Questões Citologia E Histologia - Tema: Microscopia E Processamento De Amostras - Prof.: Thiago Manchester

A parafina é uma resina muito barata e de consistência suficientemente rígida para que ocorra a microtomia do tecido ou célula.
Gelatina = mole
formalina = formol, um fixador.
latexina = não existe, é só pra confundir

Fixação é o processo de conservação de células e tecidos que evita a autólise e a degeneração celular. Durante a fixação, os tecidos são tratados com substâncias químicas, como formalina, para estabilizar as estruturas celulares e impedir a decomposição. Isso permite que os tecidos sejam preservados para análise posterior, como em estudos histológicos ou patológicos. A fixação é uma etapa crucial no processo de preparação de amostras para análise microscópica.

The correct answer is "Condensador, oculares e objetivas." This option contains only the components of the microscope lens system. The condenser is responsible for focusing the light onto the specimen, the oculars are the eyepieces through which the viewer observes the specimen, and the objectives are the lenses closest to the specimen that magnify the image.

The given answer is incorrect because it states that the first step in obtaining histological sections is to perform microtomy on the collected material, stimulating autolysis and preserving the chemical composition of the tissue. However, microtomy is the process of cutting thin sections of tissue for microscopic examination, not the first step in obtaining histological sections. The correct first step is to fix the tissue in a suitable fixative to preserve its structure and prevent autolysis.

The correct answer states that fixation is the first step in obtaining a permanent preparation. Fixatives are used to prevent autolysis, inhibit bacterial growth, enhance the affinity of cellular structures for dyes used in optical microscopy, increase contrast in electron microscopy, and harden the cells to withstand the technique's steps. This explanation highlights the importance of fixation in preserving cellular structures and allowing for better visualization and analysis under the microscope.

Para retirar a água do material é necessário imergir em concentrações crescentes de etanol, como por exemplo:

30% > 50% > 70% > 90% > 100%.

The second student is unfamiliar with the use of the micrometer screw in handling the microscope. This screw is used to adjust the focus and clarity of the image being observed. Since the second student reported that the image was not clear, it suggests that they did not know how to properly use the micrometer screw to improve the focus.

The correct sequence for the preparation of histological slides is as follows: first, the material is fixed; then, it undergoes dehydration and clearing; next, it is embedded; after that, microtomy is performed to obtain thin sections; and finally, the sections are stained and mounted. Therefore, the correct answer is 1, 4, 3, 5, 2.

The correct answer is II and III. The first statement is incorrect because a good fixative is not the one that promotes maximum tissue retraction. The second statement is correct as the objective of fixation is to provide resistance to the tissue so that it can withstand subsequent techniques. The third statement is also correct as the objective of fixation is to prevent tissue degradation mediated by lysosomal enzymes. The fourth statement is incorrect because the volume of the fixative does not need to be 2 times larger than the tissue to be fixed.

The condenser in a common optical microscope is responsible for concentrating the light rays onto the sample being viewed. This helps to improve the illumination and visibility of the sample, allowing for a clearer and more detailed image to be observed.

The correct answer is "a distância mínima entre dois pontos, que permite sua distinção." This is because the resolution limit in light microscopy refers to the minimum distance between two points that can be distinguished as separate entities. When the distance between two points is smaller than the resolution limit, they will appear as a single blurred point. Therefore, the resolution limit determines the level of detail that can be observed in a sample under a light microscope.

DNA tem característica ácida e é alvo de um corante básico como a hematoxilina.

The correct answer is "microscópio eletrônico de varredura" because it describes a type of microscope where the electrons that collide with the specimen's external surface are captured by detectors and their image appears on a monitor. This type of microscope has a resolution power of 0.02 µm.

The correct answer is "as afirmativas I, II e III, somente." This means that only statements I, II, and III are correct. Statement I states that the main objective of the optical microscope is to create an enlarged virtual image of the real object through the ocular lenses, which is correct. Statement II explains that the optical microscope has two sets of lenses, objectives, and oculars, which is also correct. Statement III mentions that the condenser lens focuses the light beams on the sample, and the diaphragm regulates the amount of light entering the condenser, which is also correct. Therefore, the correct answer is that only statements I, II, and III are correct.