Tissues Study Guide - Ch. 4 (Question 7)

Give a general description that fits all types of Connective tissue.

All Connective tissues consist largely of nonliving extracellular matrix, which separates, often widely, the living cells of the tissue. All Connective tissues arise from mesenchyme (an embryonic tissue).

Describe the similarities between the three types of cartilage.

All stand up to tension and compression. Its qualities are between those of dense connective tissue and bone. It is tough but flexible, providing a resilient rigidity to the structures it supports. Cartilage lacks nerve fibers and is avascular. It receives its nutrients by diffusion from blood vessels located in the connective tissue layer surrounding it (perichondrium). Cartilage matrix contains an exceptional amount of tissue fluid. The movement of tissue fluid in its matrix enables cartilage to rebound after being compressed and helps to nourish cartilage cells. Chondroblasts, the predominant cell type in growing cartilage, produce new matrix until the skeleton stops growing at the end of adolescents. Chondrocytes (mature cartilage cells) are found in small groups within cavities called lacunae.

If we used areolar connective tissue to build a ligament, predict how this would change the dynamic of its function.

Areolar: Widely distributed under epithelia of body. Ex: Forms lamina propria of mucous membranes; packages organs; surrounds capillaries. Supporting and binding other tissues (the job of the fibers), Holding body fluids (the ground substance's role), Defending against infection (via the activity of WBC's and macrophages), Storing nutrients as fat in adipocytes (fat cells) Dense Regular Connective Tissue forms: Ligaments: Ligaments bind bones together at joints. They contain more elastic fibers than tendons and are slightly more stretch. Dense Regular Connective Tissue: Primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast. Withstands great tensile stress when pulling force is applied in one direction.

What are the basic functions of Connective tissue?

Binding and Supporting, Protecting, Insulating, Storing reserve fuel, and Transporting substances within the body.

What is the primary difference between blood and reticular connective tissue? Cell types and locations..

Blood: Red and White blood cells in a fluid matrix; contained within blood vessels; Transports respiratory gases, nutrients, wastes, and other substances. Reticular Connective Tissue: Loose network of reticular fibers in a gel-like ground substance, reticular cells lie on the fibers. Only fibers in its matrix are reticular fibers, which form a delicate network along which fibroblasts called reticular cells are scattered. It forms a labyrinth-like stroma (bed/mattress), or internal framework that can support many free blood cells (mostly lymphocytes) in lymph nodes, the spleen, and bone marrow.

Where is Bone Tissue found in the body? What is the function of it?

Bones. Supports and protects (by enclosing); provides levers for the muscles to act on; stores calcium and other minerals and fat; marrow inside bones is the site for blood cell formation (hematopoiesis).

What are the general types of connective tissue?

Connective Tissue Proper (include fat and fibrous tissue of ligaments), Cartilage, Bone, and Blood. Connective Tissue Proper: Loose Connective Tissue: Areolar, Adipose, Reticular Dense Connective Tissue: Regular, Irregular, Elastic Cartilage: Hyaline Cartilage, Elastic Cartilage, Fibrocartilage Bone Tissue: Compact Bone, Spongy Bone Blood

Describe Collagen Fibers (a Connective Tissue Fiber).

Constructed primarily of the fibrous protein collagen. These molecules are secreted into the extracellular space, where they assemble spontaneously into cross-linked fibrils, which in turn are bundled together into the thick fibers seen with a microscope. Because their fibrils cross-link, these fibers are extremely tough and provide high tensile strength (ability to resist being pulled apart) to the matrix. Indeed, stress tests show that these fibers are stronger than steel fibers of the same size.

Where is Blood found in the body? What is the function of it?

Contained within blood vessels. Transports respiratory gases, nutrients, wastes, and other substances.

If we used dense irregular connective tissue to build a tendon, predict how this would change the dynamic of its function.

Dense Irregular Connective Tissue: Fibrous capsules of organs and of joints (kidneys, bones, cartilages, muscles, and nerves); dermis of the skin; submucosa of digestive tract. Withstands tension exerted in many direction; provides structural strength. Dense Regular Connective Tissue forms: Tendons - Tendons are cords that attach muscles to bones. Dense Regular Connective Tissue: Primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast. Withstands great tensile stress when pulling force is applied in one direction.

Describe the differences between the three types of cartilage.

Elastic: Nearly identical to Hyaline but has many more elastic fibers in matrix. Fibrocartilage: Matrix similar to but less firm than that in Hyaline cartilage.

Where is Dense Irregular Connective Tissue found in the body? What is the function of it?

Fibrous capsules of organs and of joints (kidneys, bones, cartilages, muscles, and nerves); dermis of the skin; submucosa of digestive tract. Withstands tension exerted in many direction; provides structural strength.

Where is Hyaline Cartilage found in the body? What is the function of it?

Forms most of the embryonic skeleton (before bone forms); covers the ends of long bones in joint cavities; supports the tip of the nose; connects the ribs to the sternum; Supports most of the respiratory system passages (ex: trachea) Supports and reinforces; serves as resilient cushion; resists compressive stress.

Which cartilage type is most prevalent?

Hyaline Cartilage (Gristle)

Where is each cartilage type located?

Hyaline: Covers end of long bones as articular cartilage, tip of nose, connects ribs to sternum, supports most of respiratory system passages (trachea). Elastic: Supports external ear (Pinna), and epiglottis. Fibrocartilage: Intervertebral discs, pubic symphysis, discs of knee joints.

What is the primary cell type(s) found in each cartilage tissue type?

In all 3 Cartilage: Chondroblast Hyaline: Collagen Fibers, Chondrocytes (1-10% cartilage volume) Elastic: Elastic Fibers, Chondrocytes Fibrocartilage: Chondrocytes, alternate with thick Collagen Fibers

If we built an aorta and used hyaline cartilage instead of elastic connective tissue in the wall, how would this change the function of the organ?

Instead of allowing the aorta tissue to recoil after stretching and maintaining pulsatile flow of blood through it, it would only support and reinforce, serve as resilient cushion, and resist compressive stress. It would not function properly.

Where is Fibrocartilage found in the body? What is the function of it?

Intervertebral discs; pubic symphysis; discs of knee joint. Tensile strength allows it to absorb compressive shock.

Describe Elastic Fibers (a Connective Tissue Fiber).

Long, thin, fibers form branching networks in the extracellular matrix. These fibers contain a rubberlike protein, elastin, that allows them to stretch and recoil like rubber bands. Connective tissue can stretch only so much before its thick, ropelike collagen fibers become taut. Then, when the tension lets up, theses fibers snap the connective tissue back to its normal length and shape. These are found where greater elasticity is needed. Ex: In the skin, lungs, and blood vessel walls.

Where is Loose Reticular Connective Tissue found in the body? What is the function of it?

Lymphoid organs (lymph nodes, bone marrow, and spleen). Fibers form a soft internal skeleton (stroma) that supports other cell types including WBC's, mast cells, and macrophages.

Where is Elastic Cartilage found in the body? What is the function of it?

Supports the external ear (pinna); epiglottis (flat covering opening to respiratory passage when we swallow). Maintains the shape of a structure while allowing great flexibility.

Where is Dense Regular Connective Tissue found in the body? What is the function of it?

Tendons, most ligaments, aponeuroses (flat, sheet-like tendons that attaches muscles to other muscles or to bones). Attaches muscles to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction.

What is the purpose of lacunae and what tissues have it?

The space that a chondrocyte (mature cartilage cell) occupies in the cartilage matrix. Chondrocytes (mature cartilage cells) are typically found in small groups within cavities called lacunae ("pits"). Mature bone cells, or osteocytes, reside in the lacunae within the matrix they have made. Cartilage Connective Tissue and Bone Connective Tissue have it.

Describe Reticular Fibers (a Connective Tissue Fiber).

These short, fine fibers are made of a different type of collagen than the more common, thicker collagen fibers. They connect to the coarser collagen fibers, but they branch extensively, forming delicate networks (reticul=network) that surround small blood vessels and support the soft tissue of organs. They are particularly abundant where connective tissue is next to other tissue types. Ex: In the basement membrane of epithelial tissues, and around capillaries, where they form fuzzy "nets" that allow more stretch than the larger collagen fibers.

What is the purpose of the central canal in bone?

They are located in each osteon (concentric rings of bony matrix - Lamellae) and they house blood vessels and nerves within the bone. These vessels supply blood to the interior spongy bone as well as the living cells housed within the compact bone.

What is the purpose of fibroblasts?

They give connective tissue its strength, form, and the ability to adhere to other tissue types. A cell that manufactures and maintains connective tissue, the structural framework that supports the organs. They secrete fibrous proteins and ground substances, which together form the extracellular matrix that is the basis of connective tissue. A Flat branching cell that appears spindle shaped (tapered at both ends).

Where is Loose Adipose Connective Tissue found in the body? What is the function of it?

Under skin in subcutaneous tissues; around kidneys and eyeballs; within abdomen; in breasts. Provides reserve food fuel; insulates against heat loss; supports and protects organs, acts as a shock absorber.

Where is Dense Elastic Connective Tissue found in the body? What is the function of it?

Walls of large arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes. Allows tissue to recoil after stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs following inspiration.

Where is Loose Areolar Connective Tissue found in the body? What is the function of it?

Widely distributed under epithelia of body. Ex: Forms lamina propria of mucous membranes; packages organs; surrounds capillaries. Supporting and binding other tissues (the job of the fibers), Holding body fluids (the ground substance's role), Defending against infection (via the activity of WBC's and macrophages), Storing nutrients as fat in adipocytes (fat cells)