Podcast
Questions and Answers
What is the main advantage of electron microscopy over light microscopy?
What is the main advantage of electron microscopy over light microscopy?
- Less expensive equipment
- Greater ease of sample preparation
- Ability to produce color images
- Higher resolution due to electrons being smaller than visible light wavelength (correct)
Which method uses a small point of high-intensity light and a pinhole aperture for better resolution and focus?
Which method uses a small point of high-intensity light and a pinhole aperture for better resolution and focus?
- Phase-contrast microscopy
- Confocal microscopy (correct)
- Fluorescence microscopy
- Transmission electron microscopy
What is the main difference between transmission electron microscopy (TEM) and scanning electron microscopy (SEM)?
What is the main difference between transmission electron microscopy (TEM) and scanning electron microscopy (SEM)?
- TEM forms images by passing electrons through the specimen while SEM scans the specimen surface with the electron beam (correct)
- SEM uses visible light for imaging while TEM uses electrons
- TEM can only show surface views while SEM can analyze internal surfaces after sectioning
- SEM provides higher resolution than TEM due to a different electron beam configuration
What feature of confocal microscopy helps in achieving better resolution and focus?
What feature of confocal microscopy helps in achieving better resolution and focus?
In phase-contrast microscopy, what type of objects can be imaged effectively?
In phase-contrast microscopy, what type of objects can be imaged effectively?
What is the resolving power of a conventional light microscope?
What is the resolving power of a conventional light microscope?
What type of microscopy involves staining tissues with a fluorescent dye and irradiating them with UV light?
What type of microscopy involves staining tissues with a fluorescent dye and irradiating them with UV light?
Which microscopy technique is widely used to observe live cells grown in tissue culture?
Which microscopy technique is widely used to observe live cells grown in tissue culture?
Which type of microscope utilizes bright-field illumination?
Which type of microscope utilizes bright-field illumination?
What is the function of the condenser in a microscope optical system?
What is the function of the condenser in a microscope optical system?
What is the ability of a microscope to discriminate two closely spaced points called?
What is the ability of a microscope to discriminate two closely spaced points called?
Which type of microscopy allows the visualization of cell boundaries, nuclei, and cytoplasmic structures based on their different refractive indices?
Which type of microscopy allows the visualization of cell boundaries, nuclei, and cytoplasmic structures based on their different refractive indices?
Which type of microscopy uses laser light to create high-resolution images?
Which type of microscopy uses laser light to create high-resolution images?
What is the primary tool used in the study of histology?
What is the primary tool used in the study of histology?
At what magnification level do objective lenses typically allow observation of a large area (field) of tissue?
At what magnification level do objective lenses typically allow observation of a large area (field) of tissue?
Which microscopy technique requires fixation and staining to observe cellular details?
Which microscopy technique requires fixation and staining to observe cellular details?
Among the different types of microscopes, which one provides complementary information at different levels of resolution and magnification?
Among the different types of microscopes, which one provides complementary information at different levels of resolution and magnification?
Study Notes
Histology Terminology
- Lamina: a plate or layer
- Lobule: a small lobe
- Locule: a small place or compartment
- Lumen: light or space enclosed by a tubular or vesicular structure
- Lysis: dissolution or breakdown
- Matrix: a supporting structure or framework
- Medulla: the inner portion of an organ, in contrast to the cortex
- Squamous: flat or scale-like
- Stratum: a layer or level
- Stroma: the internal supporting framework of a tissue or organ
- Tunica: a sheath or covering layer
- Zona: a girdle or zone
Microscopy
- Primary tool used in the study of histology
- Produces an enlarged image and enhances contrast for resolving details
Types of Microscopes
- Light microscope: uses bright-field illumination, with a resolving power of about 0.2μm
- Electron microscope: uses a beam of electrons, allowing a 1000-fold increase in resolution
- Phase-contrast microscopy: uses a lens system to produce visible images from transparent objects
- Confocal microscopy: uses a small point of high-intensity light (laser) and a pinhole aperture to obtain better resolution and focus
Electron Microscopy
- Transmission electron microscope (TEM): configured like an upside-down light microscope, with electrons passing through a hole in the anode and forming a beam
- Electrons reaching the objective lens form an image that is then magnified and projected on a fluorescent screen or CCD monitor
- Areas of the specimen through which electrons pass appear bright (electron lucent), while denser areas or those that bind heavy metal ions appear darker (electron dense)
Scanning Electron Microscopy (SEM)
- Has many similarities to TEM, but the focused electron beam does not pass through the specimen, instead being scanned sequentially across its surface
- Specimens are coated with metal atoms that interact with the electron beam, producing reflected electrons and secondary electrons
- Produces a black-and-white image on the monitor with a striking 3D, shadowed quality
Cell Structure and Function
- Plasma membrane: acts as a physical barrier to enclose cell contents, regulates material movement, establishes and maintains an electrical charge difference, and functions in cell communication
- Glycocalyx: a delicate cell surface coating composed of glycolipids with oligosaccharide chains that extend outward from the cell surface
Light Microscopy
- Most cells absorb very little light, so staining is needed to increase light absorption
- Types of light microscopy: bright-field, phase-contrast, and differential interference microscopy
- Optical system components: condenser, objective lenses, and eyepiece/ocular
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Description
Test your knowledge on different microscopy techniques including phase-contrast, confocal, and electron microscopy. Learn about how each technique works and their applications in biological imaging.
