Cartilage And Bone

Question 0

Describe hyaline cartilage

Answer 0

Type 2 collagen
In resp pathways, articulating surface of long bone, anterior end of ribs, foetal skeleton
Flexible and smooth for movement
Perichondrium
Avascular ( relies on diffusion)

Question 1

Describe the composition of cartilage

Answer 1

Resiliant avascular connective tissue
Composed of chondrocytesand semisolid matrix
Mesenchymal origin - differentiate into chondrocytes
Secrete a matrix which surrounds cells in lacunae
Surrounded by pericondrium

Question 2

Describe elastic cartilage

Answer 2

Type 2
Found in auditory tube, external ear, epiglottis
F - support,shape and extra flexibility
Has perichondrium
Avascular, matrix has elastic fibres

Question 3

Describe fibrocartilage

Answer 3

Type 1 collagen
Found in intervertebral discs, menisci, pubic symohysis
f - support and rigidity, weight bearing
No perichondium
Associated to joint where need resistance to compression

Question 4

Relate anatomical location of hyaline cartilage to its function

Answer 4

Firm and flexible support - respiratory passageways

Question 5

Relate anatomical location of elastic cartilage to its function

Answer 5

Flexibility and support - auditory tubes, ear, epiglottis

Question 6

Relate anatomical location of fibro cartilage to its function

Answer 6

Verystrong and resistant to compression - intervertebral discs, part of tendons

Question 7

Describe the characteristic features of bone

Answer 7

Can withstand compression, stress and deformation
Dynamic - responds to stress and strains by growth
Supplied with blood, lymph vessels and nerves
Contains cells, fibres and ground substance

Question 8

What is the function of bone

Answer 8

Support, protection, mineral storage, haemopoisis

Vascular connective tissue

Question 9

Describe compact (dense) bone

Answer 9

Concentric lamellae with central nuerovascular (haversian canal) which communicate via volkmanns canals
Osteon (haversian) system of interconnecting canals

Question 10

Describe spongy (cancellous) bone

Answer 10

Each trabeculum has Numerous osteocytes within irregular lamellae
Osteoblasts and osteoclasts remodel bone surfaces

Question 11

Describe the composition of bone matrix

Answer 11

Collagen, water and non-collagen
Calcium phosphate and carbonate
Hardness due to interaction between inorganic salts and collagen
Calcium and phosphate stores can be released if levels fall
Ca2+ required for muscle contraction, blood cosgulation, cell membrane permeability, nerve impulse transmission
Pth stimulates osteoclasts to reabsorb bone matrix
Calcitonin released to inhibit osteoclasts

Question 12

What is the role of osteoblast cells?

Answer 12

Synthesise the organic components of cells, making bone, produce osteoid matrix

Question 13

What is the function of osteocytes

Answer 13

Found in lacunae cavities, maintain bone. Formed when osteoblasts are entombed to produce osteocytes

Question 14

What are the function of osteoclasts

Answer 14

Large multinucleate cells from monocytes that digest bone

Question 15

Describe the microstructure of i mature bone

Answer 15

Immature bone, is the first type of bone to appear in development and repair replaced by mature
Collagen fibres are arranged in a random interwoven fashion
More cells and less minerals

Question 16

Describe the structure of compact bone

Answer 16

Series of haversian systems (osteons) consisting of concentric lamellae of bone around a central canal containing blood vessels, spaces inbetween haversian systems filled with bony lamellae

Question 17

Describe the structure of spongy bone

Answer 17

Forms network of trabecullae filled with marrow

Question 18

How does cartilage become bone?

Answer 18

Via endochondrial ossification
Cartilage is resorbed and replaced
Begins at primary centre in the diaphysis snd later at each end (ephysis)
Growth in length at epihysial growth plate

Question 19

How does loose connective tissue/mesenchyme via intramembrous ossification

Answer 19

Bone begins as highly vascularised loose connective tissue
Mesenchymal cells differentiate into osteoblasts surrounded by collagen fibres and ground substance
They secrete uncalcified matrix (osteoid) and become osteocytes

Question 20

Describe the remodelling of bone

Answer 20

Osteoblasts and osteoclasts release and incorporate calcium into and from the matrix

Question 21

Describe fracture repair

Answer 21

1) site of injury filled with blood (haemotoma)
2) broken ends of bone become necrotic
3) blood coagulates forming a clot - invaded by macrophages and osteoclasts that remove dead tissue and bone
4) from pro-callus of blood clot and fibrous tissue (primary)
5) calcified to form secondary bone
6) bone remodelled by osteoclasts

Question 22

Why is the extracellular matrix of cartilage highly highdrated?

Answer 22

Allows transient movement of water within the matrix to withstand varying pressure

Question 23

What is special about hyaline articular cartilage

Answer 23

At the articulating surface of long bone the hyaline cartilage does not have a perichondrium, as it is soft and would be worn away

Question 24

How are chondrocytes arranged in fibrocartilage?

Answer 24

In rows or as isogenous groups