Week 3 Derm/ Neuro Flashcards
What characterizes acne vulgaris?
comedones papules pustules nodules - all in a sebacous distribution
Close comedone versus open comedone?
Closed = white head Open = blackhead
Mild acne?
comedones and a few papulopustules
Moderate acne?
comedones
inflammatory papules
pustules
Nodulcystic acne
comedones, inflammatory lesions, large nodules greater than 5 mm
When do you culture skin acne lesions?
To rule out gram-negative folliculitis if patient does not repsond to long term abx
Treatment of acne vulgaris?
combination of:
- topical retinoids
- antibiotic therapy
What do retinoids do?
- reduce abnormal desquamation
- comedolytic
- antinflammatory effects
- normalize hyperproliferation
- normalize hyerperkeratinization
What are the 3 layers of the skin?
Epidermis
Dermis
Hypodermis
What does the epidermis consist of ?
outer layer of skin
new cells are made in the bottom layer (basal layer)
skin cancers usually start in the epidermia after sun exposure
Dermis
Connective tissue
blood vessels
nerves
contains: hair follicles, sweat glands, sebaceous glands, nerve endings
Hypodermis
Fat tissue
connective tissue
What is connective tissue?
- clusters of epithelial tissue that:
- forms organs
- binds tissues and organs together
- supports them in their location
- storage site for excess nutrients
- Has an abundance of extracellular matrix that surrounds a few cells - unlike epithelial tissue
Tendon
4 categories of connective tissue:
Loose
dense
elastic
reticular
Loose connective tissue:
provides support and elasticity i.e. deep layers of skin blood vessels nerves body organs
Dense connective tissue:
tendons
ligaments
made of higher density fibres
provides strength
Elastic connective tissue examples (4)
Lungs
arteries
trachea
vocal cords
Interactions between chemicals may affect:
Absorption Protein binding Receptor signalling Bio transformation Excretion
Synergistic effect
Combined response is greater than the sum of each (2 + 2= 20)
Potentiation
When one substance doesn’t produce and effect unless added to another chemical (0 + 2 = 10).
Antagonism
When 2 chemicals administered together interfere with each other’s action or the action of another (4 types).
4 kinds of antagonism?
Receptor
Chemical
Dispositional
Functional antagonism
Receptor antagonist
Two chemicals bind the same receptor and produce less than the fact that if they were separate
Chemical antagonism
Also known as chemical inactivation.
A direct chemical reaction between two compounds that produces a less toxic affect. Example is chelators binding to metallic ions such as arsenic, mercury, or lead
Dispositional antagonism
Absorption, distribution, biotransformation, or excretion of a chemical is altered so that the concentration or duration of the target organ is reduced.
Functional antagonism
Two chemicals counterbalance each other by producing opposing affects on the same function often through different signalling pathways. Example is barbiturates dropping blood pressure and norepinephrine increasing blood pressure.
Cross tolerance
Structurally related chemicals cause a diminished response. Typically occurs after days or weeks of repeated exposure.
Dispositional tolerance
Amount of chemical reaching site of action decreases over time.
Leads to decreased responsiveness.
Chemical or cellular tolerance
Results from a lower availability of receptors / mediators (neurotransmitters).
What determines whether a toxic response occurs?
Chemical and physical properties of the chemical
The exposure scenario
How the chemical is metabolized by the system
The concentration of the active form at the particular site
The overall susceptibility of the biological system to injury
4 categories of duration and frequency of chemical exposure?
Acute
Subacute
Subchronic
Chronic
