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Integumentary System (Skin and derivatives) - Coggle Diagram
Integumentary System
(Skin and derivatives)
Function
Sensation
Receptors for
pain
temperature
discriminative touch
nondiscriminative touch
vibration
Thermoregulation
heat loss
facilitated
by evaporation of
sweat and vasodilation of
vessels in dermis
Prevented
by hairs and adipose tissue
Protection
Invasion by microorganisms
thermal insults
Against UV
Mechanical insults
chemical insults
dehydration
Metabolic
synthesis of vitamin D
Skin
largest organ
15-20% of body
Epidermis
epithelial layer from
ECTODERM
AVASCULAR
Epidermal ridges
Stratums
Stratum Granulosum
3-5 layers flattened cells
basophilic keratohyalin granules
Cells undergoing keratinization, die later
Cells have lamellar granules
contain lipids, die, exocytose and
produce impermeable layer, against
water and outside stuff
Stratum Lucidum
ONLY THICKK, dead
thin translucent layer of flattened
eosinophilic keratinocytes, desomosomes
Nuclei and organelles lost
Cytoplasm full of keratin filaments
Stratum Spinosum
thickest layer
many layers, bigger cells,
cytoplasmic processes, connected
by desmosomes
Prominent nucleoli, basophilic
Basally located cells more mitotically
Stratum Corneum
fully keratinized, anucleate squamous cells
filled with keratin (squames)
Desquamation in outer layers
as desmosomes break down
Stratum Basale
single layer basophilic cuboidal
Hemidesmosomes
and desmosomes
Lots of mitotic activity, (15-30 days)
has basal stem cells for keratinocytes
Melanocytes
Cells
Keratinocytes
Most numerous in epidermis
Make keratin
grouped in tonofibrils (not super imp)
transform granular cells into keratinized
cells that desquamate
Melanocytes
from neural crest cells
Scattered between keratinocytes of basale
Have halo
produce
melanin
, transported by
melanosomes
through dendritic processes
to be transferred to
keratinocytes
Melanosome:
membrane bound granules from golgi
contain
tyrosine
(tyrosine --> melanin)
Number and size of melanosomes (for color)
Exposure to UV, stimulate tyrosinase
Moles
Asymmetry
Border
Color
Diameter
Evolving
Malignant Melanoma
can undergo dysplasia
invades dermis
gets picked up by vascularization
Albinism
defect in tyrosinase
can't produce melanin, sunburn, cancer
vision defects
Langerhan's
LYMPHOID
PROGENITOR
Star shaped, dendrites
mainly SPINOSUM, not in
corneum
indented nucleus,
racket-shaped Birbeck granules
APC
(hypersensitivity reactions
contact dermatitis
Irritiant
(just damage,
bleach, fertilizer...)
Allergic
(allergen)
LANGERHAN'S
Merkel's
difficult to identify
Basale, with nerve ending
Light touch, sensitive skin
fingertips
Look like melanocytes
Skin Cancer
Basal cell carcinoma
red to pink pearly
can be ulcerated, blood vessels
UV but not always
Squamous cell carcinoma
keratinocyte
red plaque with central depression
Melanoma
melanocytes, dark
Thickness
Thick
(all 5 layers)
ex: palm and soles
Thin
(NO LUCIDUM)
Dermis
MESODERM
VERY VASCULAR
dermal papillae
General
tough, flexible base
Blood supply
and
sensory nerve endings
Dermal papillae junction
Layers
will put bracket
Papillary
(thin)
dense irregular, mostly collagen
some elastic and reticular
contains dermal papillae
Reticular
(thicker)
dense irregular connective tissue
lot of collagen, some orientation
Wrinkles
Intrinsic aging
after 20, 1% less collagen
less sweat and oil glands
less elastin
Extrinsic aging
sun, pollution, smoking
corneum thicker, cancer
lots of loss of collagen and elastine
Langer's lines
C-Section better horizontal
natural orientation of collagen fibers
follows muscle
Incisions made parallel heal faster
Derivatives of skin
Hair
Follicle
down in dermis and hypo
made of epidermis and
responsible for the growth
produces the hair
lowest portion is bulb
(filled with connective tissue
= dermal papilla)
inner (grows) and outer
(stationary) root sheath
from dermis, continuous with
dermal papilla
Glassy membrane outside ERS
Growth
in hair bulb
number of follicles constant
6 mo-6 yrs
14-45 optimal growth
distribution influenced
by hromones
Cylindrical down growth of epidermis
portion above epidermis is hair shaft
but also ligne horizonatale on the hair = hair shaft
Root
within dermis and hypodermis
Arrector Pili Muscle
Smooth muscle
attach to connective tissue sheath at angle
Sympathetic fibers, Fear and Cold
Glands
make sebum (holocrine)
in dermis
connected to follicle
Sweat Glands
Eccrine
all over skin, simple coiled tubular
most palms and soles
watery product, merocrine
temp regulation, excretion
Apocrine
axila, nipple, anus, external genitalia
open onto hair follicle instead of skin
puberty
viscous and smelly, merocrine
larger lumen
Sebaceous Glands
make sebum (holocrine)
in dermis
connected to follicle
Nails
similar to skin
avascular
stain pink
Matrix
forms from root
cells divide, keratinize
Root
proximal part, covered by
fold of skin (cuticle or eponychium,
extension of corneum)
matures and hardens at plate
Plate
bound to nail bed (basal and spinous layers)
Hyponychium under very end
Hypodermis
Loose connective tissue
Subcutaneous tissue
Adipose tissue
Varies in thickness
Insulates and allows movement
Lower portions of sweat
glands and hair follicles
Extensive vascular supply
Sensory Receptors
Unencapsulated
Merkel Cells
basale, sensory never fiber
light touch and texture
Free Nerve Endings
sensory nerve within dermis
sends projections into epidermis
temperature, pain, itching
Root Hair Plexuses
web of sensory fibers
base of follicles in reticular dermis
detect movement of hair
Encapsulated
Meissner corpuscules
in dermal papillae
light touch
among flattened schwann cells
CATERPILLAR
Pacinian corpuscules
lower
in dermis (reticular and hypo)
ONION
pressure, vibration and touch (rectum, bladder)
Krause end Bulbs
low frequency vibration (penis, clit)
Ruffini Corpuscules
stretching or twisting
Skin Repair
Dermal
damaged collagen removed
by macro[hages
new collagen by fibroblasts
close edges wound with suture,
steri-strips or tissue glue to help
Epidermal
keratinocytes in basale proliferate
cover wound site with scab
proliferating cells migrate under scab
desquamate and free the scab