Integument

Question 1

What are the characteristics of the epidermal ridges?

Answer 1

primary dermal ridge

secondary dermal ridge

interpapillary peg

dermal papillae

Question 2

The primary and secondary ridges?

Answer 2

• primary dermal ridges form fingerprints and not found on forehead, ext ear, perineum, scrotum
• secondary dermal ridges occur in double rows, and thin collagenous, reticular and elastic fibers

Question 3

What are the Dermal Papillae?

Answer 3

upward projections from the secondary dermal ridges.

Question 4

What are the functions of the integument system? (list 6)

Answer 4

Protection

Prevent dessication

Bacterial protection

UV raditation protection

Thermoregulation and blood pressure

Synthesize provitamin D

Question 5

List the layers of the skin from deepest to superficial.

Answer 5

Stratum basale (germinativum)

Stratum spinosum

Stratum granulosum (represented by few cells in thin skin)

Stratum lucidum ( not in thin skin)

Stratum corneum

Question 6

Keratohyalin aggregates do what?

Answer 6

Fillagrin induce cross-linkage of keratin

No limiting membrane

Question 7

What characteristics play a role in Stratum spinosum

Answer 7

Polyhedral shaped cells

Keratohyalin granules develop

Lamellar bodies: contain lipids, carbs, hydrolytic enzymes

Tonofibrils: form intercellular bridges.

Question 8

What is the purpose and components of the Stratum basale (germinativum)

Answer 8

Columnar to high cuboidal keratinocytes

Single layer of cells held by desmosomes and hemidesmosomes to hold the basal lamina

Mitotic activity affected by chemotherapeutic and radiation treatments

Question 9

Stratum lucidum

Answer 9

Flat keratinocytes lacking nuclei and organelles

Only in thick skin

Contains eleiden

Question 10

Stratum Corneum

Answer 10

Enucleated, flattened, dead keratinocytes

Cytoplasm is replaced by keratin

Cytoplasm contains: keratin cross-linked with filaggrin to form the cornified cell envelope

Question 11

What makes up the Cornified Cell Envelope?

Answer 11

Extracellular layer: multi-lamellar lipid covalently linked to involucrine

Intracellular layer: small proline rich proteins, loricrin, fillagrin/keratin complex, involucrine

Question 12

What are characteristics of the Dermis?

Answer 12

Dense fibrous irregular CT under epidermis

From embryonic mesoderm

Induces development of epidermis and epidermal derivatives

• papillary layer is loose CT with network of elastic fiber and abundant capillaries
• reticular layer is dense irregular CT, with fibrocytes, macrophages, and adipocytes

Question 13

What cells are contained within the Dermis?

Answer 13

Keratinocytes

Langerhans Cells

Merkel Cells

Melanocytes

Question 14

What do the Merkel cells do, and where are they at?

Answer 14

Contain mechanoreceptors that can act as diffuse neuroendocrine cells

Within the stratum germinativum

Have catecholamine-like granules

Question 15

What do the Langerhans Cells do?

Answer 15

Birbeck granules

Antigen-presenting cells. Primary in stratum spinosum

Migrate from epidermis to lymph nodes

Question 16

What are characteristics/components of the Melanocytes?

Answer 16

Do not form desmosome attachments in epidermis

Inject melanin granules into keratinocytes

Pathway of the melanin formation

Tyrosine–> 3,4-dihydroxyphenylalanine (DOPA)–> dopaquinone–> melanin

Tyrosine is required

Question 17

What are the embryonic derivative of the epidermis?

Answer 17

Periderm: sloughs off to form vernix caseosa

Inner cuboidal germinal layer: continue to proliferate to form adult layers of epidermis and derivatives

Fingernails form in 10 wks, and hair buds at 12 wks.

Question 18

Describe the characteristics of stratum spinosum.

Answer 18

• polyhedral shape
• keratin 1 and 10
• lamellar bodies oflipid, carbohydrates, hydrolytic enzymes
• tonofibrils remain after staining process

Question 19

What helps to make up the stratum basale?

Answer 19

• columnar keratinocytes
• keratin 5 and 14
• joined by desmosome and hemidesmosomes
• high mitotic activity

Question 20

What layer of skin contain keratins 2 and 9, and what other things can you tell me about it?

Answer 20

• stratum granulosum
• flat nucelated keratinocytes
• fillagrin induces keratin cross-links
• have tonofilaments

Question 21

What is in the stratum lucidum?

Answer 21

• flat keratinocytes. no nuclei or organelles
• contains eleiden
• only in thick skin

Question 22

Stratum corneum contains what cells and is how many layers thick?

Answer 22

• 5–>50 layers
• enucleated, flattened, dead keratinocytes
• keratin replaces the cytoplasm

Question 23

The extracellular cornified cell envelope consists of what?

Answer 23

-multi lamellar lipid covalently linked to involucrine

Question 24

What is contained in the intracellular cornified cell envelope?

Answer 24

• involucrine
• proline rich proteins
• loricrin
• fillagrin and keratin.

Question 25

Describe characteristics of the dermis.What type of CT, where is it derived from, and what are its functions?

Answer 25

- dense fibrous irrgeular CT - derived from embryonic mesoderm, and forms epidermal derivatives - its functions to support the epidermis

Question 26

What tissue makes up the hypodermis, what other cells are contained in this layer?

Answer 26

- loose CT - contain fat cells to form the panniculus adiposus

Question 27

What are the two layers of the dermis?

Answer 27

- papillary layer - reticular layer

Question 28

What is used to make up the papillary layer?

Answer 28

- loose CT - network of fine elastic fibers and abundant capillaries

Question 29

What are involved in the reticular layer of skin? CT, and cell?

Answer 29

- dense irregular CT - fibrocytes, macrophages, and adipocytes

Question 30

Where do Langerhans cells come from and what is their primary purpose ?

Answer 30

- dendritic cells derived from monocytes - they are antigen-presenting cells - contained majorly in stratum spinosum and carry antigens to lymph nodes.

Question 31

What are mechano receptors in stratum germinativum?

Answer 31

- merkel cells that contain catecholamine granules - cause vasoconstriction?

Question 32

What do not form desmosome attachments? (cell)

Answer 32

- melanocyte derived from melanoblasts - produce melanin: tyrosine--\> dopa--\>dopaquinone--\>melanin tyrosinase

Question 33

The ectodermal cell divide at week 6 or development to form what components?

Answer 33

- periderm: form vernix caseosa - inner cuboidal germinal layer: proliferates to form adult layers --fingernails at 10wks --hair bud/tow nails at 12 wks

Question 34

What type of gland are sebaceous glands?

Answer 34

- holocrine gland - produce sebum released into the hair follicle. oily material

Question 35

What is the real function of sebum?

Answer 35

-produce oil material to maintain flexibility of the hair strands

Question 36

What type of gland are sudoriferous glands (sweat)?

Answer 36

-merocrine and apocrine

Question 37

The merocrine sudoriferous glands look like what, and have what ending types?

Answer 37

- coiled, simple tubular secretory portion - cholinergic endings. secrete glycoproteins, water and electrolytes

Question 38

Apocrine sudoriferous glands are found where, and have what types of cells?

Answer 38

- labia majora, areola, axillary and anal regions - more viscous secretions - adrenergic innervation - ceruminous glands and glands of Moll

Question 39

What makes up a hair follicle?

Answer 39

-root, free shaft, hair follicle

Question 40

What components are associated with hair follicles?

Answer 40

- sebaceous glands, arrector pili muscle - hair bulb which contains matrix and vascular dermal papilla - this is the growing portion of hair

Question 41

The down growth of the epidermis helps to form what in the hair follicle?

Answer 41

external root sheath

Question 42

The internal root sheath is formed by what?

Answer 42

the bulb matrix

Question 43

The hair shaft is formed by what layers?

Answer 43

- medulla - cortex - cuticle: free edges extend upwards to interlock with the cuticleof root sheaths to lock hair in place.

Question 44

What is a significantly important feature of keratinocyte stem cells?

Answer 44

-reestablish erpidermis after a burn

Question 45

What are the migration pathways of th keratinocyte stem cells?

Answer 45

- bulb epidermis stem cell pathway - bulb sebaceous gland stem cell - bulb hair stem cell pathway

Question 46

What are the signaling pathways to perform teh repair mechanism of kertinocytes stem cell\>

Answer 46

- Wnt - Notch pathways