Histology - Integument Flashcards
where are the nerves and blood vessels located in the integument (generally)? why?
in the inner layers
don’t want them punching through the skin to disrupt water proofing
don’t want foreign substances to get into blood
what are the 6 layers of the epidermis?
- stratum corneum
- stratum lucidum
- stratum granulosome
- stratum spinosum
- stratum basale
- basement membrane
what layer of the epidermis is this? how can you tell?
stratum spinosum
there are “spines” joining the cells (actually desmosomes)
label the parts of the epidermis
A: stratum corneum
B: statum lucidum
C: stratum granulosum
D: stratum spinosum
E: stratum basale
what layer of the epithelium is this? how can you tell?
stratum granulosum
filled with dark granules
what do the granules in the stratum granulosum do?
provide a mechanical barrier
what happens to the cells in the stratum granulosum as they move towards the outside of the body?
they become more squamous in shape because they are becoming dead
why does the stratum lucidum appear transluscent on slides?
the nuclei are lost
why doesn’t it hurt when skin cells slough off the body? what layer of the epidermis is this?
they are dead
stratum corneum
what are the functions of the stratum cornuem?
waterproofing and mechanical protection
what is an epidermal peg?
the epidermis extends into the dermis
what is a dermal papilla?
the dermis extends into the epidermis
what is the function of dermal papillae and epidermal pegs?
to provide more SA for attachment
label this image
A: epidermal peg
B: dermal papilla
what are the layers of the skin from outer to inner?
epidermis, dermis, hypodermis
what is the primary cell type of the epidermis?
keratinocyte
what are cytokeratins?
a family of fibrous proteins that polymerize as intermediate filaments
what do keratinocytes contain an abundance of?
cytokeratins
what does cornification of the epidermis achieve?
makes a physical barrier
how does the epidermis form the protective outer layer?
progressive proliferation and cornification
what is cornification?
broad term signifying all processes involved in the formation of the horny layer of the epidermis, including the consolidation of the intracellular, lipid-rich “glue”
what is keratinization?
series of programmed events whereby keratinocytes in the basal layer of the epidermis mature, polymerization of cytokeratin, and undergo apoptosis producing the stratum corneum
what is apoptosis? where do you find this in the integument?
the death of cells in normal body function.
the epidermis
what determines the thickness of the epidermis?
the rate of cell division in the stratum basale
what are the accessory cells found in the epidermis?
melanocytes, Merkel cells, Langerhans cells
what are melanocytes? where are they found?
pigment cells that contain melanosomes
stratum basale
what are Merkel cells and where can you find them?
somatosensory end organs
stratum basale
what are Langerhans cells and where can you find them?
monocyte-derived dentritic cells. they do immunosurveillance
stratum spinosum
what is the dermis made out of?
dermal fibroblasts/fibrocytes
arector pili
axons
adipocytes
what is the main cell type found in the dermis?
dermal fibroblasts/fibrocytes
what is a myocyte?
the smallest unit of muscle tissue
what is the function of arrector pili? what type of muscle are they made of?
to make hairs stand on end. smooth muscle
what are adipocytes?
fat-storing cells
what is the hypodermis made of?
adipocytes, skeletal muscle myocytes, fibrocytes
what are appendages as they relate to the integument?
things that grow out of the epidermis + dermis
what are the types of glands found in the integument?
sweat, sebaceous, anal, uropygial
what is a hair follicle?
invagination of the epidermis that holds the hair bulb/root
what shape are the cells in the stratum basale?
cuboidal
what occurs in the stratum basale?
mitosis –> cell creation
what are the granules in the stratum granulosum?
keratin
what are the fibers in the dermis made of?
collagen
glands are follicles are products of which layer of the integument?
epidermis
how are the fibers laid down in the dermis?
in a matrix
generally speaking, is the epidermis or dermis stronger?
dermis
