Bone Tissue Quiz

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Questions and Answers

What major role do osteocytes play in bone tissue?

Osteocytes are responsible for maintaining bone health. (correct)

They store minerals and provide structural support.

Osteocytes are primarily involved in bone formation.

Their primary function is to repair damaged bone.

Which component of bone makes up 50% of its dry weight?

Organic collagen fibers

Calcium carbonate crystals

Water content

Inorganic components, mainly hydroxyapatite (correct)

What is a significant feature of osteocytes in relation to their structure?

They possess a single large nucleus with nucleolus. (correct)

They are characterized by abundant organelles.

They have multiple nuclei distributed throughout the cell.

Osteocytes have a spherical shape with no processes.

Which of the following statements about the function of osteoblasts is correct?

Osteoblasts are essential in the formation of bone matrix. Signup and view all the answers

What regulates the process of mineralization in bone tissue?

Cell-regulated events involving alkaline phosphatase Signup and view all the answers

What distinguishes the territorial matrix from the interterritorial matrix?

Territorial matrix is basophilic and rich in chondroitin sulfate. Signup and view all the answers

In which zone are chondrocytes arranged into short columns perpendicular to the free surface?

Radial zone Signup and view all the answers

What is the primary characteristic of elastic cartilage?

It contains type II collagen and abundant elastic fibers. Signup and view all the answers

Which type of collagen is primarily found in the interterritorial matrix?

Type II collagen Signup and view all the answers

What is true about the chondrocytes in elastic cartilage compared to hyaline cartilage?

They are larger and more abundant. Signup and view all the answers

What types of fibers are found in the superficial (tangential) zone?

Type II collagen fibers arranged parallel to the surface Signup and view all the answers

Which component is not found in the extracellular matrix of bone?

Chondroitin sulfate Signup and view all the answers

What indicates interstitial growth in elastic cartilage?

Occasional lacunae with two chondrocytes Signup and view all the answers

What type of collagen is primarily found in the bone matrix?

Type I collagen Signup and view all the answers

Which of the following is a bone-specific protein that binds calcium and stimulates remodeling?

Osteocalcin Signup and view all the answers

What is the primary function of osteoclasts?

Bone resorption Signup and view all the answers

What is the function of Sharpey's fibers in the bone?

Attaching periosteum to bone Signup and view all the answers

What characterizes the inner layer of the periosteum?

Contains osteoprogenitor cells Signup and view all the answers

Which component of the bone matrix helps mediate cell attachment and influences mineralization?

Glycoproteins Signup and view all the answers

What is the role of bone morphogenetic proteins (BMPs)?

Acting as growth factors Signup and view all the answers

Where do osteoclasts reside during their function?

Howship's lacunae Signup and view all the answers

What is the shape of smooth muscle cells?

Fusiform or spindle-shaped Signup and view all the answers

How does smooth muscle contraction differ from striated muscle contraction?

Smooth muscle contraction is slow and long-lasting, striated is quick and vigorous Signup and view all the answers

Which component is NOT a characteristic of smooth muscle cells?

Intercalated discs Signup and view all the answers

What primarily regulates smooth muscle contraction?

Autonomic nervous system and hormones Signup and view all the answers

Where is smooth muscle NOT typically found?

Skin epidermis Signup and view all the answers

Which of the following best describes the nuclei of skeletal muscle fibers?

Peripherally placed and multinucleated Signup and view all the answers

What type of junctions are primarily found between smooth muscle cells?

Gap junctions Signup and view all the answers

How does the contractile machinery of smooth muscle differ from that of striated muscle?

Smooth muscle is dependent on calcium but organized differently Signup and view all the answers

What is the primary function of red muscle fibers?

Sustained production of force Signup and view all the answers

Which statement accurately describes white muscle fibers?

They exhibit fast contractions Signup and view all the answers

What is the primary characteristic of Type IIB/IIX fibers?

Reliance on anaerobic glycolysis Signup and view all the answers

Purkinje fibers play a critical role in which aspect of heart function?

Coordinating heart contractions Signup and view all the answers

What distinguishes Type IIA fibers from Type IIB/IIX fibers?

Type IIA fibers rely on aerobic metabolism Signup and view all the answers

What specific role does atrial natriuretic peptide play in the body?

Decreases renal tubule resorption of sodium and water Signup and view all the answers

How do Type IIA fibers differ from Type IIB/IIX fibers in terms of their activity?

Type IIA fibers produce ATP aerobically Signup and view all the answers

What is the comparative size of muscle cells between the atria and ventricles?

Atrial muscle cells are smaller than ventricular cells Signup and view all the answers

What percentage of the human population is considered Rh-positive (Rh+)?

85% Signup and view all the answers

Which component of the erythrocyte maintains its biconcave shape?

Cytoskeletal complex Signup and view all the answers

What is the primary function of erythrocytes?

Transport of oxygen and carbon dioxide Signup and view all the answers

What is the life span of a platelet?

10 days Signup and view all the answers

What happens to the nucleus of an erythrocyte during its differentiation?

It is extruded from the cell Signup and view all the answers

Which enzyme is responsible for the conversion of CO2 and H2O into bicarbonate (HCO3-)?

Carbonic anhydrase Signup and view all the answers

What is the appearance of platelets in a blood smear?

Small, basophilic fragments Signup and view all the answers

How is the majority of carbon dioxide transported in the bloodstream?

As bicarbonate (HCO3-) Signup and view all the answers

Study Notes

Colloquium 2 Study Notes

Bone and Cartilage: Both are specialized connective tissues that resist mechanical stresses.

Cartilage

Specialized: Avascular connective tissue.
Cells: Chondroblasts (produce matrix) and chondrocytes (maintain matrix).
Matrix (ECM): Composed of glycosaminoglycans, proteoglycans, collagen (types II, I), and elastic fibers.
Lacunae: Small compartments housing individual cartilage cells.
Isogenous groups: Clusters of chondrocytes derived from a single progenitor cell.
Perichondrium: A fibrous sheath surrounding cartilage (except on articular surfaces and fibrocartilage) that supports and nourishes cartilage. Cartilage supports and retains some flexibility.
Growth Patterns:
- Appositional growth: Chondrogenic cells in the perichondrium differentiate into chondroblasts, which produce the matrix and become chondrocytes, increasing tissue size from the outside.
- Interstitial growth: Existing chondrocytes divide and produce more matrix, resulting in increased cartilage size from within.

Hyaline Cartilage

Abundance: Most common type, comprises perichondrium.
Matrix: Contains type II collagen and aggrecans (proteoglycans).
Cells: Chondrogenic cells, chondroblasts, and chondrocytes.
Regions:
- Territorial matrix: Basophilic, poor in collagen, rich in chondroitin sulfate.
- Interterritorial matrix: More collagen type II, poorer in proteoglycans than territorial matrix.

Elastic Cartilage

Perichondrium: Rich in elastic fibers
Matrix: Abundant elastic fibers in addition to collagen type II. This gives it more flexibility
Cells: Chondrocytes are more abundant and larger; small isogenous cell groups (2–3 cells)
Matrix: The matrix isn't divided in territories

Fibrocartilage

Structure: Intermediate between dense regular connective tissue and hyaline cartilage. (Contains both types I and II collagen)
Matrix: Contains abundant collagen type I. Wide interterritories
Cells: Chondrocytes organized in rows separated by collagen fibers.
Location: Intervertebral discs, pubic symphysis, articular discs, and tendon insertions.

Bone

Connective tissue: Characterized by a mineralized extracellular matrix.
Extracellular matrix:
- Organic: Collagen fibers, mainly type I collagen.
- Inorganic: Hydroxyapatite crystals (calcium and phosphorus).
Cells: Osteoprogenitor cells; osteoblasts; osteocytes; osteoclasts
Periosteum: Dense fibrous connective tissue covering the bone. Includes an outer fibrous layer and an inner cellular layer (osteogenic cells).
Osteogenic or cellular layer of periosteum: osteoblast cells originate from this and develop into the osteoblasts.
Osteoprogenitor Cell: Embryonic mesenchymal cell that can differentiate osteoblasts or chondrocytes.
Osteoblast: Responsible for bone matrix secretion and mineralization.
Osteocyte: Mature bone cell, residing in lacunae and connected via canaliculi. Responsible for maintenance, and are able to detect mechanical forces in the bone.
Osteoclast: Derived from monocytes and responsible for bone resorption.

Bone Growth

Intramembranous ossification: Bone develops directly from mesenchymal tissue (Skull bones, clavicles)
Endochondral ossification: Bone develops from a cartilage model (occurs in most bones of the body)
Bone Remodelling: Continuous process of bone resorption and deposition. Crucial for maintaining calcium homeostasis, repairing micro-fractures, and adapting to mechanical stress.

Muscle Tissue

Skeletal Muscle: Long, cylindrical, multinucleated cells; peripherally placed nuclei.
Cardiac Muscle: Elongated, branched cells with centrally placed nuclei; intercalated discs.
Smooth Muscle: Fusiform cells with centrally placed nuclei.

Blood Vessels

Walls: Composed of three layers:
- Tunica intima: Endothelium (simple squamous), subendothelium (loose CT) and internal elastic lamina.
- Tunica media: Smooth muscle (in medium-sized arteries).
- Tunica adventitia: Connective tissue (fibroblasts), external elastic lamina and vasa vasorum.
Elastic arteries: Large-diameter arteries (e.g., aorta), function is to transport blood.
Muscular arteries: Medium-sized arteries(e.g., radial, splenic, mesenteric). Regulate blood flow to various organs.
Arterioles: Smallest arteries. Regulate blood flow into capillaries.
Capillaries: Composed of single layer of endothelium. Site of nutrient and gas exchange.
Venules: Collect blood from capillaries and transport to veins.
Veins: Medium and large-diameter vessels. Transport blood back to the heart.

Lymphatic System

Components: Lymphoid cells, lymphatic tissue, lymphatic vessels & lymphatic organs
Organ Functions:
- Thymus: T-cell maturation and differentiation.
- Bone Marrow: B-cell maturation and hematopoiesis.
- Lymph Nodes: Filter lymph, site of immune responses and antigen challenge.
- Spleen: Filters blood, destroys old or damaged RBCs and platelets, participates in immune function.
- Tonsils: Lymphoid tissue, protecting entrances to respiratory and digestive tracts.

Blood and Bone Marrow

Blood: Specialized connective tissue composed of formed elements (RBCs, WBCs, platelets) suspended in plasma (extracellular matrix).
Blood Functions: Transportation of gases, nutrients, wastes, and hormones.
Bone Marrow: Site of hematopoiesis (blood cell production).

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Description

Test your knowledge about bone tissue and the roles of osteocytes and osteoblasts. This quiz covers the major functions and structural features of these bone cells, as well as the components of bone that contribute to its dry weight. See how well you understand the process of mineralization in bone tissue.