Integumentary Flashcards
skin condition in which melanocytes in certain areas lose the ability to produce melanin, possibly due an autoimmune reaction that leads to loss of color in patches
Vitiligo
layer of the epidermis between the stratum granulosum and stratum corneum, found only in thick skin covering the palms, soles of the feet, and digits
Stratum lucidum
layer of the epidermis superficial to the stratum basale, characterized by the presence of desmosomes
Stratum spinosum
most superficial layer of the epidermis
Stratum Corneum
deepest layer of the epidermis, made of epidermal stem cells
stratum basale
Secretory epithelial cells that contribute to the production of sebum, a lipid-rich fluid that coats hair and the epidermis. Clusters of sebocytes comprise sebaceous glands
Sebocytes
superficial layer of the dermis, made of loose, areolar connective tissue
Papillary layer
receptor cell in the stratum basale of the epidermis that responds to the sense of touch
Merkel cell
intercellular vesicle that transfers melanin from melanocytes into keratinocytes of the epidermis
Melanosome
Cells derived from the neural crest produce the pigment melanin. It reside within the basal layers of the epidermis, producing and then transferring melanin to keratinocytes.
Melanocytes
specialized dendritic cell found in the stratum spinosum that functions as a macrophage
Langerhans cell
pigment that determines the color of hair and skin
Melanin
general term referring to epithelial cells of the epidermis, including those of the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum.
Keratinocytes
granulated protein found in the stratum granulosum
Keratohyalin
structural protein produced by keratinocytes that contribute significantly to the
structural integrity of the epidermis.
Keratin
skin and its accessory structures
Integumentary system
Connective tissue connecting the integument to the underlying bone and muscle
Hypodermis
clear protein-bound lipid found in the stratum lucidum that is derived from keratohyalin and helps to prevent water loss epidermis outermost tissue layer of the skin
Eleidin
fibers made of the protein elastin that increase the elasticity of the dermis
Elastin fibers
secretion involves the rupture of the secretory cell, thereby releasing the cytoplasmic contents. This is the major secretion form of sebaceous glands.
Holocrine
structure that forms an impermeable junction between cells
Desmosomes
secretion involves exocytosis of membrane-bound secretory vesicles. This is the major secretion form of epitrichial glands
Apocrine
extension of the papillary layer of the dermis that increases surface contact between the epidermis and dermis
the dermis layer of skin between the epidermis and hypodermis
Dermal papilla
a genetic disorder that affects the skin, in which there is no melanin production
Albinism
Functions of skins
-protects internal organ
-protection from physical and mechanical injury
-barrier to infectious organisms
-prevents dehydration
a type of stem cell found in the stratum basale and in the hair matrix that continually undergoes cell division, producing the keratinocytes of the epidermis
Basal cell
is the layer of the epidermis superficial to the stratum spinosum
Stratum granulosum
3 primary components of skin
- Epidermis
- Dermis
- Subcutaneous tissue
2 layers of skin
-Outer epidermis (orig. Ectoderm)
-Dermis (deriv. Mesenchyme)
form as outgrowths of the walls of hair follicles
Sebaceous and sweat glands
are highly keratinized epidermal structures enclosing the distal phalanx
Hooves and claws
The integumentary system comprises..
the skin, hair, skin glands, hooves, claws, digital pads, horns, and feathers
Other roles of the skin
-body temperature regulation
-reception of external sensory stimuli secretion
-immune responses
-vitamin D synthesis
-body surface pigmentation
Sweat glands on the hands and most of the body are classified as
eccrine or merocrine type
sweat glands under the arms and in the genital areas are classified as
Apocrine sweat glands
a multilayered epithelial structure composed of keratinocytes that produce the structural protein kerati
Epidermis
From innermost to outermost the layers of the epidermis are:
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
2 primary functions of the stratum basale
- Proliferation
- Attachment of the epidermis to the dermis
These cells are the most mitotically active keratinocytes and are the least differentiated.
Cells of the stratum basale
forms the “floor” of the epidermis and the junction of the epidermis and dermis
Basement membrane
3 major functions of basement membrane
- forming an adhesion interface between the epidermis and underlying dermis
- acting as a physical barrier
- forms the foundation for the generation, differentiation, and repair of the epidermal keratinocytes.
Cells of the stratum basale attach to the basement membrane via protein structures called
hemidesmosomes
Two cell types found dispersed among the basal cells in the stratum basale
Merkel cell
Melanocyte
functions as a receptor and is responsible for stimulating sensory nerves that the brain perceives as touch
Merkel cell
These cells are especially abundant on the surfaces of the hands and feet
Merkel cells
a cell that produces the pigment melanin
Melanocytes
gives hair and skin its color, and also helps protect the DNA in the nuclei of living cells of the epidermis from UV radiation damage
Melanin
have prominent cell-to-cell junctions, termed desmosomes, that appear as spiky membrane projections on histology. For this reason, these are referred to as “prickle cells”.
Cells of stratum spinosum
are protein complexes that firmly attach keratinocytes to their surrounding cells (intercellular, between cells), thereby providing significant structural integrity
Desmosomes
are intracellular (within cells) protein complexes that anchor desmosomes to the cell membranes
Tonofilaments
a thin layer of keratinocytes containing dense, basophilic (blue/purple) cytoplasmic structures called keratohyalin granules
Stratum granulosum
contain components responsible for keratinization, including fibrous proteins (keratohyalin) and a lipid-rich secretory product
Keratohyalin granules
This layer is not apparent in all regions of the skin, particularly in regions of thin skin
Stratum granulosum
a thin, transparent layer of keratinocytes that are becoming less round and have a flatter shape
Stratum lucidum
only present in the thicker skin of the palms, soles and digits
Stratum lucidum
Main function of stratum lucidum
to reduce friction between the stratum corneum and stratum granulosum
a clear protein rich in lipids, derived from keratohyalin, which gives these cells their transparent (i.e., lucid) appearance and provides a barrier to water
Eleidin
are flattened eosinophilic keratinocytes that lack nuclei
Cells of stratum corneum