INTEGUMENT (Lecture 8) Flashcards
what is the integumentary system composed of ?
- epidermis
- dermis
- epidermal appendages
integument aka ____ aka ____
skin aka cutis
characteristics of the integument
- skin is the largest mammalian organ
- invests the entire body
- continuous w/ the epithelial linings of mouth, anus, urethra, ear, eyelids
epidermal _______ are found in the dermis but are epidermally derived such as nails, hair, glands
epidermal appendages
the layer of skin that forms the external surface, composed of stratified squamous keratinized epithelium
Epidermis
layer within epidermis where:
- the keratinized layer is thicker
- LACKS hair, sebaceous glands, etc
thick skin of epidermis
layer within epidermis where:
- keratinized layer is thinner
- lacks stratum lucidum (basically artefact)
- HAS hair, sebaceous and sweat glands
thin skin of epidermis
the interior layer of skin composed of the papillary and reticular layers
DERMIS
what are the 2 layers of the dermis
Papillary - loose connective tissue that interdigitates with epidermis
Reticular - dense, irregular CT
loose connective tissue that contains fat and is not part of skin layers
Hypodermis (superficial fascia)
4 main cell types found in the epidermis
- Keratinocytes
- Melanocytes
- Langerhan’s cells
- Tactile (Merkel) cells
predominant cell type in the epidermis, is derived from ectoderm
Keratinocytes
function of keratinocytes
serve as a barrier to the external environment
cell type derived from the neural crest and secrete a pigment called melanin
melanocytes
function of melanocytes
protect the DNA of keratinocytes from UV radiation
** melanin gets phagocytosed by keratinocytes in the stratum basale and then the keratinocytes absorb the melanin
cell type derived from mesoderm (bone marrow), part of the immune system
Langerhan’s cells
**phagocytes
what are langerhan’s cells
phagocytes that capture foreign material in the epidermis and travel to regional lymph notes
***main function = present antigens to immune cells
cell type derived from ectoderm and act as mechanoreceptors associated w/ sensory nerve endings
Tactile / merkel cells
*sensitive to touch
The single layer of cells that rests on the basal membrane
Stratum basale
Layer of the epidermis where active mitosis occurs to form keratinocytes
Stratum basale
Tonofilaments
Intermediate filaments made out of keratin
Keratinocytes connect to each other via ____
Desmosomes
Keratinocytes connect to the basement membrane via _______
Hemi desmosomes
Epidermis cells that are characterized by having a large nucleus, abundant free ribosomes and they product tonofilaments
Keratinocytes
The stratum cornemuse is composed of _______
Keratinized dead cells
The stratum lucidum is essentially
Artefact (insignificant)
This layer of the epidermis is where the initiation of the binding of keratin and lipid envelope begins
Stratum granulosum
What layer of the epidermis is where the initial differentiation of cells begins
Stratum spinosum
Layer of epidermis that contains the stem cells of skins, where mitosis occurs
Stratum basale
Keratinocytes and tactile (Merkel) cells both originate from the _____?
Ectoderm
Type of epidermis cells that are characterized by rounded cell bodies, long extensions between cells that donate melanin and a lack of desmosomes
Melanocytes
What is the main function of melanocytes?
To protect the DNA of keratinocytes from UV radiation
Exposure to _______ increases the size and activity of melanocytes
UV Light
Epidermis cells that are sensitive to touch
Merkel cells
Cells found in the stratum spinosum layer
Keratinocytes and langerhan’s cells
Main function of Langerhan’s cells
To present antigens to immune cells
Main location of Langerhan’s cells
Stratum spinosum
A thick connective tissue layer of the skin divided into 2 layers: the papillary and reticular
Dermis
Collagen fiber types that make up both the papillary and reticular layers
Collagen type I & III
A dense irregular CT layer of the dermis that has an abundance of collagen fibers and some elastic fibers
** provides strength and elasticity to skin
The Reticular layer
A loose CT layer of the dermis that contains - lots of ground substance
- microvasculature
- anchoring fibrils
* does not have elastic fibers
Papillary layer
Name for where the dermis and epidermis meet
Dermal junction
The increased surface area at the dermal junction is due to __________ found at epidermal and dermal ridges
Interdigitations
Sebaceous glands produce _______
Sebum = a lipid and cell debris containing compound that moisturizes hair
Sebaceous glands are located all over the body except _________?
Where hair is lacking, like in thick skin
What happens in Holocene secretion
The entire secretory cells get discharged and then destroyed in order for secretory product to be released
What is sebum secreted through
Pilosebaceous canal
Main roles of eccrine sweat glands
- Temperature regulation (via sweat)
- Excretion
What two segments make up the eccrine sweat glands
Duct segment
- ducts open onto skin surface (sweat pores)
-NOT associated w/ hairs
-lined by stratified cuboidal epithelium
Secretory segment
- clear cells (product watery component)
- dark cells (protein component)
- contain myoepithelial cells for contraction
Secretions excreted via exocytosis from secretory cells that go into epithelial wall ducts
cells DONT die
Merocrine secretion
_______ sweat glands open into canals of the hair follicles and contain pheromones
Apocrine
Apocrine sweat glands are made up of ?
One secretory segment
- one secretory cell type
-much larger lumen size
-myoepithelial cells for expressing
What gland type is this
Apocrine sweat gland
What type of gland is this
Eccrine sweat gland
What kind of gland is this
Sebaceous gland
What is circled here
Sebaceous glands
What is in green
Hair follicle
What is shown here
Arrector pili muscle
What is shown here
Dermal junction
What layer of the dermis is this?
Reticular layer
- dense CT
What layer of the dermis is this?
Papillary layer
- loose CT
The Golgi apparatus produces an oily lipid rich substance that gets secreted by __________ and acts as a water barrier
Lamellar bodies
What part of the epidermis can lamellar bodies be found?
Stratum granulosum
What do keratohyalin granules aid in
Keratohyalin granules aid in keratinization by aggregating tonofilaments into tonofibrils
What is the purpose of tonofibrils
Tonofibrils help maintain proper water levels in the body
What is shown here ?
Langerhan’s cells (L) and their long slender processes (CP)
What layer of the epidermis is this?
Stratum spinosum “prickle cell layer”
Physical characteristics of keratinocytes
- cells are cuboidal and slightly flattened
- cytoplasm contains tonofilaments
What cells are these?
Melanocytes
- have very round cell bodies and long extensions
Melanin gets phagocytosed by _______ in the stratum _______ and assumes a supranuclear position in their cytoplasm
Phagocytosed by Keratinocytes in the stratum basale
characteristics of keratinocytes found in the stratum granulosum
- flattened
- still have nuclei
- lysosomal enzymes digest organelles
- contain KERATOHYALIN GRANULES
- aid in keratinization by aggregating tonofilaments into tonofibrils - contain LAMELLAR BODIES
- secrete oily substance that was produced by golgi
characteristics of keratinocytes found in the stratum corneum
- cells are flat
- lack nuclei
- lack organelles
- keratinized
- thick membranes
hair is associated with _____ muscle and _____ glands
arrector pili muscle and sebaceous glands
hair is important for ______ and _____
thermoregulation and display (behavioral)
where are lamellar bodies found
stratum granulosum
where are keratohyalin granules found
in the keratinocytes of the stratum granulosum
the nodes of bizzozero found between keratinocytes are essentially just ______
desmosomes
what cell makes tonofilaments
keratinocytes
what layer of the dermis interdigitates w/ the epidermis at the dermal junction?
papillary later
part of the epidermis that lacks a stratum lucidum
thin skin
