Dermatology intro stupid stuff Flashcards
What are the functions/properties of the skin (13)
- barrier
- protection
- motion an shape
- adnexa production
- temperature regulation
- storage
- indicator of health etc
- immunoregulation
- pigmentation
- antimicrobial action
- sensory perception
- secretion and excretion
- vit D production
What are the functions/properties of the skin (13)
- barrier
- protection
- motion an shape
- adnexa production
- temperature regulation
- storage
- indicator of health etc
- immunoregulation
- pigmentation
- antimicrobial action
- sensory perception
- secretion and excretion
- vit D production
What is mechanobullous disease in belgian foals?
mutated protein in basement membrane leads to separation of epidermis and dermis
How does bullois pemphigoid occur?
basement membrane molecules are targeted by auto-antibodies
What is targeted in pemphigus foliaceous and vulgaris?
desmogleins
What forms 85% of the epidermal cells?
keratinocytes
What is the basal cell layer?
A single row of cells resting on the basement membrane
What is the basement membrane zone?
a critical junction between the cells of epidermis and underlying dermis
What are the layers of the skin?
basal layer
spinous layer
granular layer
stratum cornum (horny layer)
Why is the ggranular layer called the granular layer?
because the keratinocytes have abundant deeply basophilic keratohyalin granules.
Where does the formation of the cornified cell envelope start?
in the granular layer
Where does the formation of the cornified cell envelope start?
in the granular layer
what is the stratum corneum made up of?
terminally differentiated keratinocytes (corneocytes) that are anucleate, flat, keratin-rich, water depleted and surrounded by a complex lipid matrix.
What are the functions of the stratum corneum?
- mechanical protection
- barrier to water loss
- prevents entrance of foreign molecules from the environment
What are the 4 distinct cellular events in cornification?
- keratinization
- keratohyalin synthesis
- cornified cell envelope formation
- lipid secretion
What are the 4 distinct cellular events in cornification?
- keratinization
- keratohyalin synthesis
- cornified cell envelope formation
- lipid secretion
What is cell turnover time from basal layer to granular layer?
21d (less in seborrheic cocker spaniels and irish setters)
What do melanocytes do?
Make melanin pigments, store in melanosomes and transfer the melanosomes to keratinocytes.
What are Langerhan cells? What do they do?
- dendritic antigen-processing/presenting cells of epidermis. process and present antigens to lymphocytes
What do Merkel cells do?
Function as mechanoreceptors
What are histiocytomas?
benign neoplasms of langerhans cells
What is the dermis made up of?
CT elements, nerve, vessels, epidermally derived appendages, fibrolasts, macrophages, mast cells, transient immune cells
What is the role of the dermis?
- pprovides pliability, elasticity and tensile strength of skin
- protects body from mechanical injury
- binds water
- aids in thermal regulation
- contains receptors for sensory stimuli
- coordinates and supports epidermis
- interacts in repairing and remodelling wounded skin
What makes up the ground substance in the dermis?
collgenous and elastic fibrous tissue and GAGs, glycoproteins, proteoglycans
What makes up the ground substance in the dermis?
collgenous and elastic fibrous tissue and GAGs, glycoproteins, proteoglycans
What are the roles of the subcutis?
- energy reserve
- protective padding
- insulator
What are the phases of hair growth?
- anagen
- catagen
- telogen
What factors influence hair growth?
- breed
- body region
- photoperiod
- various physiological/hormonal factors
What are the roles of sebum?
- keeps skin soft and pliable
- allows stratum corneum to retain moisture
- gives hair sheen
- some antimicrobial properties
What are the roles of sweat?
- pheromone
- antimicrobial properties
- thermoregulation–esp horse)
What are the roles of the skin microcirculation?
1.
What are the roles of the skin microcirculation?
- nutrition and oxygen delivery
- temperature regulation
- blood pressure regulation
- wound repair
- immunological events
what are the roles of the lymph channels of the skin?
- regulate pressure of interstitial fluid
2. clear the tissues of cells, proteins, lipids, bacteria and degraded substances
What are two examples of disorders of abnormal egress of fluid from cutaneous vasculature?
- urticaria
2. angioedema
What are two examples of ischemic dermatopathy?
- dermatomyositis
2. vaccine-induced dermatopathy
How may pruritus manifest in cats?
excessive grooming
What is the factor with the greatest influence on cutaneous flora?
hydratio nof the stratum corneum–increased moisture supports microbial flora
What are ways the stratum corneum defends against damage?
- tightly packed cells
- epidermial lipids, sebum, sweat
- inorganic salts and proteins that inhibits microbial growth
- free fatty acids (antimicrobial)
- IgA (sweat glands)
How do resident cutaneous microflora contribute to skin defense?
inhibit invading microbes
How do resident cutaneous microflora contribute to skin defense?
inhibit invading microbes
What are nomads of the skin?
able to colonize and reproduce for short periods of time and take advantage of changes in the skin’s environment
What is the primary cutaneous pathogen in dogs and cats?
Staph pseudintermedius
is a resident in anal, nasal and mucocutaneous regions. can spread to skin by grooming. can be commonly found on skin of normal cats and dogs
What is mlassezia pachydermatis?
lipid-dependent yeast found on normal and abnormal skin and ear canals. has a sympiotic relationship with staphylococci
What yeast is a common cuase of dermatitis and otitis in dogs?
Malassezia
How does generalized demodicosis occur?
from profound overgrowth of demodex mites in the skin. can be very severe and potentially fatal
The ear canal is lined with what kinds of glands?
sebaceous and ceruminous (cerumen=earwax) glands
What are 4 signs of external ear disease?
- head shaking
- scatching
- otic pain
- otic discharge
What are clinical signs associated with middle ear disease?
- greater otic pain than external ear dz
- increased head-shaking
- lethargy
- inappetance
- pain on opening of mouth
- facial nerve paresis or parlysis, or horner’s syndrome may be present
What are clinical signs associated with middle ear disease?
- greater otic pain than external ear dz
- increased head-shaking
- lethargy
- inappetance
- pain on opening of mouth
- facial nerve paresis or parlysis, or horner’s syndrome may be present
- peripheral vestibular symptoms
