Histology of the Skin Flashcards
This system of the bodyy is composed of the skin and epidermal derivatives
Intergumentary system
this part is the largets organ
- 15 bw
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Skin
thinnest part of the skin
Eyelids
Thickest part of the Skin
Soles
This parts functions are protection from harmful substances entering the body
- regulate body tempt
- excretes waste
- Vit D
- individual identification
Skin
Is the skin a Sensory organ
True
What are the main layers of the Skin
- Epidermis
- Dermis
- Hypodermis
This layer of the skin is most superficial
Epidermis
this part of the skin is made up of Keratinized Squamous Epithelium
Epidermis
this part of the skin if derived from the ectoderm
Epidermis
Irregular conical invaginations that project into the dermis
Epidermal Ridges
this part of the skin is the deepest layer
Dermis
this part of the skin is composed of connective tissues
Dermis
this part of the skin if derived from the mesoderm
Dermis
Elements that project into the epidermis
Dermal Papillae
this part of the skin has connective tissues beneath the dermis
Hypodermis
this part of the skin connects underlying tissues
Hypodermis
this part of the skin usually skin appendages extend to
Hypodermis
These are layers of adipose tissue in individuals who are over nourished
Panniculus Adiposus
parts of the body where there are no adipose cells
- penis
- scrotum
- eyelids
- nipple
- areola
this part of the skin is renewed 20- 30 days
Epidermis
this part of the skin is classified as thick and thin
epidermis
This helps renew skin
Keratinocyte
principle cell of the epidermis
Keratinocyte
what does Keratinocyte produce
Keratin
these cells are in the deep layers of epridermis
slowly pushes out and undergoes keratinization
Keratinocyets
5 layers of thick skin
- startum germanitivum
- startum spinosum
- stratum granulosum
stratum lucidum - stratum corneum
Layers under Startum Malpighii
- startum germanitivum
- startum spinosum
- stratum granulosum
Layer of thick skin with cells composed of keratin fiber
Cornified layers
Cornified layers of the thick skin
- stratum lucidum
- stratum corneum
This thick skin layer is deepest to most superficial
Stratum Germinativum
what is S. Germinavitum composed of/ kind of cells
Tall cuboidal cells
Binds lateral surfaces
Desmosomes
Bind basal surface of cells to basal lamina
Hemidesmosomes
This thick skin layer has large nucleus with basophilic cytoplasm with numerous ribosomes
S. Germinativum
This thick skin layer contains polyhydral cells
– cells are mitotically active
S. Spinosum
S. Basale
S. germinativum
S. spinosum have the same cytoplasm content with this thick skin layer
S. germinativum
This thick skin layer tighly bound to neighbors desomosomes
S. Spinosum
under the LM they appear like spindles or spines between cells
s. Spinosum
This thick skin layer has to skin layers of flattened keratinocytes
s. granulosum
This thick skin layer has dead cells
and more flat than spinosum
s. granulosom
This thick skin layer cannot go under mitosis
s. granulosom
This thick skin layer has pyknotic nucles
s. granulosom
what is pyknotic nucles
flat nucleus
2 types of granules in the s. granulosom
- Keratohyalin granules
- secretory granules
Type of granule in the s. granulosom that is numerous and dark, no membrane and no keratin
contains profillagrin
Keratohyaline granules
whats profillagrin
histidine rich protein
type of granule in the s. granulosom that has lipids
- membrane bound
- closelyy packed lamella
- content is deposited in intercellular space
Secretory granules
This thick skin layer that has 4 to 6 layers
- dead cells
- anucleated cells
- cytoplasm
- has keratin
Stratum lucidum
This thick skin layer has 12 to 20 layer
- cytoplasm has keratin
- deeper cells with desmosomes
- horny cells
Stratum Corneum
Types of skin according to Thickness
- Thick skin
- Thin Skin
this type of skin has longer dermal papillae than thin
- has sweat glands and lacks hair follicles
- palms and soles
Thick skin
this type of skin has
- shorter dermal papillae
- has sweat glands and hair follicles
- whole body except soles and palms
Thin skin
this skin layer has all 5 layers present
Thick skin
this skin layer has spinosum,
no lucidum
poorly granulosom
Thin layer
Cells in the Epidermis
- keratinocytes
- Melanocytes
- Langerhans cells
- Merkel Cells
this cell in the epidermis is the pricipal cell for skin renewal
- keratin
- 85% to 95%
Keratinocytes
this cell in the epidermis
- 7 to 10%
- produces melanin pigment
-
Melanocytes
where produces Melanin
Melanosomes
what contains more melanin
kerato or melato
Keratocytes
what happens to melanin when formed
moved to keratocytes via the melalanocytes
Skin color mixture of 3 pigments
- carotene
- hemoglobin
- melanin
Skin color mixture that is yellowish in color, present substance in intercellular
Carotene
Skin color mixture that is imparts brown to black shade to the skin
Melanin
Skin color mixture that is pigment is RBC which are n the capillaries of the dermis
Hemoglobin
this cell in the epidermis is 3 to 8%
- antigen presenting. limited phagocytosis
- contact Birbeck or veriform granules
Langerhan Cells
where are Langerhans cells derived from
precursor cells in the bone marrow that migrate to the skin via blood
this cell in the epidermis is least in number in the epidermis
- has sensory functions
- numerous in palm and soles
- forms merkel discs with associated nerve
- Merkel
this layer of skin is also known as corium
- thicker than epidermis
wallas have nerve endings and blood vessels
-
Dermis
2 layers of Dermis
- Papillary layer
- Reticular Layer
this layer of dermis is subepithelial, made up of loose connective tissues
and more cellular
Papillary layer
this is part of papilary layer
- conical projections into epidermis
- bulk layer
have nerve ending and capillary beds
Dermal Papillae
this layer of dermis is
- deeper layer
- has dense iregg C. tissue
- toughness of skin
- collagen fiber are parellel to the skin
- sweat gland, sebaceous and hair present
Reticular layer
this appendages of the skin consists of heavily keratinized epithelial cells
- they grow coninuously
-
Nails
what nails grow fastest
Fingernails grow faster than toenails
with middle digits the fasttest
Parts of the Nails
- Nail plate
- Nail bed
- Nail root
- Nail matrix
- Eponychium (nail cuticle)
- Hyponychium
this part of the nail rests on the nail bed and part of the stratum corneum
Nail plate
this part of the nail have spinosum and germinativum
cells in here do not coontribute in nail growing
Nail bed
this part of the nail part of the nail that is hidden in the nail groove
this extends from Lunula
Nail root
what is Lunula
the white crescent in the nails at the proximal portion
it exentends and connects to the nail root
this part of the nail is proximal to the region of the nail root
- where hair is produced
- mature cells are pushed forward
Nail matrix
this part of the nail
that is at the end of the nail
higly keratinized
above the nail root and lunula
Nail cuticle or Eponychium
this part of the nail inderior aspect of the distal end of the nail plate
- thickened accumulaion of startum corneum being shed
Hyponychium
This is also known as the subcutaneus tissue
- has adipose tissue
Hypodermis
Loose connective tissue that bind the dermis
Hypodermis
what is formed when there is an over dose of adipose tissues
Panniculus adiposus
types of Nerve endings in the Skin
- Afferent
- Efferent
this nerve ending in the skin
- free nerve endings
- expanded endings
- subserve heat, cold heat and fine touch
- end bulb of kraus
Afferent nerve ending
This corpuscle is large and ovoid in shape
like an onion cut. detects vibrations and pressure changes
- Vater pacini corpuscle
This corpuscle has touch receptors in papillary layer of hairless skin, in dermal papillae
- cylindrical shape oriented
Meissner’s corpuscle
this nerve ending in the skin
- regulates glands and caliber of blood vessels
- has naked endings of axon in interstitial space
Efferent nerve endings
What are the Appendages of the skin
Hair
Nail
Cutaneous glands
these are derived from the epidermis
have specific functions
confined in the dermis
Appendages of the skin
This appendage of the skin is highly keratinzed
- covers whole body
- varies in thickness
- imprtant sense organ
Hair
Parts of the hair
- Hair Shaft
- Hair root
This part of the hair is embedded in the skin and enclosed by epithelial sheaths
Hair Root
This part of the hair projected from the surface of the skin
Hair Shaft
Comprises of Hair root + internal root sheaths
Hair Follicle
3 segments of the Hair Follicle
- Infundibulum
- Isthmus
- Inferior segment
this segment of the hair follicle contains the hair bulb and the dermal/ hair papilla
Inferior Segment
this segment of the hair follicle extends from the end of infundibulum to the insertion of the arrector pili
Isthmus
this segment of the hair follicle from the surface opening of the hair follicle to the level of the sebaceous glands
Infundibulum
Associated structures to the Hair follicle
- Sebaceous glands
- Arrector pili muscle
- Hair bulb
- Dermal hair papillae
this is an associated structure to the hair follicle are ducts that open into the upper third of the follicle
Sebaceous Gland
this is an associated structure to the hair follicle expands terminal portion of the hair follicle
Hair Bulb
this is an associated structure to the hair follicle has smooth skin muscle
- one end is attached to the mid lenght hair other is dermis
straightens the hair
Arrector Pili muscle
this is an associated structure to the hair follicle at the base of the hair bulb in the invagination
- connectove tissue that have capillaries supporting the hair nutrients
Dermal Pappilla
Hair Formation
Hair Matrix
this hair formation envelopes the dermal papilla
- cells are mitotic and active and rich in blood
Hair Matrix
Anagen
Active growth period of the Hairs
Rest periods of the Hair growth
Telogen
Two types of Cell present in the Hair matrix
- Epithelial cells
- Melanocytes
type of cell in the hair matrix that is scattered among cells, responsible for hair color and produce melanin
Melanocytes
type of cell in the hair matrix that actively proliferate, differentiate and move upwards
- many types
- keratin
-
Epithelial cells
Concentric layers of the Hair
Medulla
Cortex
Cuticle
concentric layer of the hairt that is the thinnest and outermost
- flat
Hair cuticle
concentric layer of the hair that is the innermost. core of hair
none in thin hair
Medulla
concentric layer of the hair that surround the medulla
thickest
differentiates cells
packed with dead cells at maturity
Cortex
Hair sheath
these are 2 layers that encloses the hair root and form outer layer
2 types of root sheaths
- Internal
- External
type of root sheath that has epidermis of the skin
- near skin
deepest layer
- startum germinativum
External Root Sheath
type of root sheath
- formed by peripheral cells
- surround initial hair shaft segments
- absent above level of sebaceous glands
Internal root sheath
NErves associated with HAir
- Lanceolate endings
- free encapsulated nerve endings
Nerves associated with HAir
- Lanceolate endings
- free encapsulated nerve endings
Nerves associated with Hair
- Lanceolate endings
- free encapsulated nerve endings
Cutaneous Glands
- Sebaceous glands
- sweat glands
cutaneous glands known as to be found where there is hair present
Sebaceous glands
these glands turn into acne and pimple during puberty
Sebaceous glands
these glands are secretory product + secretion of cells + cells that produce the secretion
Holocrine glands
its the secretion of sebaceous glands that lubricates the skin
– single layer of flattened cuboidal cells
Sebum
this is the cutaneous gland that is for thermoregulation
Sweat glands
2 types of sweat glands
Ecorine
Apocrine
This type of sweat gland is spread all over the body
- has ducts that open
- start since childhood
- secretes sweat
Ecorine sweat gland
ducts that open in the ecorine sweat gland
Sweat pores
3 cells in the Ecorine csweat gland
- Myoepithelial
- Dark cells
- Light cells
this type of ecorine sweat gland rests on basal lamina
- secretes water and electroltes
- most watery sweat
Light cells
this type of ecorine sweat gland
- broad and tapered
-have dense glcoprotein
-
Dark cells
this type of ecorine sweat gland
- in epithelial cells and basal lamina
- help evacuate secretion of glands
Myoepithelial
This type of sweat gland
- found in axilla, anus
- areola and labia majora
- coiled tubular
- open direct to skin
- after puberty
- strerile and odoless
Apocrine sweat gland
Modified sweat glands
- Glands of Moll
- Glands of Zeis
- Ceruminous Glands
- Mammary Glands
Glands of Molls
Eyelids
secretes into follicles
GLands of zeis
usual sites for styes along with glands of molls
in the external auditory canal
Ceraminous glands
Sexretes Milk
Mammary gland
