Integumentary System Flashcards
What are some functions of the skin?
Protection
Mechanical abrasion, pathogen barrier (including as earwax from Ceruminous glands), dehydration, ultraviolet radiation
Temperature regulation
Dilation or constriction of superficial blood vessels. Anastomosis. Glomus body
Sensory perception
Free and encapsulated nerve endings
Excretion
Sweat contains water, sodium salts, and urea
Formation of Vitamin D pro-hormone
For mineral absorption and metabolism
What are the main layers of the skin from out to in?
Epidermis (4 layers, 5 in thick skin)
Dermis
Subcutaneous (superficial fascia or hypodermis)
What are some of the accessory structures of the skin?
Glands
Hair
Nails
Encapsulated sensory organs
Is the epidermis vascularized?
NO
What are the layers of the epidermis from outer to inner? What are some features of them?
Stratum corneum: keratinized squames in this layer DEAD CELLS
Stratum lucidum (thick skin only): clear cell layer DEAD CELLS
Stratum granulosum: squamous cells wih lamellar granules
Stratum spinosum: spiny cell layer
Stratum basale (stratum germinativum): basal cell layer
Come Lets Get Sun Burned
What are the different types of proteins from keratinocytes (in all strata layers) found in each layer of the epidermis?
Keratohyalin - stratum granulosum, spinosum, and basal
Eleidin - lucidum
Corneocytes/Squames (cells) - Stratum corneum
Where are melanocytes and merkels cells (discs) found in the epidermis?
Stratum basale
Merkels cells are generally hard to ifnd
What layer of the epidermis are langerhans cells (macrophages) found in?
Stratum spinosum
Look at this picture and Identify some of the general cell locations.
DO IT.
What are some defining features of thin skin vs thick skin?
Thin skin: hair, arrector pili, sebaceous glands, and apocrine sweat gland (empty into hair follicle)
Thick: Pacinian corpuscles (dermis, lower portion) and meissner corpuscle (in dermal papillae)
What are the layers of the dermis divided into?
Papillary (more superficial)
Reticular (more deep)
What can be seen here?
Meissners corpuscles, look in dermal papillae
Look how dark the stratum granulosum is (black)
What type of skin is in this picture? What defining structure can be seen in the lower portion of the dermal layer in this picture?
Thick skin (no hair)
can also see pacinian corpuscles at the bottom of dermis
Also eccrine sweat glands that empty at surface rather than hair follicle (no hair either)
What are the different regions of a hair from external to internal? Describe a little.
Shaft - hair extending outside epidermis
Root - has attached sebaceous gland, arrector pili attaches to this
Bulb - contians blood supply, and hair papilla (connective tissue)
Study this image and identify structures listed.
Bulb region of hair root
Hair papilla (Connective tissue)
Follicle
Epithelial root sheath
Internal (inner) root sheath
Sheath cuticle
Huxley’s layer
Henle’s layer
External (outer) root sheath
Glassy membrane
Connective tissue (dermal) root sheath
Study the layering of this hair follicle picture.
hair matrix amplifying cells
outer root sheath
henles layer
huxleys layer
inner root sheath cuticle
hair cuticle
har cortex
medulla
dermal papilla cells = hair papilla
dermal sheath cells
Hair matrix amplifying cells and keratinocyte stem cells
What are the phases of hair growth?
anagen (growth) - years
catagen (transition) - weeks
telogen (resting/shedding) - months
exogen (shedding)
What pigments do melanocytes contain in hairand what color do they correspond to?
Eumelanin (black/brown)
Pheomelanin (red/blonde)
Study this picture of a longitudical and cross section of hair.
DO IT.
Try to identify the structures of this thin skin picture with good identification of hair structures.
Arrector pili
Sebaceous gland
Apocrine sweat gland
What is another name for the accessory structures of skin?
adnexa
What are the muscle cells associated with the sweat glands called?
myoepithelial cells
What is another name for a sweat gland?
sudoriferous gland
What is the difference between an eccrine and apocrine sweat gland, where are they typically found?
Eccrine - thick and thin skin, empty to the surface
Aprcrine - thin, empty into hair follicle
Identify the structures in this sweat gland.
Arrector pili
Sebaceous gland
eccrine sweat gland
Understand the different portions of this eccrine sweat gland in the picture.
Secretory portion
Pseudostratified epithelium
Two secretory cell types:
- Clear cells
Lots of glycogen, sER, and GA
Produce the watery part of sweat
- Dark cells
Lots of rER and secretory granules
Produce the glycoprotein part of sweat
Myoepithelial cells
Duct portion
Stratified cuboidal epithelium
Duct cells are smaller and darker
than the secretory cells
No myoepithelial cells
Identify the structures of this picture of hairy skin.
Hair follicle
Sebaceous gland
Simple branched acinar
Eccrine sweat gland
Simple coiled tubular
Apocrine sweat gland
Simple coiled tubular
Pigment in epidermis
Apocrine and eccrine sweat glands and what type of glandular epithelium structure?
simple coiled tubular
Identify the following structures in this picture of the dermis.
hair follicle
eccrine sweat gland
apocrine sweat gland
myoepithelial cells
sebaceous gland
pilosebaceous unit
What is this a picture of? Where in the body is this located?
These are ceruminous glands in the external ear canal, which are modified apocrine sweat glands
Identify the structures of the nail in this picture.
D = dermis
Ep = Eponychium
FP = Fibrous periosteum
HC = Hyaline cartilage
Hy = Hyponychium
NB = Nail bed
NP = Nail plate
NR = Nail root
Nail plate
Nail bed
Nail root
Eponychium (Cuticle)
Hyponychium
Dermis, Hypodermis, Fibrous periosteum,
Phalanx bone, Hyaline cartilage
Identify the following structure in this picture of a finger tip.
Nail plate
Nail bed
Nail root
Eponychium (Cuticle)
Hyponychium
Dermis,
Hypodermis,
Fibrous periosteum,
Phalanx bones,
Hyaline cartilage
What are some defining structures found in the eyelid?
External surface = Skin (keratinized stratified squamous epithelium)
Internal surface = Palpebral conjunctiva (stratified columnar epithelium)
Tarsal glands:
- Meibomian glands (modified sebaceous glands, simple branched acinar) in tarsal plate
Meibomian glands produce meibum
Ciliary glands:
- Glands of Zeis (modified sebaceous glands, unilobar) associated with eyelash follicles
- Glands of Moll (modified apocrine sweat glands) near eyelash follicles
Orbicularis oculi is a facial expression muscle (skeletal) that encircles the eye
What are these labeled structures of the eyelid called?
CG = Ciliary gland (Gland of Moll and Zeis)
OO = Orbicularis oculi
pC = Palpebral conjunctiva
Sk = Skin
TG = tarsal glands (meibomian glands, modified sebaceous glands)
TP = Tarsal plate
Arrow = Aponeurosis of levator palpebrae superioris
What are these structures of the eye?
Skin of eyelid
Cornea
Iris
Lens
Meibomian glands
Orbicularis oculi muscle
Eyelash follicles
Eyelashes have no
arrector pili muscles
Identify these structures of the lens.
DLF = Differentiating lens fibers
LC = Lens capsule
LE = Lens epithelium (simple columnar epithelium)
MLF = Mature lens fibers
The outer surface is the lens capsule
The subcapsular lens epithelium (simple cuboidal epithelium)
cells have their basal margins near lens capsule
Differentiating lens fibers still have nuclei but are elongating, losing organelles, and are filling with proteins called crystallins
Mature lens fibers are densely packed and have lost their nuclei
Identify these structures of the cornea of the eye.
Anterior surface: Non-keratinized stratified squamous epithelium
Thin acellular Bowman’s membrane (anteriormost part of the stroma)
Stroma, with Collagen fibers
Descemet’s membrane (a basement membrane)
Posterior surface: Simple squamous epithelium (Endothelium)
Sclera is continuous with the cornea as the fibrous tunic of the eye
They meet at the corneoscleral junction (limbus)
Sclera, unlike the cornea, is not transparent
Epithelium of bulbar conjunctiva covers the anterior surface of sclera
BM = Bowman’s membrane
CF = Collagen fibers
DM = Descemet’s membrane
Ep = Epithelium
F = Fibroblast
N = Nucleus
St = Stroma
What are the tunics of the eye? Identify the structures in the picture.
Posterior compartment (housing vitreous body)
Retina
Choroid
Sclera
Lacrimal gland (compound tubuloacinar, serous)
Ch = Choroid
CT = Connective tissue
LG = Lacrimal gland
Lo = Lobule
N = Nucleus
PCo = Posterior
compartment
Re = retina
S = Sclera
SA = Serous acini
