Integument Flashcards
What are the four components of the integument system?
Skin Sweat glands Sebaceous glands Hair Nails
What are the five functions of thick skin?
Protection Regulation Reception Absorption Excretion
What areas have thick skin?
Palms and soles
Does thick skin have hair follicles, errector pilli, or sebaceous glands?
No
Does thick skin have sweat glands?
Yes
Where is thin skin found?
Over most of the body
Does thin skin have hair follicles, sebaceous glands and/or sweat glands?
Has all
The skin arises from what part of the trilaminar disc?
Ectoderm
Is the epidermis vascular?
Negative–receives nutrients from dermis
What is the layer of skin that is damaged in first degree burns?
Epidermis
What are the two layers of the skin?
Epidermis
Dermis
What is the type of epithelium in the epidermis?
Stratified squamous keratinized
What two types of connective tissue comprises the dermis?
Loose CT
Dense, irregular collagenous
What are the two types of cells that comprise the epithelium?
Keratinocytes and nonkeratinocytes
What are the layers of the epidermis that extend down into the underlying dermis?
Epidermal ridges
What are the projection of the dermis into the epidermis called?
Dermal papilla
What are the filaments that accumulate as keratinocytes approach the surface?
Keratin filaments
What ensures that the epidermis and the dermis do not separate?
The increased surface area formed by the interdigitation of the dermis and the epidermis
What is the basal layer of the epidermis?
Basal facali
Where does intense mitotic activity take place in the epidermis?
At the basal facali
How long does it take for cells to migrate from the basal facali (dermis) to the epidermis?
20-30 days
When does most of the mitotic activity take place in the dermis?
At night
What are the three types of nonkeratinocytes?
- Langerhans cells
- Merkel cells
- Melanocytes
Langerhans cells are derived from what?
Bone marrow
What is the general function of langerhans cells?
Defense
What is the route by which langerhans cells migrate to the epidermis?
- bone marrow
- Blood stream
- epidermis
What part of the epidermis do langerhans cells reside in?
Stratum spinosum
What are the histological characteristics of langerhans cells?
long, thin cytoplasmic processes which extend into the intercellular space
Prior to taking up residence in the dermis, what are langerhans cells known as?
Dendritic cells
What happens when a langerhans cell detects an antigen?
Migrates to a lymph node to aid in the immune response
What are birbeck grnules?
Rod-like structures that are unique to langerhan cells, whose function is not well understood
What is the general function of merkel cells?
Mechanoreceptors
Where are Merkel cells found?
Between keratinocytes in the stratum basale
Where are Merkel cells particularly present?
Fingertips
What are Merkel dics?
Enlarged part of a dendritic process that attaches to a Merkel cell
What are the two components of the Merkel cell-neurite processes?
Unmyelinated nerve terminals and Merkel cells
What is the general function of melanocytes?
Protect DNA of skin
Melanocytes arise from what type of cells?
Neural crest cells
Melanocytes synthesize what? Where does this go?
Melanin, which goes to surrounding keratinocytes
Where are melanocytes generally found?
In the stratum basale and superficial dermis
What is the bottom-most layer of the epidermis called?
The stratum basale
What is the enzymes that synthesizes melanin from Y?
Tyrosinase
What are melanosomes?
Packed up tyrosinase and melanin, which receive Y from vesicles that enter the melanocyte
What happens to melanosomes when they receive enough Y?
Become melanin granules, that are secreted through cytoplasmic processes
What activates Tyrosinase?
UV light
Where does melanin accumulates within cells?
Around the nucleus
True or false: the number of melanocytes is what gives different races their varying coloration?
False–it is the tyrosinase activity, distribution, number of melanin granules, size, and breakdown of melanin that varies
What is vitiligo?
Autoimmune disease against melanocytes
True or false: people with albinism lack melanocytes
False–it is the tryosinase that is defective
What are the ABCDE of malignant melanoma?
Appearance Border (irreg contour) Color (irreg) Diameter Evolution
What are the five layers of thick skin?
Stratum corneum Stratum lucidum Stratum Granulosum Stratum spinosum Stratum Basale
What does the stratum corneum contain?
Flattened, a-organellular cells with keratin filaments
True or false: the stratum corneum has desmosomes between each cell to create a tight seal
False
What is the layer of thick skin that provide waterproofing?
Stratum granulosum
What is the stratum lucidum? What is present in cells of this layer?
A subdivision of the stratum corneum that stains lightly
Keratin filaments are present, but no organelles
What is the stratum granulosum? What do cells here contain?
Granular layer of dermis
Cells here contain apoptotic nuclei, keratohylin granules and membrane coating granules
What is ressponsible for the waterproofing of the stratum granulosum? What does this also cause?
Exocytosis of lipid-rich substance to form a barrier. This causes cells in outer layers to die
What type of cell type and attachments comprises the stratum basale?
Single layer of columnar cells with desmosomes
Where does mitotic activity take place in the epidermis?
In the stratum basale
What does the stratum basale rest on?
The basement membrane
How do the stratum basale cells attach to the basement membrane?
Through hemidesmosomes
What are the two major functions of the stratum basale?
- Cell growth/renewal
2. Anchoring to the basement membrane
What is the epidermal layer above the stratum basale?
The stratum spinosum
What is the function of the stratum spinosum?
Binding, protection
What is the characteristic histological feature of the stratum spinosum?
Thick, prominent stratum with interdigitating processes
What are tonofilaments?
Fibers in the upper layer of the cells of the stratum spinosum
What forms the “railroad tracks” of the stratum spinosum layer of cells?
Desmosomes
True or false” mitosis takes place in the stratum spinosum?
True
Where in the epidermis do langerhans cells reside?
In the stratum spinosum
What are the three layers that are present in THIN skin?
- Stratum corneum
- Stratum spinosum
- Stratum basale
What glues the basement membrane of the epidermis to the underlying dermis
carbs (glue) and collagen (anchor)
What is Ichthyosis?
Fish-like scales that result from hyperkeratosis
What are the two layers of the dermis?
Papillary layer
reticular layer
The dermis arises from what embryological layer of tissue?
Mesoderm
What gives the dermis structure and strength?
Collagen
What is the papillary layer of he dermis comprised of?
Loose CT, collagen III, and elastic fibers
What are the anchoring fobrils of the papillary layer of the dermis made of?
Collagen VII
Second degree burns (partial thickness burns) involve what layer of skin?
The papillar layer of the dermis
What is the reticular layer of the skin comprised of?
Dense, irregular collagenous CT with collagen I
What are Langer’s lines?
Lines of collagen I in the reticular layer of the dermis
What is type of fibers/protis are in the reticular layer of skin?
Elastic
Collagen I
Proteoglycans
What are the functions of pacinian corpusles?
Detection of pressure, vibrations (in the dermis)
What are the functions of Ruffini corpusles?
Tensile forses
What is the hypodermis?
Suerficial fascia composed of loose CT located deep to the dermis (NOT an actual part of the skin)
What are full thickness burns (third degree)?
Burns that extend all the way down to the hypodermis
Where are hair follicles, arrector pilli, sebceous glands, and sweat glands found?
In the reticular layer of the dermis
What are the two types of sweat glands?
Eccrine sweat glands
Apocrine sweat glands
What are eccrine sweat glands?
Glands that squirt out sweat and are composed of simple, coiled tubular glands
Where are Eccrine glands located?
Scattered throughout the skin, in the dermis or hypodermis
What type of secretion do eccrine glands utilize?
Merocrine
What type of epithelium comprises the secretory segment of Eccrine sweat glands?
Simple cuboidal to low columnar (pseudostratified may also be present)
What type of cells surround the secretory unit of Eccrine glands?
Myoepithelial cells
What do Eccrine glands utilize to “squirt” out sweat?
Actin and myosin filaments
What type of epithelium is present in Eccrine sweat glands’ ducts?
Stratified cuboidal epithelium
Where are apocrine sweat glands located?
Axilla, areola of nipple, anal region
What type of excretion do apocrine sweat glands utilize?
Merocrine
What is the innervation of apocrine sweat glands?
sympathetic nervous system
Where layer of the skin are apocrine sweat glands found?
Dermis and hypodermis
What layer of the skin are sebaceous glands found?
Dermis and hypodermis
What do sebaceous glands secrete?
sebum (cholesterol, triglycerides and dead cells)
What is the secretory unit of sebaceous glands?
Acinus
Where do sebascous glands empty?
Into hair follcies
What type of secretion do sebaceous glands utilize?
Holocrine
What are the four components of hair follicles?
Hair root external root sheath internal root sheath Hair shaft (medulla)
What type of muscles are in arrector pili muscles?
Smooth muscles
How do sebaceous glands relate to the hair follicles?
Cradle it
What is the nail plate comprised of?
Keratin
The nail bed is comprised of what?
Stratum basale and stratum spinosum
Where does nail growth occur?
IN the nail matrix
What is the hyponychium of the nail?
The distal end of it
What is the proximal part of the nail? What does it consist of?
Hponychium (cuticle, stratum corneum)
