Bone Structure and Function Quiz

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Questions and Answers

What is the primary function of the perforating fibers in bone structure?

To form the compact bone layer.

To provide a blood supply to the bone matrix.

To anchor the periosteum to the bone matrix. (correct)

To line the inner surface of the bony wall.

The diaphysis of a long bone is characterized by which of the following?

Being the ends of the long bone, filled with red marrow.

Composed of hyaline cartilage for joint articulation.

Containing primarily compact bone to resist compression.

Having a hollow cavity lined by endosteum and filled with marrow. (correct)

What is the function of the articular cartilage found at the epiphyses of long bones?

To provide a smooth surface for joint movement. (correct)

To anchor the periosteum to the bone.

To facilitate bone growth at the growth plate.

To produce blood cells for the bone marrow.

What is the key difference between compact and spongy bone?

Compact bone resists linear compression and twisting, and spongy bone resists forces from many directions. (C) Signup and view all the answers

What is the significance of the epiphyseal lines in mature bones?

They mark the remnants of the growth plate. (A) Signup and view all the answers

What is the term for the spongy bone found in flat bones?

Diploe (A) Signup and view all the answers

How do nutrient arteries contribute to the blood supply of long bones?

They supply the internal structures through a small hole in diaphysis. (D) Signup and view all the answers

What is the primary composition of yellow bone marrow?

Consisting largely of adipocytes and blood vessels. (C) Signup and view all the answers

What is the primary function of collagen in the extracellular matrix of bone?

To resist torsional and tensile forces (B) Signup and view all the answers

Which of the following correctly identifies the cells primarily responsible for building new bone?

Osteoblasts (C) Signup and view all the answers

Under what circumstances might yellow bone marrow revert to producing blood cells?

During life-threatening emergencies (A) Signup and view all the answers

What is a key characteristic of osteopetrosis, or marble bone disease?

Defective osteoclast function (D) Signup and view all the answers

In the structure of compact bone, what are the functional units called?

Haversian systems (A) Signup and view all the answers

What is the primary function of the reticular fibers within red bone marrow?

To provide structural support for hematopoietic cells (C) Signup and view all the answers

Which of the following best describes the transition of bone marrow composition throughout human development?

Mostly red marrow in infancy shifting to mostly yellow marrow in adulthood. (D) Signup and view all the answers

What is the role of the branching 'ribs' of bone that form the structure of spongy bone?

To provide a framework for bone marrow and resist forces from multiple directions (D) Signup and view all the answers

If a patient is diagnosed with infantile osteopetrosis, which of the following is a likely complication?

Failure of skull openings to enlarge, leading to nerve entrapment (C) Signup and view all the answers

In adults, where is red marrow typically found?

Predominantly in flat bones like the hip bone, sternum, and ribs, and ends of long bones (B) Signup and view all the answers

What percentage of bone's total weight is comprised of the organic matrix?

35% (C) Signup and view all the answers

Which of these diseases might lead a doctor to consider bone marrow transplantation as a treatment?

Aplastic anemia, leukemia and sickle-cell anemia. (C) Signup and view all the answers

What is the process of harvesting bone marrow from a donor called?

Bone Marrow Harvest (C) Signup and view all the answers

What is the primary function of osteocytes in bone tissue?

To maintain existing bone tissue (C) Signup and view all the answers

What is the main purpose of destroying the recipient's marrow in a bone marrow transplant?

To eliminate the recipient's defective cells and prevent rejection of the donor marrow. (B) Signup and view all the answers

What is the main component of the bone inorganic matrix that lends to bone’s hardness?

Calcium salts in the form of hydroxyapatite (C) Signup and view all the answers

What structure contains blood vessels and nerves within compact bone?

Central (Haversian) Canal (C) Signup and view all the answers

Which component of bone tissue is described as rings of thin layers?

Concentric lamellae (B) Signup and view all the answers

The collagen fibers in adjacent lamellae are oriented in which way?

Opposite directions (C) Signup and view all the answers

Which of the following is characteristic of trabeculae?

Provides access to blood supply from marrow (A) Signup and view all the answers

What is the primary cause of bone fragility leading to osteoporosis?

Inadequate inorganic matrix (A) Signup and view all the answers

Which of these is a preventative measure for osteoporosis?

Weight-bearing exercises (A) Signup and view all the answers

Which of the following is NOT a factor that contributes to the development of osteoporosis?

Regular high-impact exercise (D) Signup and view all the answers

Approximately how many osteocytes and lacunae are found per cubic millimeter of bone?

20,000 - 30,000 (D) Signup and view all the answers

In healthy adult bone, what is the relationship between bone formation and bone loss?

Bone formation and bone loss occur simultaneously. (B) Signup and view all the answers

How does tension affect bone remodeling?

Tension stimulates bone deposition. (B) Signup and view all the answers

Which of the following hormones significantly promotes bone deposition?

Testosterone (B) Signup and view all the answers

What is the primary function of Vitamin D in bone remodeling?

It promotes calcium ion absorption in the intestines and prevents calcium loss in the urine. (B) Signup and view all the answers

How does Vitamin K affect osteoblasts and osteoclasts?

It promotes osteoblast proliferation and increases lifespan while inhibiting osteoclast division and activity. (D) Signup and view all the answers

Which zone of the epiphyseal plate is primarily responsible for the lengthening of long bones through chondrocyte division?

Zone of Proliferation (B) Signup and view all the answers

In what sequence do the zones of the epiphyseal plate participate in the process of longitudinal bone growth, starting from the zone farthest from the diaphysis?

Zone of Reserve Cartilage, Zone of Proliferation, Zone of Hypertrophy and Maturation, Zone of Calcification, Zone of Ossification (C) Signup and view all the answers

What occurs in the zone of hypertrophy and maturation that contributes to bone lengthening?

Chondrocytes enlarge and mature, with lacunae becoming larger (A) Signup and view all the answers

Which zone of the epiphyseal plate is characterized by the presence of calcified cartilage, far from any blood supply?

Zone of Calcification (C) Signup and view all the answers

What is the role of osteoblasts in the zone of ossification during longitudinal bone growth?

To lay down new bone tissue on calcified cartilage (A) Signup and view all the answers

Which of these is NOT a direct part of the process of longitudinal bone growth at the epiphyseal plate?

Resorption of Bone tissue within the Zone of Calcification (D) Signup and view all the answers

What is the role of osteoclasts in the process of longitudinal bone growth?

They resorb calcified cartilage and bone (B) Signup and view all the answers

If the zone of proliferation was damaged in a developing bone, what would be the most immediate consequence?

Cessation or reduction in bone lengthening (B) Signup and view all the answers

Study Notes

Human Anatomy and Physiology - BIOL3306

Course: Human Anatomy and Physiology
Semester: Fall 2024
Instructor: Nour Nissan

The Skeletal System

The skeletal system encompasses bones, joints, and supporting tissues.
Bones are the main organs of the system. Adults typically have 206 bones.
Each bone consists of bone (osseous) tissue, dense regular collagenous tissue, dense irregular connective tissue, and bone marrow.

Functions of the Skeletal System

Bones like the skull, sternum, and ribs protect underlying organs.
Bones store minerals (calcium, phosphorus, and magnesium salts). These minerals are electrolytes, acids, and bases maintaining electrolyte and acid-base balance in the blood.
Red bone marrow within bones produces blood cells.
Yellow bone marrow, found in bones, contains adipocytes (fat-storing cells).
Bones serve as attachment sites for skeletal muscles, enabling movement around joints.
The skeleton provides structural support for the body.

Classification of Bones by Shape

Long bones are longer than wide (e.g., bones in the limbs).
Short bones are roughly cube-shaped (e.g., wrist and ankle bones).
Flat bones are thin and broad (e.g., most skull bones and pelvic bones).
Irregular bones have irregular shapes (e.g., vertebrae).
Sesamoid bones are small, flat, oval-shaped bones within tendons (e.g., kneecap).

Structure of a Long Bone

Periosteum: Outer dense irregular connective tissue membrane with blood vessels and nerves.
Perforating fibers: Collagen that anchors the periosteum.
Diaphysis: Shaft of the bone, lined by the endosteum (a membrane).
Epiphyses: Ends of the long bone, filled with red bone marrow and covered with articular cartilage (hyaline cartilage).
Compact bone: Hard, dense outer bone that resists linear compression and twisting forces.
Spongy (Cancellous) bone: Inner, honeycombed-like bone. Provides space for bone marrow and resists forces in many directions.
Epiphyseal lines: Remnants of the epiphyseal plate (growth plate), a line of hyaline cartilage in children and adolescents.

Structure of Short, Flat, Irregular, and Sesamoid Bones

Share similarities with long bones but may have fewer structures.
In flat bones, the spongy bone is called diploë.
Flat and irregular bones sometimes contain air-filled spaces called sinuses.

Blood & Nerve Supply to Bone

Bones receive blood vessels and sensory fibers.
Blood supply to long bones comes from the periosteum and one or two nutrient arteries.
Short, flat, irregular, and sesamoid bones receive blood from vessels penetrating the periosteum.

Red and Yellow Marrow

Bone marrow consists primarily of blood vessels and adipocytes (yellow bone marrow).
Yellow bone marrow can convert to red bone marrow in times of emergency.
Red bone marrow is a network of reticular fibers supporting islands of hematopoietic cells.
Infants primarily have red bone marrow, but the ratio shifts to yellow marrow as they age.
Adults have mostly yellow marrow except in flat bones and ends of long bones.

Bone Marrow Transplantation

Patients with certain blood disorders may benefit.
A matching donor's marrow is harvested and given to the recipient.
Recipient's marrow is destroyed before transplantation to allow new cells to take hold.
New blood cells typically develop in 2-4 weeks.

The Extracellular Matrix of Bone

Inorganic Matrix: About 65% of bone weight, consisting mainly of calcium salts and phosphorus in a structure called hydroxyapatite. Contributes to bone hardness and resistance to compression/bending.
Organic Matrix (Osteoid): About 35% of bone weight, composed of protein fibers (mostly collagen), proteoglycans, glycosaminoglycans, glycoproteins, and bone-specific proteins like osteocalcin. Provides flexibility and resistance to twisting/tensile forces.

Bone Cells

Osteoblasts: Build bone tissue.
Osteocytes: Maintain bone tissue.
Osteoclasts: Break down bone tissue.

Osteopetrosis

Also known as "Marble Bone Disease," it's a genetic disorder involving defective osteoclasts.
Characterized by increased bone mass, but the bone is weak and brittle.
Two forms: infantile (more severe) and adult.
Symptoms vary but may include bone pain, recurrent fractures, nerve trapping, and joint pain.
Some forms may be fatal.

Histology of Bone

Compact bone: Hard, dense, outer shell, capable of resisting high stress, organized into osteons (Haversian systems).
Spongy (Cancellous) bone: Forms a protective framework for bone marrow and resists many directions of force. Organized into trabeculae with concentric lamellae containing osteocytes.

Compact Bone Structure

Lamellae: Thin layers of bone matrix.
Osteon (Haversian system): Fundamental unit of compact bone. Contains concentric lamellae, central canal (Haversian canal), and lacunae.

Osteoporosis

Bone disease caused by inadequate inorganic matrix.
Results in brittle bones, increased risk of fractures, and slow healing.
Can be affected by diet, hormones, age, lack of exercise, and other factors.

Bone Growth in Length

The epiphyseal plate is a hyaline cartilage plate that enables the lengthening of long bones.
The plate consists of five zones associated with cellular changes, calcification, and ossification.
Growth essentially ceases once the epiphyseal plate closes (usually during late adolescence).

Bone Growth in Width

Bone continues to widen through osteoblast activity in the periosteum.
The deposition of new bone outwards leads to an increase in width.
Removal of inner bone lamellae through osteoclast activity creates space for the newly formed bone.

Gigantism and Acromegaly

Gigantism results from excess growth hormone before the epiphyseal plates close leading to excessive longitudinal and appositional growth.
Acromegaly occurs after the epiphyseal plates close, resulting in enlarged bones in the skull face hands and feet and soft tissues (e.g tongue) sometimes leading to heart/kidney malfunction and diabetes mellitus.

Bone Remodeling

A continuous process of bone formation and resorption.
Driven by many factors, including calcium homeostasis, bone repair, replacement of old with new bone, and adapting to stress.
In healthy adults, bone formation roughly equals bone resorption.
In children and adolescents, bone formation typically exceeds resorption.
Factors such as hormones and nutrient intake influence remodeling.

Bone Repair

Repair of bone fractures involves hematoma formation, then fibro and chondroblast infiltration and forming a soft callus which is eventually replaced by primary and then secondary bone.
Several classes of fractures exist (simple, compound). Treatment usually involves stabilization and immobilization for several weeks.

Calcium Ion Intake and Fracture Risk

The National Academy of Sciences recommends high calcium intake, however long term studies have demonstrated no correlation between higher calcium intake and lower fracture rates in the US.
The ideal intake is around 700mg/day with appropriate vitamin D and K intake.

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Description

Test your understanding of bone structure and function with this quiz. Covering topics such as perforating fibers, the diaphysis of long bones, and the differences between compact and spongy bone, this quiz will enhance your knowledge of skeletal anatomy. Ideal for students studying biology or anatomy.