lecture 5- Bone growth and joints

Question 1

Bone growth( length and width)

Answer 1

starts with cartilage model- 6 weeks after fertilisation
Endochondral Ossification- process of turning cartilage into bone.

PRIMARY OSSIFICATION CENTRES
Diaphysis( shaft) is the primary ossification centre.
Epiphyses( distal and proximal ends of bone) remain cartilage.
SECONDARY OSSIFICATION CENTRES
Epiphyses- same ossification process as primary centres
separated by diaphysis by epithelial/growth plate.

IN WIDTH
appositional growth
osteoblasts produce circumferential lamellae. osteoclasts mould bone shape and form mellular cavity

Question 2

Whats a joint

Answer 2

How does our skeleton move?
* Bones articulate at joints
* A joint:
* holds bones together
* involves bone ends
* involves soft tissues
* allows control of movement
1

Question 3

Key soft tissues

Answer 3

A joint involves soft tissues, the two key tissues are Dense fibrous connective tissue, and Cartilage.
common MCQ
tendons connect muscle to bone and ligaments bone to bone

Question 4

Describe Cartilage tissue , the types in detail.

Answer 4

collagen fibres embedded in ground substance
- Avascular-
no blood vessels, nutrients diffused through matrix by joint loading.
HYALINE(ARTICULAR) CARTILIAGE
-resists compression
- high water content in matrix
- sparse collagen fires
* Moulds to surfaces of
bones where they
articulate
* Creates smooth surface
= frictionless movement
* Found on articulating
surfaces of bones
* Degrades with age
FIBROCARTLIAGE
resists compression and tension
many collagen fibres in bundles
organisation of fibres aligns with stresses
- useful at joints that experience both compression and tension
– acts as a shock absorber- force over wider area
- deepens articular surfaces.

Question 5

Describe DFCT

Answer 5

DFCT
* Fibroblasts cells
* Collagen fibres
* (Some) elastin fibres
* Tightly packed
* Function = resist
tension
* Little vascularity - less blood vessels etc.
* Slow to heal
Ligaments, tendons, joint capsules is a type of DFCT

Question 6

Describe Ligaments, Tendons, Body congruence

Answer 6

LIGAMENTS
* Connect bone to bone
* Collagen and elastin
—–resist tension
——allow a little stretch recoil
* Restrict movement (away
from themselves)
TENDONS
* Connect muscle to bone
* Less elastin than ligaments
* Facilitates and controls
movement
* Contraction of muscles
transmitted to bone
BONY CONGRUENCE
* Sum of bone
surfaces that form
an articulation
* Less congruence =
more soft tissue
support needed

Question 7

Describe tissue and structure

Answer 7

Tissue- group of highly organised cells, organised according to structure and function. eg DFCT

Structure- something formed from tissue, eg ligament

Question 8

Describe a Fibrous joint

Answer 8

least amount of movement
made of DFCT
structure–> ligament
Function–> limit movement and provide stability
eg distal tibiofibular joint. prevents ankle rotaion

Question 9

Describe a cartilaginous joint

Answer 9

made up of fibrocartilage
function= some movement
bones connected entirely by fibrocartilage.