32 Questions
What is the primary function of the vertebral column?
To protect the spinal cord
What is the process of producing blood cells in the red bone marrow?
Hematopoiesis
What is the function of bones in locomotion?
To act as levers to convert muscular contraction to movement
What is the function of the ossicles in the middle ear?
To transmit sound vibrations to the inner ear
What is the frequency of replacing the entire skeleton?
Every 7 years
What is the function of bones in supporting soft tissue?
To support soft tissue
What is the role of bones in storing chemicals?
To release calcium when needed
What percentage of the skeleton is recycled every week?
5-7%
What is the function of the pelvic bones?
To protect the internal reproductive organs
What is the main function of Osteoblasts?
Specialized in bone building
What happens to the amount of Osteoblasts and Osteoclasts with age?
Osteoblasts decrease and Osteoclasts increase
What is the percentage of collagen in the volume of solid bone?
40%
What is Bone Mineral composed of?
Calcium hydroxyapatite
What is the main component of compact bone by weight?
Bone Mineral
What is the surface area of Bone Mineral?
4×10^5 m2
What is the name of the condition characterized by weak bones and spontaneous fractures?
Osteoporosis
What percentage of calcium is present in bones?
2.22%
What is the primary function of trabecular bone?
To absorb compressive forces in the spine and joints
How many bones are there in the human body?
206
What is the advantage of trabecular bone over compact bone?
It is more flexible and can absorb more energy
What is the primary component of compact bone?
Solid bone tissue
What is the main reason X-rays show bones so well?
Because bones have a higher concentration of calcium
What is the primary function of bones in the body?
To provide support and structure
How are bones categorized according to their shape?
Into flat, long, cylindrical, irregular, and ribs
What is the approximate density of bone in grams per cubic centimeter?
1.9 g/cm3
What is the strength of bone in compression compared to granite?
As strong as granite
What happens to the density of bone as it becomes more porous with age?
It remains constant
What is the ratio of stress to strain in the initial linear portion of bone deformation?
Young's modulus Y
What is the approximate stress at which bone breaks?
120 N/mm2
What is the change in length of bone proportional to when it is placed under tension or compression?
The stress applied
What is the purpose of the instrument used to measure the elongation of bone under tension?
To measure the strain of bone
What is the unit of measurement for the cross-sectional area of the bone shaft in the example?
square centimeters
Study Notes
Importance of Bones
- Bones are crucial for the proper functioning of the body, which is why many medical specialists, such as dentists, orthopedic surgeons, rheumatologists, and radiologists, focus on this area.
Functions of Bones
- Provide a framework for the body
- Support soft tissue
- Serve as a point of attachment for ligaments, tendons, fascia, and muscles
- Enable locomotion by serving as levers to convert muscular contraction to movement
- Protect vital organs such as the brain, eyes, ears, spinal cord, heart, and lungs
- Act as a chemical "bank" for storing elements for future use by the body
- Release calcium when it is needed
- Facilitate nourishment through teeth
- Enable sound transmission through ossicles in the middle ear
- Produce blood cells through hematopoiesis in the red bone marrow
Bone Remodeling
- A continuous process of destroying old bone and building new bone
- The equivalent of a new skeleton is formed every 7 years
- 5-7% of the skeleton is recycled every week
- Involves two types of cells: osteoblasts (bone building) and osteoclasts (bone destroying)
- Osteoblasts predominate in young people, while osteoclasts predominate in older people, leading to a decrease in bone mass and an increased risk of osteoporosis
Composition of Bones
- Consist of two main materials: collagen and bone mineral
- Collagen is the major organic fraction, making up 40% of the weight and 60% of the volume of solid bone
- Bone mineral is made up of calcium hydroxyapatite (Ca10(PO4)6(OH)2) and accounts for 60% of the weight and 40% of the volume of solid bone
Types of Bones
- Classified into five categories based on shape: flat, long, cylindrical, irregular, and rib-like bones
- Composed of one or a combination of different types of bones, including compact and cancellous bone
- Cancellous bone is made up of thin thread-like trabecular bone
Mechanical Properties of Bone
- Density: constant throughout life at about 1.9 g/cm3
- Length: changes under tension or compression, with a stress limit of about 120 N/mm2
- Young's modulus (Y) is the ratio of stress to strain in the initial linear portion of the stress-strain curve
This quiz covers the importance of bones, functions of bones, bone remodeling, types of bones, and mechanical properties of bone. It's a part of chapter three in Medical Physics course.
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