratum spinosum

Question 18

Epidermal differentiation and replacement

Answer 18

cell replacement is initiated by the division of stem cells in the stratum basale

then they move upward where they differentiate into keratinized cells

eventually are lost by exfoliation on skin surface

Question 19

Dermal-epidermal junction

Answer 19

uneven boundary with finger like dermal papillae that project into the epidermis

complemented by epidermal protrusions, epidermal ridges

Question 20

Layers of the Dermis

Answer 20

Papillary layer

Reticular layer

Question 21

Papillary layer

Answer 21

loose CT immediately beneath epidermis

Vasculature and nerve endings

Question 22

Reticular layer

Answer 22

Deep to papillary layer
Dense irregular CT with coarse elastic fibers
form regular lines of tension-Langers lines

Question 23

Subpapillary plexus

Answer 23

rich nutritive capillary network located btwn papillary and reticular layers

Question 24

Deep plexus

Answer 24

Lies near Dermis subcutaneous layer interface

Question 25

Hypodermis

Answer 25

Subcutaneous fascia loose CT that binds the skin loosely to the subjacent organs adipocytes vary in number and size based on body regions and nutritional state extensive vasculature promotes rapid uptake or insulin or drugs injected into the tissue

Question 26

what type of sensory receptors does skin have

Answer 26

non encapsulated and encapsulated receptors

Question 27

Merkel Cells

Answer 27

Epithelial tactile cells that function as low threshold mechanoreceptors essential for sensing touch similar look to keratinocytes but lack melanosomes contain small golgi derived granules concentrated near basolateral surface

Question 28

Merkel cell carcinoma

Answer 28

rare aggressive and difficult to treat 40 times less common than malignant melanoma but double the mortality rate

Question 29

Free Nerve endings

Answer 29

located in the papillary dermis and extending into the lower epidermal layers respond primarily to high abd low temperatures, pain and itching serve as tactile receptors

Question 30

Meissners Corpuscle

Answer 30

encapsulated receptors responsive to light touch or low frequency stimuli Perpendicular to the epidermis in the dermal papillar numerous in the fingerprints and soles

Question 31

Lamellated Pacinian Corpuscle

Answer 31

Large encapsulated oval structures found deep in the reticular dermis and hypodermis specialized for sensing coarse touch, pressure (sustained touch) and vibration found in CT of visceral organs wall of the rectum and urinary bladder produce pressure sensations when distorted

Question 32

Sebaceous glands

Answer 32

several glands per follicle abundant on face and scalp produce a lipid mixture sebum via holocrine secretion waxy mix of triglycerides and cholesterol lubercates and softens the skin sebum discharges into the hair follicle

Question 33

Eccrine Sweat glands

Answer 33

simple coiled glands found throughout the skin duct is stratified cuboidal Myoepithelial cells facilitate expulsion of secretions temperature regulation via cooling

Question 34

Apocrine sweat glands

Answer 34

large lumen tubular glands duct is stratified cuboidal merocrine secretion - protein carbohydrate and ammonia rich secretion - odorless until mixed with bacteria become functional at puberty

Question 35

Hair follice

Answer 35

terminal dilation called a hair bulb dermal papilla inserts into hair bulb to provide nutrients keratinocytes form the hair matrix -are continuous w/epidermis Follicular bulge: contains epidermal stem cells

Question 36

Arrector pili muscle

Answer 36

small bundle of smooth muscle that extends from the midpoint of hair to papillary layer contraction of these form the goose bumbs and distorts the dermis

Question 37

Nails

Answer 37

Nail root Nail matrix: divide and form the keratinocytes -pushed forward with continous growth Lunula: crescent shaped white area near the nail matrix cuticle: extension of skin covering the nail root