Integumentary System Flashcards
What is the Epidermis, and what kind of cells is it composed of?
The Epidermis is the outermost protective shield of the body, and is composed of epithelial cells. Note it is also stratified.
What is the Dermis and what kind of cells is it composed of?
The Dermis makes up most of the skin, and is a tough, leathery layer composed mostly of dense connective tissue.
How do nutrients reach the dermis and epidermis?
The dermis is vascularized, but the epidermis only gains nutrients from diffusion from nearby blood vessels.
What tissues are Subcutaneous Tissue composed of and what is another name for it?
It is composed of adipose tissue and some areolar connective tissue. It can also be referred to as the hypodermis.
What are the 3 purposes of Subcutaneous Tissue besides storing fat? How does it attach to the underlying structures?
Shock Absorption, Insulation, and Anchoring. It is attached loosely so it can slide over.
What is the purpose of a keratinocyte and where are they located?
Keratinocytes produce keratin, and skin is composed mostly of keratinocyte cells.
What holds keratinocytes together for strength, and why are they waterproof?
Desmosomes hold together keratinocytes, and tight junctions between cells make them waterproof.
List the five layers of the epidermis in thick skin in order of deepest to most superficial. Which layer is not present in thin skin?
Stratum Basale, Stratum Spinosum, Stratum granulosum, stratum lucidum, stratum corneum. The stratum lucidum is not found in thin skin.
In the stratum Basale, what types of cells can be found, and what cellular process occurs?
Stem cells can be found undergoing mitosis into keratinocytes, some dendritic cells and melanocytes can be found there as well.
In the stratum spinosum, what cells are present, and what tension-resisting protein can be found?
Keratinocytes can be found containing bundles of filaments with pre-keratin inside of them. Dendritic cells are also most abundant in this layer.
In the stratum granulosum, what two types of granules are found and what are their purposes? What process is the most important in this layer?
Keratohyalin granules help form keratin in the keratinization of the keratinocytes. Lamellar granules also secretes glycolipids into the extracellular space that is water resistant.
In the stratum lucidum, what cells are found? What clear protein is found here?
It is filled with dead keratinocytes that are translucent. Eleidin is found here which gives the layer its translucent property.
How many layers of keratinocytes are found in the stratum corneum? What does the keratin found here consist of?
20-30 layers of dead keratinocytes are found here. The keratin found consists of the pre-keratin filaments bound together by the keratohyalin granules.
What 2 layers compose the dermis? What tissues compose these layers?
The papillary layer consists of areolar connective tissue and is thin and superficial. The reticular layer is composed of coarse, dense, irregular connective tissue.
What is a dermal papilla? What do they contain?
They are small projections of the papillary layer of the dermis into the epidermis. They contain capillary loops to bring nutrients to the epidermis, or nerve endings/touch receptors (tactile corpuscles).
What fibers identify the reticular dermis?
Collagen Fibers
What are flexure lines?
Dermal folds that occur at/near joints. They are where the dermis is well anchored to the underlying structure.
What tears when striae are formed?
The dermis is torn.
Where do blisters occur? What happens?
Fluid fills the space between the dermis and epidermis.
Melanin is found in which layers of the skin? Why?
Melanin is found in keratinocytes closer to the dermis, as lysosomes break down melanin in dying cells closer to the top.
Which enzyme triggers the production of melanin?
Tyrosinase
Where does carotene store to pigment the skin?
The subcutaneous tissue and the stratum corneum.
What pigment in the dermal capillaries causes fair-skinned people to have a pinkish hue?
Hemoglobin
What are the advantages of having hard keratin for hair over regular keratinocytes?
It is tougher, and cells do not slough off.
What are the 3 layers of the hair from the deepest to superficial?
Medulla, cortex, cuticle
What is differentiating about the medulla? In which hairs is it not found?
It has larger cells and has air spaces in between the cells. It is absent in fine hair (vellus hair).
What is contained within the cortex?
It is comprised of several layers of keratinocytes with pigmented melanin.
What is the organization of keratinocytes in the cuticle of a hair?
Keratinocytes are shingled together to provide strength and prevent matting.
What is replaced by what when hair turns grey/white?
Melanin is replaced with air bubbles.
What is the protrusion into a hair bulb?
A dermal papilla protrudes into each hair bulb.
What is the knot of nerve endings around the hair bulb called?
A hair follicle receptor.
What sheath of the hair follicle derives from the dermis and is the external layer of the follicle wall? What membrane is it superficial to?
The peripheral connective tissue sheathe or fibrous sheath is adjacent to the glassy membrane.
What sheath derives from the epidermis and how are its two components derived?
The epithelial root sheathe is comprised of the external root sheathe, which is a continuation of the epidermis, and the internal root sheathe, which is a derivation from the hair matrix.
What part of the hair bulb is responsible for the growth of the hair?
The hair matrix.
What cells does the hair matrix contain? Where do they come from?
The hair matrix contains stem cells that specialize into hair matrix cells. These stem cells come from a region closer to the skin surface called the hair bulge.
What is the arrector pili? What is its function?
It is a bundle of smooth muscle associated with the hair follicle. It can pull the hair upright and dimple the skin.
Where is vellus hair found?
The body hair of women and children.
Where is terminal hair found?
The hair of the eyelashes, eyebrows, and scalp.
What abnormality is characterized by high testosterone in women leading to the growth of facial hair?
Hirsutism
What general unit of measurement is used often for the growth cycle of hair?
Years.
What is the difference between general balding and male-pattern balding?
General balding is the conversion of coarse terminal hairs to vellus hairs. Male Pattern Balding is a hereditary condition that causes the hair follicles to go through very shortened hair cycles.
What is another name for the nail cuticle?
The Eponychium
What is the location of the nail matrix?
It is wrapped around the bottom of the nail plate.
What structure is the lunule distal to?
The cuticle (eponychium)
Where is the hyponychium located?
Adjacent to the most distal part of the nail bed.
What fold is located above the cuticle?
The proximal nail fold.
Why is the lunule white?
It lays over the thick part of the nail matrix, which is not heavily capillarized.
What is the more common type of sweat gland? Where are they concentrated?
The eccrine sweat glands are concentrated on the palms, forehead, and soles of the feet.
What is sweat composed of?
Mostly water, some salt, some vitamins, dermcidin, and some metabolic waste.
What is dermcidin?
It is a microbe killing peptide found in sweat.
What is the major role of sweating?
Heat distributes outside of the body to prevent overheating.
What is the less common type of sweat gland? Where are they located? Where do their ducts empty?
The Apocrine glands are located in the armpit and anogenital region. Their ducts empty into hair follicles.
What is added to apocrine secretion as opposed to eccrine secretion?
Some fatty substances and proteins.
What is the function of general apocrine glands?
Unknown, hypothesized to be linked to mating pheromones (sexual scent glands).
What are the two types of modified apocrine glands and what are their functions?
Ceruminous glands secrete earwax, and mammary glands secrete milk.
What do sebaceous glands secrete?
An oily substance called sebum.
What structure are sebaceous glands mostly attached to?
Hair follicles.
What is sebum’s purpose in hair follicles?
Lubrication and moisturization, some bactericidal purpose.
What are the 6 functions of the skin?
Protection, Temperature regulation, sensation, metabolic action, blood reservation, and excretion.
What two corpuscles are involved in sensation, an what kind of sensory input do they sense?
Tactile corpuscles (Meissner’s) record the feelings of things against the skin. Lamellar corpuscles are deeper in the subcutaneous tissue or deeper dermal tissue gives sensation deeper in the tissue.
How much of the body’s blood is held in the skin?
5%
What tissues are damaged in a first-degree burn?
Epidermal Tissue
Which layers of the skin are damaged in a second degree burn?
The epidermis and the upper region of the dermis are injured.
What characterizes a third degree burn?
A third degree burn is characterized by damage to the full extent of the epidermis and dermis.
What are the first and second main threats of burn victims?
The first is loss of fluid, and the second is infection.
What is the vernix caseosa?
The thick coating of a baby when it is born to protect its skin.
As one ages, what happens to the rate of cell replacement? What does this lead to?
The rate decreases which leads to thinner skin and more bruises and superficial injury.
What happens to collagen fibers when one ages?
They stiffen and clump.
