Tutor profile: Rodolfo B.

What is the first-line treatment for psoriasis?

First of all, you must define the type of psoriasis to treat, as there are several types: limited, intertriginous, scalp, nail, guttate, pustular and erythrodermic. Limited disease is usually trated topically with corticosteroids and emollients, having vitamin D analogs and topical retinoids as second line treatment. Intertriginous disease is usually treated with low potency (group 6, 7) topical corticosteroids due to risk of cutaneous atrophy, but higher potency ones can be used for short term periods of time. Vitamin D analogs and calcineurin inhibitors can be used as first line therapy as well, topically. In the case of scalp psoriasis, a combination of topical corticosteroids and vitamin D analogs is used, but if risking adherance to treatment, monotherapy should be used instead. When treating nail psoriasis, you must first define the severity. If mild, you may use topical corticosteroids, topical vitamin D analogs or a combination of these. If moderate-severe, biologic agents such as TNF-alpha inhibitors are used. With regards to guttate psoriasis, there are several first line therapies, which include UV phototheraphy (PUVA, UVB, etc), topical corticosteroids and topical vitamin D analogs. Pustular disease is treated with oral retinoids or methotrexate when non-disabling, but must make use of agents such as cyclosporine or infliximab is disabling, severe disease.

What types of neuronal electrical signals are there and how would you describe each?

1. Receptor potentials: Upon the stimulation of external factors (light, sound, heat), sensory neurons are activated. An example are Pacini corpuscles responding to touch. 2. Synaptic potentials: Transmission of electrical signals between neurons, when neurotransmitters released by an axon in a synapse, activate the downstream neuron. 3. Action potentials: The electrical signal generated by a change in transmembrane potential within a neuron, occurring in an all or nothing manner.

What muscles compose the rotator cuff in the shoulder and what are their origins and insertions?

Supraspinatus muscle - Origin: supraspinous fossa above the scapular spine, Insertion: greater tubercle of the superior-lateral humeral head. Before its insertion, it crosses the subacromial bursa. Infraspinatus - Origin: infraspinatus fossa (posterior scapula), Insertion: greater tubercle of the lateral aspect of the humeral head (posterior to the supraspinatus). Teres minor - Origin: inferior-posterior scapula, Insertion: greater tubercle of the lateral aspect of the humeral head (after adjoining the infraspinatus). Subscapularis - Origin: anterior scapula, below the coracoid, Insertion: Lesser tubercle of the anterior aspect of the humeral head.