Integument

Question 1

2 General Layers of Skin

Answer 1

Epidermis - protective epithelial lining

Dermis - inner connective tissue

Question 2

Epidermis Epithelium/Derivation

Answer 2

Stratified squamos keratinized epithelium derived from ectoderm

Question 3

2 Kinds of Skin (and determinant)

Answer 3

Thin (hairy) skin and thick skin, determined by thickness of epidermis (specifically stratum corneum)

Question 4

Stratum Basale (3)

Answer 4

1st Layer of Thick Skin, sits right on basement membrane
Mitotically active, cuboid cells that will eventually migrate up and eventually die
Many desmosomes/hemidesmosomes

Question 5

5 Layers of Epidermis (int-ext)

Answer 5

Stratum basale
Stratum spinosum
Stratum granulosum
Stratum lucidum
Stratum corneum

Question 6

Stratum Spinosum (4)

Answer 6

2nd layer of thick skin
Polyhedral cells - some mitotically active
Many desmosomes - intercellular bridges
Numerous IFs - tonofilaments (cytokeratin)

Question 7

Stratum Granulosum (4)

Answer 7

3rd layer of thick skin
3-5 layers of flattened cells
Keratohyalin granules - basophilic
Lipid-rich granules for exocytosis - waterproof barrier

Question 8

Stratum lucidum (4)

Answer 8

4th layer of thick skin
Only present in thick skin
Dying cells - no nuclei/organelles
Keratin filaments left behind

Question 9

Stratum corneum (3)

Answer 9

5th layer of thick skin
Flattened, keratinized dead cells
Keratin filaments/granules left behind

Question 10

Keratinocytes (4)

Answer 10

Compose 5 layers
Produce keratin/keratin filaments (IFs)
Keratohyalin granules
Lamellar bodies for lipid production/secretion - water barrier

Question 11

Melanocytes

Answer 11

Melanin-producing cells in stratum basale

Question 12

Melanin Production/Transport/Function

Answer 12

Produced in melanocytes from tyr upon UV light activation, transported to keratinocytes of stratum spinosum via cytocrine secretion (pinched off process of melanocyte). Act as barrier to UV light by shading nucleus from sunlight

Question 13

Epidermal-Melanin Unit

Answer 13

Ratio of melanocytes to keratinocytes

Question 14

Langerhans Cells (3)

Answer 14

Dendritic cells
Ag-presenting cells
Found in stratum spinosum

Question 15

Merkel Cells (2)

Answer 15

In stratum basale

MechanoRs for very fine pressure sensation

Question 16

4 Kinds of Cells in Epidermis (most-least common)

Answer 16

Keratinocytes, melanocytes, Langerhans cells, Merkel cells

Question 17

Dermis (composition and derivation)

Answer 17

(mainly) DIRC tissue derived from mesoderm

Question 18

2 Layers of Dermis

Answer 18

Papillary layer - superficial loose layer (loose connective tissue?)
Reticular layer - deep dense layer

Question 19

Papillary Layer (4)

Answer 19

Forms dermal ridges (papillae) to prevent shearing/increase SA
Numerous connective tissue cells (fibroblasts, mphages, mast cells)
Rich capillary supply for nourishment and temp reg
Meissner’s corpsucles - light touch

Question 20

Reticular Layer (5)

Answer 20

Sweat glands, sebaceous glands, arrector pili muslces, and hair follicles
Pacinian corpsucles - deep pressure/vibration
Muscles of facial expression insert into dermis
Cleavage (Langer’s) lines - orientation of collagen/elastic fibers, why we get wrinkles
Arteriovenous anastomoses - temperature regulation

Question 21

Hypodermis (3)

Answer 21

Loose connective tissue
Not part of skin - superficial fascia
Primarily adipose tissue

Question 22

Sweat Gland Structure (2)

Answer 22

Simple tubular gland
Coiled at bottom (secretory tubule), then straight duct (excretory duct), then coiled in epidermis to avoid tearing when skin moves

Question 23

Sweat Gland Secretion Type

Answer 23

Merocrine

Question 24

Apocrine sweat glands (3)

Answer 24

Kind of like larger sweat glands that drain into hair follicles
Wide lumen
Only in pubic region and armpits

Question 25

Sebaceous glands

Answer 25

Drain sebum into hair follicles, oily coat of hair

Question 26

Sebaceous gland secretion type

Answer 26

Holocrine

Question 27

5 Functions of Skin

Answer 27

``` Protection/barrier (water insoluble) Reception (sensation and immunologic) Excretion/water loss Absorption (UV light for Vit D) Temp Regulation ```

Question 28

Relationship of Sebaceous Gland to Arrector Pili Muscle

Answer 28

Between muscle and hair follicle, so when muscle contracts to make hair stand up on end, squeezes gland to release sebum

Question 29

Dermatoglyphs

Answer 29

Fingerprints, caused by dermal papillae for better grasping

Question 30

Skin Color Determinant

Answer 30

Melanocyte activity not #

Question 31

Vitiligo

Answer 31

Autoimmune destruction of melanocytes. White spotting on skin

Question 32

Albinism

Answer 32

Lack of melanosome production, usually from lack of tyrosine enzymes

Question 33

Melanoma

Answer 33

Cancer of melanocytes. Metastasize very rapidly bc right by dermis w/ tons of blood supply

Question 34

Psoriasis

Answer 34

Overproduction of stratum basale cells so turnover skin too rapidly

Question 35

2 Kinds of Skin Repair

Answer 35

Healing by first intention - standard Healing by second intention - if ends are too far away, fill with collagen and repair, creating nonfunctional scar tissue

Question 36

Basal Cell Carcinoma

Answer 36

In stratum basale, so close enough to break off and metastasize, but don't grow as rapidly as melanomas so not as bad

Question 37

Squamos Cell Carcinoma

Answer 37

Stratum granulosum usually, can dig down and metastasize if aggressive enough