Bone and skeleton Flashcards
What is the difference between bone and bones?
Bone:
- A type of connective tissue
Bones:
- Organs made of the bone connective tissue
What are the 8 main functions of bones?
- protection of organs
- support and attachment of muscle
- stem cell production
- calcium storage
- fat storage
- blood cell production
- eliminating toxins from the body
- buffering blood pH
What are the 3 main types of bone?
Give and example for each
- long bones - e.g., femur
- flat bones - e.g., scapular
- short/irregular bones e.g., bones in the carpus
What is the main function of long bones?
To make up the majority of the skeleton
What are the main functions of flat bones?
What is the structure?
Function - to provide large surface areas for muscle to attach to and to protect
Structure - 2 layers of compact bone surrounding trabecular bone but no medullary cavity
What is the main function of short/irregular bones?
What is the structure?
Function - to allow motion
Structure - small/cube shaped, light, no medullary cavity (as no space)
What are the 3 main areas of long bones?
- the diaphysis
- the epiphysis
- the metaphysis
What is the diaphysis?
The central area of the long bone
What is the epiphysis?
The end part of the bone (both ends) near the joint
What is the metaphysis?
The area between the diaphysis and epiphysis
What are the 2 main functions of the diaphysis?
- to house bone marrow
- to tolerate large forces/loads
What is the main function of the epiphysis?
The form attachment to other bones via joints
What is the main function of the metaphysis?
To transfer forces/loads to the epiphysis
What are the 2 types of bone tissue in long bones?
Where are they found
- cortical (hard) bone - on the outside of the diaphysis
- trabecular (spongy) bone - on the inside of the epiphysis under the membrane
What is the function of cortical bone?
To make the bone dense and strong
What are the 2 main functions of trabecular bone?
- To make the bone lighter and less dense by providing airspaces
- To help create red and white blood cells as it is filled with red bone marrow
Where do you find articular cartilage?
One the epiphysis of the long bone
What is the function of articular cartilage?
To form a smooth, low friction area in joints
Where is the epiphyseal plate?
Between the diaphysis and epiphysis
What is the function of the epiphyseal plate?
Where the bone grows from - extending the length of the diaphysis
Where is the medullary cavity?
Inside the diaphysis
What is the function of the medullary cavity?
Produces fat and nutrients as it contains yellow bone marrow (doesn’t make blood cells)
Where do you find the blood vessels in long bones?
On the outside and inside of the bone
What are the 2 functions of the blood vessels in long bones?
- To deliver nutrients
- To take cells produced in the red bone marrow (trabecular bone) to the rest of the body
What are the 2 membranes in long bones?
- periosteum
- endosteum
Where is the periosteum?
Lining the outside of long bones (on top of the cortical bone)
Where is the endosteum?
Lining the medullary cavity
How many layers are there in periosteum?
What are their roles?
2 layers:
1. outer layer - protective layer made from osteoblasts that create bone cells
2. inner layer - the site of sensory nerves which relay pain signals when the bone is damaged
How many layers are there in endosteum?
What are there roles?
1 layer - made of osteoblasts and osteoclasts which maintain bone tissue by making new bone and resorbing old bone
What are the 4 main types of bone cells?
- osteogenic/osteoprogenitor cells
- osteoblasts
- osteoclasts
- osteocytes
What are the functions osteogenic/osteoprogenitor cells?
Where are they located?
What is the arrangement of cells?
Function:
- stem cells - can differentiate into osteoblasts or brain cells
Location:
- in the periosteum and endosteum
Arrangement:
- single layer of cells with single nuclei
What are the functions osteoblasts?
Where are they located?
What is the arrangement of cells?
Function:
- form the bone matrix so can create new bone tissue
Location:
- in the periosteum
Arrangement:
- dense, single layer of cells with single nuclei but when bone formation is occurring there will likely be multiple layers
What are the functions osteoclasts?
Where are they located?
What is the arrangement of cells?
Function:
- resorb damaged bone
Location:
- in the endosteum
Arrangement:
- very large cells, single layer of cells with multiple nuclei
What are the functions osteocytes?
Where are they located?
What is the arrangement of cells?
Function:
- to maintain bone tissue
Location:
- in cortical bone in the lacunae
Arrangement:
- single layer of star shaped cells, single nuclei, smaller than osteoblasts
What is the microstructure of the cortical bone?
Osteons surrounded by central/Haversian (horizontal) and perforating/Volkmann’s (vertical) canals containing blood vessels
What is the microstructure of an osteon?
- A straw like structure
- Concentric rings of lamellae circled around each other surrounded by collagen
- A central canal containing nerves, arteries and veins
What is the microstructure of lamellae?
- Lacuna (small gaps) containing osteocytes with canaliculus connections (connected to each other)
- surrounded by collagen fibres
What is the function of the central canals in cortical bone?
To provide blood flow to the osteons and lamellae
What are the functions of the perforating canals in cortical bone?
- To interconnect the central canals
- To allow continuous blood flow between the periosteum, trabecular bone and medullary cavity (bone marrow)
What are the reasons for lamellae being circled around each other?
- To make it easier to slide over each other
- To give resistance to twisting forces in osteons
Why do osteocytes exist in lacuna in the lamella?
To maintain the bone tissue
