Connective Tissue

Mucoid connective tissue

A loose connective tissue found in many regions of the embryo, including the umbilical cord. Never found in adults. Also known as Wharton's Jelly.

Erythrocyte

A single cell type, the RBC is responsible for transport of oxygen and carbon dioxide in the blood.

Fibroblasts

An abundant fixed cell in connective tissue proper and are always present. Responsible for the production of all connective tissue fibers. Manufactures and secretes protein subunits that interact to form large extra cellular fibers. Also secrete hyaluronan that gives the ground substance is viscous consistency.

Collagen fibers

Are long, straight, and unbranched and most common fibers in connective tissue proper.

Facts

Are never exposed to an environment outside the body. Include bone, fat, and blood. All connective tissue are composed of specialized cells, extra cellular protein fibers and ground substance.

Fixed cells

Are stationary and are involved primarily with local maintenance, repair, and energy storage.

Chondrocytes

Are the only cells found within the cartilage matrix. Cells live in a small chambers known as lacunae. Avascular. They produce and maintain the cartilaginous matrix.

Dense regular connective tissue location

Between skeletal muscles and skeleton, between bones or stabilizing positions of internal organs; covering skeletal muscle; deep fascia.

Elastic tissue locations

Between vertebra of the spinal column, ligaments supporting the penis, ligament supporting transitional epithelia, in blood vessel walls.

Dense irregular connective tissue location

Capsules of visceral organs; periostea and perichondria; nerve and muscle sheaths; dermis

Aproneuroses

Collagenous sheets or ribbons that resemble flat, broad tendons. May cover the surface of a muscle and assist in attaching superficial muscle to other muscles.

Osteocytes

Communicate with blood vessels and with one another through slender cytoplasmic extensions. These extensions run though long, slender passages in the matrix.

Periosteum

Composed of a fibrous outer layer and a cellular inner layer. Assists in the attachment of a bone to surrounding tissues and to associated tendons and ligaments. The cellular layer functions in bone growth and participates in repairs after an injury.

Ligaments

Connect one bone to another. The parallel alignment of collagen fibers in tendons and ligaments allow them to withstand incredible forces.

Reticular tissue

Connective tissue consisting of reticular fibers, MO, fibroblasts and fibrocytes. Form the stroma of the liver, the spleen, lymph nodes, and bone marrow.

Matrix

Consists of extra cellular fibers and ground substance that surrounds the cells.

Platelets

Contain enzymes and special proteins that function in the clotting response to seal breaks in the vessel walls.

Elastic fibers

Contain the protein elastin. Elastic fibers are branching and wavy. More elastin fibers than collagen. Found in areas such as interconnecting adjacent vertebrae.

Areolar connective tissue

Contains all cells and fiber found in connective tissue proper. Has an open framework and ground substance accounts for most of its volume. Cushions organs to protect against shock and can provide support but permits independent movement. Phagocytic cells provide defense.

Compact bone

Contains blood vessels trapped within the matrix.

Tendons

Cords of dense regular connective tissue that attaches skeletal muscle to bones and cartilage. Fibers run along the longitudinal axis of the tendon and transfer the pull of the contracting muscle to the bone or cartilage.

Function

Establishing a structural framework for the body. Transporting fluid and dissolved materials from one region of the body to another. Providing protection for delicate organs. Supporting, surrounding, and interconnecting other tissue types. Storing energy reserves. Defending the body from invasion by microorganisms.

Dense irregular connective tissue

Fibers form an interwoven mesh work and do not show any consistent pattern. Provides strength and support to areas subjected to stressed from many different directions. Located in capsules of visceral organs, periostea and perichondria, nerve and muscle sheaths and dermis. Prevents over expansion of organs.

Mesenchyme

First connective tissue that appears in developing embryos. A stellate-shaped cell that gives rise to all other connective tissues, including fluid connective tissues, cartilage, and bone. Never found in adults

Adipocytes

Fixed cell containing a single lipid droplet.

Mesenchymal

Fixed cell. Present in many connective tissues and respond to local injury or infection by dividing to produce large amounts of daughter cells that differentiate into fibroblasts, macrophages, or other connective tissues.

Lymph

Forms as ISF and then enters lymphatic vessels that return it to the CVS. Along the way, cells of the IS monitor the composition of the lymph and respond to signs of injury or infection.

Elastic cartilage

Forms the external flap of the external ear (pinna), the epligottis, the auditory tube, and small cartilages of the larynx.

Adipose tissue

Found in almost all forms of areolar connective tissues. Located deep to the skin, buttocks, breasts, and padding around the eyes and kidneys. Provides padding and cushions shock. Insulates and stores energy.

Fluid connective tissues

Have a distinctive population of cells suspended in a watery matrix that contains dissolved proteins. Blood and lymph

Supportive connective tissue

Have a less diverse cell population and a matrix that contains closely packed fibers. Cartilage and bones.

Fixed MO

Large ameboid cells that are scattered among the fibers. Engulf damaged or dead cells or pathogens that enter the tissue. Release chemicals to activate the immune system and attract wandering cells.

Fibrous cartilage

Lie in high stress areas such as between spinal vertebrae, between pubic bones of the pelvis, and around or within a few joints and tendons. Resists compression, absorbs shock, and prevents damaging bone to bone contact.

Hyaline cartilage

Matrix contains closely packed collagen fibers. Is tough but flexible and is the weakest cartilage. Connections between the ribs and sternum, the supporting cartilages along the conducting passageways of the respiratory tract, and the articulate cartilages covering opposing bone surfaces within synovial joints, like the elbow and knee.

Lymphocytes

Migrate throughout the body. Increase rapidly whenever tissue damage occurs and some may develop into plasmocytes

Brown fat

Most abundant in infants and children. Highly vascularized and provides a mechanism for raising body temperature drastically. Found between should blades, around the neck, and upper body. AKA multilocular adipose cells

Dense connective tissue

Mostly composed of collagen fibers. Types: dense regular connective tissue and dense irregular tissue.

Tendons

Mostly consist of collagen fibers and connect skeletal muscle to bones.

Spongy bone

No blood vessels trapped within the mateic

Bone

One third contain collagen fibers with a mixture of calcium phosphate with lesser amounts of calcium carbonate. The minerals are organized around the collagen fibers resulting in a strong, flexible combination

Fibrous cartilage location

Pads within knee joint, between pubic bones of pelvis, and intervertebral discs.

Neutrophils & Epsinophils

Phagocytosis blood cells that are smaller than monocytes. These cells migrate through connective tissues in small numbers. Attracted by MO and mast cells during infection or injury.

Wandering cells

Primarily concerned with the defense and repair of damaged tissues.

Dense regular connective tissue function

Provides firm attachment; conducts pull of muscles; reduces friction between muscles; stabilized relative positions of bones.

White fat

Provides padding, cushions shock, acts as an insulator to heat loss through the skin, and serves as packing around structures. Common under the skin of the groin, sides, buttocks, and breast. Surrounds kidneys and connective tissue in the pericardial and abdominal cavities.

Hyaline cartilage function

Provides stiff but somewhat flexible support; reduces friction between bony surfaces.

Dense irregular connective tissue function

Provides strength to resist forces applied from many directions; helps prevent overexpansion of organs such as the urinary bladder.

Elastic cartilage function

Provides support, but tolerates distortion without damage and returns to original shape.

Connective tissue proper

Refers to connective tissue with many types of cells and extra cellular fibers in a syrupy ground substance. Adipose, ligaments, and tendons. Two classes of cells: Fixed cells and wandering cells

Fibrous cartilage function

Resists compression; prevents bone to bone contact and limits relative movement.

Plasmocytes

Responsible for the production of Ab.

Fibrocytes

Second most abundant fixed cell in connective tissue proper. Differentiate from fibroblasts and main ting the connective tissue fibers of connective tissue proper.

Perichondrium

Separates cartilage from surrounding tissues. Contains two distinct layers: an outer fibrous layer of dense irregular connective tissue that provides mechanical support and protection ant attaches cartilage to other structures. The inner, cellular layer is important to the growth and maintenance of the cartilage.

Elastic tissue function

Stabilizes positions of vertebrae and penis; cushions shocks; permits expansion and contraction of organs.

Appositional growth

Stem cells of the inner layer of the perichondrium undergo repeated cycles of division. The innermost cells differentiate into chondroblasts, which begin producing cartilage matrix. Chondroblasts differentiate into chondrocytes after they are completely surrounded by matrix.

Ground substance

Surrounds the cellular and fibrous components of connective tissue and in connective tissue proper is clear and colorless. Contains a mixture of proteoglycans and glycoproteins.

Melanocytes

Synthesize and stores the brown pigment melanin. Found in the skin and the dermis. Abundant in connective tissues of the eyes as well.

Dense regular connective tissue

The collagen fibers are packed tightly and aligned parallel to applied forces. Types: tendons, aproneuroses, elastic tissue, and ligaments

Cartilage

The matrix of cartilage is a firm gel that contains complex polysaccharides called condroitin sulfates.

Canaliculi

The passageways that form a branching network for the exchange of material between the blood vessels and the osteocytes.

Plasma

The watery matrix of blood.

Loose connective tissues

These tissues fill spaces between organs, providing cushioning, and support epithelial. Also surround and support blood vessels and nerves, store lipids, and provide a route for the diffusion of materials. Three types: areolar tissue, adipose tissue, and reticular tissues.

Reticular Fibers

Thinner than collagen fibers, and they form a branching, interwoven framework that is flexible. Abundant in spleen and liver.

Elastic tissue

Tissue is springy and has a resilient nature. Often underlies transitional epithelial and found in walls of blood vessels and surround respiratory passageways.

Ligaments

Usually connect cartilage to cartilage, bone to cartilage, or bone to another bone. Often contain significant number of elastic and collagen fibers.

Leukocytes

WBCs include neutrophils, eosinophils, basophils, lymphocytes, and monocytes. Important component of the immune system.

Free MO

Wandering cell that is phagocytosis and moves rapidly about connective tissues of the body. When circulating in the blood, called monocytes.

Interstitial growth

When chondrocytes within the cartilage matrix undergo cell division, their daughter cells produce additional matrix. Neither occurs in adult cartilage.

Mast cells

Wondering cells that are small, mobile in connective tissue often found near blood cells. Cytoplasm filled with secretory granules filled with histamine and heparin. Stimulate local inflammation