Connective Tissue Overview

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Questions and Answers

What are the four basic types of animal tissue?

Epithelial, muscular, nervous, and connective tissue.

Name the primary cell types found in connective tissue proper.

Fibroblasts, adipocytes, plasma cells, mast cells, and macrophages.

What is the main function of fibroblasts in connective tissue?

Fibroblasts are important for the synthesis of collagen fibers and ground substances.

Differentiate between unilocular and multilocular adipocytes.

Unilocular adipocytes have a single large lipid droplet, while multilocular adipocytes contain multiple smaller droplets. Signup and view all the answers

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

The ECM provides structural and biochemical support to surrounding cells. Signup and view all the answers

What is the significance of the rough endoplasmic reticulum in fibroblasts?

The rough endoplasmic reticulum is significant for the synthesis of proteins, including collagen. Signup and view all the answers

Explain how connective tissue integrates with other tissue types in the body.

Connective tissue integrates with epithelial, muscular, and nervous tissues to support and facilitate their functions. Signup and view all the answers

Identify the germ layer from which connective tissue is derived.

Connective tissue is derived from the mesoderm of embryonic germ layers. Signup and view all the answers

What is the primary morphological characteristic of multilocular adipocytes?

Multilocular adipocytes have a small spherical morphology, typically measuring 15-25 µm. Signup and view all the answers

How does the nucleus of unilocular adipocytes differ from that of multilocular adipocytes?

Unilocular adipocytes have a flattened nucleus that is displaced to the periphery, while multilocular adipocytes have a round nucleus that is centrally located. Signup and view all the answers

What is the role of rich mitochondrial presence in multilocular adipocytes?

The numerous mitochondria in multilocular adipocytes are crucial for thermogenesis and energy expenditure. Signup and view all the answers

Identify one key function of plasma cells in the immune system.

Plasma cells are responsible for producing antibodies, playing a critical role in humoral immunity. Signup and view all the answers

What type of granules do mast cells contain, and what are their components?

Mast cells contain metachromatic granules that include histamine, heparin, and chemotactic factors. Signup and view all the answers

Explain the process through which monocytes become macrophages.

Monocytes migrate from the bloodstream and differentiate into macrophages through a process called diapedesis. Signup and view all the answers

What distinguishes the staining characteristics of plasma cells?

Plasma cells exhibit intense basophilic staining due to a well-developed rough endoplasmic reticulum (rER). Signup and view all the answers

Describe the capillary network surrounding unilocular adipocytes.

Unilocular adipocytes are surrounded by a dense network of capillaries and collagen type III (reticular fibers). Signup and view all the answers

Study Notes

Connective Tissue

Connective tissue is one of four basic animal tissues, along with epithelium, muscle, and nerve.
It integrates three basic animal tissues to function physiologically.

Connective Tissue Classification

Connective tissue (CT) is classified into CT Proper and Specialized CT.
CT Proper is further categorized into Loose CT and Dense CT.
Dense CT is then divided into Dense Regular Collagenous CT, Dense Regular Elastic CT, and Dense Irregular CT.
Specialized CT includes Cartilage, Bone, and Blood.

Connective Tissue Proper

Derived from the mesoderm of embryonic germ layers.
Differentiated from pluripotent mesenchymal cells.
Composed of cellular components and extracellular matrix (ECM).
Cellular components include fibroblasts, adipocytes, plasma cells, macrophages.
ECM consists of fibers (e.g., collagen, elastic) and ground substances.

Fibroblast

Most abundant and widely distributed in animal tissues.
Crucial for synthesizing fibers (collagen and elastic) and ground substance (GAGs, proteoglycans, glycoproteins).
Elongated, fusiform cells with irregular cytoplasmic projections.
Nucleus is oval, darker-stained, with numerous euchromatin.
Cytoplasm is pale and stains weakly eosinophilic.
Contains abundant rough endoplasmic reticulum (rER) and Golgi apparatus (GA).

Adipocyte

Crucial for lipid synthesis and storage.
Two types: multilocular (brown) and unilocular (white).
Multilocular adipocytes are small, spherical, containing numerous lipid droplets. Nucleus is round and centrally located. Contain numerous mitochondria and cytochrome. Innervated with adrenergic nerve fibers and dense capillaries. Predominantly found in birds, rodents, and newborn mammals (thyroid glands and renal hilus).
Unilocular adipocytes are large, spherical to polyhedral. Contains a single large lipid droplet (lipoblast). Lipid droplet stabilized by microfilaments. Its nucleus is flattened and displaced to the periphery (signet ring). Characterized by small Golgi apparatus, few mitochondria, sparse rER, and abundance of free ribosomes. Plasma membrane has insulin, growth hormone, cortisol, and noradrenaline receptors. Surrounded by dense capillary network and collagen type III (reticular fiber).

Plasma Cell

Differentiated B-lymphocytes involved in humoral immunity.
Morphologically large, ovoid cells (20 µm).
Nucleus is eccentrically located, with heterochromatin concentrated in a peripheral clump (clock face, spoke wheel, or cartwheel).
Cytoplasm stains intensely basophilic, with well-developed rER containing closely packed cisternae.
Contains few scattered mitochondria and numerous free ribosomes.
Found in lamina propria of gastric and enteric mucosa.

Mast Cell

Large, ovoid cells (20-30 µm) found in loose connective tissue.
Nucleus is centrally located, with an ellipsoid shape.
Cytoplasm is basophilic.
Contains numerous granules (0.3-0.8 µm) with metachromatic staining.
Granules contain histamine, heparin, and chemotactic factors (ECF and NCF).
Express IgE receptors, involved in hypersensitivity type I.
Long lifespan (weeks to months).

Macrophage

Derived from hematopoietic stem cells; also known as histiocytes.
Circulating monocytes differentiate into macrophages (diapedesis).
Resident macrophages include Kupffer cells, Langerhans cells, and dust cells.
Phagocytose damaged, dead cells, cellular debris, and antigens.
Serve as antigen-presenting cells (APCs) via MHC class II.
Amoeboid, irregular cell morphology (10-30 µm).
Possess long, blunt projections (pseudopodia).
Activated macrophages show prominent membrane folding.
Nucleus is indented (kidney-shaped).
Cytoplasm is basophilic with small vacuoles and granules.
Contains abundance of lysosomes (azurophilic granules).
Well-developed Golgi apparatus and rough endoplasmic reticulum.

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Description

This quiz covers the basics of connective tissue, one of the four fundamental animal tissues. You'll explore its classifications, including CT Proper and Specialized CT, as well as the various cellular components that make up these tissues. Test your knowledge on the role of fibroblasts and the extracellular matrix.