Bone and Cartilage Physiology Practice Questions
39 free Bone and Cartilage Physiology practice questions for the Zoology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which cell type is responsible for the resorption of bone matrix by secreting lysosomal enzymes and acids?
- A Osteoblasts
- B Osteocytes
- C Osteoclasts
- D Osteoprogenitor cells
Correct answer: Osteoclasts
Osteoclasts are large, multinucleated cells derived from the monocyte-macrophage lineage. They break down bone tissue during remodeling and calcium homeostasis by acidifying the mineralized matrix.
The structural unit of compact bone, consisting of concentric lamellae surrounding a central canal, is known as the:
- A Osteon (Haversian system)
- B Trabecula (cancellous spicule)
- C Lacuna (osteocyte housing)
- D Canaliculus (nutrient channel)
Correct answer: Osteon (Haversian system)
Osteons (Haversian systems) are the functional units of compact bone. They are aligned parallel to the long axis of the bone to provide weight-bearing strength and house the Haversian canals containing blood vessels and nerves.
Which type of cartilage is characterized by the presence of thick bundles of collagen fibers and acts as a shock absorber in the intervertebral discs?
- A Hyaline cartilage
- B Elastic cartilage
- C Fibrocartilage
- D Articular cartilage
Correct answer: Fibrocartilage
Fibrocartilage contains a high density of Type I collagen fibers, making it the toughest type of cartilage. It is specifically located in areas subjected to heavy pressure and stretch, such as the pubic symphysis and intervertebral discs.
In the process of endochondral ossification, what serves as the initial template for the developing long bone?
- A Dense regular connective tissue
- B Hyaline cartilage model
- C Fibrocartilage model
- D Mesenchymal membrane
Correct answer: Hyaline cartilage model
Endochondral ossification begins with a hyaline cartilage model that is gradually replaced by bone. This process is responsible for the formation of most bones in the vertebrate skeleton, except for flat bones.
Which hormone is released in response to high blood calcium levels to inhibit bone resorption?
- A Parathyroid hormone
- B Calcitonin
- C Growth hormone
- D Thyroxine
Correct answer: Calcitonin
Calcitonin is produced by the parafollicular (C) cells of the thyroid gland. It lowers blood calcium by inhibiting osteoclast activity and promoting the deposition of calcium into the bone matrix.
What is the primary function of the canaliculi within the bone matrix?
- A Storage of bone marrow fat cells
- B Production of red blood cells via hematopoiesis
- C Provision of passages for nutrient and waste exchange between osteocytes
- D Secretion of synovial fluid into joint spaces
Correct answer: Provision of passages for nutrient and waste exchange between osteocytes
Canaliculi are tiny canals that connect lacunae to each other and to the central canal. They allow osteocytes to communicate via gap junctions and receive nutrients despite being encased in a mineralized, impermeable matrix.
The 'organic' part of the bone matrix, which provides flexibility and tensile strength, is primarily composed of:
- A Hydroxyapatite
- B Calcium carbonate
- C Collagen fibers
- D Magnesium salts
Correct answer: Collagen fibers
Bone matrix is a composite material; the organic component (osteoid) is about 90% collagen. This prevents bones from being too brittle and allows them to resist twisting and stretching forces.
Which region of a long bone is the site of longitudinal growth during childhood?
- A Diaphysis
- B Medullary cavity
- C Epiphyseal plate
- D Periosteum
Correct answer: Epiphyseal plate
The epiphyseal plate is a layer of hyaline cartilage between the epiphysis and diaphysis. Chondrocytes here divide and are eventually replaced by bone, lengthening the bone until the plate ossifies into the epiphyseal line.
Unlike bone, cartilage is 'avascular.' How do chondrocytes receive their nutrients?
- A Directly from Haversian canals that branch throughout the tissue
- B Through diffusion from the perichondrium or synovial fluid
- C Via an extensive network of canaliculi that link the chondrocytes
- D Through active transport powered by osteoblasts lining the matrix
Correct answer: Through diffusion from the perichondrium or synovial fluid
Cartilage lacks blood vessels, so nutrients must diffuse through the gel-like extracellular matrix. This low metabolic rate and lack of blood supply contribute to the slow healing process of injured cartilage.
The inorganic mineral salts of bone, which provide hardness and compressive strength, are primarily in the form of:
- A Potassium chloride crystals
- B Hydroxyapatite crystals
- C Sodium phosphate granules
- D Calcium carbonate deposits
Correct answer: Hydroxyapatite crystals
Hydroxyapatite is a mineral form of calcium apatite (Ca10(PO4)6(OH)2). These crystals are deposited within the collagen framework to make the bone hard enough to support the body's weight.
Wolff’s Law of bone physiology states that:
- A Bone growth is inhibited by the continuous force of gravity
- B Bone remodels and strengthens in response to mechanical stress placed upon it
- C Cartilage always precedes bone formation during ossification
- D Bones lose density progressively as blood calcium levels increase
Correct answer: Bone remodels and strengthens in response to mechanical stress placed upon it
Wolff's Law explains that bone is a dynamic tissue that adapts to mechanical loading. For example, the bones of athletes or the dominant arm of a tennis player often show increased density and thicker trabeculae.
Which of the following describes 'Appositional growth' in bone?
- A Bone growth in length occurring at the epiphyseal plate
- B Increase in bone diameter by adding new matrix at the periosteal surface
- C Repair of a fracture through the formation of fibrocartilage callus
- D Reduction of bone density caused by prolonged Vitamin D deficiency
Correct answer: Increase in bone diameter by adding new matrix at the periosteal surface
Appositional growth is the process by which bones grow wider. Osteoblasts in the periosteum secrete new matrix while osteoclasts in the endosteum resorb bone, allowing the bone to thicken without becoming excessively heavy.
What is the specific role of Vitamin C in bone physiology?
- A Absorption of calcium from gut
- B Inhibition of the parathyroid gland
- C Synthesis of collagen fibers
- D Stimulation of the thyroid gland
Correct answer: Synthesis of collagen fibers
Vitamin C is a required cofactor for the enzymes that cross-link collagen. A deficiency (scurvy) leads to weakened bone matrix and poor wound healing because the organic framework cannot be properly formed.
Which type of bone tissue is characterized by an open lattice of 'trabeculae' and is found in the epiphyses of long bones?
- A Compact bone with tightly packed osteons
- B Spongy cancellous bone with trabecular lattice
- C Cortical bone forming the outer shell
- D Woven bone laid down during rapid growth
Correct answer: Spongy cancellous bone with trabecular lattice
Spongy bone consists of a honeycomb-like network of trabeculae. This structure reduces the weight of the skeleton and provides spaces for red bone marrow where hematopoiesis occurs.
The process of 'Intramembranous ossification' is responsible for the formation of which bones?
- A The femur, humerus, and other long bones
- B Vertebrae and short bones of the spine
- C Flat bones of the skull and the clavicles
- D Carpals, tarsals, and other small irregular bones
Correct answer: Flat bones of the skull and the clavicles
Intramembranous ossification occurs when bone develops directly from mesenchymal (embryonic) connective tissue membranes without a cartilage intermediate. This is typical for the flat bones of the cranium and the mandible.
Which layer of the periosteum contains the osteoprogenitor cells necessary for bone repair and growth?
- A Outer fibrous layer
- B Inner osteogenic layer
- C Sharpey fiber layer
- D Subperiosteal layer
Correct answer: Inner osteogenic layer
The periosteum has two layers: an outer fibrous layer of dense irregular connective tissue and an inner osteogenic layer. The inner layer contains the stem cells (osteoprogenitor cells) that differentiate into osteoblasts.
During bone repair, what is the first structure to form at the site of a fracture after the initial hematoma?
- A Bony hard callus
- B Fibrocartilaginous soft callus
- C Periosteal collar
- D Secondary ossification center
Correct answer: Fibrocartilaginous soft callus
Following a hematoma, capillaries grow into the area and phagocytes clean the debris. Fibroblasts and chondroblasts then create a fibrocartilaginous callus that 'splints' the broken bone ends before it is later replaced by bone.
Which of the following is a characteristic of 'Elastic Cartilage'?
- A It forms the articular surfaces of movable joints
- B It contains abundant elastic fibers that maintain structural shape
- C It is the most prevalent cartilage type found throughout the body
- D It lacks a perichondrium and relies on diffusion alone
Correct answer: It contains abundant elastic fibers that maintain structural shape
Elastic cartilage is similar to hyaline cartilage but contains many more elastic fibers. This allows structures like the epiglottis and the pinna of the ear to be very flexible while maintaining their original shape.
Parathyroid hormone (PTH) increases blood calcium levels by primarily stimulating which cells?
- A Osteoblasts to build bone
- B Osteoclasts to resorb bone
- C Chondrocytes to divide
- D Osteocytes to secrete calcium
Correct answer: Osteoclasts to resorb bone
PTH is the primary regulator of blood calcium. When levels are low, PTH is secreted, which indirectly activates osteoclasts to break down bone and release calcium into the bloodstream.
The 'Sharpey’s fibers' are responsible for which of the following?
- A Connecting osteocytes to each other in the lacunae
- B Anchoring the periosteum to the underlying bone
- C Regulating the flow of blood in the Haversian canals
- D Providing attachment points for canalicular channels
Correct answer: Anchoring the periosteum to the underlying bone
Sharpey's (perforating) fibers are tufts of collagen fibers that extend from the periosteum into the bone matrix. They provide a very strong attachment point for tendons and ligaments to the bone.
Which cells are responsible for bone resorption?
- A Osteoblasts
- B Osteocytes
- C Chondrocytes
- D Osteoclasts
Correct answer: Osteoclasts
Osteoclasts break down bone tissue by secreting acids and enzymes. This process releases calcium into the bloodstream.
Which cells are responsible for bone formation?
- A Osteoblasts
- B Osteoclasts
- C Chondrocytes
- D Fibroblasts
Correct answer: Osteoblasts
Osteoblasts synthesize new bone matrix and help in mineralization. They are essential for bone growth and repair.
Which type of cartilage is found in the intervertebral discs?
- A Hyaline cartilage
- B Elastic tissue
- C Calcified cartilage
- D Fibrocartilage
Correct answer: Fibrocartilage
Fibrocartilage contains dense collagen fibers and acts as a shock absorber. It is found in intervertebral discs and joints.
Which type of cartilage is flexible and found in the ear?
- A Hyaline cartilage
- B Fibrocartilage
- C Calcified cartilage
- D Elastic cartilage
Correct answer: Elastic cartilage
Elastic cartilage contains elastic fibers that provide flexibility. It is found in structures like the ear and epiglottis.
Which part of a long bone is responsible for lengthwise growth?
- A Diaphysis
- B Epiphysis
- C Periosteum membrane
- D Epiphyseal plate
Correct answer: Epiphyseal plate
The epiphyseal plate, or growth plate, allows longitudinal bone growth. It is active during childhood and adolescence.
Which hormone decreases blood calcium levels by inhibiting bone resorption?
- A Calcitonin
- B Parathyroid hormone
- C Vitamin D
- D Growth hormone
Correct answer: Calcitonin
Calcitonin lowers blood calcium levels by inhibiting osteoclast activity. It promotes calcium deposition in bones.
Which hormone increases blood calcium levels by stimulating osteoclast activity?
- A Parathyroid hormone
- B Calcitonin from thyroid
- C Insulin
- D Estrogen
Correct answer: Parathyroid hormone
Parathyroid hormone (PTH) increases blood calcium levels by stimulating bone resorption. It acts on osteoclasts.
What is the structural unit of compact bone?
- A Lacuna
- B Osteon
- C Canaliculus
- D Trabecula
Correct answer: Osteon
The osteon is the basic unit of compact bone. It consists of concentric lamellae around a central canal.
Which type of bone tissue contains trabeculae?
- A Compact bone
- B Spongy bone
- C Cartilage
- D Dense bone
Correct answer: Spongy bone
Spongy bone has a lattice-like structure made of trabeculae. It is found in epiphyses and helps reduce bone weight.
Which vitamin is essential for collagen synthesis in bone?
- A Vitamin A
- B Vitamin C
- C Vitamin D
- D Vitamin K
Correct answer: Vitamin C
Vitamin C is necessary for collagen formation. Collagen provides tensile strength to bone.
Which vitamin aids in calcium absorption from the intestine?
- A Vitamin A
- B Vitamin B
- C Vitamin C
- D Vitamin D
Correct answer: Vitamin D
Vitamin D enhances calcium absorption from the intestine. It is essential for proper bone mineralization.
How do chondrocytes receive nutrients in cartilage?
- A Blood vessels
- B Lymphatic vessels
- C Diffusion
- D Nerves
Correct answer: Diffusion
Cartilage is avascular, so nutrients reach chondrocytes by diffusion. This process is relatively slow.
Which layer of bone contains osteoprogenitor cells?
- A Endosteum
- B Periosteum
- C Trabeculae
- D Lamellae
Correct answer: Periosteum
The inner layer of the periosteum contains osteoprogenitor cells. These cells differentiate into osteoblasts.
Which process involves bone formation from a cartilage template?
- A Intramembranous ossification
- B Endochondral ossification
- C Calcification
- D Osteolysis
Correct answer: Endochondral ossification
Endochondral ossification replaces cartilage with bone. It is responsible for forming long bones.
What is the function of canaliculi in bone?
- A Store calcium and phosphate ions
- B Produce and secrete collagen
- C Provide structural flexibility
- D Transport nutrients and waste
Correct answer: Transport nutrients and waste
Canaliculi are tiny channels that connect osteocytes. They allow exchange of nutrients and waste.
Which component provides tensile strength to bone?
- A Calcium salts
- B Ground substance
- C Hydroxyapatite crystals
- D Collagen fibers
Correct answer: Collagen fibers
Collagen fibers provide tensile strength and flexibility to bone. They prevent brittleness.
Which mineral is primarily responsible for bone hardness?
- A Sodium chloride
- B Potassium chloride
- C Magnesium carbonate
- D Calcium phosphate
Correct answer: Calcium phosphate
Calcium phosphate forms hydroxyapatite crystals. These give bones their hardness and compressive strength.
What is the first stage in bone repair after a fracture?
- A Hematoma formation
- B Callus formation
- C Bone remodeling
- D Ossification process
Correct answer: Hematoma formation
Hematoma formation occurs immediately after a fracture. Blood clots form at the injury site to initiate healing.
What does Wolff’s law state about bones?
- A Bones remain constant
- B Bones grow randomly
- C Bones adapt to stress
- D Bones shrink over time
Correct answer: Bones adapt to stress
Wolff’s law states that bones adapt to the stress placed on them. Increased stress leads to stronger bones.