Skin and Glands Flashcards
what does vasculature do when there is an increase in core temperature?
decrease smooth muscle tone –>vasodilation
core t decreases
langerhans cell
apc/dendritic cell; endocytose antigens and transport to lymph nodes initiating immune response
-pale staining among keratinocytes
layer of not true stem cells, with mitosis and melanocytes
stratum basale
layer with channels for nutrient flow, and spine-like desmosome connections; mitosis occurs here but not past here
stratum spinosum
layer with two types of granules
stratum granulosum
what are the two types of bodies in granulosum?
- keratohyalin: dark staining aggregate of keratin bound by protein
- lamellar bodies: lipid granules that provide water proofing to skin
layer sometimes present in thick skin like palms and soles; clear dead cells
s. lucidum
layer with no internal organelles; protein crosslinking on inner membrane gives strength
s corneum
order of epidermal strata (top to bottom)
corneum, lucidum, granular, spinosum, basale
how do basal cells change to toughen the epithelium as they become keratinocytes?
- crosslink cytoplasmic proteins
- lipids secreted outside cell form waterproof barrier
what layer of skin is the main source of strength?
DERMIS
two dermal layers
and layer that follows
top: papillary layer
bottom: reticular layer
then hypodermis below
papillary vs reticular dermis
papillary layer interlocks with overlying epidermis and reticular has larger collagen bundles
where do largest hair follicles begin?
hypodermis
thick vs thin skin
thin has no lucidum and a thin corneum
how does melanocyte system lead to pigmentation?
pigment is due to the melanocyte at base of basale layer
- melanocytes make melanin and packages it into melanosomes
- keratinocytes pinch off these melanosomes
melanin in pale skin v dark skin
- in pale skin, melanosomes break down quickly so highest [] is in basal
- darker skin has bigger more resistant melanosomes so highest [] is in spinosum – not more melanocytes, just bigger/more melanosomes
three common accessory organs
pacinian corpuscle
meissners corpuscle
merkel cells
looks like large onion, senses rapid vibration
pacinian corpuscle
tornado in papillae of dermis extending into epidermis
meissners corpuscle
-senses light touch, change in texture, and low freq vibration (closer to surface than pacinian)
senses sensitivity, sustained pressure
in s. basale near sweat ducts
merkel cell
rete ridges
epidermal thickenings that extend downward between dermal papillae
temperature control
capillaries vs large vessels
capillaries restrict and dilate in the dermis
while large vessels provide radiant heating
evaporative cooling
sweat gland base secretes sweat
- myoepithelial cells surround tube and squeeze w muscle properties
- up the tube some ions are resorbed
