Unit 7: Connective Tissue

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary component of elastic fibers that provides elasticity in connective tissue?

  • Keratin
  • Collagen
  • Elastin (correct)
  • Fibrillin

Which cell type is considered the active form of fibroblasts?

  • Pericyte
  • Fibroblast (correct)
  • Mast cell
  • Fibrocyte

What structural feature of fibroblasts is observed under an electron microscope?

  • Abundant rough endoplasmic reticulum (correct)
  • Granular cytoplasm
  • Scant cytoplasm
  • Mitochondria predominance

What fibers provide the predominant structural support in connective tissue?

<p>Collagen fibers (A)</p> Signup and view all the answers

What is the main characteristic of fibrocystic cells when viewed microscopically?

<p>Not granular, intensely basophilic nucleus (B)</p> Signup and view all the answers

Which of the following is NOT a component of the extracellular matrix (ECM) in connective tissue?

<p>Epithelial cells (B)</p> Signup and view all the answers

Which type of fiber appears yellowish in large quantities when viewed macroscopically?

<p>Elastic fibers (B)</p> Signup and view all the answers

What are the two main components of elastic fibers?

<p>Elastin and fibrillin microfibrils (D)</p> Signup and view all the answers

What is the primary function of connective tissue?

<p>Joining together and supporting other tissues (C)</p> Signup and view all the answers

Which germ layer gives rise to mesenchymal connective tissue?

<p>Mesoderm (C)</p> Signup and view all the answers

Which of the following is NOT classified as a specialized connective tissue?

<p>Loose connective tissue (B), Adipose tissue (C)</p> Signup and view all the answers

What type of connective tissue provides thermal regulation in the body?

<p>Adipose tissue (B)</p> Signup and view all the answers

Which component of the extracellular matrix provides resistance to compression forces?

<p>Ground substance (C)</p> Signup and view all the answers

What type of connective tissue is characterized by structural diversity and includes various types such as loose and dense connective tissues?

<p>Connective tissue proper (A)</p> Signup and view all the answers

Which of the following is a function of connective tissue related to immune response?

<p>Defense and protection (B)</p> Signup and view all the answers

Collagen fibers primarily provide which of the following properties to connective tissue?

<p>Resistance to traction forces (A)</p> Signup and view all the answers

What are the repeating units that make up Glycosaminoglycans (GAGs)?

<p>Disaccharides (D)</p> Signup and view all the answers

Which of the following types of GAGs are known to be sulfated?

<p>Dermatan sulfate (B), Heparin (C)</p> Signup and view all the answers

What is the primary function of proteoglycans in the ground substance?

<p>Storing growth factors (A), Providing structural support (B)</p> Signup and view all the answers

Which adhesive glycoprotein is known for connecting extracellular matrix components to integrins?

<p>Fibronectin (B)</p> Signup and view all the answers

What distinguishes collagen fibers under a light microscope stained with H&E?

<p>Bright white color (B)</p> Signup and view all the answers

Which type of collagen fibers is known as reticulin fibers?

<p>Type III collagen (B)</p> Signup and view all the answers

What property of GAGs contributes to their function as physical barriers?

<p>Hydrophilic nature (A), Negatively charged sulfate groups (B)</p> Signup and view all the answers

What is the diameter of collagen fibers observed under a light microscope?

<p>10 μm (A)</p> Signup and view all the answers

Which staining technique is commonly used to visualize reticular fibers?

<p>Silver stain (D)</p> Signup and view all the answers

What is the role of adhesive glycoproteins in the extracellular matrix?

<p>Facilitate cell attachment and communication (B)</p> Signup and view all the answers

What is a distinguishing feature of unilocular adipocytes?

<p>Have triglycerides in a single large droplet (D)</p> Signup and view all the answers

Which cell type is known for its contractile activity and is often found in healing areas?

<p>Myofibroblasts (B)</p> Signup and view all the answers

What is the primary function of mast cells?

<p>Immediate hypersensitivity reaction (C)</p> Signup and view all the answers

What is a characteristic feature of multilocular adipocytes?

<p>Numerous small lipid droplets (C)</p> Signup and view all the answers

Which cell type is part of the mononuclear phagocytic system?

<p>Macrophage (C)</p> Signup and view all the answers

What is the main role of fibroblasts and fibrocytes in connective tissue?

<p>Production of connective tissue fibers (A)</p> Signup and view all the answers

How do macrophages contribute to inflammation?

<p>They release cytokines as signaling molecules. (B)</p> Signup and view all the answers

Which cells are involved in controlling vascular permeability?

<p>Mast cells (D)</p> Signup and view all the answers

What is NOT characteristic of adipocytes?

<p>Have thick cell walls (C)</p> Signup and view all the answers

Flashcards

Connective Tissue: Function

Connective tissue joins other tissues, provides structural support, regulates temperature, facilitates nutrient/waste exchange, and plays a role in defense and repair.

Connective Tissue Components

Connective tissue consists of extracellular matrix (ECM) and cells.

Extracellular Matrix (ECM)

ECM provides the framework and support for cells in connective tissue.

ECM: Ground Substance

A gel-like material in the ECM that resists compression and holds cells and fibres.

Signup and view all the flashcards

ECM: Fibers

Collagen, reticular, and elastic fibers provide tensile strength and elasticity in the ECM.

Signup and view all the flashcards

Embryonic Connective Tissue

Mesenchymal and mucous tissues are types of connective tissue found in embryos.

Signup and view all the flashcards

Connective Tissue Classification

Connective tissue is categorized into embryonic, connective tissue proper, and specialized connective tissues.

Signup and view all the flashcards

Connective Tissue Proper

Loose (areolar), dense (regular/irregular), reticular, and adipose tissues are examples of connective tissue proper.

Signup and view all the flashcards

What are elastin fibers made of?

Elastin fibers are composed of two components: a central amorphous material called elastin, produced by fibroblasts and smooth muscle cells, and a sheath of fibrillin microfibrils.

Signup and view all the flashcards

What is the function of elastin fibers?

Elastin fibers provide elasticity to connective tissue, allowing it to stretch and recoil, which is essential for various organs and tissues like skin, lungs, blood vessels, and ligaments.

Signup and view all the flashcards

What are fibrillin microfibrils?

Fibrillin microfibrils are a component of elastic fibers, forming a sheath around the central elastin core.

Signup and view all the flashcards

What are fibroblasts?

Fibroblasts are the most abundant cell type in connective tissue, responsible for synthesizing almost all of the extracellular matrix (ECM) components.

Signup and view all the flashcards

What is the difference between fibroblasts and fibrocytes?

Fibroblasts are active cells that synthesize ECM, while fibrocytes are resting cells, less active, and maintain the ECM.

Signup and view all the flashcards

How do fibroblasts and fibrocytes look under a microscope?

Fibroblasts have a large, granular nucleus with a prominent nucleolus, while fibrocytes have a smaller, intensely basophilic nucleus with less granulation.

Signup and view all the flashcards

What are the functions of fixed cells in connective tissue?

Fixed cells, like fibroblasts and mast cells, are permanent residents of connective tissue and contribute to its structure and function.

Signup and view all the flashcards

What are the functions of transient cells in connective tissue?

Transient cells, like lymphocytes and macrophages, are not permanent residents and travel through connective tissue, playing a crucial role in immune responses and tissue repair.

Signup and view all the flashcards

Ground Substance

The gel-like material that fills the space between cells and fibers in connective tissue. Provides support and resistance to compression.

Signup and view all the flashcards

Glycosaminoglycans (GAGs)

Long polysaccharides that are a major component of ground substance. They attract water, forming a hydrated gel.

Signup and view all the flashcards

GAGs: Sulfated vs. Non-sulfated

Sulfated GAGs (like chondroitin sulfate) are negatively charged, attracting cations and contributing to the gel-like nature of ground substance. Non-sulfated GAGs (like hyaluronic acid) are not charged and play a different role.

Signup and view all the flashcards

Proteoglycans

Large molecules composed of a protein core attached to sulfated GAGs. Contribute to the structural integrity and resistance to compression in connective tissue.

Signup and view all the flashcards

Adhesive Glycoproteins

Proteins that link together the components of the extracellular matrix, including collagen fibers, proteoglycans, and cells.

Signup and view all the flashcards

Collagen Fibers

The most abundant type of fiber in connective tissue, providing tensile strength and flexibility.

Signup and view all the flashcards

Collagen Fiber Structure

Collagen fibers are made of bundles of collagen fibrils, which are composed of tropocollagen molecules. Tropocollagen is a triple helix of three alpha chains.

Signup and view all the flashcards

Reticular Fibers

Delicate, thin fibers made of type III collagen, forming a network around organs and cells.

Signup and view all the flashcards

Electron Microscopy: Collagen Fibers

Under an electron microscope, collagen fibers display a characteristic cross-banding pattern with regular intervals of 67 nm.

Signup and view all the flashcards

Types of Collagen

There are different types of collagen, each with specific functions and distributions. For example, type I collagen is found in bone, skin, and tendons, while type III collagen is found in reticular fibers.

Signup and view all the flashcards

Myofibroblasts

Specialized cells that combine features of fibroblasts and smooth muscle cells, exhibiting contractile activity due to actin filaments. They lack a basal lamina and are prominent in healing areas.

Signup and view all the flashcards

Pericytes

Spindle-shaped cells with numerous cytoplasmic processes that partially surround capillaries and small venules. They share characteristics of endothelial cells and smooth muscle cells, including contractile activity.

Signup and view all the flashcards

Unilocular Adipocyte

A type of fat cell containing a single large droplet of triglycerides, giving it a signet ring appearance under a microscope.

Signup and view all the flashcards

Multilocular Adipocyte

A type of fat cell containing multiple small droplets of triglycerides. It is smaller than a unilocular adipocyte and has a central nucleus. Abundant mitochondria facilitate heat production.

Signup and view all the flashcards

Mast Cell Function

Release chemical mediators like histamine and heparin to mediate immediate hypersensitivity reactions (allergies) and inflammation.

Signup and view all the flashcards

Macrophage Origins

Originate from monocytes derived from bone marrow. They have a lifespan of about two months.

Signup and view all the flashcards

Free vs. Resident Macrophages

Free macrophages migrate to specific locations based on external stimuli, while resident macrophages remain in specific tissue sites regardless.

Signup and view all the flashcards

Macrophage Morphology (Light Microscope)

Irregularly shaped cells with a large size, a pale, often vacuolated cytoplasm and an eccentric, vesicular nucleus.

Signup and view all the flashcards

Epithelioid Cell

A type of macrophage found in chronic inflammation. It has a more epithelioid shape and can fuse with other macrophages to form multinucleated giant cells.

Signup and view all the flashcards

Macrophage Function

Phagocytosis and digestion of foreign material, production of signaling molecules (cytokines) and processing and presentation of antigens to lymphocytes.

Signup and view all the flashcards

Study Notes

Connective Tissue I

  • Connective tissue is a major tissue type used to support and connect other tissues.
  • It forms a continuity of the body and maintains integration.
  • It demonstrates morphological, topographic, and structural diversity.
  • The term "connective" means "joining together."
  • Connective tissue supports and connects other tissues.

Connective Tissue: Introduction - Embryonic Origin

  • Connective tissue arises from mesoderm, the middle germ layer.
  • Mesenchymal cells are the primary cells differentiating into specialized connective tissues.
  • Mesenchymal cells are undifferentiated cells in the mesoderm layer that give rise to different connective tissues.

Connective Tissue: Classification

  • Embryonic connective tissue includes mesenchymal and mucous connective tissue.
  • Connective tissue proper includes loose (areolar), dense (regular and irregular), reticular, and adipose tissues.
  • Specialized connective tissues include cartilage, bone, and blood.

Connective Tissue: Functions

  • Connective tissue connects all four tissue types.
  • It provides structural support (bones, cartilage, ligaments, tendons, capsules, and stroma).
  • It regulates temperature (adipose tissue).
  • It exchanges nutrients and waste products.
  • It defends, protects, and repairs the body (phagocytic cells, immunocompetent cells, pharmacological substances, and physical barriers).
  • Fat stores energy.

Connective Tissue: Components - Extracellular Matrix (ECM)

  • The ECM is composed of ground substance and fibers.
  • The proportion of components varies in different connective tissues.
  • Cells are also components, varying in type and proportion depending on the tissue.

Connective Tissue: Components - Extracellular Matrix (ECM) - Ground Substance

  • Hydrated, gel-like material.
  • Provides resistance to compression forces.
  • Contains glycosaminoglycans (GAGs), proteoglycans (PGs), and adhesive glycoproteins.
    • GAGs are long polysaccharides with repeating disaccharide units (amino sugar + uronic acid).
    • GAGs are often sulfated (negatively charged), retaining liquid and acting as a physical barrier.
    • Examples include keratin sulfate, heparan sulfate, chondroitin sulfate, dermatan sulfate, and heparin.
    • Hyaluronic acid is a type of GAG that is not sulfated.
    • Proteoglycans are GAGs bound to core proteins. Aggregates of proteoglycans with hyaluronic acid are important for tissue structure, especially in cartilage.
    • Adhesive glycoproteins bind ECM components together and to cells; examples include fibronectin, laminin, entactin, tenascin, chondronectin, and osteonectin.

Connective Tissue: Components - Extracellular Matrix (ECM) - Fibers

  • Collagen fibers: Most abundant and present in most connective tissues.
    • Macroscopically: bright white.
    • Microscopically: 10 μm in diameter, organized in bundles. H&E stains collagen pink.
    • Van Gieson stain and light green techniques can also be used to distinguish collagen.
    • Electron microscopy reveals cross-banding at regular intervals (67 nm).
    • Types of collagen (I, II, III, IV, V) exist and perform different functions in different tissues (dermis, tendons, bone, hyaline cartilage, etc).
  • Reticular fibers: Thin, branching collagen fibers forming a flexible mesh.
    • Stained with silver techniques and PAS.
    • Important in organs and tissues.
  • Elastic fibers: Provide elasticity to tissues.
    • Macroscopically: yellowish.
    • Microscopically: acidophilic, shiny, wavy bundles.
    • Composed of elastin (central amorphous material) and fibrillin microfibrils.

Connective Tissue: Cells

  • Connective tissue cells are categorized as fixed or resident and transient or immigrant cells.
  • Fixed/Resident cells: include fibroblasts, pericytes, fat cells, mast cells, and macrophages.
  • Transient/Immigrant cells: include plasma cells, lymphocytes, neutrophils, eosinophils, basophils, monocytes, and some macrophages.

Connective Tissue: Cells - Fibroblasts and Fibrocytes

  • Fibroblasts are the most abundant in connective tissue.
  • Derived from mesenchymal cells.
  • Synthesize most of the ECM (collagen, elastin, ground substance)
  • Fibrocytes are the resting form of fibroblasts; less active in synthesis.

Connective Tissue: Cells - Pericytes

  • Spindle-shaped cells with cytoplasmic processes.
  • Partially surround endothelial cells of capillaries and small venules.
  • Have contractile activity.

Connective Tissue: Cells - Fat Cells/Adipocytes

  • Synthesize and store triglycerides.
  • Two types:
    • Unilocular adipocytes (white fat): single, large fat droplet.
    • Multilocular adipocytes (brown fat): multiple small fat droplets, abundant mitochondria.

Connective Tissue: Cells - Mast Cells

  • Originate in bone marrow.
  • Ovoid shape, variable size, with basophilic granules.
  • Contain heparin (anticoagulant) and histamine (vasodilator).
  • Involved in immediate hypersensitivity reactions (allergies).

Connective Tissue: Cells - Macrophages

  • Macrophages are derived from monocytes in the blood, and are a part of the mononuclear phagocytic system.
  • Phagocytic; responsible for removing foreign materials and debris.
  • Present antigens to lymphocytes, and release signaling molecules.
  • Function in chronic inflammation (epithelial cells formation, foreign body giant cells)

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Connective Tissue I PDF

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser