Bone Tissue And Its Microsophic Structure Lecture 4 Flashcards
What makes bone a living tissue
- 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
What is the connective tissue
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
What are the 2 extraceller components that bone has
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
What is extracellur components
Everything that is in your bone that is not cells
Explain the organic bit of the extraceleur maxtrix
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.
Explain the inorganic part of the ECM
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
What is HYDROXYAPATITE
The inorganic part of the ECM
What is the cellular component of bone
This is the cells that are in the ECM
What are the 4 different cells in the bone
- 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
what is the periosteum
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).
What is the foramina
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
What is the osteon structure
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
What is the central canal
This is indie the compact bone it contains blood vessels and nerves that Chanel though the bone
What is the Lamellae
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
What is the Lacunae
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
What is the Cancellous bone made up of
It’s made up of a branching bone structure that goes in all kinds of directions
What is the branching bone structure called in the cancellous bone
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
What are some of the difference and similarities of then cancellous bone and the compact bone
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
What is the canaliculi for cancellous bones and compact bones
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
How does bone remodelling happen
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.
What is Appositional growth and how does it happen
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.
What is bone homeostasis
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
What is bone homeostasis is not maintained
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
What is a disease that can happen is homeostasis is not maintained, thinking about compact bone and cancellous bones
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.
What are some risk of osteoporosis
Not sleeping
No exceesize
Not enough milk
Smoking
Drinking
Primary function of osteocytes
Recycle proteins and minerals
What component of bone tissue provide resistance to tension
Collogen
What is the primary function of osteogenic cells in bone tissue
Produce new bone matrix
What is the function of CANALICULI in bone tissue
Provide channels for osteocytes
Osteoporosis primarily affects what type of bone
Trabecular bone
Trabecular bone is also known as
Spongy bone, so cancellous bone
What component of bone provides resistance to compresssion
Hydroxyapatite
