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Flashcards in Skin Deck (17)
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How do Langerhanns cells work?

The innate imune system causes tight junctions to relax, allowing Langerhann cells to move into the Stratum Corneum and sample and foreign antigens


What is a tight junction?

A junction that links together two adjacent cells, holding them together tightly

These can be relaxed occasionaly to allow small molecules to pass through


What is the difference between desmosomes and hemidesmosomes?

Desmosomes link cells together


Hemidesmosomes link the cell and basal lamina together (basement membrane)


Name and describe the structure of the 2 layers of the dermis

Papillary - loose connective tissue, interspread with nerve fibres


Reticular - dense connective tissue, with randomly arranged collagen fibres


What is the order of the layers of the skin? (starting from the bottom)

Stratum Basale --> Stratum Spinosum --> Stratum Granulosum --> Stratum Lucidium --> Stratum Corneum


How is the adaptive immune system activated?

Cytonkines/toxins activate dendritic cells which then bind to lymphocytes


Memory T cells are then produced to speed up the immune system next time the same infection occurs


What are the two types of sweat glands in the skin, and what are the subdivisions of one of them?

Sebaceous - Contains a lipid-rich secretion, which occurs via holocrine action. It is present in all area but not plantar and palmar surfaces


Sudoriferous - Eccrine/Apocrine


Eccrine - The most common and widely distributed. The duct opens up at the epidermal surface. Secreted via merocrine action

Apocrine - Only found in a few places such as the groin and bearded regions. The duct open into the hair folicle, and its secreted via merocrine action


What is the Integumentary System?

The skin and its accessory structures Eg, hairs, nails, glands and sensory receptors


What is interwoven between the Stratum Corneum in order to prevent water loss?

A lipid matrix


Name and explain the differences between the 3 types of exocrine glands in the skin

Merocrine - The molecule is released from its vesicle in the secretory cell --> and into the duct


Apocrine - Parts of the vesicle is pinched off (with the molecule) and enters the duct


Holocrine - The secretory cells die and shed into the duct --> thus releasing its components


From where are Antimicrobial Peptides (AMPS) formed? And which type of immune system is this part of? And why?

They are formed form Keratinocytes


Part of the Innate immune system, because no triggering event has occured to cause it (done genetically)


What is the difference between the following forms of relationship....

Commensal - Mutualistic - Pathogenic

Commensal - One of the partners benefit from the relationship, but the other suffers no harm


Mutualistic - Both partners benefit from the relationship


Pathogenic - One partner can cause a disease on the other


What are the 4 phases of hair growth?

Anagen (growth)

Catagen (transition)

Telogen (resting)

Exogen (shedding)


What is the role or keratin?

And where is most of it found?

To link keratinocytes together (via desmosomes), allowing the skin to resist and dissapate mechanical forces


How do melanosomes get into keratinocytes?

Melanosomes are creates by the golgi of melanocytes, which then leave and travel and move into keratinocytes


They then position themselves in the peri-nucleur region of the cell (blocking the nucleus from UV)


What are the 4 types of mechanoreceptors in the human hand?

Meissners Corpuscle - Strong and prolonged pressure


Merkel Cells - Sharp and small area pressure


Pacinian Corpuscle - Light but targeted pressure


Ruffini Endings - Light pressure over a wide area


Name 3 ways in which the skin can be barrier to pathogens

A physical barrier


The Stratum Corenum is slightly acidic


A wide range of potent antimicrobial peptides (AMPS) are secreted in response to invading pathogens