Why does the matrix for bone need to be rigid

It allows water, salts, and various nutrients to diffuse through to adjacent or imbedded cells and tissues. Adipose tissue consists mostly of fat storage cells, with little extracellular matrix [link]. A large number of capillaries allow rapid storage and mobilization of lipid molecules. White adipose tissue is most abundant. It can appear yellow and owes its color to carotene and related pigments from plant food. White fat contributes mostly to lipid storage and can serve as insulation from cold temperatures and mechanical injuries.

White adipose tissue can be found protecting the kidneys and cushioning the back of the eye. The many mitochondria in the cytoplasm of brown adipose tissue help explain its efficiency at metabolizing stored fat. Brown adipose tissue is thermogenic, meaning that as it breaks down fats, it releases metabolic heat, rather than producing adenosine triphosphate ATP , a key molecule used in metabolism.

Areolar tissue shows little specialization. It contains all the cell types and fibers previously described and is distributed in a random, web-like fashion. It fills the spaces between muscle fibers, surrounds blood and lymph vessels, and supports organs in the abdominal cavity.

Areolar tissue underlies most epithelia and represents the connective tissue component of epithelial membranes, which are described further in a later section. Reticular tissue is a mesh-like, supportive framework for soft organs such as lymphatic tissue, the spleen, and the liver [link]. Reticular cells produce the reticular fibers that form the network onto which other cells attach. Dense Connective Tissue Dense connective tissue contains more collagen fibers than does loose connective tissue.

As a consequence, it displays greater resistance to stretching. There are two major categories of dense connective tissue: regular and irregular. Dense regular connective tissue fibers are parallel to each other, enhancing tensile strength and resistance to stretching in the direction of the fiber orientations. Ligaments and tendons are made of dense regular connective tissue, but in ligaments not all fibers are parallel.

Dense regular elastic tissue contains elastin fibers in addition to collagen fibers, which allows the ligament to return to its original length after stretching. The ligaments in the vocal folds and between the vertebrae in the vertebral column are elastic.

In dense irregular connective tissue, the direction of fibers is random. This arrangement gives the tissue greater strength in all directions and less strength in one particular direction.

In some tissues, fibers crisscross and form a mesh. In other tissues, stretching in several directions is achieved by alternating layers where fibers run in the same orientation in each layer, and it is the layers themselves that are stacked at an angle.

The dermis of the skin is an example of dense irregular connective tissue rich in collagen fibers. Dense irregular elastic tissues give arterial walls the strength and the ability to regain original shape after stretching [link]. Disorders of the… Connective Tissue: Tendinitis Your opponent stands ready as you prepare to hit the serve, but you are confident that you will smash the ball past your opponent. As you toss the ball high in the air, a burning pain shoots across your wrist and you drop the tennis racket.

That dull ache in the wrist that you ignored through the summer is now an unbearable pain. The game is over for now. After examining your swollen wrist, the doctor in the emergency room announces that you have developed wrist tendinitis. She recommends icing the tender area, taking non-steroidal anti-inflammatory medication to ease the pain and to reduce swelling, and complete rest for a few weeks.

She interrupts your protests that you cannot stop playing. She issues a stern warning about the risk of aggravating the condition and the possibility of surgery. She consoles you by mentioning that well known tennis players such as Venus and Serena Williams and Rafael Nadal have also suffered from tendinitis related injuries.

What is tendinitis and how did it happen? Tendinitis is the inflammation of a tendon, the thick band of fibrous connective tissue that attaches a muscle to a bone. The condition causes pain and tenderness in the area around a joint. On rare occasions, a sudden serious injury will cause tendinitis. Most often, the condition results from repetitive motions over time that strain the tendons needed to perform the tasks.

Persons whose jobs and hobbies involve performing the same movements over and over again are often at the greatest risk of tendinitis. In all cases, overuse of the joint causes a microtrauma that initiates the inflammatory response. Tendinitis is routinely diagnosed through a clinical examination. In case of severe pain, X-rays can be examined to rule out the possibility of a bone injury.

Severe cases of tendinitis can even tear loose a tendon. Surgical repair of a tendon is painful. Connective tissue in the tendon does not have abundant blood supply and heals slowly. While older adults are at risk for tendinitis because the elasticity of tendon tissue decreases with age, active people of all ages can develop tendinitis. Young athletes, dancers, and computer operators; anyone who performs the same movements constantly is at risk for tendinitis.

Although repetitive motions are unavoidable in many activities and may lead to tendinitis, precautions can be taken that can lessen the probability of developing tendinitis. For active individuals, stretches before exercising and cross training or changing exercises are recommended. For the passionate athlete, it may be time to take some lessons to improve technique. All of the preventive measures aim to increase the strength of the tendon and decrease the stress put on it.

With proper rest and managed care, you will be back on the court to hit that slice-spin serve over the net. Watch this animation to learn more about tendonitis, a painful condition caused by swollen or injured tendons. Two major forms of supportive connective tissue, cartilage and bone, allow the body to maintain its posture and protect internal organs. The distinctive appearance of cartilage is due to polysaccharides called chondroitin sulfates, which bind with ground substance proteins to form proteoglycans.

A layer of dense irregular connective tissue, the perichondrium, encapsulates the cartilage. Cartilaginous tissue is avascular, thus all nutrients need to diffuse through the matrix to reach the chondrocytes. This is a factor contributing to the very slow healing of cartilaginous tissues.

The three main types of cartilage tissue are hyaline cartilage, fibrocartilage, and elastic cartilage [link]. Hyaline cartilage , the most common type of cartilage in the body, consists of short and dispersed collagen fibers and contains large amounts of proteoglycans. Under the microscope, tissue samples appear clear. The surface of hyaline cartilage is smooth. Both strong and flexible, it is found in the rib cage and nose and covers bones where they meet to form moveable joints.

It makes up a template of the embryonic skeleton before bone formation. A plate of hyaline cartilage at the ends of bone allows continued growth until adulthood. Fibrocartilage is tough because it has thick bundles of collagen fibers dispersed through its matrix. Menisci in the knee joint and the intervertebral discs are examples of fibrocartilage.

Elastic cartilage contains elastic fibers as well as collagen and proteoglycans. This tissue gives rigid support as well as elasticity.

Tug gently at your ear lobes, and notice that the lobes return to their initial shape. The external ear contains elastic cartilage. Bone Bone is the hardest connective tissue.

It provides protection to internal organs and supports the body. Both components of the matrix, organic and inorganic, contribute to the unusual properties of bone. Without collagen, bones would be brittle and shatter easily. Without mineral crystals, bones would flex and provide little support. Osteocytes, bone cells like chondrocytes, are located within lacunae.

Adipose tissue is fat, and it really consists of cells called adipocytes in which fat is stored in the form of lipid droplets.

This tissue is found under the skin and it is also found around all of the organs of the body. The adipocytes can make and store fat; this is a good way to store energy long term and it provides protection and support for all the organs of the body. Cartilage tissue forms the skeleton during embryonic development and it is found between bones in the adult where the bones come together at joints.

The matrix is largely made of collagen fibers along with many sulfated compounds which together make a tough plastic type of material. The cartilage cells are called chondrocytes and these are scattered throughout the ground substance of the tissue. During the development of a child, the cartilage becomes replaced by bone cells.

Bone tissue is the hardest of all the connective tissues found in the human body. Bone functions to protect our internal organs, for example, our ribcage which protects our heart and lungs and the bones of the skull that protect our brain. The bones of the skeleton also allow for movement by providing surfaces for muscle attachment.

Muscles attach to bones by means of the connective tissue known as tendons. Ligaments are other types of tissue that connect one bone to another at joints. The matrix of bone is made of collagen which is densely impregnated with mineral salts known as calcium phosphate. There are different types of cells present in the matrix. The osteoblasts are the cells that make the matrix material that surrounds the cells. These calls can be replaced by differentiated mesenchymal stem cells that occur in the bone.

Osteoclasts are cells that do away with bone tissue by reabsorbing it, which is important when bone is being remodeled. At a microscopic level bone tissue occurs as circular structures known as Haversian systems in which the cells are arranged in a circular pattern around a central canal. Save my name, email, and website in this browser for the next time I comment. Sign in. Forgot your password? Get help. Password recovery. Bone is the hardest connective tissue. It provides protection to internal organs and supports the body.

Both components of the matrix, organic and inorganic, contribute to the unusual properties of bone. Without collagen, bones would be brittle and shatter easily. Without mineral crystals, bones would flex and provide little support.

Osteocytes , bone cells, are located within lacunae. The histology of transverse tissue from long bone shows a typical arrangement of osteocytes in concentric circles around a central canal Figure 4. Bone is a highly vascularized tissue. Unlike cartilage, bone tissue can recover from injuries in a relatively short time. Cancellous bone looks like a sponge under the microscope and contains empty spaces between trabeculae, or arches of bone proper.

It is lighter than compact bone and found in the interior of some bones and at the end of long bones. Compact bone is solid and has greater structural strength. Blood is a fluid connective tissues. Blood has two components: cells and fluid matrix Figure 4. Erythrocytes, red blood cells, transport oxygen and some carbon dioxide. Leukocytes, white blood cells, are responsible for defending against potentially harmful microorganisms or molecules. Platelets are cell fragments involved in blood clotting.

Some white blood cells have the ability to cross the endothelial layer that lines blood vessels and enter adjacent tissues. Nutrients, salts, and wastes are dissolved in the liquid matrix called plasma and transported through the body.

Lymph contains a liquid matrix and white blood cells. Lymphatic capillaries are extremely permeable, allowing larger molecules and excess fluid from interstitial spaces to enter the lymphatic vessels. Lymph drains into blood vessels, delivering molecules to the blood that could not otherwise directly enter the bloodstream. In this way, specialized lymphatic capillaries transport absorbed fats away from the intestine and deliver these molecules to the blood.

Visit this link to test your connective tissue knowledge with this question quiz. Can you name the 10 tissue types shown in the histology slides? Skip to main content. Chapter 4: The Tissue Level of Organization. Search for:. Connective Tissue Learning Objectives Identify and distinguish between the types of connective tissue: loose, dense, cartilage, bone, and blood Explain the functions of connective tissues.

Functions of Connective Tissues. Classification of Connective Tissues. Loose Connective Tissue. Dense Connective Tissue. Elastic connective tissue is a modified dense connective tissue that contains numerous elastic fibers in addition to collagen fibers, which allows the tissue to return to its original length after stretching Figure 4.

The lungs and arteries have a layer of elastic connective tissue that allows the stretch and recoil of these organs. Elastic Connective Tissue Elastic connective tissue consists of collagenous fibers with interwoven elastic fibers.