#10 bone structure and composition (spongy bone, hyaline cartilage, articulations and joints)

spongy bone →

• what does it consist of

• how is the lamellae arranged

• trabeculae (plates of bone), lamellae, osteocytes (in lacunae), canaliculi

• irregularly

where is spongy bone found

• epiphyses of long bone

• flat bones (eg. skull and ribs)

what do the spaces of spongy bone contain and what does it do

• contains red bone marrow

• produce blood cells and provide blood supply to developing osteocytes

what are the cells of hyaline cartilage, where are they found within

chondrocytes, found within lacunae

what is the matrix of hyaline cartilage composed of

• collagen fibres

• ground substance: chondroitin sulphate and hyaluronic acid

• water

what are articulations and joints? how are they classified

points of contact between two or more bones

• classified on either structure or function

functional classification is based on…

the degree of movement

synarthrotic

immovable joints

eg. sutures

amphiarthrotic

slightly moveable joints

eg. pubic symphysis

diarthrotic

freely moveable joints

structural classification is based on

• presence or absence of a joint cavity

• the type of tissue connecting two bones

the 3 functional classifications

1. synarthrotic

2. amphiarthrotic

3. diarthrotic

the three structural classifications of joints

1. fibrous joints

2. cartilaginous joints

3. synovial joints

fibrous joints →

• does it have a joint cavity

• what is it composed of

• example

• no

• fibrous connective tissue

• sutures on skull

cartilaginous joints →

• does it have a joint cavity

• what is it composed of

• example

• no

• cartilage

• pubic symphysis, intervertebral disks

synovial joints →

• does it have a joint cavity

yes, filled with synovial fluid

what are bones held together by

a joint cavity and associated ligaments

all diarthrotic joints are also

synovial joints

what do synovial joints contain

1. articular cartilage

2. joint cavity

3. joint capsule

articular cartilage

hyaline cartilage located on ends of the bones, reduces friction

joint cavity contains…

synovial fluid

joint capsule →

• what does its outer layer contain

fibrous connective tissue

• attaches to periosteum

joint capsule →

• what does its inner layer contain

inner synovial membrane that secretes synovial fluid

how are the types of synovial joints grouped

according to the shape of articulating bones

type of synovial joint → gliding (plane)

flat surfaces

type of synovial joint → hinge

concave and convex surfaces

eg. elbow, knee

type of synovial joint → pivot

rotates around a single axis

• odontoid process of the axis (allows you to shake head no)

type of synovial joint → ball and socket

allows for large freedom of movement

• hip, shoulder