Week 4 Flashcards
Is bone called “osseous tissue”
Yes
What type of tissue is bone
Hard, dense connective tissue
What are the 5 functions of the skeletal system?
1) support the body
2) facilitate movement - don’t actually move the body, but attach to muscles which do move the body
3) protect internal organs
4) produce blood cells
5) storage depot for minerals and fat
What is yellow marrow made up of
Fat storage
What process happens in red marrow?
Hematopoiesis (blood cell production: RBC’s, WBC’s, platelets)
What are the 5 types of bone?
1) long bones
2) short bones
3) flat bones
4) irregular bones
5) sesamoid
What do long bones look like and what is their function? Give an example.
Cylinder shaped, longer than wide. Provides attachment for movement. Example: femur (in leg)
What do short bones look like and what is their function?
They are cube shaped. They provide stability and support for fine motor movements.
What are the 2 only locations short bones are found, and what are they called in each place?
Carpals - wrist bones
Tarsals - ankle bones
What do flat bones look like and what is their function? Give an example.
They are thin and curved. They provide points of attachment for muscles and protect internal organs. Example: ribs, skull
What do irregular bones look like and what is their function? Give an example.
They have a complex shape. Protect internal organs. Vertebrae
What do sesamoid bones look like and where are they found? What is their function?
They are small and round (shaped like a sesame seed). They form in tendons where there is pressure. They protect tendons from compressive forces.
(*tendons attach muscle to bone)
Where are sesamoid bones found in the body? Give an example.
Found in tendons in feet, hands and knees. An example is the patella, which is in front of the knee cap.
What are the 2 parts of the long bone?
Diaphysis (shaft)
Epiphysis (end)
What does the medullary cavity consist of in the long bone? What does the spongy bone consist of?
The medullary cavity - yellow marrow
Spongy bone - red marrow
What is the epiphyseal plate in long bones? When does it stop growing and what happens to it then?
It is the growth plate that allows bone to grow in length. It stops growing at 18-21 years of age, where it then becomes the epiphyseal line.
What is the endosteum in long bones?
It is the membrane that lines the inner cavity of the diaphysis.
What is the periosteum in long bones? What does it contain and what is its function?
It covers the outer surface of bones. It contains blood vessels, nerves, and lymphatic vessels.
It attaches tendons and ligaments to bone.
What covers the ends of bone that articulate (join) with others?
Articular cartilage
What are the two things bone consists of? What are each one’s function
2/3 calcium - strength
1/3 collagen fibres - flexibility
How does remodelling work for bones (= process of breaking down and building bone) - what process happens?
Negative feedback - stress is the stimulus (i.e. weight bearing through walking
No stress = less bone (becomes more thin)
More stress = more bone (becomes more thick)
What are the 4 types of cells within bone tissues?
1) Osteoblasts
2) Osteocytes
3) Osteogenic cells
4) Osteoclasts
What is the function of osteoblasts? Where are they located?
Form bone.
Found in growing portions of bone, including periosteum and endosteum.
What is the function of osteocytes? Are they the primary cell of mature bone? Where are they located?
They are responsible for mineral balance in our body. Yes, they are.
They are stuck in the bone matrix.
What is the function of osteogenic cells? Where are they located?
They are undifferentiated stem cells that develop into osteoblasts. They are found in deep layers of periosteum and the marrow.
What is the function of osteoclasts? Where are they located?
They are responsible for bone resorption = breakdown of the bone and release its calcium to the blood. They are found in bone surfaces and at sites of old, injured or unneeded bone
The balance of which two bone cells is responsible for the constant reshaping of bone?
The balance between osteoblasts and osteoclasts.
Where is compact bone found?
It makes up the outer layer of the bone
What is an osteon / haversian system in compact bone structure?
In compact bone structure, it is a haversian canal and the surrounding lamellae (rings of calcified bone) and lacunae (bone cavities / holes). *it is the basic structural unit of compact bone.
What are perforating / volkmann’s canals? What is their function?
They are the channels found in the bone that transmits blood vessels from the periosteum into the bone and communicates with the haversian canals.
What is lamellae?
Rings of calcified matrix
What is lacunae?
Bone cavities holes
What is spongy bone made of? What characterizes this material?
Trabeculae, which is light
What happens to spongy bone when you put stress on it?
More trabeculae is made = thicker bone = healthier bone
Where do arteries enter in bone?
Through nutrient foramina / foreman, which is an opening into the bone shaft
From where do osteocytes get nourished in spongy bone?
1) From blood vessels of periosteum that penetrate through
2) by blood that passes through marrow cavities
What are the 3 functions of nerve supply in the skeletal system?
1) sense pain
2) regulate blood flow
3) regulate bone growth
What cells form cartilage and what do these cells become?
Cartilage comes from chondroblasts which become chondrocytes.
What does bone use to build tissue?
Cartilage - bone forms from cartilaginous matrix
What is the epiphyseal plate - what happens here? Was it made of?
It’s made up of cartilage.
It is the area of growth in long bone. It is where ossification occurs in immature bone.
(the new bone matrix pushes epiphysis away from diaphysis)
What is the epiphyseal line?
It is an epiphyseal plate that has become ossified (= turned into bone) in mature bone
What does appositional growth mean?
Bones growing in diameter (can continue to happen even after they stop growing in length) due to stress
What two cells are in charge of appositional growth?
1) osteoclasts = resorb old bone (break them down)
2) osteoblasts = produce new bone beneath periosteum
This increases diameter of the bone
Why is calcium needed for bones?
To make calcium phosphate and calcium carbonate, which form what gives bone its hardness
Why is vitamin D needed for bones? What is the one source of it?
Needed for calcium absorption. Sunlight.
Why is vitamin K needed for bones
It supports bone mineralization
Why is magnesium needed for bones?
It is the structural component of bones