Structure and Function of Skin

Question 1

Skin - Fxns

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Answer 1

Barrier
Thermoregulation
Convey somatosensory information from environment to nervous system
Immunologic - antigen presentation
Endocrine
Excretion

Question 2

Epidermis - Characteristics and components

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Answer 2

Keratinized stratified squamous epithelium
from Ectoderm
Avascular
Composed of kerationocytes, melanocytes and Langerhen’s cells

Question 3

Dermis - Characteristics and components, origin

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Answer 3

Dense irregular connective tissue
from Mesoderm
imparts mechanical support

Question 4

Hypodermis - Characteristics and components, origin

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Answer 4

Variable amounts of lobules of adipose tissue seperated by connective tissue
Insulates and provides energy

Question 5

Thin skin v Thick skin

Answer 5

hair follicles NOT in thick skin

Thick - adapted for great amount of abrasion e.g. palmar

Question 6

Stratum Basale - a.k.a, desc, fxn, components

Answer 6

SB - Germinativum
Stem cells on basal lamina
Give rise to to keratinocytes
includes Keratinocytes & Melanocytes

Question 7

Keratinocytes - fxn

Answer 7

Form physical and chemical barrier of skin

through production of cytokeratin proteins which organize as intermediate filaments

Question 8

Melanoctyes - location, fxn, origin

Answer 8

in SB
Synthesize melanin pigment from the amino acid tyrosine
Neural crest derivatives

Question 9

Stratum Spinosum

Answer 9

cell layers w/ desmosome at ends forming attachment between adjacent cells.

Question 10

Stratum Granulosum

Answer 10

thin layer, w/ intense basophilic (dark staining) as result of keratohyalin, a precursor to filaggrin - which bundles keratin filaments in SC.

Question 11

Stratum Corneum

Answer 11

lucidum
most superficial layer
No Nucleus or cell organelles in cells. only keratin.

Question 12

Water proofing in skin

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Answer 12

At base of SC.
by complex arrangement of submembrane proteins and lipids secreted from lamellar bodies from stratum granulosum keratinoctyes

Question 13

Life progression of Keratinocyte

Answer 13

1. Basal Cell
2. Spinous Cel
3. Granule Cell
   4 Stratum corneum
   5.

Question 14

Stage 1- keratinocyte progression

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Answer 14

Basal cell synthesize intermediate filaments( keratin), which bundles together as Tonofilaments. => Spinous layer

Question 15

Stage 2 - keratinocyte progression

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Answer 15

Spinous layer make keratohylain granules and lamellar bodies

Question 16

Stage 3 - keratinocyte progression

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Answer 16

Granule Cell layer makes Keratohyalin granules and lamellar bodies.
Secreted by exocytosis into extracellular space btwn SG and SC

Question 17

Stage 4 - keratinocyte progression

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Answer 17

Stratum Corneum cells are Keratinized

Question 18

Stage 5 - keratinocyte progression

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Answer 18

pH decrease controls desquamation of cells Protease molecules lead to digestion and detachment of most superficial layer of SC

Question 19

Filagrin - fxn, origin

Answer 19

Bundles Keratin filaments in SC.

precursors are keratohylanin granules

Question 20

Melanocyte - fxn, action, origin

Answer 20

formation of melanin pigment and secretion into keratinocytes
neural crest

Question 21

Langerhans Cells - def, origin

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Answer 21

Antigen presenting cell in epidermis

derived from Bone Marrow - part of mononuclear phagocytic system

Question 22

Dermal Papillae

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Answer 22

Fingler-like extension in dermis projecting into epidermis

accomadate mechanical stress/increased abrasion forming pattern on hands and feet

Question 23

Dermis Layers

Answer 23

Papillary Layer

Reticular Layer

Question 24

Dermis - cellular components

Answer 24

Fibroblasts
Lymphocytes, mast cells, macrophages and graanulocytes
Langerhan cells

Question 25

Dermis - EC components + other components

Answer 25

``` Collage fibers (type 1) Elastic Fibers ``` Blood vessels Muscle - Arrector pili mm Nerves and Sensory receptors

Question 26

``` Meissner Corpuscles (MC) - def, location ** ```

Answer 26

touch receptor low frequency stimuli in dermal papillae

Question 27

Pacinian Corpuscles - location, def | **

Answer 27

Dermis | Sensitive to vibration an deep pressure

Question 28

Autonomic motor nerves in skin innervate ...

Answer 28

Blood vessels, arrector pili muscle, and glands

Question 29

Eccrine Glands - def, nervous regulation, components | **

Answer 29

Simple coiled tubular glands Autonomic Cholinergic innervation for temperature regulated sweat Andergenic innervation for emotional related secretion Contains Myoepithelial cells which cause rapid excretion from sweat gland when contracted

Question 30

Apocrine Sweat Gland - def, locations, characteristics**

Answer 30

Simple coiled tubular and branched tubular gland w/ dust reaching skin through hair follicle specific to axilla, inguinial and perianal areas active at puberty, affected by pheromones Majorhistocompatabilty complex (MHC) within define scent and composition of secretions

Question 31

Sebaceous Gland - def, characteristics | **

Answer 31

Outgrowth from epithelium that gives rise to hair Contains oily sebum Cause acne when fat (skin irritant) in sebum broken down by bacteria

Question 32

Temperature regulation

Answer 32

Eccrine sweat glands and blood vessels if hot, more seat and vasodilation

Question 33

Epidermal cancers | **

Answer 33

Basal Cell Carcinoma - does not metastasize Squamous Cell Carcinoma - can metaztasize if basement membrane disrupted Malignant Melanoma - SERIOUS

Question 34

Skin Repair | **

Answer 34

``` Primary Union (least severe) Secondary Union --Dermal Repair --Epidermal Repair Skin graftin (for major damage) ```