NEET MDS Shorts
13418
Microbiology
A classic example of delayed type IV hypersensitivity is the Mantoux tuberculin test in which skin induration indicates exposure to tuberculosis. This reaction is called "delayed hypersensitivity" because it is mediated by sensitized CD4+ T lymphocytes which process antigens in association with class II HLA molecules and release lymphokines. Hypersensitivity reactions with this mode of action include: Granulomatous diseases (mycobacteria, fungi) Tuberculin skin reactions Transplant rejection Contact dermatitis Cytotoxic T lymphocyte (CTL) mediated responses: CD8+ T cells are generated and lyse specific cells. Class I HLA molecules play a role. Reactions with this mode include: Neoplastic cell lysis Transplant rejection Virus-infected cell lysis
The lymphokines promote a reaction (especially mediated through macrophages) beginning in hours but reaching a peak in 2 to 3 days.
74467
General Medicine
The heat-labile toxin (LT) of ETEC is similar to cholera toxin and acts by increasing intracellular cAMP levels in enterocytes, leading to excessive chloride and fluid secretion into the lumen of the gut, resulting in diarrhea.
16506
General MicrobiologyEndotoxins are components of the outer membrane of Gram-negative bacteria and are released when the bacteria die or divide. This structural characteristic differentiates them from exotoxins, which are secreted by living bacteria.
66412
PeriodonticsThere is no definite treatment for herpetic gingivostomatitis.
19464
PedodonticsThe OHI-S index has a high degree of correlation with the PI of Russell.
65757
General Medicine
While psychological stress, NSAIDs, and alcohol can contribute to the development of acute peptic ulcers, Helicobacter pylori is the most common causative agent, particularly in hospitalized patients who may experience increased stress and receive medications that can exacerbate the condition.
71750
Oral PathologyLichenoid reactions are mainly due to the intake of certain drugs.
46182
Oral SurgeryIn the extraoral technique for mandibular nerve block, the needle is inserted into the pterygomandibular space anterior to the lateral pterygoid plate and directed anteriorly to avoid damaging the maxillary artery and other important structures located posteriorly. The goal is to place the anesthetic solution around the mandibular nerve before it enters the pterygopalatine fossa.
60930
PhysiologyADH acts on the distal tubules and collecting ducts of the kidney to increase the permeability of the tubular epithelium to water. This results in the reabsorption of water and the concentration of urine, thereby reducing urine volume and increasing blood pressure.
59108
Physiology
Answer: 1) Acetylcholine
Explanation: The pupillary sphincter muscle is innervated by the parasympathetic nervous system, which uses acetylcholine as its primary neurotransmitter. Contraction of this muscle leads to pupil constriction, or miosis, which occurs in low-light conditions or when focusing on near objects.