Extracellular Matrix: Protein Fibers

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Questions and Answers

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

To provide tensile strength (correct)

To provide elasticity

To create scaffolding

To facilitate cell communication

Which fibers in the extracellular matrix can stretch to one and a half times their resting length?

Reticular fibers

Elastic fibers (correct)

Fibrillin fibers

Collagen fibers

What is a major complication associated with Marfan Syndrome?

Joint dislocations

Dilation of the aorta (correct)

Multiple skeletal abnormalities

Tall stature

What type of cell junction prevents the passage of macromolecules?

Tight (occluding) junctions Signup and view all the answers

What characterizes reticular fibers in the extracellular matrix?

They form a web-like structure Signup and view all the answers

What is the role of desmosomes in cellular structures?

To distribute mechanical stress Signup and view all the answers

Defects in which glycoprotein are associated with Marfan Syndrome?

Fibrillin-1 Signup and view all the answers

Which type of junction allows small substances to pass freely between adjacent cells?

Gap junctions Signup and view all the answers

What type of connective tissue is characterized by a jelly-like consistency and supports blood vessels?

Loose (Areolar) Connective Tissue Signup and view all the answers

Which type of connective tissue is primarily found in tendons and ligaments?

Dense Regular Collagenous Connective Tissue Signup and view all the answers

What is the primary characteristic of Dense Irregular Connective Tissue?

It resists tensions in multiple planes. Signup and view all the answers

Which connective tissue allows organs to stretch and is found in the lining of large blood vessels?

Dense Regular Elastic Connective Tissue Signup and view all the answers

Which type of muscle tissue is under voluntary control?

Skeletal Muscle Signup and view all the answers

What is the role of adipose tissue in the body?

Insulation, shock absorption, and energy reserve Signup and view all the answers

What unique structures do cardiac muscle cells contain that allow them to function as a unit?

Intercalated discs Signup and view all the answers

Which characteristic is NOT typical of smooth muscle cells?

Voluntary control Signup and view all the answers

What structural feature distinguishes Reticular Tissue?

Numerous reticular fibers forming a mesh Signup and view all the answers

What is the primary function of neuroglial cells?

Support neurons Signup and view all the answers

What type of connective tissue has a predominantly collagenous structure with fibers arranged in parallel bundles?

Dense Regular Collagenous Connective Tissue Signup and view all the answers

Which connective tissue type is primarily responsible for protecting organs and providing body warmth?

Adipose Tissue Signup and view all the answers

Which component of a neuron transmits impulses away from the cell body?

Axon Signup and view all the answers

In which location would smooth muscle primarily be found?

Walls of hollow organs Signup and view all the answers

What happens to neurons during mitosis?

They do not divide. Signup and view all the answers

Which of the following accurately describes skeletal muscle fibers?

Multinucleate and voluntary Signup and view all the answers

What is a key characteristic of simple epithelial tissues?

They are one cell layer thick. Signup and view all the answers

Where can simple squamous epithelia primarily be found?

In air sacs of lungs. Signup and view all the answers

Which type of simple epithelium is characterized by cube-shaped cells?

Simple Cuboidal Signup and view all the answers

What function is NOT typically associated with simple columnar epithelia?

Mechanical protection Signup and view all the answers

Which feature distinguishes pseudostratified columnar epithelia?

Variable nucleus heights within the cells Signup and view all the answers

What is a primary location for simple cuboidal epithelia?

Kidney tubules Signup and view all the answers

What role do cilia play in simple columnar epithelium located in the uterine tube?

Facilitating the movement of substances Signup and view all the answers

What type of secretion is most often related to goblet cells found within pseudostratified columnar epithelia?

Mucus Signup and view all the answers

What is the primary outcome of regeneration in tissue repair?

Replacement with cells of the same type Signup and view all the answers

Which condition is likely to lead to fibrosis rather than regeneration?

Extensive damage to tissue structure Signup and view all the answers

Which tissue types are noted for having high regenerative capacity?

Bone and skin Signup and view all the answers

What role do fibroblasts play in tissue repair?

Produce collagen to form scar tissue Signup and view all the answers

What factor can enhance the likelihood of regeneration in tissue repair?

Intact extracellular matrix Signup and view all the answers

Which factor is associated with the development of excessive collagen deposition?

Prolonged inflammation Signup and view all the answers

Which type of tissue is least likely to regenerate after an injury?

Cardiac muscle Signup and view all the answers

What is a common result of significant disruption of the extracellular matrix during injury?

Interference with ability to regenerate Signup and view all the answers

Study Notes

Extracellular Matrix (ECM)

Composed of fibrous protein subunits providing tensile strength; three primary types: collagen, elastic, and reticular fibers.
Collagen Fibers: Over 20 types produced in the body, constitute 20-25% of total body protein, resemble steel cables, and exhibit high resistance to tension and pressure.
Elastic Fibers: Comprised of elastin and glycoproteins; capable of extending to 1.5 times resting length and returning to original size, providing distensibility and elasticity.
Reticular Fibers: Thinner and shorter than collagen, form supportive networks in various tissues, and trap foreign cells in organs.

Marfan Syndrome

Caused by defects in the fibrillin-1 gene, leading to dysfunctional elastic fibers in the ECM.
Symptoms include tall stature, long limbs, skeletal abnormalities, joint dislocations, and heart and eye issues.
High risk of aortic dilation, which can lead to rupture and fatal blood loss without prompt intervention.

Cell Junctions

Tight Junctions: Integral proteins forming a seal, preventing macromolecule passage, though some may be leaky.
Desmosomes: Linker proteins that distribute mechanical stress, providing structural integrity.
Gap Junctions: Protein channel pores that allow small molecules to pass between adjacent cells, facilitating communication.

Covering and Lining Epithelia

Simple Epithelia: One cell layer thick, lacking protective function; involved in diffusion and transport.
- Simple Squamous: Flat cells, efficient for diffusion; found in lungs and blood vessels.
- Simple Cuboidal: Cube-shaped cells; involved in secretion and diffusion; located in kidneys and glands.
- Simple Columnar: Tall cells that may have microvilli or cilia; found in gastrointestinal tract and glands.
- Pseudostratified Columnar: Appears stratified; contains goblet cells for mucus production; located in respiratory passages.

Types of Connective Tissue Proper

Loose (Areolar) Connective Tissue: Contains all three protein fibers, supporting blood vessels and underlying epithelium; has a jelly-like consistency.
Dense Irregular Connective Tissue: Collagen fibers arranged randomly; resists tension from multiple directions; found in the dermis and around organs.
Dense Regular Collagenous Connective Tissue: Parallel thick collagen fibers; resists tension unidirectionally; makes up tendons and ligaments.
Dense Regular Elastic Connective Tissue: Contains parallel elastic fibers; allows stretching; found in large blood vessels and some ligaments.
Reticular Tissue: Forms supportive networks using reticular fibers; traps foreign cells; comprises part of the basement membrane.
Adipose Tissue: Consists of fat cells (adipocytes); provides insulation, shock absorption, protection, and energy reserves.

Types of Muscle Tissue

Skeletal Muscle: Voluntary control; attaches to skeleton for movement; consists of multinucleate fibers formed from myoblast fusion.
Cardiac Muscle: Involuntary control; found only in the heart; shorter cells with intercalated discs enabling coordinated contractions.
Smooth Muscle: Involuntary; located in hollow organs and blood vessels; cells are single-nucleated and interconnected by gap junctions.

Nervous Tissue

Comprises neurons and neuroglial cells; forms the brain, spinal cord, and nerves.
Neurons: Generate and conduct nerve impulses, featuring cell bodies, axons, and dendrites; do not undergo mitosis.
Neuroglial Cells: Provide support, facilitate nerve impulse transmission, and maintain homeostasis; capable of mitosis.

Tissue Repair

Regeneration: Damaged cells are replaced with similar cell types; high in tissues like skin and liver.
Fibrosis: Fibroblasts create collagen to repair injury, leading to scar tissue formation, which is dense and irregular.
Conditions favoring regeneration include tissue with high regenerative capacity, minimal extent of damage, presence of stem cells, intact ECM.
Conditions leading to fibrosis include severe injury, chronic inflammation, lack of regenerative capacity in certain tissues, and significant ECM disruption.

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Description

Explore the fascinating world of the extracellular matrix, focusing on the three types of protein fibers: collagen, elastic, and reticular fibers. Learn about their unique structural properties and importance in providing tensile strength. Test your knowledge on their composition and functionality.