Histology Final Chapter 9 Cartilage and Bones

Cartilage

Tough, durable form of supporting connective tissue, characterized by an extracellular matrix (ECM) with high concentrations of GAGs and proteoglycans, interacting with collagen and elastic fibers

Bear mechanical stresses

ECM has a firm consistency that allows the tissue to ____________________ without permanent distortion

Respiratory Tract, Ears, and Nose

Where does cartilage form framework supporting softer tissues?

Cushioning and sliding regions

Cartilage Provides ___________________ within Skeletal Joints and Facilitates bone movements

Chondrocytes

Cartilage consists of cells called _____________ embedded in the ECM.

Lacunae

Chondrocytes synthesize and maintain all ECM components and are located in cavities called?

long bones

Cartilage also guides development and growth of _____________, both before and after birth

electrostatic bonds between type II collagen fibrils, hyaluronan, and the sulfated GAGs on densely packed proteoglycans

What gives cartilage its physical properties?

The high content of bound water

What allows cartilage to serve as a shock absorber?

Blood vessels and Nerves

What does Cartilage Lack?

Diffusion from capillaries in surrounding connective tissue (Perichondrium)

How does chondrocytes receive nutrients?

Low metabolic Activity

Since chondrocytes are avascular they exhibit_________________

Perichondrium

A sheath of dense connective tissue that surrounds cartilage in most places, forming an interface between the cartilage and the tissues supported by the cartilage. harbouring blood supply to the cartilage.

Synovial Fluid

Articular cartilage lack perichondrium so there fore it gets it oxygen and nutrients from the ________

Hyaline Cartilage

the most common of the three types of cartilage, homogeneous and semitransparent in the fresh state

Nose, Larynx, trachea, bronchi, ventral ends of ribs and in epiphyseal plates of long bones

Where is hyaline cartilage located?

Temporary skeleton

Hyaline cartilage forms the ____________ in the embryo that is gradually replaced by bone

Osteoarthritis

A chronic Condition that commonly occurs during aging, involves the gradual loss or changed physical properties of the hyaline cartilage that lines the articular ends of bones in joints

Aging and “wear and tear” of hyaline cartilage

What is osteoarthritis caused by?

Benign

Chondroma is what type of cancer tumor?

Malignant

Chondrosacroma tumors are what type of cancer tumor?

Elastic Cartilage

What is similar to hyaline cartilage but contains an abundant network of elastic fibers and collagen type II fibrils. (yellowish color)?

Auricle of the ear, the walls of the external auditory canals, the auditory (Eustachian) tubes, the epiglottis and the upper respiratory track.

Where can elastic cartilage be located?

Fibrocartilage

A mingling of hyaline cartilage and dense connective tissue. Serves as a very tough, yet cushioning support tissue for bone

Intervertebral discs, in attachments of certain ligaments, and in the public symphysis

Where can fibrocartilage be located?

Isogenous aggregates, Type II Collagen

Chondrocytes of fibrocartilage occur singly and often in aligned _____________ __producing__ ____________ and other ECM components

Fibroblasts and dense bundles of type I collagen

What brings extra strength to Fibrocartilage?

The relative scarcity of proteoglycans

What makes fibrocartilage matrix more acidophilic than that of hyaline or elastic cartilage?

Surrounding perichondrium

There is no ________________________ in fibrocartilage

Bone marrow

Where are blood cells formed?

Bone

What provides solid support for the body, protects vital organs such as those in the cranial and thoracic cavities?

Bone Tissue

What serves as a reservoir of calcium, phosphate, and other ions that can be released or stored in a controlled fashion to maintain constant concentrations in body fluids?

Osteocytes

What is found in cavities (lacunae) between bone matrix layers (lamellae), with cytoplasmic processes in small canaliculi?

Osteoblasts

What are growing cells which synthesize and secrete the organic components of the matrix?

Osteoclasts

What are giant, multinucleated cells involved in removing calcified bone matrix and bone remodeling?

Cylindrical spaces of the canaliculi

How do osteocytes and blood capillaries communicate?

Endosteum

What layers of connective tissue containing osteogenic cells surround internal surfaces such as the marrow cavity?

Periosteum

What layers of connective tissue containing osteogenic cells surround the external surface?

Decalcified

What is done to bones so that it can be prepared for sectioning?

Metastatic Tumors

The skeleton is a secondary site for?

Osteosacroma

What is the name of cancer tumors that come from bones?

Small blood and Lymphatic Vessels

How do cancer cells move into the bones?

Breast, Lung, Prostate gland, kidney, or thyroid gland

What are the most common locations where bones get their malignant cancer cells from?

Increase in density

When you exercise and move the bones what happens to them?

Decrease in density

When you DONT exercise and move the bones what happens to them?

Mechanostat

The extensive network of osteocyte dendritic processes and other bones cells have been called?

M-CSF and RANKL

What are the two polypeptides produced by osteoblasts needed for osteoclast development?

enzymatically etched depressions or cavities in the matrix

Whats the resorption Lacunae (Howship Lucunae)

A ruffled border

What does an osteoclast do in order to work with the matrix?

Perforating/Sharpey fibers

What penetrates the bone matrix and binds the periosteum to the bone?

Osteogenitor cells

What plays a prominent role in bone growth and repair?

The periosteum’s inner layer

Osteoblasts, bone lining cells, and mesenchymal stem cells (the osteoprogenitor cells) all make up?

small trabeculae of bony matrix that project into the marrow cavities

what does the endosteum cover?

Endosteum within a sparse, delicate matrix of collagen fibers

What is the difference between Perioseum and Endosteum?

Osteopetrosis

what is a genetic disease characterised by dense and heavy bones?

DEXA Scans

How are patients tested for BMD?

Calcium loss from bones and reduced bone mineral density (BMD)

What is Osteoporosis?

bicarbonate, citrate, magnesium, potassium, and sodium ions. also Noncrystalline calcium phosphate

WHat is also found in the bone matrix other than Calcium Hydroxyapatite?

Type I Collagen

What makes up the majority of the organic matter embedded in the calcified matrix?

Osteonectin

What are the preteoglycans and multiadhesive glycoproteins that are embedded in the calcified matrix?

Osteocalcin

What are calcium binding proteins called?

Osteogenesis

What is bone development also referred as?

Intramembranous ossification

what is process in which osteoblasts differentiate directly from mesenchyme and begin secreting osteoid

Endochondral ossification

What is the process in which a preexisting matrix of hyaline cartilage is eroded and invaded by osteoblasts, which then begin osteoid production?

Osteogenesis imperfecta

What is also known as the “brittle bone disease”?

Defect in collagen Type I

Why is the bone so brittle in osteogenesis imperfecta?

Fragility of bones

what does he defect in Collagen Type I in bone cause?

Joints

Regions where adjacent bones are capped and held together firmly by other connective tissues?

very limited or no movement

What are synarthroses joints classified as?

Fibrous and Cartilaginous

What are joints subdivided into?

synostoses

Whats involves bones linked to other bones and allow essentially no movement. usually In older adults _________ unite the skull bones?

Syndesmoses

Whats joins bones by dense connective tissue only. Examples include the interosseous ligament of the inferior tibiofibular joint and the posterior region of the sacroiliac joints?

Symphyses

what has a thick pad of fibrocartilage between the thin articular cartilage covering the ends of the bones such as the intervertebral discs?

Permit free bone movement. such as the elbow and knee. Unite long bones and allow great mobility

What are diarthroses joints classified as?

Irregular and random arragnment of cells and collagen; lightly calcified

What are the histological features of woven bones?

Developing and growing bones; hard callus of bone fractures

What is the major location of Woven Bones?

Immature bone; primary bone; bundle bone

What are the synonyms of woven bones?

Parallel bundles of collagen in thin layers (lamellae), with regularly spaced cells between; heavily calcified

What are the histological features of Lamellar bones?

All normal regions of adult bone

What is the major location of the lamellar bones?

Mature bone; secondary bone

What are the synonyms for Lamellar bone?

Parallel lamellae or densely

What are the histological features of compact bones?

Thick, outer region (beneath periosteum) of bones

What is the major location of compact bone?

Cortical bone

What is the synonym for Compact bones?

Interconnected thin spicules or trabeculae covered by endosteum

What are the histological features of cancellous bone?

Inner region of bones, adjacent to marrow cavities

What is the major locations of cancellous cone?

Spongy bone; trabecular bone; medullary bone

What is the synonyms of cancellous bone?

Compact Bone

what makes up 80% of all lamellar bone?

Cancellous Bone

What makes up 20% of lamellar bone?

Homogenous, with type II collagen and aggrecan

What are the main features of the ECM in hyaline cartilage?

Type II collagen, aggrecan, and darker elastic fibers

What is the main features of the ECM in Elastic Cartilage?

Type II collagen and large areas of dense connective tissue with type I collagen

What is the main features of the ECM in Fibrocartilage?

Chondrocytes and Chondroblasts

What are the major cells in Hyaline and Elastic Cartilage?

Chondrocytes and fibroblasts

What are the major cells in fibrocartilage?

isolated or in small isogenous groups

what is the typical arrangment of chondrocytes in Hyaline cartilage?

Usually in small isogenous groups

What is the typical arrangement of chondrocytes in Elastic cartilage?

Isolated or in isogenous groups arranged axially

what is the typical arrangement of chondrocytes in Fibrocartilage?

Yes

Is there a presence of perichondrium in Elastic and Hyaline cartilage?

No

Is there a presence of perichondrium in fibrocartilage?

Many components of upper respiratory tract; articular ends and epiphyseal plates of long bones; fetal skeleton

What are the main locations or examples of hyaline cartilage?

External ear, external acoustic meatus, auditory tube, epiglottis and certain other laryngeal cartilages

What are the main locations or examples of elastic cartilage?