Skin Disorders Flashcards
(59 cards)
key functions of stratum granulosum
o 3-5 rows of flattened keratinocytes starting apoptosis, terminal differentiation, organelles degenerate, keratohyalin protein and waterproof glycolipid present
How does imiquimod work
an immune-modulator
Releases cytokines which destroy skin cancer cells by modifying the immune response to stimulate apoptosis.
It may also increase lymphocytes, dendritic cells, and macrophages to the tumour lesion.
Describe psoriasis
The undifferentiated cells come to the surface as the stratum granulosum is reduced or absent.
This forms skin-scales as the keratinocytes do not stack, adhere, or secrete glycolipids.
Blood vessels are also closer to the surface layer of the skin, and so the skin has a red tinge.
What 5 factors influence peripheral tolerance
- Negative Selection in the Peripheral Immune System
- Lack of Co-stimulation
- Failure to Encounter Self Antigens
- Receipt of Death Signals
- Control by Regulatory T Cells
What are privileged sites in the body?
Tissues hidden behind anatomical barriers so T cells can’t reach them i.e.
• interior of the eye
• testes
• the brain
Key functions of stratum lucidum
Transparent layer present on palms and soles
what do the epitopes recognised by the t-cell receptor contain
- small ‘self’ proteins
- major histocompatibility complex
What are the Bcl-2 family proteins
interact with each other to determine whether a cell undergoes apoptosis or stays alive. Some Bcl-2 family proteins promote survival, and block apoptosis. Others are ‘pro-death’, and trigger apoptosis
What happens to the T cells whose receptors bind to self epitopes so tightly that they could attack the cell displaying them
they are deleted by apoptosis
What is psoralen used for
sensitises the skin, preventing side effects such as burns from the UV waves. This allows a higher, more potent dose of UV to be used.
Define proto-oncogenes
Genes which code for proteins involved in the regulation of cell growth, either coding for cell division or death.
Define psoriasis
excessive proliferation of basal cells
How do metastasis occur
cancer cells that break off from the main tumour travel through the bloodstream.
Once in the blood, they can go to any part of the body. Many of these cells die, but some may settle in a new area, start to grow, and form new tumours.
Give 2 effects of anti-microbial peptides
o Bind to bacterial cell membranes and break them down o Effect the electrostatic balance o Effect chemotactic gradient o Enhance nucleic acid recognition o Neutralise PAMPS
key functions of stratum corneum
Keratinised squamous layer, dead cells, densely packed, structural support, no nucleus, these cells form dust- filled with keratin
define keratinocyte
cell that stores and produces keratin protein
How can PUVA improve symptoms of psoriasis
- increases keratinocyte anti-inflammatory cytokine (IL-10) to supress IFN-Y from CD4 cells.
- Increases prostaglandins which have an immunosuppressive effect in the skin causing the depletion of Langerhans and dendritic cells
- Suppresses cytokine-induced upregulation of cell-surface adhesion molecules.
- Modulates keratinocyte cytokine and growth factor receptor expression and function.
- Induces apoptosis of T cells.
Give 2 side effects of immunosuppressants
- Increased susceptibility to infection
- Kidney problems
- High Blood Pressure
- GI tract problems
- Reduced production of red and white blood cells
What is imiquimod
Imiquimod cream is a cancer treatment and is also known by its brand name, Aldara
Where do t cells develop
the thymus
Define an antimicrobial
Any agent which kills microorganisms or stops their growth
If a T cell survives negative selection, what happens
They migrate throughout the immune system
Define apoptosis
cell death that prevents immune activation
What are death receptor proteins
Found on the surface of the cell.
When they are bound by certain cytokines they cause changes in the cell that can lead to cell death.
