Histology PDF

Histology 1. Histology studies the organization of tissues and how they form organs. 2. Tissues consist of cells and extracellular matrix (ECM) that support and nourish cells. 3. Cells produce and interact with the ECM through cell surface receptors. 4. Development leads to specialized tissues with unique structural features. 5. Organs are formed by the combination of different tissue types. 6. Microscopes and molecular methods are essential for studying tissues. 7. Tissue preparation for light microscopy involves fixation, dehydration, clearing, infiltration, embedding, and sectioning. 8. Fixation preserves tissue structure using fixatives like formalin or glutaraldehyde. 9. Dehydration and clearing remove water and make the tissue translucent. 10. Embedding and sectioning allow for the creation of thin tissue sections for microscopic examination. 1. The extracellular matrix (ECM) provides support to cells and facilitates the transport of nutrients and waste products. 2. Matrix molecules strongly influence cell behavior and function. 3. Tissue biology benefits from advancements in biochemistry, molecular biology, physiology, immunology, and pathology. 4. Familiarity with scientific tools and methods is crucial for understanding tissue biology. 5. The most common method in histologic research is the preparation of tissue sections for microscopic examination. 6. Fixation is a crucial step in tissue preparation to preserve tissue structure and prevent degradation. 7. Formalin and glutaraldehyde are commonly used fixatives for light and electron microscopy, respectively. 8. Electron microscopy provides higher magnification and resolution for studying cellular structures. 9. Different techniques are used for preparing tissues for light microscopy and electron microscopy. 10. Tissues can be embedded in paraffin or plastic resin for sectioning, depending on the microscopy technique used. 1. Biopsies are tissue samples used for microscopic analysis in pathology laboratories. 2. Biopsies can be fixed in formalin or rapidly frozen in liquid nitrogen for processing. 3. Rapid freezing of biopsies preserves cell structures and enables quick sectioning. 4. Cryostat microtome is used to section frozen tissue blocks for staining and examination. 5. Freezing of tissues is effective for studying sensitive enzymes and structures containing lipids. 6. Staining is necessary to make tissue components distinguishable under a microscope. 7. Dyes selectively stain tissue components based on their properties and composition. 8. Hematoxylin and eosin (H&E) staining is commonly used for basic tissue examination. 9. The periodic acid-Schiff (PAS) reaction stains carbohydrate-rich structures in tissues. 10. Different staining methods and microscopy techniques, such as virtual microscopy, are used to study tissue features. 1. Fluorescence microscopy uses UV light to make fluorescent substances appear bright on a dark background. 2. Fluorescent stains like acridine orange and DAPI allow visualization of nucleic acids and cell nuclei. 3. Fluorescent compounds can be coupled with molecules to specifically bind to cellular components for identification. 4. Phase-contrast microscopy produces visible images from transparent objects, including living cells. 5. Phase-contrast microscopy utilizes changes in light speed to enhance cellular structures' visibility. 6. Differential interference microscopy with Nomarski optics provides a more apparent 3D aspect of living cells. 7. Confocal microscopy achieves high resolution and sharp focus by using a small point of high-intensity light and a pinhole aperture. 8. Confocal microscopes create optical sections by capturing digital images at different focal planes. 9. Polarizing microscopy allows the recognition of highly organized subunits in stained or unstained structures. 10. Transmission electron microscopy (TEM) provides high-resolution imaging of tissue sections by passing electrons through the sample. 1. Scanning electron microscopy (SEM) provides high-resolution images of cell and tissue surfaces. 2. SEM uses a narrow beam of electrons and a metal-coated specimen to produce a black-and-white image. 3. SEM images present a three-dimensional view with highlights and shadows. 4. Microscopic autoradiography localizes newly synthesized macromolecules using radioactive labels. 5. Autoradiography helps identify replicating cells and track the migration of proteins. 6. Cell and tissue culture allows the observation of cellular behavior outside the body. 7. Cultured cells are grown in solutions with known composition and can be maintained for long periods. 8. Fluorescent compounds can be used to study cellular compartments in cultured cells. 9. Enzyme histochemistry localizes cellular structures using specific enzymatic activity. 10. Specific compounds or macromolecules can be used to detect and localize sugars, proteins, and nucleic acids in tissues. 1. Phalloidin interacts strongly with actin protein, allowing staining of microfilaments. 2. Protein A binds to antibody molecules and is used to localize antibodies in immunohistochemistry. 3. Lectins bind to specific sugars and can be used to stain specific glycoproteins. 4. Labeled antibodies are used in immunohistochemistry to identify and localize specific proteins. 5. Antibodies interact with antigens and help eliminate foreign substances. 6. Immunohistochemical techniques require antibodies against the protein of interest. 7. Antibodies can be produced by injecting the protein into an animal and collecting plasma. 8. Monoclonal antibodies are highly specific and bind strongly to the target protein. 9. Immunohistochemistry involves incubating tissue sections with labeled antibodies for visualization. 10. Indirect immunohistochemistry amplifies the signal using a secondary antibody and is more sensitive. 1. Hybridization techniques can be used to determine the presence of specific DNA sequences, mRNA, or gene localization. 2. Probes consisting of complementary single-stranded DNA are used to detect the nucleotide sequences of interest. 3. Infection with human papillomavirus (HPV) can be demonstrated using in situ hybridization (ISH) in cells with characteristic proliferative growth. 4. Histologic sections may exhibit artifacts due to tissue processing, such as shrinkage, spaces between cells, and cracks in sections. 5. Different staining methods and techniques like TEM are necessary to fully understand the composition and structure of cells and tissues, as well as to account for the limitations of two-dimensional sectioning. 1. Chemical fixatives like formalin preserve tissue structure. 2. Dehydration and clearing prepare tissue for embedding and sectioning. 3. Paraffin wax or epoxy resin embedding allows thin sectioning. 4. Staining reveals cellular and tissue components. 5. Hematoxylin and eosin (H&E) staining is commonly used. 6. Hematoxylin stains basophilic material (e.g., DNA, RNA). 7. Eosin stains acidophilic material (e.g., collagen, cytoplasmic proteins). 8. Bright-field microscopy uses ordinary light for visualization. 9. Fluorescence microscopy visualizes fluorescent probes. 10. Phase-contrast microscopy observes living cells without staining. 11. Confocal microscopy reconstructs 3D images using laser scanning. 12. Autoradiography detects silver grains from radioactive precursors. 13. Cell culture allows examination of cells in vitro. 14. Enzyme histochemistry visualizes enzymatic activities in tissue sections. 15. Histochemistry is often performed on frozen tissue sections. 16. Immunohistochemistry uses visible markers to detect antigen-antibody reactions. 17. Direct immunohistochemistry uses labeled primary antibodies. 18. Indirect immunohistochemistry uses labeled secondary antibodies. 19. In situ hybridization (ISH) detects gene sequences or mRNAs with labeled probes. 20. Tissue processing and staining can introduce artifacts, and sections are 2D representations of 3D structures. 1. In preparing tissue for routine light microscopic study, which procedure immediately precedes clearing the specimen with an organic solvent? a. Dehydration 2. Which of the following staining procedures relies on the cationic and anionic properties of the material to be stained? c. Hematoxylin & eosin staining 3. In a light microscope used for histology, resolution and magnification of cells are largely dependent on which component? b. Objective lens 4. Cellular storage deposits of glycogen, a free polysaccharide, could best be detected histologically using what procedure? e. Periodic acid-Schiff reaction 5. Adding heavy metal compounds to the fixative and ultrathin sectioning of the embedded tissue with a glass knife are techniques used for which histological procedure? e. Transmission electron microscopy 7. Microscopic autoradiography uses radioactivity and can be employed to study what features in a tissue section? b. Cellular sites where various macromolecules are synthesized c. The sequences of mRNA made in the cells 8. To identify and localize a specific protein within cells or the extracellular matrix one would best use what approach? c. Immunohistochemistry 9. In situ hybridization is a histological technique used to visualize what type of macromolecule? d. Nucleic acids 1. a. Dehydration 2. c. Hematoxylin & eosin staining 3. b. Objective lens 4. e. Periodic acid-Schiff reaction 5. e. Transmission electron microscopy 6. a. The wavelength of the electrons in the microscope beam is shorter than that of a beam of light. 7. b. Cellular sites where various macromolecules are synthesized 8. c. Immunohistochemistry 9. d. Nucleic acids 10. b. Small mRNA ………………………………………………………………………………………………………………………….. Histology, Chapter 2 1. Cells and extracellular material form the tissues and organs of multicellular animals. 2. Animal cells are eukaryotic with distinct nuclei and organelles, while prokaryotic cells lack nuclei and membrane-bound structures. 3. Cell differentiation occurs during development, leading to specialized cell types with specific functions. 4. The plasma membrane regulates the passage of materials into and out of the cell and facilitates transport. 5. Cells can have variable features and activities due to changes in their microenvironments. 6. The plasma membrane consists of phospholipids, cholesterol, and proteins, and plays a key role in cell interactions. 7. Membrane proteins are either integral (within the lipid bilayer) or peripheral (bound to the membrane surface). 8. Membrane proteins are mobile within the fluid lipid bilayer, but their diffusion can be restricted by cytoskeletal attachments. 9. Membrane transport occurs through diffusion, channels, carriers, and pumps, allowing substances to move across membranes. 10. Active transport involves membrane pumps that utilize ATP to move solutes against concentration gradients. 1. Endocytosis is the process by which cells engulf particles or fluids by forming membrane-bound vesicles. 2. Three major types of endocytosis are recognized: phagocytosis (ingestion of particles), pinocytosis (ingestion of fluids), and receptor-mediated endocytosis (specific ligands binding to membrane receptors). 3. Phagocytosis involves the ingestion of particles such as bacteria or dead cell remnants by specialized cells like macrophages and neutrophils. 4. Pinocytosis involves the formation of smaller vesicles that trap extracellular fluid and its dissolved contents. 5. Receptor-mediated endocytosis occurs when integral membrane proteins aggregate in special membrane regions, leading to the formation of vesicles. 6. Vesicles produced during endocytosis fuse with the endosomal compartment, where they may fuse with lysosomes for degradation or follow other pathways. 7. Exocytosis is the process by which cytoplasmic vesicles fuse with the plasma membrane, releasing their contents into the extracellular space. It can occur constitutively or in response to specific stimuli. 1. Passive processes: Substances move down a concentration gradient without cellular energy expenditure until equilibrium is reached. 2. Simple diffusion: Unassisted movement of small, nonpolar substances across a selectively permeable membrane along their concentration gradient. 3. Facilitated diffusion: Movement of ions and small, polar molecules down their concentration gradient with the assistance of transport proteins. 4. Channel-mediated: Movement of ions through protein channels along their concentration gradient. 5. Carrier-mediated: Movement of small, polar molecules down their concentration gradient facilitated by carrier proteins. 6. Osmosis: Diffusion of water across a selectively permeable membrane driven by relative solute concentrations. 7. Active transport: Cellular energy is required to transport ions or small molecules against their concentration gradient using transmembrane protein pumps. 8. Primary active transport: Directly powered by ATP, substances move up their concentration gradient. 9. Secondary active transport: The movement of a substance up its concentration gradient is powered by harnessing the movement of a second substance down its concentration gradient. 10. Vesicular transport: Formation or release of vesicles to bring materials into or out of the cell. 11. Exocytosis: Bulk movement of substances out of the cell through fusion of secretory vesicles with the plasma membrane. 12. Endocytosis: Bulk movement of substances into the cell through the formation of vesicles at the plasma membrane. 13. Phagocytosis: Type of endocytosis where external particulate materials are engulfed by pseudopodia. 14. Pinocytosis: Type of endocytosis where interstitial fluid is taken up by the cell, forming small vesicles. 15. Receptor-mediated endocytosis: Specific substances first bind to plasma membrane receptors, and the receptor-bound complex is taken up by the cell. 16. Uptake of cholesterol into cells: Example of receptor-mediated endocytosis involving the uptake of cholesterol. 1. Cell differentiation is the process of cells becoming specialized for specific functions in tissues and organs. 2. The plasma membrane surrounds the cell and consists of a lipid bilayer with embedded proteins. 3. Endocytosis is the uptake of macromolecules or fluid by the plasma membrane, while exocytosis is the release of contents from membrane vesicles. 4. Ribosomes translate mRNA into proteins, and multiple ribosomes on the same mRNA form polyribosomes. 5. The endoplasmic reticulum (ER) is a network of membranes involved in protein synthesis and processing. 6. The ER can be rough (RER) or smooth (SER), with RER involved in protein synthesis and SER in lipid and glycogen metabolism. 7. The Golgi apparatus modifies and packages proteins for secretion or other functions. 8. Lysosomes contain enzymes for degrading cellular macromolecules, and autophagy involves lysosomal digestion of organelles 1. In transmission EM preparations of cells, the cell membrane often appears as a trilaminar structure having two parallel dark-staining components on either side of an unstained middle layer. This central poorly stained region of the membrane is primarily responsible for which of the following functions? a. Creation of a barrier to water-soluble molecules 2. Chaperonins are cytoplasmic proteins most likely to be found in which of the following organelles? e. Mitochondria 3. Which of the following best defines the term "exocytosis"? b. The uptake of material at one domain of a cell’s surface and its discharge from the opposite side of the cell 4. Cytoplasm often stains poorly because its lipid content is removed by the organic solvents used in the clearing step in routine histological preparations. This problem is most likely to occur with cytoplasmic regions rich in which of the following organelles? b. Mitochondria 5. Polarity in microtubules is important in determining which of the following? c. The overall dynamic instability of the microtubules 6. Which of the following proteins is/are most likely to have initially contained a "signal peptide" that bound a "signal recognition particle" during its translation? c. Proteins in secretory granules 7. Vesicles of a Golgi apparatus that are destined to become part of other organelles most likely have which of the following on their membranes? c. COP II …………………………………………………………………………………………………….. Chapter 3 1. The nucleus is the command center of the cell, containing the code for enzymes and proteins. 2. The nucleus replicates DNA and synthesizes and processes RNA. 3. Pore complexes in the nuclear membrane regulate transfer between the nucleus and cytoplasm. 4. RNA molecules pass into the cytoplasm for protein synthesis, while nuclear proteins are imported from the cytoplasm. 5. Protein synthesis is restricted to the cytoplasm to ensure complete RNA processing before translation. 6. The nucleus consists of a nuclear envelope, chromatin, and nucleoli. 7. The nuclear envelope is a selectively permeable barrier composed of inner and outer membranes. 8. Chromatin consists of DNA and associated proteins, organized as nucleosomes. 9. Chromatin undergoes compaction and forms chromosomes during cell division. 10. Euchromatin is more open and active, while heterochromatin is more compact and transcriptionally silent. 1. Nucleoli are basophilic subdomains in cells engaged in protein synthesis due to concentrated ribosomal RNA (rRNA). 2. Nucleoli contain fibrillar and granular subregions involved in rRNA maturation and ribosomal subunit assembly. 3. The nuclear envelope separates cytoplasm from nucleoplasm and contains nuclear pore complexes for molecular movement. 4. The nuclear envelope is supported by a meshwork called the nuclear lamina composed of lamin proteins. 5. Chromatin is a combination of DNA and associated proteins. 6. Euchromatin is lightly stained and active in transcription, while heterochromatin is darkly stained and inactive. 7. DNA wraps around histone proteins to form nucleosomes. 8. Chromatin condensation involves nonhistone proteins like condensins. 9. The extra X chromosome in female mammals forms facultative heterochromatin called the Barr body. 10. The nucleolus is a basophilic area where rRNA transcription and ribosomal subunit assembly occur. 11. The cell cycle controls cell growth and division. 12. The G1 phase prepares for DNA replication. 13. The S phase is when DNA and histone synthesis occurs. 14. The G2 phase prepares for mitosis. 15. Cyclins and cyclin-dependent kinases (CDKs) regulate cell cycle progression. 16. Checkpoints monitor completion of each cell cycle phase. 17. Mitosis involves prophase, metaphase, anaphase, and telophase. 18. Cytokinesis completes mitosis by cleaving the cell into two daughter cells. 19. Stem cells divide asymmetrically, with one daughter cell remaining a stem cell and the other committing to differentiation. 20. Transit amplifying or progenitor cells divide rapidly before differentiating. 21. Meiosis produces gametes with half the number of chromosomes as somatic cells. 22. Prophase of the first meiotic division involves pairing and recombination of homologous chromosomes. 23. The second meiotic division separates sister chromatids into haploid cells. 24. Apoptosis is a process for eliminating redundant or defective cells without causing inflammation. 25. Apoptosis involves a cascade of events controlled by the Bcl-2 protein family, including cytochrome c release and caspase activation, leading to cell degradation and phagocytosis. 1. Which of the following facilitates breakdown of the nuclear envelope during the onset of mitosis? c. Phosphorylation of lamin subunits by a cyclin-dependent kinase (CDK) 2. Binding of histone H1 proteins to importins is important for which of the following? a. Transport through the nuclear pores complexes b. Properly directed vesicular transport through the Golgi apparatus c. Transport from the granular part of the nucleolus d. Further binding to the “linker DNA” and proper assembly of nucleosomes e. Phosphorylation of cyclins 3. Which of the following is a region of chromatin that is well developed in large neurons active in protein synthesis? c. The Nissl substance (neuronal RER) 4. Which of the following is found during meiosis but not mitosis? d. Synapsis 5. Transitions in the cell cycle from one phase to the next are regulated by protein kinases whose activity depends on what other proteins? b. Cyclins 6. Mitotic figures visible in a tissue section from the lining of the small intestine are most likely to belong to which of the following categories? e. Progenitor cells 7. Key differences between apoptotic and necrotic cell death include which of the following? a. Apoptotic cells do not release factors that induce inflammation. Sure! Let's start with mitosis: Mitosis is the process of cell division that occurs in somatic cells (body cells). It is responsible for growth, tissue repair, and asexual reproduction in some organisms. Mitosis consists of four main phases: prophase, metaphase, anaphase, and telophase. 1. Prophase: During prophase, the genetic material inside the cell's nucleus condenses and becomes visible as chromosomes. The nuclear envelope breaks down, and the mitotic spindle, composed of microtubules, begins to form. The chromosomes attach to the spindle fibers. 2. Metaphase: In metaphase, the chromosomes align along the center of the cell called the metaphase plate. This arrangement ensures that each daughter cell will receive an equal number of chromosomes during division. 3. Anaphase: Anaphase is the phase where the sister chromatids of each chromosome separate and move towards opposite ends of the cell. This ensures that each daughter cell receives one complete set of chromosomes. 4. Telophase: During telophase, the separated chromosomes reach the opposite poles of the cell. Nuclear envelopes form around each set of chromosomes, creating two nuclei. The chromosomes begin to decondense, and the mitotic spindle disassembles. Lastly, cytokinesis follows mitosis and involves the physical division of the cell into two daughter cells. Now let's move on to meiosis: Meiosis is a specialized form of cell division that occurs in cells involved in sexual reproduction. It produces gametes (sperm and eggs) with half the number of chromosomes as the parent cells. Meiosis consists of two rounds of division, known as meiosis I and meiosis II, each with four phases. Meiosis I: 1. Prophase I: This is the longest and most complex phase of meiosis. Chromosomes condense, and homologous chromosomes pair up and undergo crossing over, exchanging genetic material. This genetic recombination increases genetic diversity. The nuclear envelope breaks down, and the spindle apparatus forms. 2. Metaphase I: The homologous chromosome pairs align along the metaphase plate, with one chromosome from each pair facing opposite poles of the cell. 3. Anaphase I: The homologous chromosomes separate and move toward opposite poles of the cell. The sister chromatids remain attached. 4. Telophase I: The chromosomes reach the poles of the cell, and nuclear envelopes form around each set. Cytokinesis then occurs, resulting in two haploid daughter cells. Meiosis II: 5. Prophase II: The nuclear envelopes dissolve, and a new spindle apparatus forms. 6. Metaphase II: The chromosomes align along the metaphase plate, similar to metaphase in mitosis. 7. Anaphase II: The sister chromatids separate and move towards opposite poles of the cell. 8. Telophase II: The chromosomes reach the poles of the cell, and nuclear envelopes form around each set. Cytokinesis occurs, resulting in the formation of four haploid daughter cells. In summary, mitosis produces two identical daughter cells with the same number of chromosomes as the parent cell, while meiosis produces four genetically unique daughter cells with half the number of chromosomes as the parent cell. ……………………………………………………………………………….. Chapter 4 1. Epithelial cells have variable shapes and dimensions, ranging from tall columnar to cuboidal to low squamous cells. 2. The size and morphology of epithelial cells are dictated by their function. 3. Epithelial cell nuclei vary in shape, corresponding roughly to cell shape. 4. The number and shape of stained nuclei are important indicators of cell shape and density. 5. Most epithelia are adjacent to connective tissue called the lamina propria, which provides nutrients and oxygen to epithelial cells. 6. Epithelial cells show polarity, with distinct basal and apical poles having different structures and functions. 7. The basal surface of epithelia rests on a basement membrane, which acts as a semipermeable filter and provides structural support. 8. The basement membrane consists of macromolecules such as collagen, laminin, nidogen, and perlecan. 9. Basement membranes also exist around muscle cells, nerves, and fat-storing cells, regulating macromolecular exchange. 10. Epithelial cells have specialized intercellular junctions, including tight junctions, adherent junctions, and gap junctions, which provide adhesion and communication between cells. 1. Epithelia are tissues with tightly bound cells forming sheet-like or tubular structures. 2. Epithelial cells have an apical side facing the free surface and a basal side facing the basement membrane. 3. Epithelia are specialized for absorption, transcytosis, pinocytosis, and exocytosis. 4. Epithelial cells undergo continuous renewal, with variable locations of stem cells and cell turnover rates. 5. The basement membrane consists of a basal lamina and a reticular lamina, providing attachment and regulation. 6. Intercellular junctions in epithelia include tight junctions, adherent junctions, and gap junctions. 7. Tight junctions prevent substances from passing between cells. 8. Adherent junctions hold epithelial cells together. 9. Gap junctions allow small molecule passage between cells. 10. Apical structures of epithelial cells include microvilli, stereocilia, and cilia. 11. Microvilli increase the apical surface area for absorption. 12. Stereocilia have mechanosensory functions or aid in absorption. 13. Cilia propel material along the epithelial surface. 14. Epithelia can be simple (one cell layer) or stratified (multiple layers). 15. Stratified squamous epithelia protect underlying tissues. 16. Pseudostratified epithelia appear to have multiple cell layers but all attach to the basal lamina. 17. Transitional epithelium lines the urinary system and protects against urine. 18. Epithelial cells in glands synthesize and secrete specialized products. 19. Exocrine glands have ducts, while endocrine glands lack ducts. 20. Exocrine glands can have acini or tubules as secretory units. 21. Endocrine glands secrete hormones carried by interstitial fluid and blood. 22. Glands have merocrine, holocrine, or apocrine secretory mechanisms. 23. Mucous glands produce mucus, and serous glands produce enzymes. 24. Mucus stains poorly with routine dyes but well with PAS stain. 25. Serous glands stain darkly with H&E due to their content of RER and secretory granules. 1. Functions of the basement membrane include which of the following? - b. Molecular filtering 2. Using immunohistochemistry, a population of cells is shown to be positive for the protein connexin. From this, we can infer that the cells are connected by what type of junction? - c. Gap junctions 3. An individual genetically unable to synthesize normal occludin is likely to have epithelia with defective regulation in which of the following? - a. Material crossing the epithelium between the cells (paracellular movement) 4. An intermediate filament protein found in the cytoplasm of most epithelial cells is which of the following? - e. Keratin 5. Which of the following cellular features is used in naming types of epithelia? - b. Number of cell layers 6. The release of lipid droplets from cells is which type of secretion? - e. Holocrine 7. Exocrine glands in which the acini all produce a secretion of heavily glycosylated, hydrophilic proteins are an example of which type of gland? - a. Serous gland 1. The human body is composed of four basic tissue types: epithelial, connective, muscular, and nervous tissues. 2. Epithelial tissues form cellular sheets that line organ cavities and cover the body surface, playing a role in covering, lining, and protecting surfaces, absorption, and secretion. 3. Connective tissue produces abundant extracellular matrix (ECM), muscle tissue is specialized for contraction and movement, and nervous tissue is specialized for receiving and transmitting nerve impulses. 4. Organs have a parenchyma composed of cells responsible for specialized functions and a stroma composed of connective tissue cells that provide support. 5. Some epithelial tissues have specialized cells, such as contractile myoepithelial cells or sensory cells in taste buds or olfactory epithelium. ………………………………………………………………………………………………………………… Chapter 5 1. Connective tissue provides physical support and connection between cells and organs. 2. Interstitial fluid in connective tissue supports cell metabolism. 3. Connective tissue is primarily composed of extracellular matrix (ECM) rather than cells. 4. ECM consists of protein fibers (collagen and elastic fibers) and ground substance. 5. Ground substance includes proteoglycans, glycosaminoglycans (GAGs), and glycoproteins. 6. Water in ground substance facilitates nutrient and waste exchange between cells and blood. 7. Connective tissue types vary in composition, leading to structural and functional diversity. 8. All connective tissues originate from embryonic mesenchyme. 9. Mesenchyme is rich in ground substance and contains undifferentiated cells. 10. Fibroblasts are the main cells in connective tissue proper. 11. Fibroblasts produce and maintain ECM components. 12. Fibroblasts synthesize collagen, elastin, and ground substance components. 13. Fibroblasts can be active or quiescent based on their synthetic activity. 14. Adipocytes are fat cells found in connective tissue. 15. Macrophages are phagocytic cells that remove debris and dead cells. 16. Mast cells are oval cells involved in local inflammation and tissue repair. 17. Mast cells contain granules with substances like heparin, histamine, and proteases. 18. Mast cells release bioactive substances that regulate inflammation and immunity. 19. Mast cells can change the color of certain dyes due to metachromasia. 20. Mast cells attract leukocytes involved in immune response. 1. Connective tissue supports and connects other tissues. 2. Connective tissue consists primarily of extracellular material. 3. Connective tissue proper forms the supportive stroma of organs. 4. The extracellular matrix (ECM) contains protein fibers and ground substance. 5. Adult connective tissues are derived from embryonic mesenchyme. 6. Fibroblasts synthesize and secrete components of the ECM. 7. Adipocytes store triglycerides in adipose tissue. 8. Macrophages remove debris and phagocytose dead cells. 9. Mast cells release substances during inflammation and allergic reactions. 10. Plasma cells secrete specific antibodies. 11. Leukocytes provide surveillance and tissue repair. 12. Collagen is the most abundant fiber in connective tissue. 13. Collagen synthesis involves posttranslational modifications. 14. Collagen molecules aggregate to form fibrils. 15. Collagenase enzymes degrade collagen fibrils. 16. Type III collagen forms reticular fibers. 17. Elastic fibers provide elasticity to certain connective tissues. 18. Ground substance is an abundant, watery extracellular material. 19. It contains hydrated glycosaminoglycans (GAGs) and proteoglycans. 20. Hyaluronan and sulfated GAGs are major components of ground substance. 21. Proteoglycans bind to hyaluronan and regulate fibroblast proliferation. 22. Multiadhesive glycoproteins facilitate cell-ECM attachments. 23. Connective tissue proper can be loose or dense. 24. Loose connective tissue has more ground substance. 25. Dense irregular connective tissue has randomly distributed collagen bundles. 26. Dense regular connective tissue has parallel collagen bundles. 27. Reticular tissue consists of delicate networks of collagen. 28. Mucoid tissue is a gel-like connective tissue found in the umbilical cord. 29. Connective tissue provides strength, support, and elasticity to the body. 30. Different types of connective tissue have specific functions in organs and tissues. 1. Which of the following connective tissue components is located in the ECM but not in the ground substance? - Answer: b. Fibronectin 2. What cells numerous in loose connective tissue are filled with secretory granules and stain with metachromasia? - Answer: b. Mast cells 3. What is the first step of collagen production that occurs after the protein undergoes exocytosis? - Answer: b. Removal of the terminal nonhelical domains by peptidases 4. What is an important part of the role played by macrophages during maintenance and renewal of strong extracellular fibers in connective tissue? - Answer: d. Secretion of matrix metalloproteinases 5. Sulfated GAGs are important constituents of what extracellular structures? - Answer: d. Proteoglycans 6. Which of the following contains binding sites for integrins and is an important part of the ECM in both loose connective tissue and dense irregular connective tissue? - Answer: b. Fibronectin 7. Dense regular connective tissue typically involves which of the following features? - Answer: e. Predominantly located in tendons and ligaments ……………………………………………………………………………………………………. Chapter 6 1. Adipose tissue is connective tissue dominated by fat-storing cells called adipocytes. 2. Adipose tissue serves as a storage depot for triglycerides and regulates the body's energy metabolism. 3. Adipose tissue is now recognized as an endocrine organ involved in nutritional homeostasis. 4. There are two major types of adipose tissue: white adipose tissue (WAT) and brown adipose tissue (BAT). 5. WAT is specialized for long-term energy storage and consists of large adipocytes with a single large lipid droplet. 6. WAT can store triglycerides derived from dietary fats, lipids synthesized in the liver, and fatty acids and glycerol synthesized by adipocytes. 7. Adipocytes in WAT can release stored lipids in response to hormonal and nervous stimuli. 8. BAT contains adipocytes with multiple lipid droplets and functions to generate heat. 9. The distribution and color of white adipose tissue can change throughout life and are influenced by sex hormones and diet. 10. Adipose tissue development involves the differentiation of mesenchymal stem cells into preadipocytes, which then mature into adipocytes. 1. Adipose tissue contains large adipocytes specialized for lipid storage. 2. Adipocytes store lipids from dietary fats, liver-produced triglycerides, and locally synthesized fatty acids. 3. Lipid mobilization from adipocytes is triggered by hormones and norepinephrine. 4. Adipose tissue is supported by reticular fibers and divided into lobules. 5. There are two types of adipose tissue: white fat and brown fat. 6. White adipose tissue is found throughout the body and constitutes about 20% of adult body weight. 7. White adipocytes are large, unilocular cells with a single large lipid droplet. 8. Fatty acids are released from white adipocytes and transported by plasma proteins. 9. Leptin, released by white adipocytes, regulates eating behavior. 10. Brown adipose tissue is present in smaller amounts compared to white fat. 11. Brown adipocytes are smaller, multilocular cells with many small lipid droplets and mitochondria. 12. Fatty acids released from brown adipocytes are metabolized for thermogenesis. 13. Brown adipose tissue utilizes uncoupling protein-1 for thermogenesis. 1. White adipocytes are derived developmentally from what precursor cells? c. Mesenchymal cells 2. What are the relatively large particles formed in the intestinal epithelial cells and rich in ingested lipids? b. Chylomicrons 3. What substance, released from the adrenal gland and some autonomic neurons, increases lipolytic activity in white adipocytes? c. Norepinephrine 4. What is the most important form of lipid storage in both white and brown adipocytes? e. Triglycerides 5. Important target cells of leptin are found in which organ? d. Hypothalamus 6. The hormone-sensitive lipase in the cells of adipose tissue acts primarily on what substrate? d. Triglycerides 7. Applied to adipocytes, the term "multilocular" refers to which of the following? a. The large number of small cytoplasmic lipid droplets …………………………………………………………. Chapter 7 1. Cartilage is a tough connective tissue with a high concentration of GAGs and proteoglycans in its extracellular matrix. 2. It provides mechanical support and protection in the skeleton and other areas of the body. 3. Cartilage has a firm consistency that allows it to bear mechanical stresses without permanent distortion. 4. It forms the framework supporting softer tissues in the respiratory tract, ears, and nose. 5. Cartilage cushions and facilitates bone movements within joints. 6. Chondrocytes are the cells found in cartilage and are responsible for synthesizing and maintaining the extracellular matrix. 7. The physical properties of cartilage are due to the electrostatic bonds between collagen fibrils, hyaluronan, and sulfated GAGs. 8. Cartilage lacks vascular supplies and receives nutrients through diffusion from surrounding connective tissue. 9. Cartilage is divided into three main types: hyaline cartilage, elastic cartilage, and fibrocartilage. 10. Hyaline cartilage is the most common type and is found in articular surfaces, respiratory passages, ribs, and epiphyseal plates. 1. Cartilage is a tough connective tissue that supports soft tissues and provides cushioning in joints. 2. Chondrocytes are cartilage cells embedded within the extracellular matrix (ECM). 3. The ECM of cartilage contains collagen and proteoglycans, such as aggrecan. 4. Cartilage lacks blood vessels, lymphatics, and nerves but is usually surrounded by a vascularized perichondrium. 5. There are three major types of cartilage: hyaline, elastic, and fibrocartilage. 6. Hyaline cartilage has a homogenous ECM rich in collagen and proteoglycans. 7. Chondrocytes in hyaline cartilage occur singly or in groups. 8. Elastic cartilage has similar components to hyaline cartilage but contains abundant elastic fibers. 9. Elastic cartilage provides flexible support for structures like the external ear. 10. Fibrocartilage contains hyaline cartilage and dense connective tissue. 11. Fibrocartilage is characterized by small chondrocytes and bundled collagen fibers. 12. Fibrocartilage provides tough support at tendon insertions and in intervertebral discs. 13. All forms of cartilage originate from embryonic mesenchyme. 14. Cartilage can grow through interstitial growth (mitosis of existing chondrocytes) or appositional growth (formation of new chondrocytes from progenitor cells in the perichondrium). 15. Cartilage repair is slow and ineffective due to its avascularity and low metabolic rate. 1. The molecular basis for the shock absorbing properties of cartilage involves which of the following? Correct answer: e. Hydration of glycosaminoglycans 2. What distinguishes cartilage from most other connective tissues? Correct answer: d. It lacks blood vessels. 3. Which feature is typical of elastic cartilage? Correct aswer: e. Collagen is mainly type II 4. Which area in cartilage is relatively collagen-poor and proteoglycan-rich? Correct answer: b. Territorial matrix 5. What is the source of the mesenchymal progenitor cells activated for the repair of hyaline cartilage of accident-damaged costal cartilages? Correct answer: a. Perichondrium 6. How does articular cartilage differ from most other hyaline cartilage? Correct answer: c. It lacks a perichondrium. 7. Which step occurs first in chondrogenesis? Correct answer: c. Formation of mesenchymal condensations 8. Osteoarthritis is characterized by the progressive erosion of articular cartilage. The matrix metalloproteinases involved in this erosion primarily act on which matrix component? Correct answer: a. Aggrecan ………………………………………………………………………… Chapter 8 1. Bone tissue provides support, protection, and serves as a reservoir for ions. 2. Bones act as levers, converting muscle forces into movement. 3. Bone is composed of osteocytes, osteoblasts, and osteoclasts. 4. Osteoblasts produce organic components of the bone matrix. 5. Osteoblasts deposit inorganic components and promote bone growth. 6. Matrix mineralization involves the secretion of proteins and the formation of hydroxyapatite crystals. 7. Osteocytes are mature bone cells located within lacunae and communicate through canaliculi. 8. Osteocytes maintain the calcified matrix and play a role in bone remodeling. 9. Osteocytes detect microdamage in bone and trigger repair processes. 10. Osteoclasts are involved in removing calcified bone matrix and remodeling bone tissue. 1. Bone is a connective tissue with a calcified matrix that supports the body and protects organs. 2. Osteoblasts secrete osteoid, which allows matrix mineralization. 3. Osteoid contains collagen, osteocalcin, and matrix vesicles. 4. Hydroxyapatite crystals form in the matrix due to high concentrations of calcium and phosphate ions. 5. Osteocytes maintain the matrix and detect mechanical stresses in bone. 6. Osteocytes communicate through dendritic processes and canaliculi. 7. Osteoclasts erode bone matrix during bone formation and remodeling. 8. Periosteum is a layer of connective tissue on the outer surface of bone. 9. Periosteum contains osteoprogenitor cells and osteoblasts for bone growth and remodeling. 10. Endosteum is a thin layer of osteoblasts lining internal bone surfaces. 11. Compact bone is dense bone beneath the periosteum, while cancellous bone is trabecular. 12. Both types of bone occur in epiphyses and diaphysis of long bones. 13. Woven bone is immature and has randomly arranged collagen fibers. 14. Woven bone is remodeled into lamellar bone by osteoclasts and osteoblasts. 15. Lamellar bone consists of concentric lamellae organized around central canals. 16. Osteons are the basic structural units of lamellar bone. 17. Osteocytes reside in lacunae and communicate through canaliculi within osteons. 18. Skull and jaw bones form by intramembranous ossification. 19. Other bones form by endochondral ossification, with osteoprogenitor cells invading cartilage models. 20. Primary ossification centers form in diaphyses, followed by secondary ossification centers in epiphyses. 21. Growth plates in long bones allow bone elongation during childhood. 22. Growth plates contain resting, proliferative, hypertrophic, calcification, and ossification zones. 23. Bone repair involves the formation of a soft callus followed by a hard callus. 24. Bone remodeling occurs throughout life, with continuous turnover of cells and matrix. 25. Bone remodeling involves the replacement and rebuilding of lamellae and osteons. 26. Bone stores and mobilizes calcium, regulated by interactions among osteoblasts, osteoclasts, and other cells. 27. Parathyroid hormone stimulates osteoclasts to elevate blood calcium levels. 28. Calcitonin inhibits osteoclast activity, lowering blood calcium levels. 29. Joints allow movement and are classified as synarthroses or diarthroses. 30. Synovial joints have a joint cavity filled with synovial fluid and are lined by a synovial membrane. 1. Which component of bone impedes the distribution of nutrients and oxygen to osteocytes? Correct answer: b. Canaliculi 2. Which if the following most accurately describes compact bone? Correct answer: c. Characterized by the presence of osteons 3. In healthy bone canaliculi are likely to contain which one of the following? Correct answer: c. Osteocytic processes 4. Which of the following most accurately describes the endosteum? Correct answer: d. Lines the medullary cavity 5. In the diaphysis of a typical long bone which of the following structures is in closest proximity to the trabeculae of cancellous bone? Correct answer: b. Osteons 6. Which "zone" of endochondral ossification in the growing femur of an adolescent is the farthest from that bone's secondary ossification center? Correct answer: a. Zone of hypertrophy 7. The major lubricant for diarthrotic joints is synthesized by cells located in which joint structure? Correct answer: b. Synovial membrane ………………………………………………………………… Chapter 9 1. The human nervous system consists of billions of neurons and supporting glial cells. 2. The nervous system has two major divisions: the central nervous system (CNS) and the peripheral nervous system (PNS). 3. Neurons are excitable cells that respond to stimuli by generating and conducting nerve impulses. 4. Neurons have three main parts: the cell body, dendrites, and axon. 5. Neurons can be classified based on the number of processes extending from the cell body: multipolar, bipolar, unipolar, and anaxonic. 6. The nervous system develops from the ectoderm, with the neural tube giving rise to the CNS and the neural crest cells forming the PNS. 7. Sensory neurons receive stimuli from receptors, while motor neurons send impulses to muscles and glands. 8. Interneurons establish connections between other neurons and form complex networks in the CNS. 9. Neuronal cell bodies are located in the gray matter of the CNS, while axons are concentrated in the white matter. 10. The cell body of a neuron contains the nucleus and serves as the synthetic center for the entire neuron. 1. Synapses transmit nerve impulses between neurons and other cells. 2. Synapses convert electrical signals into chemical signals using neurotransmitters. 3. Synapses have presynaptic axon terminals and postsynaptic cell membranes separated by a synaptic cleft. 4. Neurotransmitters from excitatory synapses cause depolarization, while inhibitory synapses cause hyperpolarization. 5. Different neurotransmitters have various effects and are quickly removed after release. 1. Nervous tissue develops from the neural tube and neural crest cells. 2. Neurons consist of a cell body, axon, and dendrites. 3. Neurons use excitability to transmit nerve impulses through synapses. 4. Glial cells support neurons and include types like oligodendrocytes, astrocytes, and microglia. 5. The central nervous system (CNS) is composed of gray matter and white matter. 6. The CNS is protected by meninges and the blood-brain barrier. 7. The peripheral nervous system (PNS) consists of motor, sensory, and autonomic neurons. 8. Peripheral nerves are surrounded by Schwann cells and connective tissue layers. 9. Ganglia contain neuronal cell bodies and satellite cells. 10. Neural plasticity and regeneration are limited in the CNS but more possible in the PNS. 1. Which of the following is characteristic of the chromatophilic material called Nissl substance in neural tissue? - a. Found throughout neurons 2. Which of the following events occurs immediately after an action potential reaches a synapse at an axon terminal? - d. Neurotransmitter release into the synaptic cleft 3. A report from a hospital pathology laboratory indicates that a microscope slide with a small specimen of neural tissue contains "numerous GFAP-positive" cells. What is the most likely source of this specimen? - d. A region of gray matter 4. In the choroid plexus, water from capillaries is transported directly into the cerebrospinal fluid by what structure(s)? - a. Ependyma 5. What term applies to collections of neuronal cell bodies (somata) in the central nervous system? - e. Nuclei 6. Which structure contains trabeculae around which cerebrospinal fluid (CSF) flows? - a. Arachnoid mater 7. Which of the following is a characteristic of the connective tissue layer that surrounds individual fascicles in large peripheral nerves? - c. Important as part of the blood-nerve barrier in the nervex ` 1. Nervous tissue develops from the neural tube and neural crest cells. 2. Neurons consist of a cell body, axon, and dendrites. 3. Neurons transmit nerve impulses through synapses and neurotransmitters. 4. Glial cells support neurons and include types like oligodendrocytes, astrocytes, and microglia. 5. Schwann cells myelinate axons in the peripheral nervous system (PNS). 6. The central nervous system (CNS) has gray matter (neuronal perikarya) and white matter (myelinated axon tracts). 7. The CNS is protected by meninges and the blood-brain barrier. 8. The choroid plexus produces cerebrospinal fluid (CSF). 9. Ganglia contain neuronal cell bodies and satellite cells. 10. Neural plasticity involves the formation and remodeling of synaptic connections. 11. Certain regions of the CNS have neural stem cells that allow limited neuron replacement. 12. Axonal regeneration is more possible in the PNS than in the CNS. 13. The CNS is enclosed by three meninges: dura mater, arachnoid layer, and pia mater. 14. Astrocytes regulate neuronal microenvironments in the CNS. 15. Ependymal cells line the fluid-filled cerebral ventricles and central canal. 16. Microglia mediate immune defense activity within the CNS. 17. Oligodendrocytes form myelin sheaths around axons in the CNS. 18. Satellite cells regulate the microenvironment of PNS neuronal cell bodies. 19. The CNS consists of regions rich in neuronal perikarya and astrocytes (gray matter) and myelinated axon tracts (white matter). 20. The arachnoid layer contains cerebrospinal fluid (CSF) that cushions the CNS. 21. Water is removed from capillaries by the choroid plexus and transferred into the ventricles as CSF. 22. The blood-brain barrier protects neurons in most CNS regions. 23. Peripheral nerves contain motor, sensory, and autonomic neurons. 24. Schwann cells enclose and myelinate axons in peripheral nerves. 25. Connective tissue layers (endoneurium, perineurium, and epineurium) surround axons in peripheral nerves. 26. Ganglia are surrounded by connective tissue and contain neuronal cell bodies. 27. Neural stem and progenitor cells in certain CNS regions allow limited neuron replacement. 28. Regeneration and restoration of function in the CNS after major injury are challenging. 29. Axonal regeneration in the PNS involves the reactivation of the perikaryon, Schwann cells, and macrophages. 30. Neural plasticity involving synaptic connections occurs throughout life. …………………………………………………………………………………………………… Chapter 10 1. Muscle tissue is the fourth basic tissue type and is composed of cells that have the property of contractility. 2. There are three types of muscle tissue: skeletal, cardiac, and smooth. 3. Skeletal muscle is voluntary and consists of long, multinucleated cells with cross-striations. 4. Cardiac muscle is involuntary, has cross-striations, and is composed of elongated, branched cells bound together by intercalated discs. 5. Smooth muscle is involuntary, lacks striations, and consists of fusiform cells with slow contractions. 6. Muscle contraction is caused by the sliding interaction of thick myosin filaments along thin actin filaments. 7. Muscle cells have specialized organelles: sarcoplasm (cytoplasm), sarcoplasmic reticulum (smooth ER), and sarcolemma (cell membrane). 8. Skeletal muscle fibers are long, cylindrical, multinucleated cells that differentiate from myoblasts and have elongated nuclei located under the sarcolemma. 9. Muscle fibers are organized into fascicles surrounded by connective tissue layers: epimysium, perimysium, and endomysium. 10. Skeletal muscle fibers contain myofibrils, which are bundles of filamentous proteins (myosin and actin) organized into sarcomeres, the functional units of contraction. 1. Cardiac muscle cells form complex junctions between interdigitating processes and are tightly woven together in spiraling layers. 2. Cardiac muscle cells have a striated banding pattern and usually have one centrally located nucleus. 3. Intercalated discs are present in cardiac muscle and provide strong intercellular adhesion through desmosomes and fascia adherens junctions. 4. Cardiac muscle cells have a similar contractile apparatus to skeletal muscle, with mitochondria occupying a significant portion of the cell volume. 5. The muscle of the heart ventricles is thicker than that of the atria, reflecting its role in pumping blood. 6. T-tubules are well-developed in ventricular muscle fibers, while in atrial muscle they are smaller or absent. 7. The sarcoplasmic reticulum is less organized in cardiac muscle compared to skeletal muscle fibers. 8. Cardiac muscle fiber contraction is intrinsic and spontaneous, regulated by specialized myocardial fibers. 9. Cardiac muscle cells release the hormone atrial natriuretic factor (ANF) and serve an endocrine function. 10. Smooth muscle is specialized for slow, steady contraction and is found in blood vessels and various organs. Smooth muscle cells are elongated, unstriated, and linked by numerous gap junctions. 1. Three major types of muscle: skeletal, cardiac, and smooth. 2. Skeletal muscle cells are long, multinucleated fibers. 3. Skeletal muscle fibers have myofibrils composed of myosin and actin filaments. 4. Sarcomeres are contractile units within myofibrils. 5. Z discs separate sarcomeres. 6. Sarcoplasmic reticulum (SR) stores and releases calcium ions (Ca2+). 7. T-tubules are invaginations of the sarcolemma that trigger Ca2+ release. 8. Ca2+ binding to troponin allows myosin heads to bind actin, initiating contraction. 9. Myosin heads pivot with ATP hydrolysis, pulling the thin filaments. 10. Contraction occurs as filaments slide past each other. 11. Acetylcholine is the neurotransmitter at the neuromuscular junction. 12. Motor units consist of motor axons and the muscle fibers they innervate. 13. Muscle spindles and tendon organs are sensory proprioceptors. 14. Skeletal muscle fibers can be classified into slow and fast types. 15. Cardiac muscle fibers are cylindrical cells with central nuclei. 16. Cardiac muscle contraction is intrinsic and regulated by pacemaker fibers. 17. Intercalated discs connect cardiac muscle cells. 18. Sarcomeres in cardiac muscle function similarly to those in skeletal muscle. 19. Smooth muscle fibers are small and fusiform, linked by gap junctions. 20. Smooth muscle lacks sarcomeres and striations. 21. Contraction of smooth muscle cells is controlled by dense bodies and α-actinin. 22. Smooth muscle has a less organized sarcoplasmic reticulum and no T-tubules. 23. Regeneration of skeletal muscle is possible due to satellite cells. 24. Cardiac muscle has limited regenerative capacity. 25. Smooth muscle can regenerate through mitotic activity. 26. Skeletal muscle repair involves proliferation and fusion of satellite cells. 27. Cardiac muscle cells are linked by adherent and gap junctions. 28. Myosin light-chain kinase and calmodulin regulate smooth muscle contraction. 29. Smooth muscle cells have a small size and less differentiation, allowing rapid regeneration. 30. Smooth muscle lacks troponin but has proteins controlling sliding filaments. 1. The basal lamina of a muscle fiber is part of which structure? Correct answer: d. Endomysium 2. With the transmission electron microscope skeletal muscle fibers can be seen to contain structures called triads. What do the two lateral components of a triad represent? Correct answer: b. Sites for calcium sequestration and release 3. Which characteristic is unique to cardiac muscle? Correct answer: c. Often branched 4. In smooth muscle calcium released by the smooth ER initiates contraction by binding to what protein? Correct answer: b. Calmodulin 5. Which feature typifies T-tubules? Correct answer: c. Carry depolarization to the muscle fiber interior 6. Which characteristic is unique to smooth muscle? Correct answer: c. Thin filaments attach to dense bodies 7. In one type of muscle, numerous gap junctions, desmosomes, and adherens junctions are specifically localized in which structures? Correct answer: e. Intercalated discs ………………………………………………………………………………………………………………………………………. Chapter 11 1. The circulatory system pumps and directs blood throughout the body. 2. The cardiovascular system consists of the heart, arteries, capillaries, and veins. 3. Capillaries facilitate the exchange of oxygen, carbon dioxide, nutrients, and waste products between blood and tissues. 4. Veins carry blood back to the heart, completing the circulation. 5. The lymphatic system collects and returns fluid from tissues to the blood. 6. The heart has four chambers and consists of the endocardium, myocardium, and epicardium. 7. The cardiac skeleton provides support, anchors heart valves, and coordinates the heartbeat. 8. The heart has an impulse-conducting system composed of specialized muscle cells. 9. The parasympathetic and sympathetic nervous systems innervate the heart, affecting heart rate and rhythm. 10. Endothelial cells line blood vessels, regulate blood flow, prevent clotting, and have immune and growth- promoting functions. 1. The heart has three layers: endocardium, myocardium, and epicardium. 2. The cardiac conducting system controls rhythmic contractions. 3. Purkinje fibers are specialized cardiac muscle fibers. 4. The cardiac skeleton provides support and anchors heart valves. 5. Blood vessels have three layers: intima, media, and adventitia. 6. Endothelial cells in blood vessels produce factors that regulate clotting, muscle contraction, and inflammation. 7. Arteries are classified as large elastic, muscular, or small arteries. 8. Microvasculature consists of arterioles, capillaries, and venules. 9. Metarterioles control blood flow into capillary beds. 10. Capillaries are classified as continuous, fenestrated, or discontinuous. 11. Venules drain capillaries and are entry points for white blood cells. 12. Pericytes surround capillaries and assist in microvascular remodeling. 13. Arteriovenous anastomoses and venous portal systems are alternative microvascular pathways. 14. Veins carry blood back to the heart and have valves to prevent backflow. 15. Lymphatic vessels collect interstitial fluid as lymph. 16. Lymphatic capillaries have thin endothelial walls. 17. Lymphatic vessels propel lymph through muscle and organ movements. 18. Intimal valves in lymphatic vessels maintain unidirectional flow. 19. The thoracic duct and right lymphatic duct return lymph to the circulatory system. 20. The thoracic duct and right lymphatic duct have tunics similar to veins. 21. Lymphatic vessels join veins near the heart. 22. Lymphatics help maintain fluid balance and immune function. 23. Lymphatic vessels play a role in returning excess interstitial fluid to the bloodstream. 1. Vasa vasorum serve a function analogous to that of which of the following? Correct answer: c. Coronary arteries 2. What tissue is directly associated with and extends into the heart valves? Correct answer: d. Cardiac skeleton 3. Which of the following is true for ventricles? Correct answer: d. Walls contain Purkinje fibers of the right and left branches from the atrioventricular bundle 4. Individuals with Marfan syndrome have mutations in the fibrillin gene and commonly experience aortic aneurysms. What portion of the arterial wall is most likely to be affected by the malformed fibrillin? Correct answer: c. Tunica media 5. Which description is true of continuous capillaries? Correct answer: d. Lack a complete basement membrane 6. Which of the following is true of pericytes? Correct answer: a. Are associated with the basal lamina of capillary endothelial cells 7. During light microscopic examination of a tissue, you note a vessel that has no smooth muscle but a large amount of connective tissue at its periphery. Which of the following vessels are you examining? Correct answer: b. Venule ……………………………………………………………………….. Chapter 12 1. Blood is a connective tissue composed of cells and plasma. 2. It circulates unidirectionally within the closed circulatory system. 3. The formed elements in blood are erythrocytes, leukocytes, and platelets. 4. Blood can clot when it leaves the circulatory system, forming a clot and serum. 5. Blood can be separated by centrifugation into layers: erythrocytes, plasma, and a buffy coat. 6. Blood transports oxygen, carbon dioxide, hormones, nutrients, and waste products. 7. Leukocytes play a role in defending against infection and inflammation. 8. Plasma is an aqueous solution containing plasma proteins, nutrients, gases, waste products, hormones, and electrolytes. 9. Major plasma proteins include albumin, globulins, immunoglobulins, fibrinogen, and complement proteins. 10. Erythrocytes are red blood cells filled with hemoglobin, lack a nucleus, and have a biconcave shape. 1. Erythrocytes lack mitochondria and nuclei, relying on anaerobic glycolysis for energy. 2. Erythrocytes survive in circulation for about 120 days before being removed by macrophages. 3. Leukocytes are divided into granulocytes (neutrophils, eosinophils, and basophils) and agranulocytes (lymphocytes and monocytes). 4. Leukocytes leave the blood vessels, become amoeboid, and perform immune functions in tissues. 5. Granulocytes have specific and lysosomal granules, polymorphic nuclei, and a short lifespan. 6. Agranulocytes lack specific granules but contain lysosomes and have spherical or indented nuclei. 7. Leukocytes defend against microorganisms and aid in tissue repair by leaving blood vessels. 8. Cytokines trigger leukocyte adhesion to endothelial cells and subsequent migration to sites of injury or infection. 9. Neutrophils are the most abundant leukocytes, have multilobed nuclei, and are highly active in phagocytosis. 10. Neutrophils have azurophilic granules containing antibacterial proteins and enzymes. 11. Eosinophils are less numerous, have bilobed nuclei, and contain granules involved in combating parasites. 12. Basophils are the rarest leukocytes, have lobulated nuclei, and possess granules with mediators of inflammation. 13. Lymphocytes are small, spherical leukocytes that can be subdivided based on surface molecules. 14. B lymphocytes are involved in antibody production, while T lymphocytes play a role in cell-mediated immunity. 15. Monocytes are agranulocytes that differentiate into macrophages and participate in phagocytosis and antigen presentation. 1. Lymphocytes are the most numerous agranulocytes in blood and have spherical nuclei. 2. Mature lymphocytes can be divided into functional groups based on surface molecules. 3. B lymphocytes are a major class of lymphocytes. 4. Plasma is the liquid portion of circulating blood, while cells and platelets are the formed elements. 5. Plasma contains important proteins such as albumin, globulins, complement system proteins, fibrinogen, and immunoglobulins. 6. Red blood cells (erythrocytes) are enucleated, biconcave discs filled with hemoglobin. 7. Erythrocytes have a lifespan of about 120 days. 8. White blood cells (leukocytes) are categorized as granulocytes or agranulocytes. 9. Leukocytes become active outside the circulation through a process involving cytokines and adhesion. 10. Granulocytes have specialized lysosomes called azurophilic and specific granules. 11. Neutrophils are the most abundant leukocytes and have multilobed nuclei and cytoplasmic granules for phagocytosis. 12. Eosinophils have bilobed nuclei and granules for combating parasites and modulating inflammation. 13. Basophils are the rarest leukocytes and have irregular bilobed nuclei and granules involved in allergies and inflammation. 14. Lymphocytes have various functions as T and B cell subtypes in the immune system. 15. Lymphocytes range in size and have spherical nuclei with minimal cytoplasm. 16. Monocytes are larger agranulocytes with indented or C-shaped nuclei and differentiate into macrophages. 17. Platelets are small cell fragments derived from megakaryocytes and play a role in blood clotting. 18. Platelets have actin filaments, alpha and delta granules, and an open canalicular system. 19. Platelet degranulation is triggered by contact with collagen. 20. Albumin, globulins, complement proteins, and fibrinogen are secreted by the liver. 21. Red blood cells make up approximately 45% of a blood sample's hematocrit portion. 22. Granulocytes and agranulocytes are subgroups of white blood cells. 23. Leukocytes leave the microvasculature through a process called transendothelial migration or diapedesis. 24. Neutrophils have pink cytoplasmic granules containing factors for bacterial killing. 25. Eosinophils have eosinophilic granules for combating parasites and modulating inflammation. 1. What biochemical component of the erythrocyte cell surface primarily determines blood type? - Correct answer: b. Carbohydrate 2. Which cell in circulating blood is the precursor to microglia and most antigen-presenting cells? - Correct answer: d. Monocyte 3. What is the approximate lifespan of a circulating erythrocyte? - Correct answer: d. 4 months 4. Which cell type has cytoplasmic granules that contain heparin and histamine? - Correct answer: b. Basophils 5. A differential cell count of a blood smear from a patient with a parasitic infection is likely to reveal an increase in the circulating numbers of which cell type? - Correct answer: e. Eosinophils 6. Which of the following blood cells differentiate outside of the bone marrow? - Correct answer: d. T lymphocytes 7. Examination of a normal peripheral blood smear reveals a cell more than twice the diameter of an erythrocyte with a kidney-shaped nucleus. These cells are < 10% of the total leukocytes. Which of the following cell types is being described? - Correct answer: a. Monocyte ………………………………………………………………………………….. Chapter 13 1. Blood cells have a short lifespan and are continuously replaced through hemopoiesis. 2. Hemopoiesis occurs in the yolk sac mesoderm during early embryo development and primarily in the liver during the second trimester. 3. Bone marrow becomes the major hemopoietic organ in the third trimester. 4. Erythrocytes, granulocytes, monocytes, and platelets continue to form from stem cells in bone marrow throughout life. 5. Lymphopoiesis, the development of lymphocytes, occurs in both the bone marrow and lymphoid organs. 6. Hemopoietic stem cells are pluripotent cells that give rise to all blood cell types. 7. In vitro and in vivo techniques are used to study hemopoietic stem cells. 8. Progenitor cells give rise to specific blood cell types and can be identified as colony-forming units (CFUs). 9. Differentiation of progenitor cells leads to the formation of mature blood cell types. 10. Hemopoiesis relies on a microenvironment or niche and is regulated by hemopoietic growth factors. 1. Erythrocyte maturation involves changes in cell and nuclear volumes, nucleoli disappearance, and extrusion of the nucleus. 2. Erythropoiesis requires approximately a week and is stimulated by the glycoprotein erythropoietin. 3. The stages of erythroid progenitor cells include proerythroblast, basophilic erythroblast, polychromatophilic erythroblast, orthochromatophilic erythroblast, and reticulocytes. 4. Granulopoiesis involves cytoplasmic changes for the synthesis of azurophilic and specific granules. 5. Myeloblast is the most immature cell in the myeloid series, followed by promyelocyte and myelocyte stages. 6. Differentiation of promyelocytes leads to the production of specific granules in granulocytes. 7. Metamyelocytes mature with further condensation of their nuclei. 8. Neutrophils pass through an intermediate stage called the band cell before complete maturation. 9. Neutrophils exist in four compartments: granulopoietic compartment, storage in marrow, circulating population, and margination. 10. Monocytes and lymphocytes are distinguished based on size and nuclear shape, as they do not have specific cytoplasmic granules or nuclear lobulation. Summary of the 10 most important points: 1. Monocytes are large cells with basophilic cytoplasm and a slightly indented nucleus. They divide twice to develop into monocytes. 2. Monocytes contain extensive endoplasmic reticulum (ER) and large Golgi complexes forming lysosomes. 3. Monocytes circulate in the blood for several hours and mature into macrophages in tissues, where they function for several months. 4. Lymphocytes originate mainly in the thymus and peripheral lymphoid organs, but lymphocyte progenitor cells originate in the bone marrow. 5. Lymphoblasts are the first identifiable progenitors of lymphoid cells and can divide to form lymphocytes. 6. As lymphocytes develop, their nuclei become smaller, nucleoli disappear, and cell size decreases. 7. B lymphocytes differentiate in the bone marrow, while T lymphocytes acquire properties in the thymus. 8. Platelets or thrombocytes originate from megakaryocytes in the red bone marrow. 9. Megakaryocytes are giant cells with polyploid nuclei and cytoplasm containing mitochondria, RER, and Golgi apparatus. 10. Megakaryocytes extend proplatelets, which are cellular extensions that penetrate the sinusoidal endothelium and eventually form platelets. Please note that this summary may not include all the details from the original text, but it captures the key points in a concise manner. Summary of the 23 most important points: 1. Hemopoiesis occurs in the bone marrow and involves pluripotent stem cells. 2. Progenitor cells differentiate with specific growth factors in microenvironmental niches. 3. Progenitor cells are also known as colony-forming units (CFUs), and the growth factors are called colony- stimulating factors (CSFs) or cytokines. 4. Red bone marrow is active in hemopoiesis, while yellow bone marrow is mostly adipose tissue. 5. Erythropoietic islands in marrow contain developing red blood cells. 6. During erythropoiesis, cell nuclei are extruded, producing reticulocytes. 7. Granulopoiesis involves myeloblasts, promyelocytes, myelocytes, and metamyelocytes. 8. Band cells are immature neutrophils released prematurely during bacterial infections. 9. Monoblasts produce monocytes, while lymphoblasts give rise to lymphocytes. 10. Megakaryocytes produce platelets through proplatelet formation. 11. Formed elements of blood enter the circulation by crossing sinusoidal endothelium in the red marrow. 11. Hemopoiesis occurs in the bone marrow and involves pluripotent stem cells. 12. Progenitor cells differentiate with specific growth factors in microenvironmental niches. 13. Progenitor cells are also known as colony-forming units (CFUs), and the growth factors are called colony- stimulating factors (CSFs) or cytokines. 14. Red bone marrow is active in hemopoiesis, while yellow bone marrow is mostly adipose tissue. 15. Erythropoietic islands in marrow contain developing red blood cells. 16. During erythropoiesis, cell nuclei are extruded, producing reticulocytes. 17. Granulopoiesis involves myeloblasts, promyelocytes, myelocytes, and metamyelocytes. 18. Band cells are immature neutrophils released prematurely during bacterial infections. 19. Monoblasts produce monocytes, while lymphoblasts give rise to lymphocytes. 20. Megakaryocytes produce platelets through proplatelet formation. 21. Formed elements of blood enter the circulation by crossing sinusoidal endothelium in the red marrow. 22. These processes involve various stages of cell development and differentiation. 23. The bone marrow microenvironment plays a crucial role in supporting hemopoiesis. 1. In which of the following cells involved in erythropoiesis does hemoglobin synthesis begin? e. Proerythroblast 2. Which of the following can be used to describe megakaryocytes? a. Multinucleated formed element is released 3. Which cytoplasmic components are the main constituents of the dark precipitate that forms in reticulocytes upon staining with the dye cresyl blue? e. Polyribosomes 4. Which process occurs during granulopoiesis but not during erythropoiesis? c. Nucleus becomes increasingly lobulated 5. What fate often awaits granulocytes that have entered the marginating compartment? c. Cannot reenter the circulation 6. What is the earliest stage at which specific granulocyte types can be distinguished from one another? e. Promyelocyte 7. Which cell type is capable of further mitosis after leaving the hemopoietic organ in which it is formed? d. Lymphocyte 8. Shortly after her birth a baby is diagnosed with a mutation in the erythropoietin receptor gene which leads to familial erythrocytosis (familial polycythemia). During the seventh to ninth months of fetal development, the primary effect on her red blood cell production was in which of the following? b. Yolk sac ………………………………………………………………………………………………….. Chapter 14 1. Innate immunity involves leukocytes and proteins like defensins and complement. 2. Adaptive immunity develops more slowly and is based on antigen presentation to lymphocytes. 3. Cytokines are polypeptide hormones that regulate immune cell activities. 4. Antigens are regions of macromolecules recognized by lymphocytes. 5. Antibodies are immunoglobulins produced by plasma cells in response to specific antigens. 6. Major histocompatibility complex (MHC) class I molecules present protein fragments on cell surfaces. 7. Antigen-presenting cells (APCs) present foreign protein fragments on MHC class II molecules. 8. B lymphocytes originate in the bone marrow, while T lymphocytes originate in the thymus. 9. B cells produce antibodies for humoral immunity, while T cells function in cell-mediated immunity. 10. T cells have receptors (TCRs) that bind antigens along with CD proteins. 11. Important classes of T cells include helper T cells, cytotoxic T cells, regulatory T cells, and γδ T cells. 12. B-cell receptors (BCRs) are antibodies on the cell surface that bind specific antigens. 13. Secondary lymphoid organs are where B and T cells are activated and function. 14. Lymphocytes are distributed in reticulin meshwork in secondary lymphoid tissues. 15. Follicular dendritic cells (FDCs) present antigens to B cells in secondary lymphoid tissues. 16. B cells activated by FDCs proliferate to form lymphoid nodules with germinal centers. 17. Cells produced in lymphoid nodules disperse as plasma cells, memory cells, and various T cells. 18. Thymocytes attach to thymic epithelial cells (TECs) in the thymus. 19. TECs secrete cytokines and compartmentalize the thymus into cortex and medulla. 20. Positive selection in the thymic cortex removes T cells with nonfunctional TCRs. 21. Negative selection in the thymic medulla induces apoptosis in T cells that bind strongly to self-proteins. 22. Thymic selection produces functional T cells that do not bind to host proteins. 23. Peripheral immune tolerance is maintained by regulatory T cells. 24. Regulatory T cells form in the thymus and interact with dendritic cells presenting self-antigens. 25. Mucosa-associated lymphoid tissue (MALT) is found in mucosal tracts. 26. Lymph nodes filter lymph and provide a site for B-cell activation. 27. Lymph nodes have cortex, paracortex, and medulla compartments. 28. B cells encounter antigens in the cortex of lymph nodes and then move deeper into the node. 29. T helper cells are mainly found in the paracortex of lymph nodes. 30. Lymphatic vessels enter the lymph node at the cortex. 31. The medulla of lymph nodes contains medullary cords and lymph-filled sinuses. 32. The spleen has white pulp and red pulp regions. 33. White pulp in the spleen is associated with central arterioles and periarteriolar lymphoid sheaths (PALS). 34. Red pulp in the spleen filters blood and contains splenic cords and sinusoids. 35. Splenic sinusoids are lined by elongated endothelial cells called stave cells. 36. Blood flow in the red pulp of the spleen can be closed or open circulation. 37. Open circulation in the spleen involves interaction with splenic cord macrophages. 38. Splenic cord macrophages remove old and swollen red blood cells. 39. Red pulp of the spleen is involved in recycling hemoglobin iron. 40. Lymph nodes are encapsulated and occur along lymphatic vessels. 41. Each lymph node has afferent and efferent lymphatics. 42. The spleen does not have a cortex/medulla structure like lymph nodes. 43. The spleen has white pulp associated with central arterioles and red pulp involved in blood filtration. 44. Lymph enters the lymph node at the cortex, where B cells encounter antigens. 45. T helper cells are mainly found in the paracortex of lymph nodes. 46. Medulla of lymph nodes contains medullary cords and lymph-filled sinuses. 47. The spleen has white pulp associated with arterial vessels and red pulp involved in blood filtration. 48. Splenic sinusoids are lined by elongated endothelial cells called stave cells. 49. Blood flow in the red pulp of the spleen can be closed or open circulation. 50. Splenic cord macrophages in the spleen remove old and swollen red blood cells. 1. Which function is carried out by all lymphoid tissues and organs? d. Production of lymphocytes 2. Which structure is partly encapsulated and covered by nonkeratinized stratified squamous epithelium? c. Palatine tonsil 3. Which cell type gives rise to both memory and effector cells and is primarily associated with humoral immunity? a. B lymphocyte 4. Recycling of iron and heme, the major complex containing iron, occurs most actively in which lymphoid organ(s)/tissue(s)? d. Spleen 5. Which description is true of all secondary (peripheral) lymphoid organs? e. Contain lymphoid nodules 6. Which structure would be most heavily labeled by an immunohistochemical method targeting the CD8 surface antigen? b. Paracortex 7. Many immune-related cellular activities are often impaired in aged patients. Which lymphoid organ(s) normally develop less functionality and increasing amounts of adipose tissue with age? c. Thymus ……………………………………………………………………………….. Chapter 18 Summary of 40 important points: 1. Skin consists of the epidermis and dermis layers. 2. The epidermis is composed of keratinocytes undergoing keratinization. 3. The stratum basale is a layer of actively dividing cells attached to the basement membrane. 4. The stratum spinosum consists of polyhedral cells attached by desmosomes. 5. The stratum granulosum contains flattened keratinocytes filled with granules. 6. The stratum corneum is the outermost layer of flattened, differentiated cells. 7. Epidermal ridges and dermal papillae strengthen the epidermis-dermis interface. 8. Melanocytes produce melanin to protect against UV damage. 9. Langerhans cells are antigen-presenting cells in the epidermis. 10. The dermis has a papillary layer and a reticular layer. 11. Sensory receptors in the skin include free nerve endings and Merkel cells. 12. Meissner corpuscles detect light touch. 13. Pacinian corpuscles detect pressure and firm touch. 14. Hairs form in hair follicles through keratinocyte proliferation and differentiation. 15. Hair follicles have a dermal papilla and surrounding sheaths. 16. Nails are formed by keratinocyte proliferation and differentiation. 17. Sebaceous glands produce sebum onto hair in follicles. 18. Eccrine sweat glands produce watery sweat for cooling the body. 19. Apocrine sweat glands secrete protein-rich sweat onto hair. 20. The immune system has lymphoid tissues and organs. 21. Lymphoid tissues and organs carry out various functions. 22. Filtration of lymph is a function of lymphoid tissues and organs. 23. Production of lymphocytes is a function of lymphoid tissues and organs. 24. The lymph node is partly encapsulated and covered by nonkeratinized stratified squamous epithelium. 25. B lymphocytes give rise to memory and effector cells and are associated with humoral immunity. 26. The spleen is involved in the recycling of iron and heme. 27. Secondary lymphoid organs contain lymphoid nodules. 28. The paracortex is labeled heavily by targeting the CD8 surface antigen. 29. Aging affects the functionality of lymphoid organs. 30. The thymus develops less functionality and more adipose tissue with age. 31. The skin acts as a barrier against water loss and microbial invasion. 32. Epidermal strata undergo distinct differentiation processes. 33. Melanocytes produce melanin to protect against UV damage. 34. Langerhans cells intercept and sample microbial invaders in the epidermis. 35. The dermis provides support and contains sensory receptors. 36. Sensory receptors detect pain, temperature, and touch. 37. Hair follicles produce hairs through keratinocyte proliferation and differentiation. 38. Sebaceous and sweat glands secrete substances onto the skin. 39. Lymphoid tissues and organs play a crucial role in the immune system. 40. Aging affects the functionality of specific lymphoid organs. 1. Which of the following components of the epidermis provides sealant between adjacent cells? Correct Answer: d. Desmosomes 2. Which cells derive from precursors originating in the bone marrow and function as antigen-presenting cells in the skin? Correct Answer: b. Langerhans cells 3. Cells responsible for producing the pigment for dark hair are located in which of the following? Correct Answer: d. The dermal papilla of the hair bulb 4. Which of the following separates the hair follicle from the connective tissue of the dermis? Correct Answer: c. Glassy membrane 5. Which structure typifies reticular dermis but not papillary dermis? Correct Answer: b. Dense irregular connective tissue 6. Which of the following best characterizes sebaceous glands? Correct Answer: b. It releases its contents via holocrine secretion. 7. Myoepithelial cells aid in the secretory process of which of the following? Correct Answer: d. Eccrine sweat glands

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