2. Basic Histology Quiz- Cartilage and Bone Created by: Maureen Bain Start

3. Question 1 What type of cartilage is represented in Figure 1? Give a reason for your answer. What cell type forms the extracellular matrix in this type of supporting connective tissue? From where do these cells originate? Isogenous groups arise by interstitial growth. What do you understand by this term? What other type of growth mechanism takes place in this type of cartilage? Precisely where does this second type of growth occur? How do the cells forming and maintaining the cartilage matrix obtain their nourishment? Give another example of where you might find this type of cartilage. Answers at end of Quiz BackNext

4. Question 2 What type of cartilage is represented here? In terms of number of cells, type of fibre and amount of ground substance, how does this type of cartilage differ from the type of cartilage in question 1? Why do you think this type of cartilage is best suited to this location? By considering your answer to the previous question give another example of where you might find this type of cartilage. Note: This is section of the ear pinna stained with Gomori’s trichrome. This stain is useful for distinguishing between collagen and elastic fibres in the extracellular matrix - collagen fibres are stained green and elastic fibres are stained pink to red. With normal H&E staining it is much more difficult to distinguish between these two types of connective tissue fibre Answers at end of Quiz BackNext

5. Question 3 In figure 3 the ear pinna is shown at a lower power. The cartilage is surrounded and supported by general connective tissue. How would you classify this type of general connective tissue? Answers at end of Quiz BackNext

6. Question 4 Which of the labeled regions in this image corresponds to i) Periosteum ii) Compact Bone and, iii) Endosteum iv) hematopoietic tissue Where you would expect to find i) the Osteoblasts and, ii) the Osteocytes in this image? What are the functions of these two types of cell? What is the function of an Osteoclast? Longitudinal section of bone stained with H&E Answers at end of Quiz BackNext

7. Question 5 What name is given to the vascular connective tissue which covers the external surface of this developing bone? Bony spicules can be seen within the marrow cavity. These will eventually be reabsorbed as the bony collar increases in diameter. What type of bone do these bony spicules consist of- Compact or Spongy bone? What collective name is given to the tissue which is found in the marrow cavity of long bones? What name is given to the vascular connective tissue which lines all of the internal surfaces of compact bone? (This tissue also covers all surfaces of the bony spicules within the marrow cavity)? Developing long bone (H&E stain) Answers at end of Quiz BackNext

8. Question 6 This is a higher power view of the bony collar associated with the diaphysis of a developing long bone. Identify cell type A, cell type B and connective tissue C. Describe the relationship between A, B and C. Where would you expect to find octeoclasts- on the bony surface or within the bony matrix? What is the functional role of the osteoclasts? B A C C Answers at end of Quiz BackNext

9. Question 7 Identify the epiphyseal growth plate the secondary centre of ossification and the metaphysis in this figure. What name is given to the process which occurs at the growth plate where cartilage is constantly being replaced by bone? Developing long bone (H&E stain) Answers at end of Quiz BackNext

10. Question 8 Identify the zone labeled A-E in this high power view of the growth plate of a developing long bone Why is the epiphyseal plate so important in the growth of long bones? ABCDE Developing long bone (H&E stain) Answers at end of Quiz BackNext

11. Question 9 What type of bone is represented here, Compact or spicular (cancellus/trabecular)? What name(s) is given to the functional main units in this type of bone? In this longitudinal section these functional units are aligned in parallel with the bony surface. The spaces in the bone represent the location of the central canals and Volkmann’s canals which are in direct communication with the vascular tissue on the external and internal surfaces of the bone (periosteum and endosteum). periosteum Developing long bone (H&E stain) Answers at end of Quiz BackNext

12. Question 10 Identify the articular cartilage in this high power view. What type of cartilage does this represent? ( See insert). Can you see a perichondrium associated with this articular cartilage? If not then how does the cartilage get its nourishment? Does the cartilage in this location grow by appositional or interstitial growth or both? Developing long bone (H&E stain) Answers at end of Quiz BackNext

13. Answers 1. Hyaline cartilage Isogeneous groups widely spaced with lots of extracellular matrix. Chondroblasts form the matrix, chondrocytes maintain! The perichondrium- Note: this is the dense connective tissue on the outer surface of cartilage. At the interface the fibroblasts of the CT differentiate into chondroblasts which secrete the cartilage matrix. This is appositional growth (new cartilage forms on existing cartilage). Chondrocytes within the cartilage become activated; divide and each daughter cell (chondroblast) start to produce more cartilage matrix. This causes the cartilage to swell /grow from within itself. Appositional growth ( see comment above). At the interface between the perichondrium and the cartilage. By simple diffusion. Articulating joints, tracheal rings, at the tip of the nose. 2. Elastic cartilage More fibres (elastic rather than collagen) less ground substance, more cells per unit area. Increased flexibility and resilience required- springs back into shape when deformed. Another example would be the epiglottis – again the epiglottis deforms but springs back into shape after food passes over the entrance to the larynx during swallowing. 3. Lots of collagen fibres laying in multiple directions- this is dense irregular CT. 4. Periosteum 1 Compact Bone 4 Endosteum 3 Marrow cavity containing haematopoietic tissue. 2 Osteoblasts - periosteum and endosteum (Surface of existing bone) 1 and 3 Osteocytes- within the bony matrix- 4 Osteoblasts produce the bony matrix (osteoid), osteocytes maintain the boney matrix Bone remodeling Back to quiz

14. Answers 5. Periosteum Spongy Hematopoietic tissue Endosteum 6. A= osteoblast; B= osteocyte, C= periosteum Periosteum consists of fibroblasts which can differentiate into bone forming cells/ osteoblasts. The latter secrete bony matrix. Once surrounded by the bony matrix these cells become osteocytes. Bony surface Reabsorb bone 7. The epiphyseal growth plate B the secondary centre A of ossification and the metaphysis C Endochondrial ossification 8. Zone of resorption; D Zone of proliferation (interstitial growth); B Zone of ossification; E Resting or reserve zone (Chondrocytes); A Zone of hypertrophy (cartilage calcifies) C It allows the bones to increase in length- cartilage undergoes interstitial growth and runs ahead of the advancing osteogenic cells (chase) preventing the two centers of ossification from merging. As soon as this takes place growth in length is prohibited. 9. Compact Haversian systems or osteones 10. Hyaline cartilage No Via the synovial membrane which lines the joint cavity. Interstitial only as no perichondrium Back to quiz