integument Flashcards
basale layer of epidermis
Stratum Germinativum
Cells occupying the Stratum Germinativum
Melanocytes, Langerhans, Merkel
purpose of melanin
protects DNA of germinal cells of stratum gerinativum
function of Langerhans cells
antigen presentation - they migrate through the dermis to lymph nodes and interact with helper T cells
the layers of the epidermis from bottom to top
germinativum, spinosum, granulosum, lucidum, corneum
what cell type is partcular to the spinosum
prickle cells anchored to one another by tonofilaments making tonofibrils called prekeratin. Prickle cells distribute tesile stress.
function of Merkel cell
paracrine mechanorececptors. may migrate up to spinosum. associate with free nerve endings of cutaneous sensory receptors
keratohyalin
soft keratin mixed with a few other proteins that cause the granulosum to stain basophilic
which layer is only predominant in thick skin
lucidum.
cells that occupy lucidum
dead keratinocytes filled with keratin filaments and a few organelles
Psoriasis
extreme turn over of keratinocytes (a week) do not allow cohesive corneum layer
what layer is most noticeable in thick skin
corneum
what is the specific tissue of dermis
dense irregular CT
Rete pegs
epidermal reaching into the dermis
Papillae
dermis projections into the epidermis
3 components of the DE Junction
hemidesmosomes, basalamina, CT fibers (collagen type 1)
2 layers of the dermis
papillary loose CT (more collagen type 3, capillary loops), reticular dermis dense irregular CT (more collagen type 1, capillary and nerve networks)
the plexuses from bottom to top
subcutaneous, cutaneous, subpapillary
what type of specific tissue is the hypodermis (AKA superficial fascia)
adipose
to what layers do hair follicles descend
the dermis and hypodermis
layers of a hair follicle from the outside to inside
CT sheath, external root sheath, internal root sheath, shaft (cuticle, cortex, medulla)
which parts of a hair contain which types of keratin
from the inside out: medulla is soft, cortex is hard, internal root sheath is soft
how long are the growing and resting phases of hair follicles
growth phase 2-6 years, resting phase 2-6 months
myoepitheilium
epithelial cells with contractile properties that surround the secretory portion of sweat glands. a thick basement membrane lies beneath.
entire cell is secreted
holocrine (sebaceuous)
muscle that makes hair stand on end and squeezes the sebaceous gland
arrector pilli
the only skin appendage in thick skin
eccrine sweat gland
secretions are made via exocytosis
merocrine (eccrine, apocrine)
4 cell types of eccrine glands
low columnar clear cells (water, salts), low columnar dark cells (glycoprotein), myoepithelium, stratified cuboidal duct cells
eponychium
the cuticle (superior to the nail groove)
how do apocrine glands differ from eccrine glands (3 reasons)
- they are found only in specific body regions 2.open onto the hair follicle
- wider lumens
pacinian (patchinian) corpuscles
DEEP pressure unmyelinated nerve of thick skin; Ct capsule around onionbulb modified Schwann capsules (perineural epithelium) around the terminals in the dermis, hypodermis (subcutaneuous)
which layer of the epidermis contains keratohyaline?
stratum granulosa
Meissner’s corpuscles
SENSITIVE mechanoreceptors found in dermal papilla of thick skin encapsulated by CT. contain several axon terminals and stacks of modified Schwann cells
3 layers lining hair follicle
conn tissue sheath, external root sheath (epitheilium of hair follicle) , internal root sheath (soft keratin proximal to the hair)
nerve structure in Meissner’s
2 to 9 myelinated fibers enter at the base and sides, branch repeatedly and terminate on the receptor cells
where does one find connective tissue papilla?
base of hair root just below the MATRIX, dermal region
Where can one find free sensory nerve endings of skin
in the papillary dermis, epidermis, may be assoc with Merkel cells or hair follicles - pain, and fine touch
What adnexa are found in the hypodermis
sebaceous glands and hair follicles and eccrine sweat glands
Which plexus is found in the hypdermis
subcutaneous
what is the purpose of AV shunts
they facilitate bypass of the subpapillary plexus to control body heat
what structures of the skin are made of stratified cuboidal epithelium
ducts of sweat glands
what is the functional structural unit of the skin
the keratinocyte
