Histology: Integument

Front 1

Superficial layer of integument composed of epithelial tissue?

Back 1

Epidermis

Front 2

Thicker layer of integument deep to the epidermis that is composed of connective tissues?

Back 2

Dermis

Front 3

Layer of integument deep to the dermis that consists of areolar and adipose tissues as well as nerve endings and blood vessels?

Back 3

Subcutaneous layer (Hypodermis)


Note: Fibers extending from dermis anchors skin to the hypodermis. The hypodermis hen connects to underlying fascia (muscle and bone).

Front 4

Type of epithelium the epidermis is composed of?

Back 4

Keratinized stratified squamous epithelium

Front 5

Four principal cells of the epidermis?

Back 5

1) Keratinocytes
2) Melanocytes
3) Langerhans cells
4) Merkel cells

Front 6

Function of keratinocytes? (2)

Back 6

1) Produce keratin
2) Produce lamellar granules which release a water repellent sealant that decreases water entry and loss. Also inhibits entry of foreign materials

Front 7

Function of keratin?

Back 7

Tough fibrous tissue that protects the skin and underlying tissues from heat, microbes, and chemicals

Front 8

Rounded cells with numerous projections that secrete melanin and that extend between keratinocytes through the stratum basale and stratum spinosum?

Back 8

Melanocytes

Front 9

Function of melanin?

Back 9

Protects keratinocyte DNA

Note: Melanocytres transfer their melanin to keratinocytes

Front 10

Langerhans cells differentiate from _______________ and migrate from the bone marrow to the epidermis?

Back 10

monocytes

Front 11

Function of langerhans cells in the immune response?

Back 11

Helps naive T-cells recognize invading microbes

Note: Activates these cells via presentation of antigen and costimulatory signals

Front 12

Which layer of the epidermis are merkel cells located?

Back 12

Stratum basale (deepest layer)

Front 13

Why do keratinocytes in the stratum basale stain basophilic?

Note: these keratinocytes are also associated with mitotic figures

Back 13

Has large numbers of ribosomes associated with the production of tonofilaments

Tonofilaments ultimately will produce keratin.

Front 14

What are mitotic figures?

Back 14

Cells visualized as actively undergoing mitosis

Front 15

Function of merkel cells?

Back 15

Mechanoreceptors


-Communicate with merkel discs (afferent sensory neuron)

Front 16

What are the five layers of the epidermis from deepest to most superficial?

Back 16

1) Stratum Basale (germinativum)
2) Stratum Spinosum
3) Stratum Granulosum
4) Stratum Lucidum (Only in thick skin)
5) Stratum Corneum

Front 17

The stratum basale is composed of a a single row of ________________/______________ germinal keratinocytes?

Note: This single layer of cells are basal cells which can differentiate in to mature keratinocytes.

Note: Keratinocytes are at different stages of development in different epidermal layers

Back 17

Cuboidal/columnar

Front 18

This layer of the epidermis is located superficially to the stratum basale and contains many layers of keratinocytes. It's desmosomes have a spiny appearance?

Back 18

Stratum spinosum

Front 19

What are the spine like projections on the desmosomes in the stratum spinosum?

Note: These projections also add strength in terms of connections between the cells via desmosomal junctions.

Back 19

Bundles of keratin filaments called "tonofilaments"

Front 20

This layer of epidermis consists of 3-5 layers of flattened keratinocytes that are undergoing apoptosis?

Note: Nuclear fragmentation and loss of organelles is visualized. Tonofilaments become more apparent.

Back 20

Stratum granulosum

Front 21

What protein do the cells of stratum granulosum contain that convert tonofilaments into keratin?

Note: These contain intermediate filament associated proteins that promote aggregation of tonofibrils and formation of keratin

Back 21

Keratohyalin

Front 22

What is the function of the lamellar granules produced by keratinocytes in the stratum granulosum?

Back 22

Release lipid rich secretion that fills spaces between cells of stratum granulosum, lucidum, and corneum forming a water tight barrier and a barrier for entry of foreign material.

Front 23

What areas of the body would stratum lucidum be found?

Back 23

Thick skin areas of:
1) Fingertips
2) Palms
3) Soles

Front 24

Epidermal layer found only in thick skin that consists of 3-5 layers of flattened clear, dead, keratinocytes that contain large amounts of keratin and thickened plasma membranes?

Back 24

Stratum lucidum

Front 25

Epidermal layer that consists of 25-30 layers of flattened, dessicated, anucleate keratinocytes. This is the most superficial layer of the epidermis?

Back 25

Stratum corneum

Front 26

What layer of the integument is being referenced in regards to thickness vs. thinness?

Back 26

The epidermis

Front 27

Where is thick skin found?

Back 27

Only on soles of feet and palms of hands

Front 28

What two things does thick skin not contain?

Back 28

1) Hair
2) Sebaceous Glands

Front 29

Does thick skin have hair follicles?

Back 29

Yes

Note: They are not associated with hair follicles

Front 30

Does thin skin have hair and sebaceous glands?

Back 30

Yes.

Note: Sebaceous glands are associated with hair follicles

Front 31

Do the cells in the stratum spinosum appear basophilic or eosinophilic?

Back 31

Eosiniophilic

Front 32

Name of the process by which keratinocytes differentiate?

Note: This means that a fully matured keratinocyte is dead

Back 32

Terminal differentiation

Front 33

What are the dead keratinocytes in the stratum corneum referred to as? (2)

Back 33

Cell remnants or husks

Front 34

One will notice that as the layers of the stratum corneum are traversed there are less and less connections between keratinocytes. The process by which these keratinocytes slough off is called _______________________?

Back 34

Desquamation

Front 35

Abnormal thickening of the stratum corneum caused by constant exposure of skin to friction?

Back 35

Callus

Front 36

Are cells of the stratum lucidum fully keratinized?

Note: This contributes to their lighter staining

Back 36

No

Front 37

Two components of the water barrier of the epidermis?

Back 37

1) Cell Envelope
2) Lipid Envelope

Front 38

Components that aid in the water barrier afforded by of the cell envelope?

Back 38

1) Thickened cell membrane
2) Insoluble proteins on the inner aspects

Front 39

Components that aid in the water barrier afforded by of the lipid envelope?

Back 39

1) Vesicles extruded from keratinocytes
2) Lipids
3) Lipases
4) Proteases
5) Desmosomal connections between cells

Front 40

How do keratinocytes get melanin from melanocytes?

Back 40

Keratinocytes phagocytose a portion of a melanocyte process

Front 41

Eumelanin is a melanin pigment that appears____________/_________?

Back 41

brown/black

Front 42

Pheomelanin is a melanin pigment that appears ________________/_______________?

Back 42

red/yellow

Front 43

Ratio of melanocytes to keratinocytes is always changing? T or F

Back 43

False, always constant

Front 44

What causes the keratinocytes to have less melanin?

Back 44

Degradation of melanin by lysosomes in keratinocytes.

Note: Higher rates of degradation=lighter pigmentation

Front 45

How does UV exposure affect the rate at which melanin is produced?

Back 45

It increases the rate of melanin production and number of melanocytes temporarily

Note: The production rate is genetically determined

Front 46

What type of hypersensitivity reactions are langerhans cells involved in?

Back 46

Delayed type hypersensitivity

i.e. Contact dermatitis

Front 47

Which virus can l;angerhans cells serve as a reservoir for?

Back 47

HIV virus

Front 48

Do melanocytes and langerhans cells form desmosomal contacts with keratinocytes?

Back 48

No

Front 49

Merkel's cells are touch receptors found in most sensitive areas of the body? T or F

Back 49

True

Front 50

Do merkel's cells form desmosomal contacts with keratinocytes?

Back 50

Yes

Note: Merkel cells contain neurosecretory granules that have a neuroendocrine type action on the associated merkel disc.

Front 52

What layer of the epidermis are merkel's cell located?

Back 52

Stratum basale

Front 53

Two common skin cancers associated with keratinocytes

Back 53

1) Basal cell carcinoma
2) Squamous cell

Front 54

Where do basal cell carcinoma's originate?

Back 54

At the base of a hair follicle

Front 55

Where do squamous cell carcinoma's originate?

Back 55

Epidermal layer

Front 56

Most serious skin cancer?

Back 56

Malignant melanoma

Front 57

What is Histiocytosis X?

Back 57

Immune disease: Tumor of langerhans cells

Front 58

Rare cancer derived from Merkel cells?

Back 58

Merkel cell carcinoma

Front 59

Two components of the epidermal/dermal junction?

Back 59

1) Basal lamina connected to keratinocytes
2) Interdigitations

Front 60

What two components allow for the connection between the keratinocytes and the basal lamina?

Back 60

1) Intermediate filaments by hemidesmosomes
2) Microfilaments by focal adhesions

Front 61

What are rete ridges?

Back 61

Interdigitations of the epidermis

Front 62

What are dermal papillae?

Back 62

Interdigitations of dermis

Front 63

Function of the interdigitations?

Back 63

1) Increase surface area for attachment and nutrient/waste exchange
2) Protect from abrasion
-We see deeper ridges at sites of abrasion

Front 64

What are dermal ridges?

Back 64

These are regions where the epidermal-dermal junction fold to forms characteristics finger-prints and toe-prints

Front 65

Dermal ridges are typically found in areas of higher abrasion? T or F

Back 65

True

Front 66

Two regions of the dermis?

Back 66

1) Papillary
2) Reticular Region

Front 67

Components of the papillary region?

Note: Similar to lamina propria

Back 67

-Loose connective tissue with small blood vessels, nerves, lymphatics, and Meissner's corpuscles

Front 68

What type(s) of collagen and fiber(s) are present in the papillary layer?

Back 68

-Type I and III collagen
-Elastic Fibers

Front 69

Layer of dermis located between papillary layer and hypodermis?

Back 69

Reticular layer

Front 70

Components of the reticular layer?

Back 70

-Dense irregular connective tissue and elastic fibers with large nerves, blood vessels, hair follicles, Pacinian corpuscles, and Ruffini Endings

Front 71

Regular lines of tension formed b y collagen and elastic fibers in the reticular layer?

Back 71

Langer's lines

Note: Also called lines of cleavage

Front 72

Two plexuses that the arteriovenous anastomoses shunt blood between in the dermis?

Back 72

1) Papillary plexus
2) Cutaneous plexus

Front 73

Where is the cutaneous plexus located?

Back 73

The reticular layer

Front 74

This layer of the integument is known as the superficial fascia? It consists of loose connective tissue and adipose that anchors the skin to the underlying tissue. It also forms the base for sweat glands and hair follicles?

Back 74

Hypodermis

Note: May also contain muscle striations in some areas

Front 75

Which sensory receptors are located in the hypodermis?

Back 75

Pacinian Corpuscles

Front 76

Sweat glands are simple ___________ _____________ glands?

Back 76

simple coiled tubular

Front 77

Modified epithelial cells that surround sweat glands and contract to aid in expulsion of sweat?

Back 77

Myoepithelial cells

Front 78

What division of the autonomic nervous system innervates the sweat glands?

Back 78

Sympathetic

Front 79

Two types of sweat glands?

Back 79

1) Eccrine
2) Apocrine

Front 80

Where are eccrine sweat glands located?

Back 80

All regions of the body except:
1) Lips
2) External Genitalia

Front 81

Function of eccrine sweat glands?

Back 81

Empty watery sweat secretion onto free surface of epidermis to regulate body temperature

Front 82

Where are apocrine sweat glands found?

Back 82

1) Axilla
2) Areola and nipple
3) Anal Region
4) External genitalia

Front 83

Which type of sweat gland tends to be broader with a wider lumen?

Back 83

Apocrine

Front 84

In what way do apocrine sweat glands secrete their products?

Back 84

Merricrine method.

Note: Same as eccrine sweat glands

Front 85

Aprocrine secretions contain pheromones? T or F

Back 85

True

Front 86

Where is the secretion of aprocrine glands secreted?

Back 86

Into hair follicles

Front 87

These are simple branched acinar glands that secrete a lipid based secretion called sebum into the hair follicle?

Back 87

Sebaceous glands

Front 88

By what mode of secretion do sebaceous glands secrete their product?

Note: This means the secretion contains lipid and debris of secreting cells

Back 88

Holocrine method

Front 89

Two classes of sensory structures of the integument?

Back 89

1) Non-encapsulated
2) Encapsulated

Front 90

Class of integumentary sensory structures that are free nerve endings in the epidermis. They can respond to touch, pressure, heat, cold, pain, and can be associated with hair follicles (i.e. mechanoreceptors)?

Back 90

Non-encapsulated

Front 91

Three types of encapsulated sensory structures?

Back 91

1) Pacinian Corpuscles (Dermis and Hypodermis)
2) Meissner's Corpuscle (Dermal Papillae)
3) Ruffini endings (Dermis)

Front 92

Small groups of collagen encapsulated mechanoreceptors that respond to touch and pressure (stretching)?

Note: Axonal endings respond to displacement of collagen fibers

Back 92

Ruffini endings

Front 93

Encapsulated mechanoreceptor gound in hairless regions of the dermal papillae and respond to light touch?

Back 93

Meissner's Corpuscles

Note: Found a lot in finger tips

Front 94

Characteristics of the Meissner's corpuscles nerve fibers?

Back 94

-Spiral shaped nerve fibers wrapped by endoneurial cells
-Schwann cells for lamellae

Note: It is the spiral ends of the nerve fibers that are unmylelinated

Front 95

Encapsulated mechanoreceptor that responds to deep pressure and vibration?

Back 95

Pacinian corpuscles

Front 96

What is the function of the concentric layers of endoneurial cells that line the myelinated nerve terminal?

Back 96

Amplify the single coming from exterior towards nerve terminal


Note: This nerve terminal eventually becomes demyelinated

Front 97

Hair follicles are invaginations of the epidermis and are made of keratinocytes hat secrete hard ____________?

Back 97

Hard keratin

Note: Has more sulfur than soft keratin of stratum corneum

Front 98

Where could the bulb of the hair follicle be located?

Back 98

-Hypodermis
-Deep layers of the dermis

Front 99

Tuft of capillaries at base of hair follicle that provide nourishment for the growing hair follicle?

Back 99

Dermal papillae

Note: Not the same as the interdigitation of the dermis

Front 100

What does the arrector pili muscles do?

Back 100

1) Help regulate body heat by manipulating hair follicle
2) Can aid in secretion of sebum

Front 101

When the arrector pili muscles contract, the hair follicle is pulled into the integument? T of F

Back 101

False, it extends out

Note: This would conserve heat

Front 102

Stages of hair development?

Back 102

1) Matrix cells proliferate in bulb
2) Matrix cells can then differentiate into keratin producing cells
3) Melanosomes add pigment

Front 103

Three layers of mature thick hair from deep to superficial?

Back 103

1) Medulla
2) Cortex
3) Cuticle

Front 104

What layers are present in thin hair?

Back 104

1) Cortex
2) Cuticle

Front 105

What cells does the cuticle contain?

Back 105

Heavily keratinized squamous cells

Front 106

What cells are located in the cortex?

Back 106

Cuboidal cells which are filling with keratin

Front 107

What type of cells are nails made from?

Back 107

Keratinized epithelial cells are corneocytes

Note: Hard keratin

Front 108

What two layers of integument does the nail bed correspond to?

Back 108

1) Stratum Basale
2) Stratum Spinosum

Front 109

Fold overlying the nail root and nail plate (formed from stratum corneum)?

Back 109

Eponychium

Front 110

Structure formed underneath nail plate where the nail leaves the nail bed at the tip of the finger (formed from stratum corneum)?

Back 110

Hyponychium

Front 111

Process of Nail development?

Back 111

1) Matrix at nail route is producing corneocytes and other epithelial cells
-Stem cells
-Langerhans cells
-Merkel's cells
-Melanocytes
2) Nail route is composed of immature corneocytes
3) Terminal differentiation occurs
-Cells die
-Fill with hard keratin

Front 112

Structure at the base (tip) of nail that is white due to partial keratinization?

Back 112

Lunula

Front 113

Is the nail plate attached to the nail bed?

Back 113

No

Front 114

Skin injury in which layers of epidermis have been lost but not the stratum basale?

Note: Regeneration without scarring

Back 114

Scrape

Front 115

Skin injury that results in minimal loss of stratum basale?

Back 115

Laceration/Incision

Note: Surgical wounds. Heals by first intention

Front 116

Healing by first intention?

Back 116

Healing of a small space by filling that space with collagen. The scarring will be minimal or will disappear.

Front 117

Skin injury that results in substantial loss of stratum basale with the presence of foreign material and infection?

Note: Damage in stratum basal, basal lamina, and dermis

Back 117

Sever Injury

Note: Heals by second intention

Front 118

Healing by second intention?

Back 118

1) Neutrophils infiltrate and remove debris
2) Scar formation
-Fibrous connective tissue is deposited: called granulation tissue
3) Slow regeneration of epidermal tissues from proteases from surrounded cells that break down collagen.