Lecture 9 - Integument part I Flashcards
What is considered a part of the integument?
skin and it’s appendages
What are considered appendages of the skin?
Nails, claws, hair, sweat glands, and sebaceous glands
What is special about the integument system?
Largest organ and continuous with the lining of the mouth, anus, urethra, ears, and eyelids
What are the functions of the integument?
barrier for protection, immunologic information, sensory information, excretion, thermoregulation
What is the primary function of the skin?
Protection
What are the three skin layers?
Epidermis - Dermis - Hypodermis
What is contained in the hypodermis?
loose CT with fat, not an actual part of the skin layers
What is the hypodermis used for?
fat storage
What is another name fore the hypodermis?
Superficial fascia
What is the rete apparatus?
Interdigitiations of epidermal ridges and dermal ridges
What does the rete apparatus do?
attach epidermis to dermis
What cell type does the epidermis consist of?
Stratified squamous keratinized epithelium
What is the cycle of the epidermis?
20-30 days
What are two “types” of skin?
thin and thick
What is thick skin’s general characteristics?
glabrous, smooth, and non-hairy; lacks hair follicles and sebaceous glands
Why isnt back thick skin?
it has fair follicles, the dermis is thick
Where is thick skin found?
Palm and soles
How many layers of epidermis does thick skin have?
all five
How many layers of epidermis does thin skin have?
3-4
What is included in thin skin?
Hair follicles, sebaceous, and sweat glands
What are the five layers of the epidermis (stratum)?
Corneum - Lucidum - Granulosum - Spinosum - Basale
How are keratinocytes arranged throughout the layers of epidermis?
They are throughout with different jobs and appearances
What is the stratum basale?
Cells that lie on basement membrane, actively dividing
How often are the cells at the stratum basale renewed?
15-30 days (differs with species)
What does a cell at the stratum basale look like?
Large nucleus, abundant free ribosomes,
What do the cells at the stratum basale make?
intermediate filaments = keratin
What do these keratin filaments make?
tonofilaments
What happens to the tonofilaments?
Bundled into tonofibrils in the basale and spinosum
What type of adhesion occurs at s. basale?
desmosomes, hemidesmosomes
What cell is responsible for skin color?
melanocytes
Where are melanocytes located?
stratum basale
What is the mitotic activity in s. spinosum?
Cells adjacent to s. basale are active
What type of cells are present in the spinosum?
cubodial or slightly flattened
What type of cell adhesion occurs in the s. spinosum?
filament-filled cytoplasmic spines and desmosomes
What is the name for the spaces between desmosomes?
nodes of bizzozero
What type of filaments are in the spines at the s. spinosum?
tonofibrils - numerous bundles
Where do these spines terminate?
desmosome
What immune cell is in the s. spinosum?
Langerhan cells
What is a special characteristic about the s. granulosum?
last layer with nuclei, lysosomal enzymes digest organelles
What are two types of granules within s. granulosum?
Keratohyalin and lamellar bodies
What is happening to the keratinocytes in s. granulosum?
they come from the s. spinosum and being to flatten
What are the characteristics of keratohyalin granules?
intensely basophilic and not surounde by a membrane
What are keratohyalin granules made by?
ribosomes
What is the function of keratohyalin granules?
associate with tonofibrils and help strengthen them
What is the function of lamellar bodies?
discharge lipid rich content, to water proof skin = barrier for foreign substances
What produces lamellar bodies?
Golgi apparatus
What evolutionary function does the s. granulosum provide?
Adaptation to terrestrial life
Where is s. lucidum found?
thick skin only
What are the characteristics of the s. lucidium?
no nuclei or organelles, densely packed keratin, clear thin eosinophilic layer
What are the layers in the s. corneum?
deep and superficial
What adhesions occur in the deep layer of s. corneum?
desmosomes
What adhesions occur in the superficial layer of s. corneum?
lose desmosomes and undergo desquamation
What is the major characteristics of the s. corneum?
15-20 layers of flat, non-nucleated, keratinized cells with thick membranes and no organelles (more layers in thick skin)
What do melanocytes look like?
Rounded cell bodies w/ long irregular extensions between cells of stratum basale and s. spinosum
What is the organelle composition in melanocytes?
numerous mitochondria, rER, Golgi
What activates melanocytes?
UV light
What does the rER make in melanocytes?
precursor to melanin
What does the golgi do with the precursor melanin?
packages it into melanosomes
What occurs at the tips of melanocytes?
melanosomes travel to here and are pinched off via cytocrine secretion
Where is melanin stored?
Keratinocytes
What is the pigment donation?
melanin produced in melanocytes but stored in keratinocytes
What happens to melanin?
Attacked and degraded by lysosomes of keratinocyte
How does the number of melanocytes change between groups?
Same number, distribution and amount of melanin varies
What is the origin of melanocytes?
neural crest
Where are langerhans cells located?
s. spinosum
Where do langerhans cells originate?
bone marrow
What is the function of langerhans cells?
APC
What are the characteristics of langerhans cells?
irregular nuclei, pale cytoplasm, long slender processes
What is a special structure of langerhans cells?
birbeck granules
What are birbeck granules?
unknown
What is psoriasis?
Greater epidermal thickness w/ rapid renewal of epidermis
Where is rapid cell proliferation occur in psoriasis?
s. basale and s. spinosum
What happens to keratinocytes in psoriasis?
Accumulate in s. corneum
What happens cycle time in psoriasis?
decreases
Where does basal cell carcinoma occur?
s. basale
What is the growth/placement characteristics of basal cell carcinoma?
slow-growing, most common on nose
Is basal cell carcinoma metastatic?
not metastatic
