Connective Tissue Cells and Fibers

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Questions and Answers

Which type of cartilage is characterized by the presence of elastic fibers in its extracellular matrix?

Hyaline cartilage

Elastic cartilage (correct)

Fibrocartilage

None of the above

What is the primary function of bone tissue?

Facilitate digestion

Conduct nerve signals

Support and protect the body (correct)

Regulate blood circulation

Which cellular component is responsible for the mineralization of bone?

Osteocytes

Chondrocytes

Osteoblasts (correct)

Osteoclasts

Which type of cartilage has a matrix composed primarily of collagen I and II?

Fibrocartilage Signup and view all the answers

What is the function of chondronectin in cartilage?

Maintains cartilage structure Signup and view all the answers

What type of bone structure is referred to as trabecular bone?

Spongy bone Signup and view all the answers

Which type of growth is characterized by the expansion of cartilage from the outer surface?

Apositional growth Signup and view all the answers

Which element is NOT a component of hydroxyapatite crystals in bone?

Sodium Signup and view all the answers

Which cell type is primarily responsible for synthesizing the extracellular matrix in connective tissue?

Fibroblasts Signup and view all the answers

What type of fibers are indicated as being very thin and visible only with special staining methods?

Reticular fibers Signup and view all the answers

Which type of ground substance consists of protein combined with glycosaminoglycans (GAGs)?

Proteoglycans Signup and view all the answers

How are leukocytes primarily triggered to migrate from blood vessels during an inflammatory response?

Diapedesis Signup and view all the answers

What is the role of mast cells in connective tissue?

Inflammatory/immune response Signup and view all the answers

Which cartilage type's extracellular matrix composition distinguishes it from other types?

All cartilage types have the same matrix Signup and view all the answers

What is identified as a key structural protein family in connective tissue?

Collagens Signup and view all the answers

Which component is NOT a major part of the ground substance in connective tissue?

Elastin fibers Signup and view all the answers

What is the primary role of parathormone in bone health?

Raises low blood calcium and stimulates osteoclasts Signup and view all the answers

Which condition results from a deficiency of calcium or vitamin D during growth?

Osteomalacia Signup and view all the answers

What effect does calcitonin have on blood calcium levels?

Lowers elevated blood calcium levels Signup and view all the answers

Which of the following describes the osteon or Haversian system?

Made up of concentric lamellae and surrounds a major blood vessel Signup and view all the answers

Which factor is NOT associated with osteoporosis?

Increased calcium absorption in the gut Signup and view all the answers

What is a defining characteristic of Paget’s disease?

Disorganized bone structure prone to fractures Signup and view all the answers

What type of cartilage is found in synovial joints?

Hyaline cartilage Signup and view all the answers

What is the primary function of synovial fluid in joints?

Helps with lubrication and nutrition of joint tissues Signup and view all the answers

Study Notes

Cells of Connective Tissue

Most common cell type is the fibroblast, responsible for synthesizing the extracellular matrix and playing a role in healing and scar formation.
Macrophages are phagocytes responsible for the inflammatory and immune response, derived from bone marrow.
Mast cells release histamine and are involved in the inflammatory and immune response, derived from bone marrow.
Plasma cells produce antibodies, with a large basophilic cytoplasm due to the abundance of rough endoplasmic reticulum (RER).
Adipose cells store fat.
Leukocytes, including neutrophils, lymphocytes, and monocytes, migrate from blood vessels via diapedesis and play a crucial role in the inflammatory response.

Fibers of Connective Tissue

Collagen fibers are a family of structural proteins with over 25 members, providing strength and support to connective tissue.
Reticular fibers, composed of collagen type III, are thin and only visible with special staining.
Elastic fibers are resistant to pulling and provide elasticity to connective tissue.

Ground Substance of Connective Tissue

Glycosaminoglycans (GAGs) are polysaccharides like hyaluronic acid, responsible for hydration and providing a gel-like consistency to the ground substance.
Proteoglycans are complexes of proteins and GAGs, including dermatan sulfate, chondroitin sulfate, keratan sulfate, and heparan sulfate, that bind to water and contribute to the structural integrity of the ground substance.
Glycoproteins are protein-carbohydrate complexes like fibronectin and laminin that help with cell attachment and migration.

Cartilage

Cartilage is a specialized connective tissue with chondrocytes embedded in an extracellular matrix.
Hyaline cartilage, the most common type, features collagen type II, proteoglycans, and chondronectin in its matrix. It undergoes both appositional and interstitial growth.
Elastic cartilage, found in the ear and epiglottis, contains elastic fibers in addition to collagen type II.
Fibrocartilage, with collagen type I and II, provides strength and support, found in intervertebral discs and menisci.

Bone

Bone is a connective tissue with osteogenic cells, a mineralized extracellular matrix rich in collagen type I and proteoglycans, and hydroxyapatite crystals.
Bone performs several functions: support, protection, and storage of calcium and phosphate.
Osteoblasts are bone-forming cells derived from mesenchymal osteoprogenitor cells, responsible for synthesizing the organic matrix (osteoid) and depositing calcium phosphate crystals.
Osteocytes are mature bone cells residing in lacunae, connected via canaliculi, responsible for maintaining the bone matrix.
Osteoclasts are multinucleated cells responsible for bone resorption, featuring a ruffled border and clear zone, involved in the regulation of blood calcium levels under the influence of parathyroid hormone and calcitonin.

Ossification

Intramembranous ossification occurs directly within mesenchymal tissue, forming flat bones like the skull.
Endochondral ossification involves the replacement of hyaline cartilage by bone, forming long bones.
Endochondral ossification progresses through a series of stages: a hyaline cartilage model, formation of the primary ossification center, development of the secondary ossification center, and eventually bone replaces cartilage.

Bone Repair

Bone repair is initiated by a blood clot, followed by the formation of a soft callus composed of cartilage-like fibrocartilage and woven bone.
The soft callus is eventually replaced by a hard callus of lamellar bone, which is remodeled and remodeled into normal bone structure.

Joints

Joints are connections between bones, classified as fibrous (immovable), cartilaginous (slightly movable), and synovial (freely movable).
Synovial joints have a synovial cavity filled with synovial fluid, providing lubrication, nutrition, and phagocytosis.

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Description

Explore the essential components of connective tissue in this quiz. Learn about the various cell types such as fibroblasts, macrophages, and mast cells, as well as the different types of fibers including collagen and elastic fibers. Test your understanding of their roles and significance in the body.