18 Questions
What is the main reason histology depends on microscopes and molecular methods?
The small size of cells and matrix components
Why are thin translucent sections prepared from tissues for microscopic examination?
To allow light to pass through tissues
What is the main purpose of preparing tissue slices or sections in histologic research?
To visualize internal structures of tissues
Which branch of science is essential for a proper understanding of tissue biology?
Biochemistry
Why are advances in biochemistry, molecular biology, physiology, immunology, and pathology considered essential for a better knowledge of tissue biology?
To provide insights into tissue functions
Which method is commonly used to study cells and tissues according to the text?
Preparation of tissue slices for microscopic examination
What is the primary focus of the study of histology?
The arrangement and interactions of different tissues within organs
What are the two main interacting components of tissues?
Cells and the extracellular matrix
What is the primary function of the extracellular matrix (ECM)?
All of the above
How are cells and the extracellular matrix connected?
All of the above
How do cells and their associated matrix become specialized during development?
They become functionally specialized and give rise to fundamental types of tissues with characteristic structural features.
Which of the following is NOT a key component of tissues?
Mitochondria
What is the primary function of chemical fixatives in the preparation of tissues for histological study?
To preserve the natural structure and composition of the tissue
What is the purpose of dehydrating and clearing the fixed tissue before embedding?
To remove water and replace it with a medium that can be easily sectioned
What is the primary purpose of staining tissue sections mounted on glass slides?
To reveal specific cellular and tissue components under the microscope
What is the significance of the terms "basophilic" and "acidophilic" in the context of tissue staining?
They refer to the ability of a tissue component to absorb basic or acidic stains
What is the primary advantage of using fluorescence microscopy compared to bright-field microscopy?
Fluorescence microscopy can visualize specific molecules or structures labeled with fluorescent probes
Which of the following is the most commonly used staining method in histology?
Hematoxylin and eosin (H&E) staining
Study Notes
Histology and Its Methods of Study
- Histology is the study of the tissues of the body and how these tissues are arranged to constitute organs.
- Tissues have two interacting components: cells and extracellular matrix (ECM).
- The ECM consists of many kinds of macromolecules, such as collagen fibrils, which support the cells and contain fluids transporting nutrients to the cells and carrying away their wastes and secretory products.
Preparation of Tissues for Study
- Chemical fixatives like formalin are used to preserve tissue structure by cross-linking and denaturing proteins, inactivating enzymes, and preventing cell autolysis or self-digestion.
- Dehydration of the fixed tissue in alcohol and clearing in organic solvents prepare it for embedding and sectioning.
- Embedding in paraffin wax or epoxy resin allows the tissue to be cut into very thin sections (slices) with a microtome.
- Sections are mounted on glass slides for staining, which is required to reveal specific cellular and tissue components with the microscope.
Staining and Microscopy
- The most commonly used staining method is a combination of the stains H&E, which act as basic and acidic dyes, respectively.
- Cell substances with a net negative (anionic) charge, such as DNA and RNA, react strongly with hematoxylin and basic stains and are said to be “basophilic.”
- Cationic substances, such as collagen and many cytoplasmic proteins react with eosin and other acidic stains and are said to be “acidophilic.”
- Bright-field microscopy uses ordinary light and the colors are imparted by tissue staining.
- Fluorescence microscopy uses UV light, under which only fluorescent molecules are visible, allowing localization of fluorescent probes which can be much more specific than routine stains.
Other Microscopy Techniques
- Phase-Contrast Microscopy
- Confocal Microscopy
- Polarizing Microscopy
- Autoradiography
- Transmission Electron Microscopy
- Scanning Electron Microscopy
Test your knowledge on the formation and arrangement of tissues to create organs, as well as the study methods and advancements in histology. Explore topics like cell and tissue culture, enzyme histochemistry, and visualizing specific molecules.
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