A 3 Integumentary Flashcards
what are the 3 layers of the skin?
epidermis, dermis, hypodermis
which of the three layers of the skin provides the support and elasticity of the skin?
Reticular dermis
which layer of the skin contains immune cells that act as a defense of foreign invaders through skin?
the dermis generally contain these cells and they are called langerhans cells.
what is another name for the hypodermis?
subcutaneous connective tissue.
what are the layers of the skin from superficial to deep?
corneum, lucidum (only where skin is thick), granulosum, spinosum, and basale.
what is a keratinocyte?
cells of the epidermis that produce keratin an intermediate filament. Note that about 70% of the cells in the epidermis are keratinocytes.
what is another name for the keratin intermediate filaments?
tonofilaments
when tonofilaments agregate, what do they become?
tonofibrils
keratin always exists as:
1) singles
2) pairs
3) triplets
pairs of one acidic and one basic
what types of keratin are located in the stratum basale?
keratin types 5 &14. (these types are those found deeper)
what types of keratin are located in the stratum spinosum & more superficial layers?
keratin types 1 &10
which cell layer is mitotically active?
stratum basale
what causes the spinous cells of the epidermis to be spiny?
the desmosomes cause this.
what makes up the cytoplasmic plaques in desmosomes?
plakoglobin and desmoplakin
What is the glycoprotein that connect the two plaques in desmosomes called?
cadherins
what are the two types of cadherins called?
desmogleins and desmocollins.
what is keratinization?
the progressive maturation of keratinocytes characterized by the accumulation of keratin.
the stratum granulosum is how many layers thick?
1-3 cells thick normally and up to 10 in palms and soles of feet.
in the epidermis, where does the cell normally die?
Normally in the stratum granulosum as these cells release lysosomal enzymes that destroy the nucleus and organelles. (furthers the process of keratinization) note: A few cell may even die in the stratum corneum.
what is a keratohyaline granule?
non membrane bound granules that contain proteins and lipids used for form filaggrin and the marginal band.
what is filaggrin?
a cement like substance that holds keratin filaments together.
what is the marginal band?
the inner lining of the horny (cornified) cells.
where will you find stratum lucidum?
in the areas of your body with thick skin such as feet and hands.
what major function does the stratum corneum play?
creates a barrier for micororganisms, water loss, physical protection, uv absorption, etc.
which cell layer has a lot of keratohyaline granules
stratum granulosum.
which layers make up the basal lamina?
lamina lucida and lamina densa
which layers make up the basement membrane?
the lamina lucida, lamina densa, and the lamina reticularis
which type of collagen is largely found in the lamina densa?
type 4 collagen
which 4 things make up the basement membrane ZONE?
plasma membrane, lamina lucida, lamina densa, and sub basal lamina.
what is the plaque of a hemidesmosome composed of?
bullous pemphigoid antigen (BP1, BP230) NOTE: desmosomal plaques are made of plakoglobin and desmoplakin!
the majority of the cells in the dermis are?
fibroblasts
fibroblast secrete what?
collagen, elastin, and ground substance
what percentage of the skins weight is collagen?
75%
what are the two divisions of the dermis?
papillary dermis and reticular dermis
what type of collagen predominates in the papillary dermis layer?
type 3 collagen and it is considered a loose connective tissue
what are meissners corpuscles?
nerve endings that are sensitive to touch that are located in the papillary dermis layer.
what is the dermal papillae?
the area of the dermis (papillary dermis) that the vasculature is located which regulates thermoregulation.
what type of collagen predominates in the reticular dermis?
type 1 collagen. It is considered a dense and irregular connective tissue.
T/F
autonomic nerves innervate all glands.
false, sebaceous glands. They are controlled hormonally.
what is the function of Vater-Pacine corpuscles?
they are large nerve endings that mediate the sense of PRESSURE
what do melanocytes produce?
melanin
what makes skin black or white?
the differences are based off of the melanocytes.
1) Stage that its in (1-4)
2) Melanosome size
3) The number of melanosomes
4) How melanosomes are grouped
5) How quickly melanosomes are degraded.
what effect does UV light have on langerhans cells?
their numbers are decreased because it can kill them
where are sebaceous glands found?
everywhere but palms and soles of feet.
what type of gland is a sebaceous gland?
a holocrine gland
where do you generally find apocrine glands?
axilla, genital region, areola, eyelid.
what is decapitation secretion?
APOCRINE gland secretion
what controls apocrine glands
they are controlled by adrenergic sympathetic innervation
what is another way to say eccrine gland?
merocrine gland.
sweat glands are classified as which types of glands?
eccrine glands.
what do “clear cells” secrete?
aqueous material and glycogen
what do “dark cells” secrete?
sialomucin
the myoepithelial cells that surround the eccrine glands are controled by?
cholinergic stimuli (acetylcholine through parasympathetics)
what is the hair follicle and sebaceous gland collectively called?
pilosebaceous unit
what causes hair pigmentation?
melanocytes
what is the average rate of hair growth?
1cm/month
what are the 3 cycles of hair growth?
1 Anagen (active growth phase 89%)
2) Catagen (growth arresting phase 1%)
3) Telogen (resting phase with fallout 10%)
where does the nail plate arise?
from the matrix
what is the hyponychium?
the skin underlying the free end of the finger nail
