Lab #3 (exercise 5-2)

What is the main function of connective tissue?

Connects and supports tissues throughout the body.

What embryonic tissue do all connective tissues originate from?

Mesenchyme.

What distinguishes connective tissue from epithelial tissue?

Connective tissue has a prominent extracellular matrix.

What are the 4 general types of connective tissue?

Connective tissue proper, cartilage, bone, and blood.

What makes up the ECM of connective tissue?

Ground substance and protein fibers.

What are the three major types of protein fibers in connective tissue?

Collagen, elastic, and reticular fibers.

What do collagen fibers look like?

Thick strands that resist tension, pulling, and stretching.

What is the main function of collagen fibers?

Providing tensile strength.

What do elastic fibers do?

Allow tissue to stretch and return to its original shape.

What do reticular fibers look like?

Thin, netlike fibers.

What are reticular fibers a special type of?

Collagen fiber.

Where is reticular connective tissue found?

Spleen, lymph nodes, bone marrow, and around blood vessels and nerves.

What is loose areolar connective tissue?

Connective tissue with abundant ground substance and all three types of fibers scattered throughout.

What is the main component of loose areolar connective tissue?

Ground substance.

Where is loose areolar connective tissue found?

Around basement membranes and in walls of hollow organs.

What is the main function of loose areolar connective tissue?

Glues tissue layers together.

How do you identify loose areolar connective tissue?

Look for a loose, open appearance with scattered collagen, elastic, and reticular fibers.

What is reticular connective tissue?

Connective tissue dominated by a network of reticular fibers.

Where is reticular connective tissue found in your lab?

Spleen or lymph node.

What is the function of reticular connective tissue in immune organs?

It provides a network/roadway for immune cells and acts as a sieve/filter.

How do reticular fibers usually appear on a slide?

Thin brownish-black fibers forming a network with a special stain.

What is adipose tissue?

Connective tissue composed mostly of adipocytes.

What is the main feature of an adipocyte?

A large lipid droplet.

Where is the nucleus of an adipocyte located?

Pushed toward the edge of the cell.

Where is adipose tissue found?

Under the skin and around organs.

How do you identify adipose tissue?

Look for many large, empty-looking cells with nuclei pushed toward the edges.

What is dense regular collagenous connective tissue?

Connective tissue with mostly parallel bundles of collagen fibers.

Where is dense regular collagenous CT found?

Tendons and ligaments.

What is the main function of dense regular collagenous CT?

Provides strong tensile strength in one direction/plane.

How do you identify dense regular collagenous CT?

Look for thick collagen fibers arranged in straight, parallel rows.

What is dense irregular connective tissue?

Connective tissue with collagen bundles arranged irregularly in many directions.

Where is dense irregular CT found?

Dermis of skin and joint/organ capsules.

What is the main function of dense irregular CT?

Provides tensile strength in multiple directions.

How do you identify dense irregular CT?

Look for thick collagen bundles arranged in many different directions.

What is dense regular elastic connective tissue?

Connective tissue with mostly parallel elastic fibers.

Where is dense regular elastic CT found?

Walls of large arteries and some ligaments.

What is the main function of dense regular elastic CT?

Allows distensibility and elasticity.

How can you distinguish dense regular elastic CT from elastic cartilage?

Dense regular elastic CT has mostly fibers with few cells, while elastic cartilage has many visible cells in lacunae.

What is cartilage?

A tough and flexible connective tissue that resists tension, twisting, and compression.

What cells are found in cartilage?

Chondrocytes.

Where are chondrocytes located?

In lacunae within the cartilage ECM.

Is cartilage vascular or avascular?

Avascular.

What are the three types of cartilage?

Hyaline cartilage, fibrocartilage, and elastic cartilage.

What is hyaline cartilage?

Cartilage with a smooth, glassy-looking ECM and few visible fibers.

Where is hyaline cartilage found in your lab?

Trachea.

What is the main function of hyaline cartilage at joints?

Provides a smooth surface for bone articulation.

How do you identify hyaline cartilage?

Look for chondrocytes in lacunae within a smooth/glassy-looking matrix.

What is fibrocartilage?

Cartilage with abundant collagen fibers in its ECM.

What is the main function of fibrocartilage?

Provides strength and support and absorbs shock.

Where is fibrocartilage found?

Intervertebral discs and articular discs.

How do you identify fibrocartilage?

Look for chondrocytes in lacunae surrounded by obvious collagen fibers.

What is elastic cartilage?

Cartilage with many elastic fibers in its ECM.

What is the main function of elastic cartilage?

Allows stretching and recoil.

Where is elastic cartilage found in your lab?

Epiglottis or ear.

How do you identify elastic cartilage?

Look for chondrocytes in lacunae with many visible elastic fibers.

How can you tell cartilage from connective tissue proper?

Cartilage has chondrocytes sitting in lacunae.

What do fibroblasts look like compared with chondrocytes?

Fibroblasts usually appear as small, flat/purple dots rather than cells surrounded by lacunae.

What is bone also called?

Osseous tissue.

What are osteocytes?

Mature bone cells located in lacunae.

What makes bone ECM hard?

Calcium hydroxyapatite crystals.

What are the two major components of bone ECM?

Organic matrix and inorganic matrix.

What is blood?

A connective tissue with a liquid ECM called plasma.

What are the major cellular components of blood?

Erythrocytes, leukocytes, and platelets.

What is the function of blood?

Transports oxygen, nutrients, electrolytes, and wastes.

What is unique about mature erythrocytes?

They lack a nucleus.

How do you identify blood on a slide?

Look for many small erythrocytes suspended in a liquid matrix.

What is the connective tissue slide from the spleen or lymph node?

Reticular connective tissue.

What is the connective tissue slide with large lipid-filled cells?

Adipose.

What is the connective tissue slide with parallel collagen bundles?

Dense regular collagenous CT.

What is the connective tissue slide with irregular collagen bundles?

Dense irregular CT.

What is the cartilage slide from the trachea?

Hyaline cartilage.

What are the two key clues for identifying cartilage?

Chondrocytes and lacunae.