A&P: Integumentary System Flashcards
Cutaneous Membrane
skin
Layers of Skin
Epidermis and Dermis
Epidermis
keratinized stratified squamous epithelium; avascular
contains keratinocytes, dendritic cells, melanocytes, tactile epithelial cells
Keratinocytes
produces keratin (tough protein for protection)
majority
Melanocytes
produce pigment Melanin
Melanin
protects against UV radiation
DNA protection
Dendritic Cells
involved in immune responses
arises from red bone marrow
Tactile Epithelial Cells
aka Merkel Cells
f(x) in sensation of touch along with adjacent nonencapsulated sensory corpuscle (Merkel Disc)
Layers of Epidermis
“Come, Let’s Get Sun Burned!”
Stratum Corneum
Stratum Lucidum (non existant in thin skin)
Stratum Granulosum
Stratum Spinosum
Stratum Basale
Stratum Basale
continuous cell division occurs
aka ~ germinativum
Stratum Spinosum
not quite keratinized yet
held together by desmosomes
Stratum Granulosum
beginning of Apoptosis of keratinocytes
Keratohyalin and Lamellar Granules present
Keratohyalin
assembles keratin in Stratum Granulosum
Lamellar Granules
in Stratum Granulosum; waterproofs cell
Stratum Lucidum
extra layer only present in thick skins (sole, fingertips, etc)
Stratum Corneum
stratified squamous dead keratinocytes (Corneocyte or Squames) present
Callus may be formed
Dermis
connective tissue of Cutaneous Membrane
thicker than epidermis
houses blood vessels, nerves, glands, hair follicles
Papillary Region and Reticular Region
Papillary Region
composed of of Areolar CT (loose)
contains Dermal Papillae, Capillary Loops, Corpuscles of Touch (Meissner Corpuscles), and Free Nerve Ending
Reticular Region
composed of Dense Irregular CT
blood vessels, nerves, hair follicles, sebaceous glands, sudoriferous glands
Subcutaneous Layer
aka Hypodermis; NOT part of skin
attaches skin to underlying tissues and organs
contains Lamellar Corpuscles (sensitive to pressure)
Pili
hair
protection, reduction of heat loss, sensing light touch
entirely keratinized epidermal cells
Structure of Hair
Shaft
Root
Hair Bulb
Hair Root Plexus
Hair Follicle
Sebaceous Glands
secrete oil substance called sebum (holocrine)
Sebum
prevents dehydration of hair and skin
inhibit growth of certain bacteria
Sudoriferous Gland
sweat gland
eccrine vs apocrine
Eccrine Sweat Glands
opens to surface of the skin
sweat mostly water (and some ions)
Apocrine Sweat Glands
opens into hair follicle
eccrine sweat + lipids and proteins
Ceruminous Glands
modified sweat glands in the ear
prevents entry of foreign bodies
Nail
composed of keratinized epidermal cells
f(x) couterpressure to palmar surface for enhanced touch perception and manipulation
pick things up
scratching
protect underlying structures
Structure of Nail
free edge
nail body (plate)
lunula at base
nail root (under the skin)
Functions of Integumentary System
Thermoregulation
Blood Reservoir
Protection
Sensation
Excretion and Absorption
Vitamin D Synthesis
Epidermal Wound Healing
migration of basal epithelial cells across the wound and thickening
Dermal Wound Healing
Inflammatory
Migratory
Proliferation
Maturation
Inflammatory phase of Deep Wound Healing
blood clot forms uniting wound edge
blood vessels dilate increasing permeability and allow delivery of white blood cells, macrophages, mesenchymal fibroblasts
Migratory phase of Deep Wound Healing
clot scabs
epithelium cell creat bridge under scab
Proliferation phase of deep wound healing
extensive growth of epithelial cells
fibroblasts deposit collagen fibers
blood vessels grow
Maturation phase of deep wound healing
scab falls off
collagen fibers more organized
fibroblasts decrease
blood vessels restore to normal
