What is osteoid made up of?
Collagen and calcium-binding proteins.
Where is red marrow found in adults?
In the heads of the femur and humerus, and in the diploë of flat bones.
1/183
p.5
Bone Structure and Anatomy

What is osteoid made up of?

Collagen and calcium-binding proteins.

p.5
Bone Cells and Their Functions

Where is red marrow found in adults?

In the heads of the femur and humerus, and in the diploë of flat bones.

p.6
Bone Cells and Their Functions

How do osteocytes respond to mechanical stimuli?

They respond to increased force on bone or weightlessness.

p.5
Bone Cells and Their Functions

What is the function of yellow marrow?

It can convert to red marrow if a person becomes anemic.

p.15
Bone Disorders and Diseases

What are the two types of fractures based on skin penetration?

Open (compound) fractures penetrate the skin, while closed (simple) fractures do not.

p.9
Bone Development and Ossification

Until when does postnatal bone growth occur?

Until early adulthood.

p.5
Bone Structure and Anatomy

What are the three types of bone markings?

Projections, surfaces, and depressions/openings.

p.5
Bone Cells and Their Functions

What is the role of osteoblasts?

They are bone-forming cells that secrete unmineralized bone matrix called osteoid.

p.6
Bone Cells and Their Functions

What is the function of osteoclasts?

They are giant, multinucleate cells that function in bone resorption (breakdown of bone).

p.6
Bone Cells and Their Functions

Where are osteoclasts located when active?

In depressions called resorption bays.

p.2
Bone Development and Ossification

What occurs during normal bone growth in youth regarding cartilage?

Calcification of cartilage.

p.11
Bone Development and Ossification

At what ages does bone lengthening typically cease for females and males?

Females around 18 years of age and males around 21 years of age.

p.11
Bone Development and Ossification

How do bones grow in width?

Through appositional growth, which can occur throughout life.

p.7
Bone Structure and Anatomy

What do lacunae contain?

Osteocytes.

p.13
Bone Structure and Anatomy

Where is 99% of the body's calcium found?

In bone.

p.3
Bone Structure and Anatomy

What covers the outside and inside of compact bone?

The periosteum covers the outside, and the endosteum covers the inside portion.

p.8
Bone Structure and Anatomy

What allows bone to resist compression?

Hard inorganic components such as mineral salts.

p.5
Bone Cells and Their Functions

What do osteoprogenitor cells do?

They are mitotically active stem cells that can differentiate into osteoblasts or bone-lining cells.

p.15
Bone Remodeling and Repair

What is the first stage of fracture repair?

Hematoma formation.

p.15
Bone Remodeling and Repair

What occurs during hematoma formation?

Torn blood vessels hemorrhage, forming a mass of clotted blood called a hematoma.

p.15
Bone Remodeling and Repair

What is involved in the treatment of fractures?

Reduction, immobilization, and healing time depending on severity, bone, and age.

p.2
Bone Development and Ossification

What do chondrocytes within lacunae do?

They divide and secrete new matrix, expanding cartilage from within.

p.15
Bone Remodeling and Repair

What is the mass of repair tissue formed during fibrocartilaginous callus formation called?

Fibrocartilaginous callus.

p.3
Bone Structure and Anatomy

Why are bones considered organs?

Because they contain different types of tissues, including osseous tissue, nervous tissue, cartilage, fibrous connective tissue, muscle cells, and epithelial cells in blood vessels.

p.15
Bone Remodeling and Repair

What happens during bony callus formation?

New trabeculae appear in the fibrocartilaginous callus, converting it to a bony callus of spongy bone.

p.3
Bone Structure and Anatomy

What are the three levels of bone structure?

Gross, microscopic, and chemical.

p.15
Bone Remodeling and Repair

What is the final stage of fracture repair?

Bone remodeling.

p.3
Bone Structure and Anatomy

What is compact bone?

A dense outer layer on every bone that appears smooth and solid.

p.12
Bone Remodeling and Repair

How often is compact bone replaced?

Approximately every 10 years.

p.7
Bone Structure and Anatomy

What are canaliculi?

Hairlike canals that connect lacunae to each other and to the central canal.

p.16
Bone Remodeling and Repair

What is the final structure of bone after remodeling?

It resembles the original structure and responds to the same mechanical stressors.

p.12
Bone Cells and Their Functions

What cells are responsible for bone resorption?

Osteoclasts.

p.5
Bone Structure and Anatomy

What are bone markings?

Sites of muscle, ligament, and tendon attachment, areas involved in joint formation, or conduits for blood vessels and nerves.

p.9
Bone Development and Ossification

What is ossification (osteogenesis)?

The process of bone tissue formation.

p.6
Bone Cells and Their Functions

What are bone-lining cells?

Flat cells on bone surfaces believed to help maintain the bone matrix.

p.3
Classification of Bones

What are sesamoid bones and give an example?

Sesamoid bones form within tendons; an example is the patella.

p.3
Classification of Bones

What are flat bones and provide examples?

Flat bones are thin, flat, and slightly curved; examples include the sternum, scapulae, ribs, and most skull bones.

p.3
Classification of Bones

What defines irregular bones and give examples?

Irregular bones have complicated shapes; examples include vertebrae and hip bones.

p.2
Functions of Bones

What is the role of bones in blood cell formation?

Hematopoiesis occurs in red marrow cavities of certain bones.

p.7
Bone Structure and Anatomy

What are perforating (Volkmann’s) canals?

Canals lined with endosteum that occur at right angles to the central canal, connecting blood vessels and nerves.

p.9
Bone Development and Ossification

What is the primary ossification center?

The center of the shaft where ossification begins.

p.2
Classification of Bones

What does the axial skeleton include?

Skull, vertebral column, and rib cage.

p.11
Hormonal Regulation of Bone Growth

What is the most important hormone for stimulating epiphyseal plate activity?

Growth hormone.

p.2
Classification of Bones

What are long bones?

Bones that are longer than they are wide, such as limb bones.

p.7
Bone Development and Ossification

What happens when the bone matrix hardens?

Canaliculi form, allowing communication between osteocytes.

p.8
Bone Structure and Anatomy

How strong is bone in resisting compression compared to steel?

Bone is half as strong as steel in resisting compression.

p.12
Bone Structure and Anatomy

What is the osteoid seam?

A band of unmineralized bone matrix that marks the area of new matrix.

p.8
Bone Structure and Anatomy

What are the organic components of bone?

Osteoprogenitor cells, osteoblasts, osteocytes, bone lining cells, osteoclasts, and osteoid.

p.16
Bone Disorders and Diseases

What causes osteomalacia and rickets?

Vitamin D deficiency or insufficient dietary calcium.

p.8
Bone Structure and Anatomy

What is osteoid and what does it consist of?

Osteoid is secreted by osteoblasts and consists of ground substance and collagen fibers.

p.17
Bone Disorders and Diseases

What type of drugs inhibit osteoclasts in osteoporosis treatment?

Bone-sparing drugs.

p.8
Bone Structure and Anatomy

What contributes to the resilience of bone?

Sacrificial bonds in or between collagen molecules.

p.7
Bone Structure and Anatomy

How does spongy bone appear microscopically?

It appears poorly organized but is actually organized along lines of stress.

p.14
Bone Structure and Anatomy

Why can bones be hollow?

Because compression and tension cancel each other out in the center of the bone.

p.17
Bone Disorders and Diseases

What is the effect of PTH when given as a daily injection?

It slows bone loss.

p.14
Bone Disorders and Diseases

What are fractures?

Breaks in the bone.

p.1
Bone Structure and Anatomy

What is skeletal cartilage primarily made of?

Highly resilient, molded cartilage tissue that consists primarily of water.

p.6
Bone Cells and Their Functions

What are osteocytes?

Mature bone cells in lacunae that no longer divide, maintaining bone matrix and acting as stress sensors.

p.6
Bone Cells and Their Functions

What role do osteocytes play in bone remodeling?

They communicate information to osteoblasts and osteoclasts.

p.5
Bone Structure and Anatomy

What percentage of bone protein is collagen?

90%.

p.5
Bone Cells and Their Functions

What are the five major cell types in bone tissue?

Osteoprogenitor cells, osteoblasts, osteocytes, bone-lining cells, and osteoclasts.

p.9
Bone Development and Ossification

What is endochondral ossification?

Bone forms by replacing hyaline cartilage.

p.12
Bone Remodeling and Repair

How often is spongy bone replaced?

Approximately every 3-4 years.

p.6
Bone Structure and Anatomy

What is the function of the central (Haversian) canal?

It runs through the core of the osteon and contains blood vessels and nerve fibers.

p.11
Bone Remodeling and Repair

What role do osteoblasts and osteoclasts play in bone thickness?

Osteoblasts secrete bone matrix on the external surface, while osteoclasts remove bone on the endosteal surface.

p.12
Bone Remodeling and Repair

What are the two processes involved in bone remodeling?

Bone deposit and bone resorption.

p.9
Bone Development and Ossification

What remains of hyaline cartilage after ossification?

Only in epiphyseal plates and articular cartilages.

p.11
Hormonal Regulation of Bone Growth

How do thyroid hormones affect bone growth?

They modulate the activity of growth hormone, ensuring proper proportions.

p.16
Bone Disorders and Diseases

What underlies nearly every disease affecting the human skeleton?

Imbalances between bone deposit and bone resorption.

p.10
Bone Development and Ossification

Which bones are formed through intramembranous ossification?

Frontal, parietal, occipital, temporal bones, and clavicle.

p.13
Hormonal Regulation of Bone Growth

What effect does parathyroid hormone have on bones?

It stimulates osteoclasts to resorb bone, releasing calcium into the blood.

p.3
Bone Structure and Anatomy

What covers the articular surfaces of long bones?

Hyaline cartilage.

p.17
Bone Disorders and Diseases

What dietary components are important for preventing osteoporosis?

Adequate Calcium and Vitamin D intake.

p.16
Bone Disorders and Diseases

What are the effects of rickets in children?

Results in bowed legs and other bone deformities due to enlarged and abnormally long bone ends.

p.8
Bone Structure and Anatomy

What is the matrix composition of osseous tissue?

About one-third organic and two-thirds inorganic matter.

p.14
Bone Development and Ossification

What does Wolf's law explain about handedness?

Right- or left-handedness results in thicker and stronger bone in the corresponding upper limb.

p.1
Components of the Skeletal System

What are the main components of the skeletal system?

Bones, cartilages, and ligaments.

p.14
Bone Cells and Their Functions

What do osteocytes detect when bone is deformed?

Electrical currents created by fluid movement through canaliculi.

p.1
Components of the Skeletal System

What is the function of tendons?

They attach muscle to bone.

p.17
Bone Disorders and Diseases

What treatments are included for Paget’s Disease?

Calcitonin and bisphosphonates.

p.4
Bone Structure and Anatomy

What is the periosteum?

A glistening white, double-layered membrane that covers external surfaces except joints.

p.4
Bone Structure and Anatomy

How are bones vascularized?

Bones are well vascularized with nutrient arteries and veins serving the diaphysis.

p.9
Bone Development and Ossification

When does the formation of the bony skeleton begin during development?

In the second month of development.

p.9
Bone Development and Ossification

What are the two types of ossification?

Endochondral ossification and intramembranous ossification.

p.11
Bone Development and Ossification

What occurs in the ossification zone?

Chondrocyte deterioration leaves long spicules of calcified cartilage, which are eroded by osteoclasts and covered with new bone by osteoblasts.

p.6
Bone Structure and Anatomy

What is an osteon?

The structural unit of compact bone, consisting of an elongated cylinder that runs parallel to the long axis of the bone.

p.12
Bone Remodeling and Repair

What percentage of bone mass is recycled each year?

About 5–10%.

p.9
Bone Development and Ossification

What bones are formed through endochondral ossification?

Most bones of the skeleton, except clavicles.

p.2
Classification of Bones

How are bones classified based on location?

Into axial skeleton and appendicular skeleton.

p.15
Bone Remodeling and Repair

What occurs during bone remodeling?

Excess material is removed, and compact bone is laid down to reconstruct shaft walls.

p.9
Bone Development and Ossification

What are the five main steps in the process of ossification?

1. Bone collar forms, 2. Central cartilage calcifies, 3. Periosteal bud invades cavities, 4. Diaphysis elongates, 5. Epiphyses ossify.

p.13
Hormonal Regulation of Bone Growth

What vitamin is required for intestinal absorption of calcium?

Vitamin D.

p.12
Bone Cells and Their Functions

What do osteoclasts secrete to digest the bone matrix?

Lysosomal enzymes and protons (H+).

p.17
Bone Disorders and Diseases

What is a key factor in preventing and treating osteoporosis?

Weight-bearing exercise.

p.13
Hormonal Regulation of Bone Growth

What hormone is produced in response to high blood calcium levels?

Calcitonin.

p.17
Bone Disorders and Diseases

What is a potential risk of estrogen replacement therapy (ERT) for osteoporosis?

Increased risk of breast cancer, stroke, and heart disease.

p.17
Bone Disorders and Diseases

Which drugs are known to destroy osteoclasts?

Fosamax and Actonel.

p.13
Bone Disorders and Diseases

What can sustained high blood calcium levels lead to?

Deposits of calcium salts in blood vessels or kidneys and formation of stones.

p.17
Bone Disorders and Diseases

What is Forteo and its effect on bone density?

A PTH derivative that increases density by 10% in 1 year.

p.17
Bone Disorders and Diseases

What is Paget’s Disease characterized by?

Excessive and haphazard bone deposit and resorption.

p.7
Bone Structure and Anatomy

What allows bone to resist tension?

Soft organic components such as bone cells and osteoid.

p.1
Types of Cartilage

What is fibrocartilage known for?

Its thick collagen fibers and great tensile strength.

p.11
Bone Development and Ossification

What happens in the calcification zone during bone growth?

Surrounding cartilage matrix calcifies; chondrocytes die and deteriorate.

p.15
Bone Remodeling and Repair

What is the role of fibroblasts during fibrocartilaginous callus formation?

Fibroblasts secrete collagen fibers to span the break and connect broken ends.

p.11
Bone Development and Ossification

What happens to the epiphyseal plate near the end of adolescence?

It thins and is replaced by bone, leading to epiphyseal plate closure.

p.2
Functions of Bones

What are the seven important functions of bones?

Support, protection, anchorage, mineral and growth factor storage, blood cell formation, triglyceride storage, and hormone production.

p.6
Bone Structure and Anatomy

What are the components of an osteon?

Several rings of bone matrix called lamellae, which contain collagen fibers.

p.13
Hormonal Regulation of Bone Growth

What is the critical role of calcium in the body?

It is essential for maintaining extracellular homeostatic fluid levels, nerve firing, and muscle contraction.

p.3
Bone Structure and Anatomy

What is spongy bone made of?

It is made up of a honeycomb of small, needle-like or flat pieces of bone called trabeculae.

p.2
Classification of Bones

What are the four shapes bones can be classified into?

Long bones, short bones, flat bones, and irregular bones.

p.7
Bone Cells and Their Functions

How do osteoblasts maintain contact with each other and osteocytes?

Via cell projections with gap junctions.

p.10
Bone Development and Ossification

What is intramembranous ossification?

A process that begins within fibrous connective tissue membranes formed by mesenchymal cells.

p.13
Hormonal Regulation of Bone Growth

What hormone is produced in response to low blood calcium levels?

Parathyroid hormone (PTH).

p.3
Bone Structure and Anatomy

What is found in the central medullary cavity of long bones in adults?

Yellow marrow.

p.11
Bone Disorders and Diseases

What can cause abnormal skeletal growth?

Excesses or deficits of any hormones.

p.14
Bone Remodeling and Repair

What happens to bones when stress is usually off center?

Bones tend to bend.

p.10
Bone Development and Ossification

How do long bones grow in length?

Through interstitial (longitudinal) growth of the epiphyseal plate.

p.7
Bone Structure and Anatomy

What do circumferential lamellae do?

Help long bones resist twisting by extending around the entire surface of the diaphysis.

p.14
Bone Structure and Anatomy

What occurs on one side of the bone when it bends?

Compression occurs on one side, while stretching occurs on the other side.

p.8
Bone Structure and Anatomy

What percentage of bone mass is made up of hydroxyapatites?

65%.

p.10
Bone Development and Ossification

What happens to bone growth during adolescence?

Bones stop growing, although some facial bones may continue to grow slowly.

p.7
Bone Structure and Anatomy

What is the role of trabeculae in spongy bone?

They confer strength to bone, similar to cables on a suspension bridge.

p.12
Bone Remodeling and Repair

How do mechanical and gravitational forces affect bone?

They can cause remodeling, resulting in increased bone strength.

p.17
Bone Disorders and Diseases

What type of bone is referred to as Pagetic bone?

Bone that has a very high ratio of spongy to compact bone and reduced mineralization.

p.1
Components of the Skeletal System

What is the role of cartilage in the skeletal system?

It serves as the forerunner of most bones and covers many joint surfaces of mature bone.

p.14
Bone Disorders and Diseases

What are the two classifications of fracture position?

Nondisplaced (normal position) and displaced (out of alignment).

p.4
Bone Structure and Anatomy

What are the two layers of the periosteum?

The fibrous layer (outer) and the osteogenic layer (inner).

p.4
Bone Structure and Anatomy

What are epiphyseal arteries and veins responsible for?

They service the epiphysis of the bone.

p.3
Bone Structure and Anatomy

What is the structure of a typical long bone?

It has a shaft (diaphysis), bone ends (epiphyses), and membranes.

p.11
Hormonal Regulation of Bone Growth

What effect do testosterone and estrogens have during puberty?

They promote adolescent growth spurts and induce epiphyseal plate closure.

p.16
Bone Disorders and Diseases

What are the three major bone diseases?

Osteomalacia and rickets, osteoporosis, and Paget’s disease.

p.13
Bone Disorders and Diseases

What condition is characterized by high levels of calcium?

Hypercalcemia, which causes nonresponsiveness.

p.12
Hormonal Regulation of Bone Growth

What are the two control loops that regulate bone remodeling?

Hormonal controls and response to mechanical stress.

p.16
Bone Disorders and Diseases

Who is most at risk for osteoporosis?

Aged, postmenopausal women.

p.8
Bone Disorders and Diseases

What characterizes Osteogenesis Imperfecta?

Over-modified collagen molecules and thinner collagen fibers.

p.4
Bone Development and Ossification

What is the epiphyseal plate?

A remnant of childhood where bone growth occurs.

p.1
Types of Cartilage

Where is hyaline cartilage found?

In articular surfaces, costal areas, respiratory structures, and the nasal tip.

p.1
Bone Development and Ossification

What occurs during appositional growth?

Cartilage-forming cells in the perichondrium secrete matrix against the external face of existing cartilage.

p.2
Classification of Bones

What are short bones?

Cube-shaped bones found in the wrist and ankle.

p.7
Bone Structure and Anatomy

What are interstitial lamellae?

Lamellae that are not part of an osteon, filling gaps between forming osteons.

p.10
Bone Development and Ossification

What are the four major steps involved in intramembranous ossification?

1. Ossification centers form; 2. Osteoid is secreted and calcified; 3. Woven bone forms around blood vessels; 4. Lamellar bone replaces woven bone.

p.12
Bone Structure and Anatomy

What is the calcification front?

The abrupt transition zone between the osteoid seam and older mineralized bone.

p.16
Bone Disorders and Diseases

What are the characteristics of osteomalacia?

Bones are poorly mineralized, resulting in soft, weak bones and pain upon bearing weight.

p.13
Bone Disorders and Diseases

What condition is characterized by low levels of calcium?

Hypocalcemia, which causes hyperexcitability.

p.12
Bone Development and Ossification

What role do alkaline phosphatase play in bone calcification?

It removes phosphate ions from osteoid proteins, increasing local concentrations of phosphate ions.

p.10
Bone Development and Ossification

What is appositional growth?

The process by which bones increase in thickness.

p.12
Bone Development and Ossification

What triggers the release of matrix vesicles by osteoblasts?

Increased calcium ion concentration.

p.16
Bone Disorders and Diseases

What characterizes osteoporosis?

Bone resorption exceeds deposit, leading to a decline in bone mass.

p.14
Bone Structure and Anatomy

Where is the diaphysis thickest?

Where bending stresses are greatest.

p.13
Bone Remodeling and Repair

What is Wolf's law?

It states that bones grow or remodel in response to the demands placed on them.

p.16
Bone Disorders and Diseases

Which areas of the body are most susceptible to osteoporosis?

Spongy bone of the spine and neck of the femur.

p.10
Bone Development and Ossification

What is the resting (quiescent) zone in the epiphyseal plate?

An area of cartilage on the epiphyseal side that is relatively inactive.

p.8
Bone Disorders and Diseases

What is Rickets and how can it be prevented?

Rickets is a vitamin D deficiency causing hypomineralization, preventable through supplementation.

p.10
Bone Development and Ossification

What are the four zones of the epiphyseal plate below the resting zone?

1. Proliferation (growth) zone; 2. Hypertrophic zone; 3. Calcification zone; 4. Ossification (osteogenic) zone.

p.16
Bone Disorders and Diseases

What role does estrogen play in bone density?

Estrogen helps maintain bone density, and its drop at menopause increases the risk of osteoporosis.

p.10
Bone Development and Ossification

What occurs in the proliferation (growth) zone?

Cartilage on the diaphysis side rapidly divides, pushing the epiphysis away from the diaphysis.

p.16
Bone Disorders and Diseases

What are additional risk factors for osteoporosis?

Insufficient exercise, poor diet in calcium and protein, smoking, genetics, and hormone-related conditions like hyperthyroidism.

p.14
Bone Structure and Anatomy

Where are curved bones thickest?

Where they are most likely to buckle.

p.7
Bone Structure and Anatomy

What is the chemical composition of bone?

Bone is made up of both organic components (like bone cells and osteoid) and inorganic components.

p.10
Bone Development and Ossification

What happens in the hypertrophic zone?

Older chondrocytes enlarge and erode, forming interconnecting spaces.

p.14
Bone Structure and Anatomy

What forms trusses along lines of stress in bones?

Trabeculae.

p.17
Bone Disorders and Diseases

Where does Paget’s Disease usually occur?

In the spine, pelvis, femur, and skull.

p.14
Bone Disorders and Diseases

What happens to bones of fetuses and bedridden people?

They become featureless due to lack of stress.

p.14
Bone Disorders and Diseases

What is atrophy in the context of bones?

Loss of tissue mass due to disease or lack of use.

p.17
Bone Disorders and Diseases

At what age does Paget’s Disease rarely occur?

Before age 40.

p.1
Components of the Skeletal System

What do ligaments do in the skeletal system?

They hold bones together at the joints.

p.17
Bone Disorders and Diseases

What is a possible trigger for Paget’s Disease?

A virus.

p.14
Hormonal Regulation of Bone Growth

What determines whether and when remodeling occurs in bones?

Hormonal controls in response to changing blood calcium levels.

p.1
Bone Development and Ossification

What is the initial composition of the human skeleton?

It initially consists of just cartilage, which is later replaced by bone.

p.4
Types of Cartilage

What type of cartilage covers the joint surface where one bone meets another?

Articular cartilage, which is a layer of hyaline cartilage.

p.4
Functions of Bones

What is the function of articular cartilage?

It allows joints to move more freely and relatively friction-free.

p.14
Bone Disorders and Diseases

What are the two classifications of fracture completeness?

Complete (broken all the way through) and incomplete (not broken all the way through).

p.4
Bone Structure and Anatomy

What is the endosteum?

A delicate connective tissue membrane covering the internal bone surface.

p.1
Bone Structure and Anatomy

What is the perichondrium?

A layer of dense connective tissue surrounding cartilage that helps resist outward expansion.

p.1
Bone Cells and Their Functions

What are chondrocytes?

Cells encased in small cavities (lacunae) within the jelly-like extracellular matrix of cartilage.

p.1
Bone Development and Ossification

What are the two ways cartilage grows?

Appositional growth and interstitial growth.

p.4
Bone Structure and Anatomy

What are the two types of membranes associated with bones?

Periosteum and endosteum.

p.4
Bone Structure and Anatomy

What type of tissue covers trabeculae of spongy bone?

Endosteum, which contains reticular connective tissue.

p.1
Types of Cartilage

What are the three types of cartilage?

Hyaline cartilage, elastic cartilage, and fibrocartilage.

p.4
Bone Structure and Anatomy

What do nutrient arteries and veins supply?

They supply bone marrow and spongy bone, branching outward to supply compact bone.

p.4
Bone Structure and Anatomy

What is the function of perforating fibers?

They secure the periosteum to the underlying bone.

p.1
Types of Cartilage

What distinguishes elastic cartilage from hyaline cartilage?

Elastic cartilage contains elastic fibers, while hyaline cartilage contains only collagen fibers.

p.4
Bone Structure and Anatomy

What accompanies blood vessels in bones?

Nerves, which also pass through nutrient foramen.

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