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51 Cards in this Set

  • Front
  • Back
CT layer under the epidermis
Dermis provides ________ and ___________ to the epidermis
nutrients, gas exchange
A desmosome is also known as a...
macula adherens
A desmosome is...
(also known as macula adherens) is a cell structure specialized for cell-to-cell adhesion. Desmosomes, a type of junctional complex, are localized spot-like adhesions randomly arranged on the lateral sides of plasma membranes. They are molecular complexes of cell adhesion proteins and linking proteins that attach the cell surface adhesion proteins to intracellular keratin cytoskeletal filaments.
Tight juntions are also known as...
zonula occludens
Tight junctions are...
are the closely associated areas of two cells whose membranes join together forming a virtual impermeable barrier to fluid. It is a type of junctional complex. They perform three vital functions:
They hold cells together
They block the movement of integral membrane proteins between the apical and basolateral surfaces of the cell.
Thus the specialized functions of each surface, for example
receptor-mediated endocytosis at the apical surface
exocytosis at the basolateral surface
can be preserved.
They prevent the passage of molecules and ions through the space between cells. So materials must actually enter the cells (by diffusion or active transport) in order to pass through the tissue. This pathway provides control over what substances are allowed through. (Tight junctions play this role in maintaining the blood-brain barrier.)
Dermis is derived from...
Skin is classified as thick or thin depending on the thickness of the...
Accessory structures associated with the skin are called...
Skin appendages, and include hair, nails, and glands.
Does thick skin usually have hair associated with it?
Does thin skin usually have hair associated with it?
This cell is generated in the deepest layer of the epidermis and matures as it move toward the surface of the skin.
The cycle of a skin cell
4 weeks
The five epidermal layers (from deep to superficial)
1. Stratum germinativum
2. Stratum spinosum
3. Stratum granulosum
4. Stratum lucidum
5. Stratum corneum
Describe the stratum germinativum
a single layer of mitotically active columnar cells that give rise to new keratinocytes. Has a basal layer of cells laying on the basal lamina, that separates the epithelium from the dermis. Connected to CT. As name implies, is the germ area of where these cells arise. These are the cells that divide mitotically. One or 2 cell layers at most. One of the daughter cells will form this new skin cell, whereas the other daughter cell will remain and stay at that basal level as a stem cell.
Stratum germinativum is how many layers thick?
One or two at the most
Cell type of stratum germinativum
Mitotically active columnar cells
Describe stratum spinosum
several cell layers thick, these cells continue to undergo mitosis, is the largest area, cells are joined with bridge-like processes giving them a “prickle-cell” appearance. These cells are also mitotically active. The stratum germinativum and the spinosum together are sometimes called the malphighian layer). This area is the largest area. These cells continue to divide and then form the next layer, the granulosum.
The stratum germinativum and the spinosum together are sometimes called the..
malphighian layer
Melanin from melanocytes gets transferred to which layers of the epidermis?
Germinativum and spinosum
Describe stratum granulosum
a few (3-4) cells thick, consists of flattened cells containing keratohyalin granules –the protein component of soft keratin. Cells begin to differentiate (morphologically changing, chemically changing), and are now synthesizing high amounts of keratin. Keratin is a protein that has structure similar to collagen, high in certain amino acids that make it very rigid.
The protein component of soft keratin.
keratohyalin granules
The layer of epidermis where keratin begins to be produced
Stratum granulosum
Keratin has a structure very similar to...
This layer is only present in thick skin...
Stratum lucidum
Describe stratum lucidum
a thin transparent layer seen distinctly only in thick skin. An area whereby the keratin is changing its characteristic to become softer. After protein is made, there are some sugars added to it and it gets softer. Consists of dead cells filled with densely packed keratin and a transformation product of keratohyalin, called eleidin. Is a softer region. As it becomes softer, it becomes translucent. At this point the cells are dying. They have made so much keratin, the cells start to die. Their membranes start to dissappear, their organnelles dissapear, leaving us only with layers of keratin and dead and dying cells (corneum).
a transformation product of keratohyalin is
Describe stratum corneum
compact layers of dead cells called squames, filled with soft keratin
Compact layer of dead cells in epidermis is called...
Squames are filled with...
soft keratin
Corneum is bigger in which skin type?
Basal cell carcinoma originates from where?
basal layer, the germinativum
Basal cell carcinoma cause
is usually because it has not been protected by the melanosomes that come from the melanocytes, so it is usually UV radiation that causes a mutation of the DNA in these cells, and they now become a tumor –most common skin cancer we will see in the clinic – usually fixed easily with surgery – because basal cells are highly mitotic, they undergo mitosis rapidly, often invade basal lamina they sit on…most cases can be removed rapidly with surgery – particularly if they have not breached the basal lamina and entered the dermis
These cells protect us from UV radiation
melanosomes that come from the melanocytes
This is the 2nd most common type of cancer
squamous cell carcinoma
Squamous cell carcinoma originates from...
Stratum lucidum
Melanocytes were dervied from...
Neural crest cells
This is a much more serious cancer of the integument
Melanoma -- get treatment right away
The stratum spinosum contains intercellular...
Stratum spinosum gets its name from...
the spines on the cells, so as those cells differentiate into that spinosal layer, the outside of the cells have little spines that are associated with them. These spines are essential/y keratin, in this case they are termed tonofilaments, because this keratin attaches to the desmosomes, the junctions between these cells, and so as these cells are next to each other, and desmosomes are formed, these tonofilaments attach to the desmosomes, so we see these intercellular bridges that look like spines
Tonofilaments are...
the "spines" of keratin, which attaches to the desmosomes, the juntions between cells
Psoriasis is...
Psoriasis is a skin condition observed when cell mitosis occurs in all three deeper layers of the skin. Keratinocytes reach the surface of the skin in less than 1 week so they don’t have time to mature. This results in dark red lesions of the skin and silvery-white scales
Psoriasis is usually found on...
Extensor sides
With psoriasis, the stratum corneum contains...
With psoriasis, this layer of skin is missing...
The stratum granulosum
The red skin associated with psoriasis is because...
The deep red color of the lesion is due to the fact that the epidermis overlying the tall dermal papillae is relatively thin.
What is another main characteristic of psoriasis?
Another main characteristic of psoriasis is accompanying inflammation. The connective tissue in the affected dermal papillae is edematous, containing fluid and exudate from damaged and leaking venules and capillaries.
With psoriasis, skin reaches the surface how much faster?
4 times faster
Common places to see psoriasis
elbow, hands, plantar side of feet
This area is where melanin is mostly incorporated into the epidermis
Spinosum layer (the thickest area)
-Melanin is mostly incorporated in spinosum layer (thickest area – here the processes of the melanocytes expell their melanosomes, and the spinosal cells will incorporate those melanosomes (or organelles) into their cytoplasm. So when we increase the speed at which they mitose, they don’t hve the time to incorporate the melanin granules.