Bone Growth And Structure Lecture 5

Question 1

What bones do you have when your young

Answer 1

Don’t have bone, you are a skeleton that is made up of cartilage

Question 2

When does the cartilage model start to form

Answer 2

6 weeks after fertilisation, the cartilage model starts to form and after years your bone will ossify and grow

Question 3

What is ossification

Answer 3

This is turning into bone, turning. Cartilage into bone

Question 4

What is Edochondral ossification

Answer 4

This is turning cartilage into bone

Question 5

How does turning cartilage into bone happen and where does it take place

Answer 5

It starts off with calcification which is just cartilage and then the blood vessels and osteoblast will surround the wall of the cartilage but we want these inside so after the blood vessels and osteoblasts push their way inside, and once they are inside they can now start to turn that bone cartilage into bone tissue. And this happens in the primary ossification centre

Question 6

What is the primary ossification centre ( thinking about long bones )

Answer 6

If we are thinking about the long bone This is where the formation of cartilage into bone takes place. We start off at the Diaphysis, this is where the osteoblasts will end up first and this is where the process of turning cartilage into bone starts and this is what’s called the primary ossification centre.
While for the end of the bones they remain as cartilage for a bit longer

Question 7

Secondary ossification centre

Answer 7

Because there is a primary there must be a secondary. So once the Diaphysis has started to turn into bone from the osteoblasts and the blood vessels, we can move onto the ephithysis, this is the ends of the long bone. This is basically the same process that happens in the diaphysis but as it is turning the cartilage into bone tissue not all of the cartilage is going to be used up. And that cartilage that is not used up is called the GROWTH PLATE

Question 8

What is the growth plate

Answer 8

This is when not all of the cartilage is used up in the secondary ossification centre. The growth plate is for the length of your bones, we need this so that the bone can grow in length as we are getting older and older. After about 18 years to 20 your growth plate won’t be there anymore and so there will be no more cartilage and the bone will be fully grown

Question 9

What is the name for bone growth in the WIDTH direction and what is the cell used to help that ?

Answer 9

Appositional growth ! This is the building of bone outwards, using osteoblast as the call

Question 10

How does the bone grow in the width direction

Answer 10

So basically what building bone outwards is called APPOSITIONAL GROWTH, this is done by osteoblast, osteoblast on the outside of the bone ( on the bone surface ) are going to start adding more bone tissue, making the bone wider and wider, but this adds a lot of weight and we don’t want it to be so heavy. So therefore in the MEDULLARY CAVITY osteoclast are going to break the bone from the inside to hallow it out and make sure that we are getting balance of growth without the weight of the bone changing too much.

Question 11

How does the skeleton move

Answer 11

Joints

Question 12

What are 4 types of things in joints that helps a skeleton move

Answer 12

Hold bones together
Bone end touch each other
Involves soft tissue allowing things to attach to each other
Allows control and movement

Question 13

What are the key soft tissues

Answer 13

Cartilage , there are 2 forms of cartilage, Hyaline And fibrocartilage
DFCT , these have a lot of fibres and are mostly Collagen that are closely packed together and they make multiple structures like, ligaments, tendons and joint capitals.

Question 14

What are chondrocytes

Answer 14

These are a part of cartilage, they sit in the lacuna and they maintain the extracellular matrix of the cartilage and produce the cartilage matrix

Question 15

What is ground substance

Answer 15

In the matrix there is something called the ground substance and this is what the collagen frites stick onto.

Question 16

What are collagen fibres

Answer 16

They are dense and kind of like the strongest rope that you can think of

Question 17

What kind of tissue is the cartilage and explain what that tissue is

Answer 17

It is an AVASCULAR TISSUE!
so there is no blood vessels and this may cause problems as we need the nutrients and we get the nutrients from the blood, so in order for the cartilage to get the nutrients that it needs the nutrients will fuse through the matrix by JOINT LOADING

Question 18

What happens in joint loading

Answer 18

Joint loading happens at the end of the joints where you move your bone, there is a fluid that has nutrients in it and so every time we move it squishes the fluids that have the nutrients in it into the cartilage and gives it its nutriends

Question 19

What is the function of the HYALINE cartilage

Answer 19

This is found at the ends of the bones, so its main function is to Resist compression, so if you were to push on the bone it won’t crumble into pieces, it does this by having a high water content in its extracelleiour matrix as water is great for resisting compression
So basically Hyaline cartilage is slippery and smooth which helps your bones move smoothly past each other in your joints. It’s flexible but strong enough to help your joints hold their shape this is important because every time we move we are going to apply pressure and so the bones will rub with each other if it didn’t have the hyaline cartilage. And this will hurt really bad

Question 20

What is the hyaline cartilage was not there

Answer 20

Bones will rub against each other and the blood vessels and the nerves in the bone and so it will just hurt

Question 21

What is Fibrocartilage

Answer 21

It is a transitional tissue, Its main function is to act as a cushion within joints, where it helps manage compression forces and reduces stress placed on joints. So relaxing the stress can be like it makes the bone be able to fit together more nicely
It resist both compression and tension while hyaline cartilage only resist compression

Question 22

What is DFCT ( dense fibrous connective tissue)

Answer 22

Fibrous connective tissue supports, protects, and holds bones, muscles, and other tissues and organs in place. Ligaments, tendons, the inner layer of the skin, and the sclera (the white outer layer of the eye) are all types of dense connective tissue. Also called fibrous connective tissue, so this means that they are made from the fibroblast, and its main function is to resist tension

Question 23

What are some things that DFCT can make

Answer 23

LIGAMENTS
They are made of DFCT that has a lot of fibres in, connecting bone to bone, they are made of collagen and elastin

TENDONS
Tendon is a fibrous connective tissue that attaches muscle to bone.

Question 24

What is BONY CONGRUENCE

Answer 24

This is how much the bone touches each other, if the bone was not to touch as much then we would need a lot of soft tissue to support it, for example the knee needs a lot of soft tissues

Question 25

What are the 3 joint CLASSIFICATIONS

Answer 25

Fibrous
Cartilaginous
synovial

Question 26

What are fibrous JOINTS and give an example

Answer 26

They are the joints that have the less movement, and the tissue here is DFCT

Fibrous joints, such as the cranial sutures which connect cranial bones and protect the brain, are made of ligaments, formed of DFCT. As ligaments are able to tightly hold bones together and resist tension because of the tightly packed collagen fibres, this limits movement completely, ensuring stability and protection.

Question 27

What is the cartilaginous JOINT and give an example

Answer 27

Thus has a little bit of movement and the tissue here is fibrocartilage

An example can be, such as in the pubic symphysis, which connects the two hip bones together. The slight movement allows for the bones to move a little during walking, and also for the joint to soften during childbirth to widen the pelvic cavity. Cartilaginous joints are made of fibrocartilage. Similar to fibrous joints, the collagen fibres in the fibrocartilage resist tension, but the ground substance component allows it to also resist compression.

Question 28

What is the synovial joints and give an example of it

Answer 28

These are the joints that provide the most movement and it has many tissues

There are 7 types of synovial joint, with each type differing based on the bone shapes and planes of movement possible at each joint.
One example is the knee, which is a condylar synovial joint. Synovial joints contain many tissues, including a joint capsule of DFCT which surrounds the joint and holds it together, and is lined with a synovial membrane that secretes fluid important for lubrication and nutrient provision to avascular structures. Also ensuring smooth, frictionless movement is l the hyaline cartilage which covers the articulating bone surfaces.