Bone Tissue And Its Microsophic Structure Lecture 4

Question 1

What makes bone a living tissue

Answer 1

• it is able to react to what your body is going through
• it has cells in it so it is able to communicate with one another and can also communicate with the rest of the body and can change up what the bone is doing depending on the environment
• depending on how you are using your body, the bone can change. For example if you were a rugby player your bones would build up more to take the blows
• your bones are able to change shape through your life depending on how you are using them
• bone is able to respond to trauma and repair itself , so if you were to break a bone, bone tissues will form and reform to connect these bits of bone

Question 2

What is the connective tissue

Answer 2

It supports other tissues and makes sure that the form of the structure that they are making keeps shape. It is a tissue that supports, protects, and gives structure to other tissues and organs in the body

Question 3

What are the 2 extraceller components that bone has

Answer 3

So most of the bone is not made up of cells it is made up of extracellerur matrix, it has INORGANIC OR ORGANIC.
Inorganic - made up of minerals , this is the thing that makes the bone hard, it’s the thing that make the bone unique among the other tissues
Organic - this is just organic molecules

Question 4

What is extracellur components

Answer 4

Everything that is in your bone that is not cells

Question 5

Explain the organic bit of the extraceleur maxtrix

Answer 5

33% of the extracelleur maxtrix is made up of organic molecules, and it is mostly COLLAGEN, This is a protein macromolecule that sits in the ground substance, this is the watery stuff around it. (Protoglygcans ) this is not the hard bit of the bone but rather the stretchy bit of the bone. So in your bone you have collagen fibres that cris cross throughout and this helps resist tension so it allows force to come at it and give it the flexiblity, if you had no collagen on your bones and you were to put pressure on it your bones will break, so therefore it’s important to have collagen, and this is why the organic part if really important as it helps take the weight and have a little bit of flexibility.

Question 6

Explain the inorganic part of the ECM

Answer 6

This is 67% of bone, this is called HYDROXYAPATITE, it is a Ca mineral but can also contain trace elements that are mineral salts
The mineral but makes the bone hard and resist the compression so if you were to push on the bone it wouldn’t just bend we need this part so it can take the weight of the forces

Question 7

What is HYDROXYAPATITE

Answer 7

The inorganic part of the ECM

Question 8

What is the cellular component of bone

Answer 8

This is the cells that are in the ECM

Question 9

What are the 4 different cells in the bone

Answer 9

• osteogenic cells - this is the cell that starts the whole process
• osteoblast - this is the cells that make the bone, good for growing and produce new bone matrix
• osteocytes - these maintain the bone, recycle proteins and minerals from matrix, communicate with the other cells to know if the bone needs to be distoryed, these stay in the same place ( in the lacunae).
• osteoclast - these break the bones. Or in other words remove the bone matrix if it’s too old

Question 10

what is the periosteum

Answer 10

This is what we can see from the outside of the compact bone. It is smooth strong and dense. It is a thin layer of connective tissue that covers the outer surface of a bone in all places except at joints (which are protected by articular cartilage).

Question 11

What is the foramina

Answer 11

This is holes for blood supply to get into the compact bone and this is what’s in the inside , we need the blood supply as we have living cells in the bones

Question 12

What is the osteon structure

Answer 12

This is what the compact bone is made up of/ what’s in the compact bone, this is how the blood supply gets in and then gets distributed out to cells
The ostens is a cylinder shape structure and it looks like a tree ring structure, they provide the pathway for blood vessels gas nerves to get into the cell withen the extracelleur matrix

Question 13

What is the central canal

Answer 13

This is indie the compact bone it contains blood vessels and nerves that Chanel though the bone

Question 14

What is the Lamellae

Answer 14

Lamellae. It’s the extracellular matrix around the cells that gives compact bone its hardness and rigidity. This matrix is made of both organic and inorganic materials. For example, collagen provides tensile strength and hydroxyapatite crystals provide the bone with compressive strength

Question 15

What is the Lacunae

Answer 15

Lacunae are spaces in which bone cells are present. The main purpose of a lacuna in bone or cartilage is to provide a home for the cells it contains while also keeping them alive and functional. In bones, lacunae encase osteocytes; in cartilage, lacunae enclose chondrocytes. So basically the main function of the lacunae is to provide a home for the cells. However the lucunae is not on top of the central canal and the centrral canal is where all the blood supply is and for the osteocytes to function it needs its blood supply. And so we get it through CANALICULI, these are channels for blood supply to go through

Question 16

What is the Cancellous bone made up of

Answer 16

It’s made up of a branching bone structure that goes in all kinds of directions

Question 17

What is the branching bone structure called in the cancellous bone

Answer 17

trabeculae - Trabeculae are the thin columns and plates of bone that create a spongy structure in a cancellous bone, which is located at the ends of long bones and in the pelvis, ribs, skull, and vertebrae.
- they are also surrounded by red marrow where the red blood cell function is normally happening

Question 18

What are some of the difference and similarities of then cancellous bone and the compact bone

Answer 18

They both have lamalle, the lacunae with osteocytes and they have the canaliculi which help with the blood supply to the lacunae
HOWEVER the cancellous bone has no central canal, this is because the bone branches are relatively thin and they have indirect contact with blood supply all around the outside of them where the bone marrow is, also the branches are thin and delicate so they don’t need the central canal as it is easier for them to get their nutrients from outside

Question 19

What is the canaliculi for cancellous bones and compact bones

Answer 19

Cancellous bones does not have osteocytes, unlike compact bone. Spongy bone does not require a blood supply. Nutrients and wastes cannot diffuse through spongy bone Nutrients and wastes cannot diffuse through compact bone

Question 20

How does bone remodelling happen

Answer 20

This is where cells that form the bone, osteoblast and the cells that destroy the bone, osteoclasts want to be functioning at the same same time so that homeostasis can be maintained and for adults we want them to be relatively at the same rate.

Question 21

What is Appositional growth and how does it happen

Answer 21

Appositional growth is the increase in a bone’s width rather than length. And how this occurs is that bone is taken away from the inside of the bone
And how does the width get wider ?, so the osteoblasts they are mainly concentrated on the outside of the bone and when it needs to get wider the osteocytes tell the osteoblasts to form more bone and so the osteoblasts will add bone matrix in lamalle to bone suface, and at the same time the osteoclast is inside the bone, so they remove bone to make sure the bones don’t get to heavy and dense.

Question 22

What is bone homeostasis

Answer 22

This is when we want a balance of osteoblast and osteoclast activity, so we don’t end up with some bone becoming less dense or more dense. The bones are being constantly destroyed and formed this allows the body to mobilise calcium, phosphate and other minerals from the bone matrix, these useful things are
Modolised into the blood stream so the body can use them when needed

Question 23

What is bone homeostasis is not maintained

Answer 23

So to maintain homeostasis we must have enough cslcuium in our diet and a good way to get this is if we exxcersize , without doing this an imbalance dangerous things can happen so this means that one can outweigh the other and diseases can happen. Like for example osteopenia, this is when osteoclast is moving way too much bone then osteoblast forming the bone

Question 24

What is a disease that can happen is homeostasis is not maintained, thinking about compact bone and cancellous bones

Answer 24

2 things can happen, osteoporosis or opstiopenia, these are both basically the same, so the osteoclast is removing way too much bone than the osteoblasts forming the bone. And this is actually normal, around 30+ years old your body’s osteoblast will start to slow down. So giving an example, on a normal bone, you have a nice compact bone surrounding the outside of the bone but as you get older the osteoclast eat away most of the bone so that the compact bone is getting thinner and thinner and unable to take as much a weight as it use to

This also happens in the cancellous bone, so a normal cancellous bone would be having healthy looking branches to branches that have been eaten away from osteoclast, the risk of this is that we are more likely to have breaks in bones and the risk of fractures, an example can be the vertebrae, the vertebrae is mostly made up of cancellous bone, the bones can squish if homeostasis is not maintained and this is what we call compression fractures

WOMEN ARE MORE AT RISK because an example can be your period, this stops getting signals to osteoblast.

Question 25

What are some risk of osteoporosis

Answer 25

Not sleeping
No exceesize
Not enough milk
Smoking
Drinking

Question 26

Primary function of osteocytes

Answer 26

Recycle proteins and minerals

Question 27

What component of bone tissue provide resistance to tension

Answer 27

Collogen

Question 28

What is the primary function of osteogenic cells in bone tissue

Answer 28

Produce new bone matrix

Question 29

What is the function of CANALICULI in bone tissue

Answer 29

Provide channels for osteocytes

Question 30

Osteoporosis primarily affects what type of bone

Answer 30

Trabecular bone

Question 31

Trabecular bone is also known as

Answer 31

Spongy bone, so cancellous bone

Question 32

What component of bone provides resistance to compresssion

Answer 32

Hydroxyapatite