Connective Tissue Quiz

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Questions and Answers

Which of the following is NOT a primary function of connective tissue?

Providing structural support to organs

Facilitating exchange of nutrients with the circulatory system

Generating electrical impulses for body movement (correct)

Mediating the exchange of waste products

Which type of connective tissue is characterized by its abundance throughout the body and wide distribution among other primary tissues?

Connective tissue (correct)

Epithelial tissue

Muscle tissue

Nervous tissue

In addition to structural roles, what is another key function of connective tissues relating to the circulatory system?

Regulating body temperature

Facilitating nutrient, metabolite and waste product exchange (correct)

Synthesizing hormones for systemic regulation

Producing red blood cells

Connective tissues are derived from which of the following germ layers?

Mesoderm Signup and view all the answers

Which of the following is a structural characteristic generally associated with connective tissues?

The presence of blood & lymphatic vessels within the tissue Signup and view all the answers

Which of the following is NOT considered a main category of connective tissue?

Muscle tissue Signup and view all the answers

What is a key characteristic of connective tissues, pertaining to their origin?

Mesodermal origin (Mesenchyme) Signup and view all the answers

Which of these is NOT a main function of connective tissues?

Muscle contraction Signup and view all the answers

In connective tissue, what are the main components of the extracellular matrix?

Fibers and ground substance Signup and view all the answers

Which of these cells is considered a resident cell of connective tissue?

Fibroblast Signup and view all the answers

What is the primary role of ground substance in connective tissue?

Serving as a molecular sieve for nutrient diffusion Signup and view all the answers

Which of the following is a characteristic of glycosaminoglycans (GAGs) within the ground substance?

Hydrophilic with abundant negative charges Signup and view all the answers

What is the main function of multiadhesive glycoproteins like fibronectin and laminin in connective tissues?

Promoting cell adhesion to the basal lamina Signup and view all the answers

Which type of collagen is a primary component of reticular fibers and is characterized by its argyrophilic nature?

Type III collagen Signup and view all the answers

A deficiency in which vitamin leads to Scurvy, affecting the hydroxylation of proline and lysine during collagen synthesis?

Vitamin C Signup and view all the answers

Which of the following is a characteristic feature of elastin fibers, distinguishing them from collagen?

Presence of desmosine and isodesmosine cross-links Signup and view all the answers

What is the primary cause of the hypermobility of digits and other joint issues observed in individuals with Ehlers-Danlos syndrome?

Faulty assembly of collagens due to lysyl hydroxylase deficiency Signup and view all the answers

How does the diameter of reticular fibers compare to the diameter of type I collagen fibrils?

Reticular fibers are considerably thinner than type I collagen fibrils. Signup and view all the answers

Which type of collagen is most abundant in the human body?

Type I Signup and view all the answers

What is the primary function of reticular fibers?

To form a delicate supporting framework for highly cellular organs Signup and view all the answers

Which of the following tissues does not contain collagen type I?

Cartilage Signup and view all the answers

Which type of collagen is a major component of basement membranes?

Type IV Signup and view all the answers

What characteristics are associated with elastic fibers?

Thin, branched and providing elastic properties to tissues Signup and view all the answers

Where is type II collagen typically found?

Cartilage and the vitreous of the eye Signup and view all the answers

Which type of collagen is known as reticulin?

Type III Signup and view all the answers

Which collagen type plays a role in binding between fibrils and the extracellular matrix?

Type VI and IX Signup and view all the answers

Which type of collagen is primarily found within the lamina densa?

Type IV collagen Signup and view all the answers

Which of the following is NOT a fixed (resident) cell type in connective tissue?

Lymphocytes Signup and view all the answers

What role do fibroblasts play in wound healing?

They synthesize and secrete components of the extracellular matrix. Signup and view all the answers

Which of these is a component that helps anchor the basal lamina to the underlying connective tissue?

Fibrillin Signup and view all the answers

Cells such as tissue macrophages, mast cells, and lymphocytes are derived from which of the following?

Hematopoietic stem cells Signup and view all the answers

What is the function of the fibroreticular lamina?

To provide structural support, merging with underlying connective tissue. Signup and view all the answers

Which cell type is responsible for synthesizing and secreting the components of the extracellular matrix?

Fibroblasts Signup and view all the answers

Which of the following is a component involved in cell-to-basal lamina attachment?

Integrin/Laminin Signup and view all the answers

Which of the following is the primary function of adipocytes related to glucose?

Participating in glucose metabolism Signup and view all the answers

Besides leptin, which of these is a bioactive molecule secreted by adipocytes?

Angiotensinogen Signup and view all the answers

What is the primary function of uncoupling protein in the mitochondria of brown fat cells?

To generate heat Signup and view all the answers

What is the main difference between white and brown adipose tissue according to the text?

White fat provides insulation and cushioning, while brown fat is for thermoregulation Signup and view all the answers

What is the primary role of macrophages in connective tissue?

Phagocytosis and antigen presentation Signup and view all the answers

What are plasma cells?

Mature B lymphocytes that secrete antibodies Signup and view all the answers

Which of these best describes the function of histamine released by mast cells?

Mediating the immune response associated with allergies and inflammation Signup and view all the answers

Where are mucosal mast cells typically found?

Digestive and respiratory tract linings Signup and view all the answers

Study Notes

Connective Tissues

Connective tissue is a primary tissue type of mesodermal origin, providing structural and metabolic support to other tissues and organs throughout the body.
It is one of the four basic tissue types (epithelial, connective, muscle, and nervous).
Connective tissues facilitate nutrient, metabolite, and waste exchange between tissues and the circulatory system.
They commonly contain blood and lymphatic vessels.

Learning Objectives

Students should be able to describe the functions of connective tissue and identify common cell types within.
Identify interstitial collagen and elastic fibers.
Differentiate between elastic fibers, type I collagen, type III (reticular) collagen.
Apply knowledge of collagen and elastin properties to explain tissue function.
Recognize and classify various connective tissue types (e.g., dense irregular, dense regular, loose, adipose).
Identify basement membranes in tissue sections and understand their function.

Components of Connective Tissue

Ground substance: Unstructured material between cells, filling space.
Fibers: Collagen, elastic, and reticular fibers contribute to tissue properties like tensile strength and elasticity.
Cells: Fibroblasts, chondroblasts, osteoblasts, and hematopoietic stem cells are prominent cell types in connective tissues. Other cells such as macrophages, mast cells, lymphocytes, plasma cells, and neutrophils may also be present within specific types of connective tissues.

Ground Substance Components

Interstitial (tissue) fluid: A component of ground substance.
Glycosaminoglycans (GAGs): Unbranched polysaccharides with negative charges, highly hydrophilic.
Proteoglycans: Protein core with GAG side chains, creating a bottlebrush-like structure.
Multiadhesive glycoproteins: Fibronectin and laminin, with multiple binding sites for cells, signaling molecules, and other ECM components.
- These molecules facilitate cell adhesion to the basal lamina.

Fibers

Collagen fibers: The most abundant protein in humans (up to 30% of dry weight). Present in multiple forms, including fibril-forming and fibril-associated, critical for tensile strength.
Reticular fibers: Delicate, supporting framework found in organs with high cell density (e.g., lymph nodes, liver). Made from Type III collagen.
Elastic fibers: Thin, branched, or fenestrated fibers that provide elasticity (e.g., skin, blood vessels, lung, bladder). Contain glycoproteins including elastin.

Major Collagen Fiber Types

Different types of collagen (at least 20 present) have unique tissue locations and functions, like resistance to tension, pressure, and structural support.

Cells in Connective Tissue

Fibroblasts: The most common, synthesize and secrete ECM components.
Adipocytes: Found in adipose tissue, function in triglyceride storage and a wide array of bioactive secretion (e.g., leptin, regulating satiety).
Macrophages: Derived from monocytes, responsible for phagocytosis and antigen presentation.
Plasma Cells: Mature B lymphocytes that secrete antibodies.
Mast Cells: Store and release secretory granules with mediators of inflammation and hypersensitivity reactions (e.g., histamine).
Neutrophils: Short-lived phagocytes that are a key component if the immune response.

Embryonic Connective Tissue

Mesenchyme is embryonic connective tissue, with a gel-like ground substance, fibers, and star-shaped mesenchymal cells.
It is the precursor to all other connective tissue types.

Connective Tissue Proper

Loose Connective tissue:
- Areolar: A subtype, with a gel-like matrix of collagen, reticular, and elastin fibers; supportive cells include fibroblasts, macrophages, and mast cells.
- Adipose: Contains adipocytes for fat storage, insulation, and protection.
- Reticular: Forms a soft internal skeleton, or stroma, found in lymphoid organs.
Dense Connective tissues include:
- Dense Regular: Densely packed, parallel collagen fibers; found in tendons, ligaments, and aponeuroses.
- Dense Irregular: Irregularly arranged collagen fibers, found in the dermis of skin, submucosa, and fibrous capsules.

Cartilage

Hyaline Cartilage:
- Amorphous firm matrix with imperceptible collagen fibers.
- Chondrocytes lie in lacunae.
- Supports, reinforces, cushions, resists compression, and forms costal cartilage, embryonic skeleton, ends of long bones, nose, trachea, and larynx.
Elastic Cartilage:
- Similar to hyaline cartilage but has more elastic fibers.
- Maintains shape and structure, allowing flexibility.
- Supports structures including external ear and epiglottis.
Fibrocartilage:
- Similar to hyaline cartilage but less firm with thick collagen fibers.
- Provides tensile strength and absorbs shock.
- Found in intervertebral discs, pubic symphysis, and meniscus.

Bone (Osseous Tissue)

Hard, calcified matrix with collagen fibers.
Osteocytes are found in lacunae and are well-vascularized.
Supports, protects, provides levers for muscular action, and stores calcium, minerals, and fat, with marrow inside bones responsible for hematopoiesis.

Blood

Composed of red and white blood cells, and a fluid matrix (plasma).
Transports respiratory gases, nutrients, wastes, and other substances.
Located within blood vessels.

Basement Membrane

Sheets of extracellular matrix proteins separating parenchymal tissues from connective tissues.
Major substances include glycosaminoglycans and fibrous proteins like collagen type IV.
Not a plasma membrane.
Layers (viewed with EM) include: lamina lucida, lamina densa, and fibroreticular lamina.

Clinical Implications

Defects in collagen synthesis can lead to clinical disorders like osteogenesis imperfecta, Ehlers-Danlos syndrome, or scurvy.

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Description

Test your knowledge on connective tissues with this quiz. Explore their primary functions, structural characteristics, and their roles within the circulatory system. Perfect for students studying biology or related fields.