Skin And Appendages (Lecom)

Front 1

Origin and epithelium cell type of the epidermis

Back 1

ectodermal- stratified, squamous, keritinized, epithelium

Front 2

Layers of the epidermis

(Come, Let's Get Sun Burned)

Back 2

1. Stratum germinativum (basale) (deep)

2. Stratum spinosum

3. Stratum granulosum

4. Stratum lucidum

5. Stratum corneum (superficial)

Front 3

Stratum Germintivum

Back 3

Single layer of cuboidal or columnar cells that rest on basil lamina. Hemidesmosomes attach them to Basil Lamina, desmosomes attach them to each other.

Cell mitosis occurs here

Front 4

Stratum Spinosum

Back 4

Polygonal cells that have spiny projections that form intercellular bridges. Many desmosomes that contribute to the cohesiveness of the epidermis. Mitosis is seen here.

Front 5

Malphigian Layer

Back 5

Stratum Germitivum and Stratum Spinosum

Front 6

Stratum Granulosum

Back 6

Characterized by basophilic keratohyaline granules. Also contains membrane bound membrane coating granules. These contain glycoaminoglycans that are exuded into extracellular space and form a barrier to microorganisms foreign substances and water.

Front 7

Stratum Lucidum

Back 7

Most prominent in thick skin (often unidentifiable in thin skin) Translucent layer of acidophilic cells devoid of nuclei and organelles.

Front 8

Stratum Corneum

Back 8

Flattened keratin filled cells.No nuclei or organelles. Called horny cells or squams.

Front 9

Cutaneous Burns

Back 9

1st degree- damage to the superficial epidermis. cells of the stratum germitivum remain viable and regenerate the epidermis

2nd degree-epidermis is competely destroyed, remnants of hair follicles and sweat glands regenerate the epidermis.

3rd degree- epidermis and dermis destroyed. Skin grafts required.

Front 10

Keritinocytes

Back 10

predominant cells in the epidermis, ectoderm origin. Specialized differentiation gives rise to stratum corneum.

Front 11

Basil Cell Carcinoma

Back 11

70% of skin caners.

typically occurs in ages forty and up, especially n fair skinned people. Usually on eyelids or nose. Histologically cells form nests or islands. Seldom metastasize.

Front 12

Squamous Cell Carcinoma

Back 12

20% of skin cancers

effects fair skinned blondes with lots of sun exposure

Late stage dermis penetration- prognosis is based on location, size, and depth of lesion.

2-5% chance of metastasis

Front 13

Langerhans cells

Back 13

dendritic cells found primarily in stratum spinosum. Not attached to adjacent cells by desmosomes. Engulf invading microorganism can migrate. May serve as reservoir for HIV

Front 14

Melanocytes

Back 14

Neural crest origin. Located in the stratum germativum. Regionally replicate and maintain melanin units. Not connected to adjacent cells by desmosomes, but can be attached to the basil lamina by hemidesmosomes. Contains tyrosinase for melanin conversion. Mealnin i primarily found in keritinocytes.

Front 15

Melanin granules

Back 15

Granules take position above the nuclei of the keritinocytes in the stratum germitivum and spinosum. Protects the dividing cells from UV radiation.

Front 16

Malignant melanoma

Back 16

2% of skin cancers. Very metastatic. Histologically, appears as nests of pigmented melanocytes that penetrate the epidermis. They will also invade the dermis where the can access the lymph and blood stream.

Front 17

Merkel cells

Back 17

Typically found in thick skin. Mechanoreceptive cells (associated with nerve endings) Neurosecratory granules.

Front 18

Papillary layer of the dermis

Back 18

Loose connective tissue that contains fibroblasts, mast cells, macrophages, and some luekocytes- forms dermal papillae/ pegs.

Front 19

Reticular layer of the dermis

Back 19

Dense irregular connective tissue, type I collagen, contains fewer cells than the papillary layer.

Front 20

Thick skin

Back 20

Also called glaborous skin, found in areas of greater wear and abrasion such as the palms of the hands an soles of the feet. Will contain all five layers of epidermis with a very prominant stratum lucidum and a thick stratum corneum.

No hair.

Front 21

Thin skin

Back 21

Also called hairy skin, this is the skin that covers most of the body. It had no distinct stratum lucidum and a very thin stratum corneum.

Front 22

Hypodermis

Back 22

Not considered a part of the skin. Lies deep to the dermis and is also called superficial fascia or subcutaneous connective tissue. It is comprised of loose connective tissue and fat cells.

Front 23

Hair follicles

Back 23

Invagination of the epidermis, bulbous terminal dilutions (while growing). The bulb rests upon dermal papilla that contain organelles that nourish the follicle.

Front 24

Eccrine sweat glands.

Back 24

Simple coiled tubular glands that secrete a nonviscous fluid. Evaporation of this fluid cools the skin. Contain catabolites. Light staining simple cuboidal acini and dark staining stratifies cuboidal ducts. Associated with myopithelia cells.

Front 25

Apocrine sweat glands.

Back 25

Specialist sweat glands in axillary, areolar, and anal regions. Open into hair follicles and secrete a viscous odorless fluid (acquires distinct odor due to bacteria). In primitive mammals serves to attract opposite sex. In humans these glands become active at puberty.

Front 26

Sebaceous glands

Back 26

Develop in association with hair follicles (not found on palms and soles) However, they are found on lips, glans, penis and clitoris. Secrete sebum via holocrine secretion. More active during puberty- when clogged promote bacterial growth- acne. As cells fill with sebum the nuclei become pynotic and are lost.

Front 27

Mammary glands

Back 27

Elaborate lactiferous duct system. Enlarged during lactation.

Front 28

Nails

Back 28

Plates of keritinized epithelial cells. Clear and used for quick assessment of blood oxygenation.Nail bed is malpigian layer.

Front 29

Free nerve endings in skin

Back 29

Unmylenated axons penetrate the basil lamina and enter the stratum germitivum, spinosum Involved in temperature and pain perception. May function in crude touch (eyeballs)

Front 30

Meisseners corpuscles

Back 30

Most abundant in thick skin as well as the skin of the lips and the nipples. Specialized encapsulated receptors in dermal papillae. Involved in discriminate touch.

Front 31

Pacian corpuscles

Back 31

Found in the dermis (and hypodermis) of thick and thin skin. Especially abundant in the skin of the finger tips. Involved in perception of pressure and vibration.

Front 32

Back 32

Stratum Spinosum

Front 33

Back 33

Stratum Germitivum

Front 34

Back 34

Statum Granulosum

Front 35

What are layers A and B

Back 35

Stratum lucidum and stratum corneum. (Since these are very prominent in this section we know that we are looking at thick skin.

Front 36

What are the cells shown?

Back 36

Keratininocytes

Front 37

What skin cancer is shown?

Back 37

Basil cell carcinoma- basil cells form discrete islands or cell nests.

Front 38

What skin cancer is shown?

Back 38

Squamous cell carcinoma, complete change in morphology.

Front 39

What are the clear cells in the basil layer?

Back 39

Melanocytes- recognized by their ovoid nuclei in a clear space.

Front 40

What cancer is shown?

Back 40

Malignant melanoma- will appear as abnormal nests of pigmented melanocytes that penetrate the epidermis.

Front 41

What's in the box?

Back 41

Papillary layer of dermis

Front 42

Back 42

Reticular layer of dermis

Front 43

Back 43

Hypodermis

Front 44

Back 44

Hair follicle

Front 45

Back 45

Eccrine sweat glands

Front 46

Back 46

Apocrine sweat glands

Front 47

Back 47

Sebaceous gland

Front 48

Back 48

Meissners Courpuscle

Front 49

Back 49

Pacinian Corpuscle