Connective Tissue Introduction

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Questions and Answers

What is the primary function of tissues with a large amount of adipose connective tissue?

To facilitate the removal of apoptotic cells

To cushion and insulate skin and other organs (correct)

To provide structural support to organs

To synthesize proteins for tissue growth

What is the phagocytic ability of macrophages responsible for?

Regulating the inflammatory response

Removing protein fibers from the body

Removing apoptotic cells and tissue debris (correct)

Producing antibodies for immune response

What is the typical diameter of a macrophage?

30-50 um

5-10 um

10-30 um (correct)

50-70 um

What is the source of macrophages in the body?

Maturation of monocytes Signup and view all the answers

What is the function of the Golgi complex in macrophage development?

Protein synthesis Signup and view all the answers

What is the name given to monocytes that become resident in developing organs during embryonic development?

Mononuclear Phagocyte System Signup and view all the answers

What is the typical shape of mast cells?

Oval or irregularly shaped Signup and view all the answers

What is the diameter range of mast cells?

7-20 um Signup and view all the answers

What is the primary function of connective tissue in the body?

To provide a matrix that supports and physically connects other tissues and cells together Signup and view all the answers

What is the main component of the extracellular matrix (ECM) in connective tissue?

Ground substance Signup and view all the answers

What is the characteristic shape of mesenchymal cells?

Spindle-shaped Signup and view all the answers

Which type of cell is responsible for synthesizing and secreting collagen and elastin?

Fibroblast Signup and view all the answers

What stimulates the division of connective tissue fibroblasts?

Growth factors Signup and view all the answers

What is the function of adipocytes in connective tissue?

To store lipids as neutral fats for the production of heat Signup and view all the answers

What is the origin of connective tissue cells?

Embryonic mesenchyme Signup and view all the answers

What type of proteins are fibroblasts targets of?

Growth factors Signup and view all the answers

What is the average diameter of granules in mast cells?

0.3-2.0 um Signup and view all the answers

What is the purpose of heparin in mast cells?

It acts as an anticoagulant Signup and view all the answers

What is the effect of histamine on blood vessels?

It increases vascular permeability Signup and view all the answers

What type of molecules are phospholipid precursors converted into?

Lipid mediators Signup and view all the answers

What type of cells are attracted by eosinophil and neutrophil chemotactic factors?

Eosinophils and neutrophils Signup and view all the answers

What is the function of cytokines in mast cells?

They direct the activities of leukocytes and other cells Signup and view all the answers

Where are mast cells typically located?

Near small blood vessels in the skin and mesenteries, and in mucosa Signup and view all the answers

What is the result of the release of chemical mediators from mast cells?

An immediate hypersensitivity reaction Signup and view all the answers

What is the characteristic of reticular fibers after impregnation with silver salts?

Stained black Signup and view all the answers

What percentage of reticular fibers are composed of sugar chains bound to collagen?

10% Signup and view all the answers

What is the primary function of delicate reticular networks in the liver and endocrine glands?

To serve as a supportive stroma for the parenchymal secretory cells and microvasculature Signup and view all the answers

What is the primary component of elastic fibers that provides their rubber-like properties?

Elastin Signup and view all the answers

What is the function of microfibrils in the formation of elastic fibers?

To act as a scaffolding upon which elastin is deposited Signup and view all the answers

What type of cells are responsible for producing reticular fibers in certain locations?

Fibroblasts Signup and view all the answers

What is the characteristic of tissues that contain reticular fibers?

They are able to be stretched or distended and return to their original shape Signup and view all the answers

What is the component of elastic fibers that forms a network with microfibrils?

Fibrillin Signup and view all the answers

What is the main function of linking/anchoring collagens?

To link fibrillar collagens to one another and to other components of the ECM Signup and view all the answers

What is the primary component of reticular fibers?

Type III collagen Signup and view all the answers

What is the function of Type VII collagen in basement membranes?

To anchor the basal lamina to the underlying reticular lamina Signup and view all the answers

What is the approximate percentage of collagen in the human body's dry weight?

30% Signup and view all the answers

What is the main characteristic of collagen fibers?

They are extremely strong and resistant to normal shearing and tearing forces Signup and view all the answers

What type of collagen is mainly involved in the formation of structures such as tendons and organ capsules?

Type I collagen Signup and view all the answers

What is the role of fibroblasts in collagen production?

They are a major product of collagen production Signup and view all the answers

What is the function of network or sheet-forming collagens?

To form external laminae and epithelial basal laminae Signup and view all the answers

Study Notes

Overview of Connective Tissue

Connective tissue consists of extracellular matrix (ECM) that supports and connects other tissues and cells, forming the body's organs.
ECM is composed of protein fibers and ground substance, primarily derived from embryonic mesenchyme, which has a viscous consistency and few collagen fibers.
Mesenchymal cells, the progenitor cells of connective tissue, possess large nuclei and a spindle-shaped appearance with minimal cytoplasm.

Types of Cells in Connective Tissue

Fibroblasts
- Most common cells in connective tissue, responsible for synthesizing collagen, elastin, GAGs, and proteoglycans.
- Essential for maintaining the ECM and undergo division stimulated by growth factors during tissue repair.
Adipocytes (Fat Cells)
- Specialized for storing lipids as neutral fats, playing a vital role in cushioning and insulating organs.
- Predominant in areas rich in adipose connective tissue.
Macrophages
- Phagocytic cells involved in the turnover of protein fibers, removal of apoptotic cells, and debris, especially during inflammation.
- Eccentric kidney-shaped nucleus, originating from monocytes that migrate from blood into connective tissues.
- Part of the mononuclear phagocyte system, crucial for immune responses, formed from yolk sac during early development.
Mast Cells
- Oval or irregular cells containing basophilic secretory granules, contributing to local inflammatory responses and innate immunity.
- Release bioactive substances such as heparin (anticoagulant), histamine (increases vascular permeability), and cytokines.
- Significant in immediate hypersensitivity reactions, primarily found near small blood vessels.

Types of Fibers in Connective Tissue

Reticular Fibers
- Composed mostly of type III collagen, providing a delicate supportive network.
- Found in organs like the liver, spleen, and lymph nodes, aiding in structure for secretory cells and blood vessels.
Elastic Fibers
- Composed of elastin and fibrillin, allowing tissues to be stretched and return to original shape.
- Found in large blood vessels and contribute to the elasticity of organs, e.g., lungs.
Collagen Fibers
- Type I collagen is the most abundant and forms dense bundles within connective tissues such as tendons and dermis.
- Type IV collagen is major in structuring epithelial basal laminae and external laminae of muscle and nerve cells.
- Collagen represents approximately 30% of the human body's dry weight and is crucial for the structural integrity of connective tissues.

Functions of Connective Tissue

Provides structural support and protection to organs.
Plays a role in defense mechanisms through immune cells like macrophages and mast cells.
Facilitates repair processes after injury via fibroblasts and ECM remodeling.

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Description

Learn about the basics of connective tissue, its composition, and function in supporting and connecting other tissues and cells. Understand the role of ECM, protein fibers, and ground substance. Explore the origin of connective tissues from embryonic mesenchyme.