Histology: Connective Tissue (Junque)

Questions and Answers

What is the primary function of mast cells as described?

Stimulating immune cell differentiation

Regulating blood vessel permeability

Detecting and responding to pathogen invasion (correct)

Producing antibodies to fight off infections

Which type of hypersensitivity reaction is associated with mast cells?

Autoimmune hypersensitivity

Cytotoxic hypersensitivity

Delayed-type hypersensitivity

Immediate hypersensitivity (correct)

Where do mast cells originate from?

Lymphatic system progenitor cells

Bone marrow progenitor cells (correct)

Skin epithelial cells

Splenic precursor cells

What distinguishes mucosal mast cells from perivascular mast cells?

Their granule content and location within the body Signup and view all the answers

What is a characteristic feature of plasma cells?

Lymphocyte-derived and antibody-producing Signup and view all the answers

What is the result of the release of chemical mediators from mast cells?

Promotion of allergic reactions such as anaphylaxis Signup and view all the answers

Which anatomical locations are associated with mast cells?

In the connective tissue of organs and mucosal surfaces Signup and view all the answers

What unique feature is typically seen in the cytoplasm of plasma cells?

Rich endoplasmic reticulum and large Golgi apparatus Signup and view all the answers

What is primarily responsible for increased vascular permeability during inflammation?

Vasoactive substances such as histamine Signup and view all the answers

What are the classic signs of inflammation represented in Latin terms?

Tumor, calor, rubor, dolor Signup and view all the answers

Which statement accurately describes collagens?

Collagens form structures resistant to shearing forces. Signup and view all the answers

What is the primary role of chemotaxis in the inflammatory response?

To draw leukocytes into inflamed tissues Signup and view all the answers

How much of the human body's dry weight does collagen represent?

30% Signup and view all the answers

What is the main function of fibroblasts in relation to collagen?

They secrete collagen into the extracellular matrix. Signup and view all the answers

Which type of connective tissue is shaped primarily by the type of collagen present?

Cartilage Signup and view all the answers

What kind of forces do collagen fibers predominantly resist?

Shearing and tearing forces Signup and view all the answers

What structural feature of elastin allows it to stretch and relax under force?

Random-coil domains that can straighten or stretch Signup and view all the answers

Which of the following is the unique synthesis process for hyaluronan compared to other glycosaminoglycans?

Direct synthesis into the extracellular matrix by hyaluronan synthase Signup and view all the answers

What is the primary function of glycosaminoglycans (GAGs) in connective tissue?

To sequester cations and water through their negative charge Signup and view all the answers

Which process facilitates the cross-linking of elastin molecules?

Conversion of lysines’ amino groups to aldehydes by lysyl oxidase Signup and view all the answers

Which of the following GAGs is known for having different tissue distributions due to varying disaccharide units?

All of the above Signup and view all the answers

What impact does the high negative charge of GAGs have on their function in the extracellular matrix?

It leads to an extended conformation that binds water and cations Signup and view all the answers

Which component primarily differentiates elastin from other glycosaminoglycans?

Formation of cyclic desmosine cross-links Signup and view all the answers

Which of the following statements best describes the role of lysyl oxidase in elastin structure?

It catalyzes the conversion of lysines to aldehydes for cross-linking Signup and view all the answers

What primarily causes water to be forced out of capillaries?

Hydrostatic pressure of the blood Signup and view all the answers

What role do plasma proteins like albumin play in capillaries?

They draw water back into the capillaries through colloid osmotic pressure Signup and view all the answers

What happens to the excess fluid that is not reabsorbed into capillaries?

It drains into lymphatic capillaries Signup and view all the answers

Why do the osmotic pressures exerted by ions and low-molecular-weight compounds cancel each other out across capillary walls?

They are equal on either side of the capillaries Signup and view all the answers

What is the primary source of colloid osmotic pressure in blood?

Albumin and other plasma proteins Signup and view all the answers

What is the relationship between hydrostatic pressure and colloid osmotic pressure in capillaries?

They work together to maintain fluid balance in capillaries Signup and view all the answers

Which of the following best describes the effect of heart action on capillary function?

Generates hydrostatic pressure that forces water out Signup and view all the answers

What happens to the fluid that exits the capillaries through hydrostatic pressure?

It is partially reabsorbed back into the capillaries Signup and view all the answers

What are the primary components of loose connective tissue?

Cells, fibers, and ground substance in roughly equal parts Signup and view all the answers

Which type of connective tissue cells are most numerous in loose connective tissue?

Fibroblasts Signup and view all the answers

What role do capillaries play in connective tissues?

They transport metabolic waste and nutrients Signup and view all the answers

What primarily draws water back into the capillary at the venule end?

Colloid osmotic pressure Signup and view all the answers

Which fibrous proteins are predominantly found in loose connective tissue?

Collagen, elastic, and reticular fibers Signup and view all the answers

How does interstitial fluid contribute to cellular functions in connective tissue?

It acts as a solvent for nutrients and metabolic wastes. Signup and view all the answers

What effect does hydrostatic pressure have on the movement of fluid in connective tissue?

It causes fluid to exit capillaries into surrounding tissues. Signup and view all the answers

Which organs are primarily involved in excreting metabolic waste products from connective tissue?

Liver and kidneys Signup and view all the answers

Study Notes

Mast Cells

Mast cells are abundant near small blood vessels in skin and mesenteries, known as perivascular mast cells, and in mucosal areas like the digestive and respiratory tracts.
They originate from bone marrow progenitor cells, circulating in blood and entering tissues via venules.
Mast cells release chemical mediators such as histamine, playing a central role in immediate hypersensitivity reactions, including anaphylactic shock.
These cells act as sentinels, strategically positioned to detect microbial invasion.

Plasma Cells

Plasma cells, derived from lymphocytes, are antibody-producing cells with basophilic cytoplasm rich in rough endoplasmic reticulum and a large Golgi apparatus.
The nucleus of plasma cells is typically spherical, often eccentrically positioned.
They play a crucial role in the immune response, rapidly producing antibodies in response to antigens.

Collagen

Collagen is the most abundant protein in the human body, constituting 30% of its dry weight, forming strong extracellular fibers and networks.
Different types of collagen provide varied tissue properties and are predominant in tendons, organ capsules, and the dermis.
Collagen fibers display resistance against shearing and tearing forces, contributing to the structural integrity of connective tissues.

Elastin

Elastin provides elastic properties to connective tissues through its unique polypeptide structure, containing desmosine cross-links which allow flexibility.
The network formed by elastin can stretch and relax, aiding in the function of various organs and joints.

Glycosaminoglycans (GAGs)

GAGs are a family of large carbohydrates, with hyaluronan being notable for its direct synthesis into the extracellular matrix, providing lubrication and space-filling functions.
Other major GAGs include dermatan sulfate, chondroitin sulfates, keratan sulfate, and heparan sulfate, each with distinct roles and tissue distributions.
GAGs are important in attracting water and cations, facilitating hydration and cushioning in tissues.

Fluid Dynamics in Connective Tissue

Water movement in capillaries is regulated by hydrostatic pressure and colloid osmotic pressure, ensuring nutrient delivery and waste removal.
At the arterial end of capillaries, hydrostatic pressure drives fluid out, while the venous end sees greater osmotic pressure drawing fluid back, maintaining fluid balance.
Excess interstitial fluid drains into lymphatic capillaries, preventing accumulation in connective tissues.

Interstitial Fluid

Interstitial fluid acts as a solvent for nutrients and waste products, circulated through connective tissue via blood capillaries.
This fluid plays a vital role in nourishing cells and transporting metabolic by-products to detoxifying organs like the liver and kidneys.
Loose connective tissue, or areolar tissue, is characterized by a roughly equal mix of cells, fibers, and ground substance.

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Description

Explore the role of mast cells and complement molecules in immunologic reactions as discussed in Chapter 14. This quiz delves into their significance in connective tissues and interactions with small blood vessels in various organs.