Biomedicine · every answer carries the reasoning, and why each
other option fails.
555 questions
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Tap an option to see the answer, the reasoning, and why the other three fail.
Question 1 of 10
Which drug class has the side effect of nausea, drowsiness and itching but no rash?
AAntidepressantsAntidepressants typically cause dry mouth, weight change, and sexual dysfunction; pruritus is not a characteristic effect.
BBenzodiazepinesBenzodiazepines cause sedation, ataxia, and dependence, without the nausea-plus-itching pattern.
CNarcotics
DHMG-CoAHMG-CoA reductase inhibitors (statins) characteristically cause myalgia and elevated liver enzymes, unrelated to this triad.
Why C is correct
Narcotics (opioids) act on mu receptors: analgesia plus stimulation of the medullary chemoreceptor trigger zone (nausea), central depression (drowsiness), and non-immune mast cell histamine release. Because the histamine release is pharmacologic rather than allergic, patients itch without developing a rash. Nausea, drowsiness, and rash-free pruritus together point to the opioid class.
Question 2 of 10
What action should an acupuncturist take if a needle breaks off below the skin while treating the patient?
ADo not inform the patient because he or she may pass outWithholding the information breaches the duty to inform, and continued movement can displace the fragment.
BConsult a physician for surgical removal of the broken needle
CTell the patient to calm down and call another more experienced acupuncturistCalling a more experienced acupuncturist changes nothing, since removal of a subcutaneous fragment is a surgical procedure.
DUse aseptic technique to cut open the skin and try to withdraw the broken needleIncising the skin is surgery and lies outside the acupuncturist's scope of practice.
Why B is correct
When a needle breaks below the skin surface and the fragment cannot be seen or safely grasped, the standard response is to mark the site, inform the patient, keep the part still, and refer to a physician for surgical removal under imaging. Cutting down on the fragment falls outside the acupuncturist's scope, and blind probing drives the fragment deeper.
Question 3 of 10
Standing on one’s heels is the action of which muscle or muscle group?
AQuadricepsThe quadriceps extends the knee under femoral nerve supply from L2 to L4 and is tested by rising from a squat.
BHamstringsThe hamstrings flex the knee and extend the hip without acting at the ankle.
CGastrocnemiusGastrocnemius plantarflexes and is tested by toe walking at S1 and S2.
DTibialis anterior
Why D is correct
Standing on the heels lifts the forefoot and holds the ankle in dorsiflexion, driven by the tibialis anterior, which arises from the lateral surface of the tibia, inserts on the medial cuneiform and first metatarsal base, and is supplied by the deep peroneal nerve from L4 and L5. Heel walking therefore tests those roots and that nerve, and inability to heel walk indicates dorsiflexion weakness, as in L5 radiculopathy or peroneal palsy with foot drop.
Question 4 of 10
A test of position sense is positive when the patient has difficulty standing stably with feet together and eyes closed. This is also known as a positive
AKernig’s signKernig sign is painful limitation of knee extension with the hip flexed, indicating meningeal irritation.
BMurphy’s signMurphy sign is arrest of inspiration on right upper quadrant pressure, indicating acute cholecystitis.
CRovsing’s signRovsing sign is right lower quadrant pain on pressing the left lower quadrant, indicating appendicitis.
DRomberg’s sign
Why D is correct
The Romberg test examines the proprioceptive pathway: the patient stands with feet together, steady with eyes open, and sways or falls once the eyes close. Closing the eyes removes visual compensation and exposes a deficit in the posterior columns or proprioceptive input, as in subacute combined degeneration or tabes dorsalis.
Question 5 of 10
Patients with chronic obstructive pulmonary disease (COPD) may develop respiratory acidosis, which, on the blood chemistry screen, is revealed by
AHypercapnia
BHyperkalemiaHyperkalemia can accompany acidosis as potassium shifts out of cells, but it is a secondary finding, not the defining marker of respiratory acidosis.
CHypernatremiaHypernatremia reflects water and sodium balance, unrelated to ventilation.
DHyperchloremiaHyperchloremia occurs in normal anion gap metabolic acidosis; chloride tends to fall, not rise, during compensation for respiratory acidosis.
Why A is correct
In COPD, alveolar hypoventilation impairs CO2 elimination, raising PaCO2 (hypercapnia). This is the direct laboratory marker of respiratory acidosis: pH falls as PaCO2 rises, with compensatory renal retention of HCO3- over time. PaCO2 is the primary variable in a respiratory acid-base disturbance.
Question 6 of 10
Both sex hormones and adrenal cortex hormones are steroid hormones. Their mechanism of action is
ATo activate the genes in the nucleus
BTo activate the second messenger in the cytoplasmActivation of cytoplasmic second messengers such as cAMP belongs to water-soluble hormones, which relay their signal through membrane receptors because they cannot cross the bilayer.
CTo bind to the surface receptors on the plasma membraneBinding plasma membrane surface receptors is also the route of water-soluble hormones; steroids are lipid-soluble and pass through the membrane without them.
DTo bind to the surface receptors on the nuclear membraneSteroid receptors sit in the cytoplasm or nucleus and act directly on DNA, and no nuclear membrane surface receptor pathway exists for them.
Why A is correct
Steroid hormones are lipid-soluble and diffuse straight through the phospholipid bilayer into the cell, where they bind cytoplasmic or nuclear receptors; the hormone-receptor complex then binds DNA and regulates gene transcription, producing new protein synthesis. Water-soluble hormones such as peptides and catecholamines cannot cross the membrane and work through surface receptors and second messengers, so the deciding feature is membrane permeability.
Question 7 of 10
A chronic, recurring skin disease that causes one or more raised, red patches with silvery scales and a distinct border between the patch and normal skin, and is commonly found on the scalp, elbows, knees, and back is most likely to be
AEczemaEczema lesions have indistinct borders, are dominated by itching and oozing or lichenification, favor flexor surfaces, and lack thick silvery scales.
BPsoriasis
CContact dermatitisContact dermatitis has a clear history of exposure, with lesions confined to the area of contact and shaped by the contours of the contactant.
DSeborrheic dermatitisSeborrheic dermatitis produces greasy yellow scales and favors sebum-rich areas such as the scalp, eyebrows, and nasolabial folds, unlike the dry silvery scales of psoriasis.
Why B is correct
Every diagnostic feature of psoriasis appears in the stem: a chronic, relapsing course, raised red plaques covered with silvery scales, sharply demarcated borders between the lesion and normal skin, and a predilection for the scalp, elbows, knees, and back. The underlying pathology is excessive proliferation of epidermal keratinocytes. The combination of silvery scales, sharply demarcated borders, and extensor surface distribution distinguishes psoriasis from the various forms of eczema and dermatitis.
Question 8 of 10
What is the largest, thinnest, and heaviest organ in the body?
ASkin
BBrainThe brain weighs about 1.4 kilograms, far less than the skin, and is not the largest organ.
CLiverThe liver weighs about 1.5 kilograms and is the largest solid internal organ, still short of the skin overall.
DSpleenThe spleen weighs only about 150 grams.
Why A is correct
The skin is the largest and heaviest organ of the body. In an adult it covers roughly 1.5 to 2 square meters and accounts for about 15 percent of body weight, while its thickness is only about 0.5 to 4 millimeters, so it is simultaneously the largest, the thinnest as a sheet, and the heaviest. It serves as barrier, thermoregulator, sensory surface, and site of vitamin D synthesis.
Question 9 of 10
Nyctalopia (night blindness) may be caused by a deficiency of
AVitamin A
BVitamin CVitamin C deficiency causes scurvy with gingival bleeding and poor wound healing, unrelated to dim-light vision.
CVitamin EVitamin E deficiency is rare and presents chiefly with hemolysis and neuropathy.
DVitamin KVitamin K deficiency causes bleeding from impaired coagulation and has no visual effect.
Why A is correct
Night blindness results from vitamin A deficiency. Rhodopsin, the photopigment of retinal rod cells, is formed from opsin combined with 11-cis-retinal, a vitamin A derivative, and serves vision in dim light. Deficiency limits rhodopsin synthesis and impairs dark adaptation, with nyctalopia as the earliest sign; progression brings xerophthalmia and keratomalacia.
Question 10 of 10
A college student comes to the campus clinic, complaining of painful urination with pus–containing urethral discharge. He mentions a weekend fling of his promiscuous sexual activity not long ago. Upon examination, there is no skin eruption discovered around the genital area. But numerous Gram–negative diplococci are observed under the light microscope from his urethral discharge sample. What is the most likely medical diagnosis?
ASyphilisPrimary syphilis presents as a painless indurated chancre caused by a spirochete seen on darkfield microscopy rather than gram-negative diplococci.
BGonorrhea
CChlamydiaChlamydia is an intracellular organism invisible on routine Gram stain, and its discharge is typically thin and mucoid.
DGenital herpesGenital herpes presents with clustered painful vesicles and ulcers, and this patient has no skin lesions; a virus cannot be demonstrated by Gram stain.
Why B is correct
Painful urination with purulent urethral discharge, a history of recent high-risk sexual activity, and numerous gram-negative diplococci on smear of the discharge give the classic morphologic evidence of Neisseria gonorrhoeae, establishing gonorrhea. Absence of genital skin lesions fits as well, since neither a chancre nor herpetic vesicles are present.
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