Skin Practical Part
Skin Practical part
Dr. Heba Kalbouneh Associate Professor ofAnatomy and Histology ##PLEASE NOTE: The doctor mentioned at the beginning that the lab slides required for the exam are those mentioned at the end of lec 2 Histology.
Writer: Ghazal Al-Attiyat
Skin and the of eyelids back!!! a
Dr. Heba Kalbouneh
Types of skin
Kalbouneh
Heba Dr.
Thin skin Thick skin
*4 layers *5 layers *less Prominent *Prominent stratum stratum corneum corneum * Less developed * Well developed stratum granulosum stratum granulosum *Dominant and *Palms of the hands lines most of the and soles of the feet body surface * Thinner dermis * Thicker dermis * No hair and * hair and sebaceous sebaceous glands glands The skin is composed of two layers: the outer epidermis and the deeper dermis, both of which rest on the
hypodermis
Kalbouneh
Heba Dr. Stratum corneum
Stratum granulosum Melanin granules Kalbouneh
Stratum spinosum Dermal papilla Heba
Stratum basale Epidermal ridge Dr. Duct Stratum Stratum Stratum Stratum of eccrine granulosum basale spinosum corneum sweat gland
Dr. Heba Kalbouneh Stratum Stratum spines Stratum Spinosum spinosum basale basale → the cells arecells→ the connectedby
Dr. Heba Kalbouneh → prominent papillae → prominent follicles hair → No → →has isThick**It prominent stratum stratum skin granulosum lucidum corneum (lightstained stratum) layer outerskin prominent,thiscausesridges the friction on #When the prominentthe Dermal Epidermal interdigitations papillae (rete) ridges ridges are
Dr. Heba Kalbouneh ** Thick skin Prominent stratum granulosum No apocrine sweat glands, sebaceous glands or hair follicles thick stratum corneum
Dr. Heba Kalbouneh ** Thin skin Thin stratum corneum Not prominent stratum granulosum Can find sebaceous gland→ so there is a hair follicle not seen in this section The papillae are not prominent The normal histologic appearance of the skin is shown here. At the top is the epidermis.A thin layer of keratin overlies the epidermis. This layer of keratinization is thicker on the palms and soles and in areas where skin is rubbed or irritated. Beneath the epidermis is the dermis containing connective tissue with collagen and elastic fibers.At the center can be seen a hair follicle with surrounding sebaceous glands.
Associated with the hair follicle is a small bundle of smooth muscle known as the Kalbouneh
arrector pili that can cause the hair to "stand on end" and dimple the skin to form Heba
"goose bumps". Dr.
Skin section: keratin, epidermis The hair shaft isn’t seen because we lose it during section preparation
Sebaceous glands → small cells, light stained because the sebum isn’t stained with H&E A small nucleus in the center of the cell
Kalbouneh
Heba Dr.
Sebaceous gland Hair root
Inner root sheath Arrector pili Outer root sheath
Glassy membrane Dermis Dermal sheath
Sweat gland Hair matrix (ducts)
Dermal papilla Sweat gland (secretory cells) Hair bulb
* ducts → dark stained, stratified cuboidal #It’s not required to differentiate between epithelium apocrine and eccrine sweat glands * secretory → light stained, single layer of **except if we’re given 2 histological section cuboidal epithelium next to each other A: Dermal papilla B: Hair matrix Melanocytes: Attached to basal lamina by hemidesmoses Not attached to neighboring keratinocytes Lightly stained cytoplasm > Found in stratum basale
1 melanocyte for every 10 basal keratinocytes
Kalbouneh
Heba Dr. Melanocyte Under the light microscope: The outline of the cell is rounded → because its processes don’t appear in histological preparation → It undergoes shrinkage during histological preparation → it is not attached to neighboring keratinocytes
Dr. Heba Kalbouneh Freckles are clusters of concentrated melaninized cells
Freckles do not have an increased number of the melanin-producing cells, or melanocytes, but instead have melanocytes that overproduce melanosomes changing the coloration of
keratinocytes
Kalbouneh
Heba Dr.
→ larger and more active melanocytes
Is there anything abnormal in the epidermis? If so, what might it indicate.
Look for cells with pale cytoplasm in the epidermis. These cells are melanocytes and the large number of melanocytes in upper layers of epidermis is abnormal. In normal skin,
melanocytes are found only in the basal layer of the epidermis. The condition suggests the Kalbouneh
early stages in the development of melanoma.
Heba Dr.
We do immunohistochemistry against melanocytes in order to getthe dingnosis Langerhans cells: Originate from bone marrow (monocytes) Mainly in the stratum spinosum
Langerhans cells recognize, phagocytose, and process foreign antigens
Kalbouneh
Heba Dr. Langerhans cells
→ rounded cells, lightly stained cytoplasm, with processes
Dr. Heba Kalbouneh Melanocytes and Langerhans Cells Melanocytes localize to the stratum basale and extend processes between the keratinocytes of the stratum basale and spinosum. Melanocytes produce the pigment melanin that protects against ultraviolet radiation. Melanin is produced in membrane-bound organelles called melanosomes that derive from the Golgi. Melanosomes are transported to the ends of the melanocyte Melanocyte
processes where neighboring keratinocytes phagocytose the Kalbouneh Langerhansmelanosomes.cell Langerhans cells are antigen-presenting cells in Keratinocyte Heba
the immune system. Dr.
Melanocytes :according to the location Sweat glands
**apocrine sweat glands secrete in both modes of secretion: merocrine and aprocrine 21
Dr. Heba Kalbouneh Sweat Glands Eccrine sweat gland Apocrine sweat gland
. Merocrine secretion . Empty into hair follicle . Empty directly onto skin surface . Location: armpits, groin, nipples . Viscous, cloudy secretion good . Location: most all over body (esp. nutrient source for bacteria (odor !!) abundant on palms & soles: ~ 500/cm2) . Secretion may contain Pheromones . Secretion begins at puberty and is . Clear, watery secretion (99% stimulated during emotional distress H2O; rest NaCl + some waste Scent glands
products
Kalbouneh
Heba Dr. → simple coiled tubular glands: when a section is taken we find rounded: • Dark stained: duct • Lightly stained: secretary portion
Apocrine sweat glands Eccrine (merocrine) sweat glands Kalbouneh
24 Heba
Sweat glands appears rounded profiles within the epidermis: Dr. Apocrine larger in size with wide lumens in comparing with eccrine sweat glands. Apocrine sweat gland
Eccrine sweat gland Kalbouneh
Heba Dr.
*Once I see the hair follicle , I realize it’s a skin This section is taken from axilla, genital a skin section area (where we have apocrine sweat ** The hair follicle is surrounded by glands) adipocytes, then the hair follicle extends down in the dermis ** Can’t be taken from the scalp because it doesn’t have apocrine sweat glands
Apocrine or eccrine sweat glands????
Kalbouneh
Heba Dr. Apocrine: Because the apical surfaces of • Eccrine sweat glands are seen in thin and the cells have apocrine mode thick skin, not only thick skin of secretion (separation of apical part of cells) Apocrine or eccrine sweat glands????
A: Duct B: secretory portion
• Apocrine sweat glands: → wide lumens → not clear apical part of cells (separation of apical part) Meissner's corpuscles localize in the dermis between epidermal ridges.
Meissner's corpuscles are touch receptors and enriched in fingers and toes
Kalbouneh
Heba Dr. Meissner’s corpuscle → according to its shape and location
Dr. Heba Kalbouneh Meissner’s corpuscle
Dr. Heba Kalbouneh Pacinian Corpuscle Pacinian corpuscles are large (~ 1 mm), onion-like structures in the dermis and hypodermis. Pacinian corpuscles contain a myelinated nerve ending in the central core of the structure. Pacinian corpuscles are sensitive to mechanical and vibratory pressure, Kalbouneh
rapidly changing pressure Heba Dr.
Kalbouneh
Heba Dr.
Sweat glands Pacinian corpusle Nerve Adipocytes
Ring shaped cells: white adipocytes
• This section is taken from: deep part of the reticular layer of dermis
• eccrine sweat glands Meissner corpuscle Epidermal ridge
Dermal papilla
Kalbouneh
Heba Dr.
Pacinian corpuscles
Kalbouneh Heba
**In the center of Pacinian corpuscles! There is sensory nerve ending Dr. surrounded by connective tissue capsule forming the corpuscle
Pacinian corpuscles
Kalbouneh
Heba Dr. The junction between dermis and epidermis
Sebaceous gland Hair follicle Hair shaft/root /Hair fiber Arrector pili Dermal papilla Pacinian corpuscle Hair matrix Kalbouneh
Sweat gland Heba Dr. Sebaceous gland Hair follicle Kalbouneh
Arrector pili Heba Dr.