Human Bone Structure and Types

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Questions and Answers

What is the primary function of flat bones in the human body?

To store minerals and nutrients

To provide support and structure to the body

To facilitate movement and flexibility

To protect internal organs and provide muscle attachment (correct)

During which week of gestation do limb buds begin to develop?

8th week of gestation

6th week of gestation

10th week of gestation

4th week of gestation (correct)

What is the term for the process of converting a cartilage template into a long bone?

Intramembranous ossification

Endochondral ossification (correct)

Bone resorption

Bone remodeling

Which of the following bones is an example of a sesamoid bone?

Patella Signup and view all the answers

What is the term for the bones that make up the central line of the body?

Axial skeleton Signup and view all the answers

Which of the following bones is an example of an irregular bone?

Vertebrae Signup and view all the answers

What is the union between the axial and appendicular skeletons facilitated by?

Pelvic girdle Signup and view all the answers

What is the primary function of short bones in the human body?

To form joints and allow for movement Signup and view all the answers

What is the primary function of osteoclasts in bone remodeling?

To break down and remove old bone tissue Signup and view all the answers

What is the main characteristic of compact bone?

It is more dense and rigid Signup and view all the answers

What is the primary component of the inorganic substance of bone extracellular matrix?

Hydroxyapatite crystals Signup and view all the answers

What is the function of haversian systems (osteons) in bone structure?

To strengthen bones and enhance resistance and durability Signup and view all the answers

What is the role of osteoblasts in bone formation?

To secrete collagen and other components for building mineralized bone matrix Signup and view all the answers

What is the main difference between compact bone and cancellous bone?

Compact bone is more dense and rigid, while cancellous bone is less dense and has more space in between the bony lamellae Signup and view all the answers

What is the function of glycoproteins and proteoglycans in bone extracellular matrix?

To aid in organization and stress resistance Signup and view all the answers

What is the primary function of osteocytes in bone structure?

To maintain bone tissue and respond to mechanical signals Signup and view all the answers

What is the primary function of osteoclasts in the bone remodelling process?

Breaking down and removing old or damaged bone tissue Signup and view all the answers

During the inflammatory phase of fracture repair, what type of cells rush to the injury site?

Specialized cells, including immune cells and debris-cleaning cells Signup and view all the answers

What is the primary function of osteoblasts in the bone remodelling process?

Synthesizing and laying down new bone tissue Signup and view all the answers

During the hard/bony callus formation stage of fracture repair, what type of bone is formed?

Woven bone Signup and view all the answers

What is the term for the process of removing old bone tissue and forming new bone tissue?

Bone remodelling Signup and view all the answers

During which stage of fracture repair is a soft callus composed of cartilage and collagen formed?

Soft/Fibrocartilaginous callus formation Signup and view all the answers

What is the number of ossification centers in the cartilage model?

3 Signup and view all the answers

At what stage of development is the primary ossification center formed?

12 weeks Signup and view all the answers

What is the function of epiphyseal growth plates?

To contribute to the lengthening of long bones through growth Signup and view all the answers

What is the term for the production of flat bone from stem cells without a cartilage template?

Intra-membranous ossification Signup and view all the answers

What is the region of bone where the diaphysis meets the epiphysis?

Metaphysis Signup and view all the answers

What is the function of osteoblasts?

To form new bone tissue Signup and view all the answers

At what stage of development do the epiphyseal growth plates fuse?

When full bone length is achieved Signup and view all the answers

What is the term for the process of bone development resulting from the replacement of cartilage with bone tissue?

Endochondral ossification Signup and view all the answers

Study Notes

Bone Structure

The skeleton consists of two large parts: Axial and Appendicular.
Axial part: composed of bones of the skull, vertebral column, ribs, and sternum, forming the central line of the body.
Appendicular part: consists of the axial part and bones of the limbs.

Axial and Appendicular Skeleton

The union between axial and appendicular skeletons is formed by the pectoral girdle and pelvic girdle.

Types of Bones

Long bones: examples include femur and humerus.
Flat bones: generally used for protection or muscle attachment (e.g. sternum or parietal).
Short bones: small bones found in some joints (e.g. carpal bones in the wrist and tarsal bones in the ankles).
Sesamoid bones: bones embedded within tendons or muscle, used to transfer force (e.g. patella).
Irregular bones: bones that do not occupy any of the other categories (e.g. vertebrae).

Limb Development

Limb development begins during the 4th week of gestation, with limb buds appearing from the lateral plate mesoderm.

Bone Development

Endochondral ossification: the process of converting a cartilage template into a long bone.
Intra-membranous ossification: the production of flat bone from stem cells without a cartilage template.

Endochondral Ossification Process

5 weeks: complete cartilage template for long bones.
8 weeks: collar of bone starts forming around the middle of the bone.
12 weeks: primary ossification centre develops, causing bone development.
At birth: secondary ossification centres form at the ends of the bone.
During childhood: epiphyseal growth plates develop, and secondary ossification centres develop into bone.
Adulthood: full bone length is achieved, epiphyseal growth plates fuse, and the ends of the bones remain capped with cartilage.

Descriptive Regions of Bones

Epiphysis: ends of long bones, develop from secondary ossification centres.
Epiphyseal plate: growth site in length, contains cartilage in actively growing bones.
Metaphysis: junction where the diaphysis meets the epiphysis.
Diaphysis: shaft of a long bone, represents the primary ossification centre.

Bone Cells

Osteoblasts: cells responsible for bone formation, secrete collagen and other components for building mineralized bone matrix.
Osteocytes: mature bone cells from osteoblasts, regulate osteoblasts and osteoclasts in response to mechanical signals.
Osteoclasts: large cells responsible for bone resorption, essential for bone remodeling, repairing microdamage, and regulating calcium levels.

Osseous Tissues

Compact bone: bony lamellae are strongly packed together with no space in between, more dense and rigid.
Cancellous/Spongy/Trabecular bone: irregular bone trabeculae are loosely distributed, leaving space for bone marrow.

Haversian Systems (Osteons)

Rings around a central canal with blood vessels and nerves for osteocytes, strengthen bones, enhance resistance and durability.

Bone Extracellular Matrix

Organic substance: collagen provides flexibility and strength to bone, glycoproteins and proteoglycans aid in organization and stress resistance.
Inorganic substance: primarily hydroxyapatite crystals, a calcium phosphate compound, gives bone hardness and resistance to compression.

Bone Remodelling

Process that involves the removal of old bone tissue (resorption) and the formation of new bone tissue.

Stages of Fracture Repair

Inflammatory phase (hematoma): blood clotting and inflammatory response begins, specialized cells rush to the injury site.
Soft/fibrocartilaginous callus formation: fibroblasts and chondrocytes create a soft callus composed of cartilage and collagen, stabilizing the fracture site.
Hard/bony callus formation: osteoblasts produce new bone tissue, replacing the cartilaginous callus, forming a hard bony callus made of woven bone.
Remodeling phase: the final stage of fracture repair, where the bone is fully restored to its original shape and function.

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Description

This quiz covers the basics of human bone structure, including the axial and appendicular skeletons, and the different types of bones in the human body.