Histology PDF - Tissues, Cells, and Structures
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Uploaded by FelicitousGroup2887
Mapúa University
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Summary
This document discusses histology, the microscopic study of tissues. It covers four main tissue types: epithelial, connective, muscle, and nervous. The document also details their functions, classifications, and examples, like epithelial tissue types and their surface modifications. It’s a useful tool for students learning about biology.
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Histology Pseudostratified Epithelium: Appears layered due to varying cell heights but is a single layer Definition: Histology is the microscopic study of (e.g., in the respiratory tract, often ciliated)....
Histology Pseudostratified Epithelium: Appears layered due to varying cell heights but is a single layer Definition: Histology is the microscopic study of (e.g., in the respiratory tract, often ciliated). tissue appearance, organization, and function. It forms the foundation for understanding pathology Transitional Epithelium: Found in the urinary (diseases and abnormalities at the tissue level). bladder; stretches and changes shape depending on the bladder's fullness. Four Main Types of Tissues 1. Epithelial Tissue: ○ Functions: Covers body surfaces, lines cavities, and forms glands. Provides protection, absorption, secretion, and filtration. ○ Classification: Based on Layers: ○ Surface Modifications: Simple Epithelium: Single layer of cells, Cilia: Found in respiratory tract; specialized for absorption, secretion, or filtration. helps remove debris. Stratified Epithelium: Multiple layers of cells, Microvilli: Increases surface providing protection in areas with wear and tear. area for absorption (e.g., in intestines). Based on Shape: 2. Connective Tissue: Squamous: Flat and thin cells (e.g., found in ○ Functions: Supports, binds, and alveoli of lungs for gas exchange). protects other tissues and organs. Cuboidal: Cube-shaped cells (e.g., in gland ducts ○ Components: and kidney tubules). Cells: Include fibroblasts (secrete Columnar: Tall and narrow cells (e.g., in the fibers), adipocytes (fat digestive tract for absorption and secretion). cells), and immune cells. Fibers: Collagen (strength), elastic (flexibility), reticular (support). Ground Substance: Gel-like material filling spaces between fibers and cells. ○ Examples: Adipose Tissue: Stores energy and provides insulation. Bone: Rigid structure for support and Specialized Types: protection. Cartilage: Provides Key Features of Tissues flexibility and cushioning. Regeneration: Blood: Fluid connective ○ Epithelial tissue regenerates tissue for transport of quickly due to its exposure to nutrients, gases, and wear and tear. waste. ○ Connective tissues vary in their 3. Muscle Tissue: ability to regenerate (e.g., ○ Functions: Specialized for cartilage heals slowly due to low contraction, enabling movement. blood supply). ○ Types: Matrix Composition: Skeletal Muscle: ○ Connective tissues have an Voluntary, striated, extracellular matrix composed attached to bones for of fibers and ground substance, movement. providing structural and Cardiac Muscle: functional support. Involuntary, striated, found in the heart; Glands pumps blood. Smooth Muscle: Definition: Structures composed of Involuntary, epithelial cells that synthesize and non-striated, found in secrete substances. walls of hollow organs Types: (e.g., intestines, blood 1. Endocrine Glands: vessels). Ductless glands. 4. Nervous Tissue: Secrete hormones ○ Functions: Facilitates directly into the communication and control bloodstream (e.g., through electrical signals. thyroid gland, adrenal ○ Components: gland). Neurons: Functional 2. Exocrine Glands: cells that transmit Have ducts that secrete signals. substances onto surfaces or into cavities. Examples: Sweat glands: Produce sweat to regulate temperature. Digestive glands: Secrete enzymes and mucus. Parts of Neurons: Microscopic Features of Tissues Cell Body: Contains the nucleus and Epithelial Tissue: organelles. ○ Cells are closely packed with Dendrites: Receive signals. minimal extracellular matrix. Axon: Transmits signals to other cells. ○ Often supported by a basement Glial Cells: Supportive cells that protect, membrane that anchors the nourish, and insulate neurons. tissue to connective tissue beneath. Connective Tissue: ○ Variable in structure, with sparse cells embedded in a matrix. ○ Found throughout the body, supporting and binding other tissues. MEMORIZE THIS SHIT 1. 2. 3. 8. 4. 9. 5. 10. 6. 11. 7. 12. 13. 17. 14. 18. 15. 16.
