Connective Tissue Lecture Notes

Flashcards covering the definitions, functions, types, and cellular components of connective tissue, cartilage, and bone as described in the lecture notes.

Connective Tissue

The most abundant, widespread, and varied of all tissue types in the body, serving to connect and support other tissues.

Collagen Fibers

Large fibers made of the protein collagen; they are the most abundant fibers and promote tissue flexibility.

Elastic Fibers

Branching intermediate fibers made of the protein elastin that allow structures to stretch and recoil.

Reticular Fibers

Small, delicate, branched fibers that form the structural framework for organs such as the spleen and lymph nodes.

Connective Tissue Proper

A category of connective tissue divided into loose types (Areolar, Adipose, Reticular) and dense types (Regular, Irregular, Elastic).

Areolar Connective Tissue

A widely distributed universal packing material that supports other tissues and helps defend against infection.

Edema

A condition where areolar tissue soaks up excess fluid like a sponge during inflammation, causing the affected area to swell.

Adipocytes

Fat cells with a "signet ring" appearance that store energy in the form of triglycerides (lipids).

Stroma

The internal framework of organs like the liver and spleen, formed by reticular connective tissue.

Dense Regular Connective Tissue

Highly fibrous tissue containing collagen designed to withstand high tensile stress in the direction of fiber alignment, such as in tendons.

Dense Irregular Connective Tissue

Tissue containing irregularly arranged collagen fibers found in the dermis and heart valves, capable of withstanding tension from many directions.

Perichondrium

The layer of dense irregular connective tissue that surrounds cartilage.

Periosteum

The dense fibrous membrane that covers the external surface of bones.

Elastic Connective Tissue

A type of dense connective tissue dominated by elastic fibers, which are composed of a central elastin core (roughly $90\%$) and a mantle of fibrillin microfibrils.

Marfan Syndrome

A genetic condition caused by mutations in elastic fiber proteins, specifically affecting fibrillin.

Chondroblasts

Specialized cells responsible for the composition and formation of cartilage.

Hyaline Cartilage

The most abundant cartilage in the body, characterized by a smooth, glassy appearance and a low-friction surface for joints.

Elastic Cartilage

Also known as yellow cartilage, it is the most flexible connective tissue and is found in the ear canal and respiratory tubes.

Fibrocartilage

The strongest and least flexible type of cartilage; it acts as a "dense rubber bumper" to absorb shock and protect joint margins.

Lacunae

Small spaces within the matrix of fibrocartilage or bone tissue that contain cells like chondrocytes or osteocytes.

Compact Bone (Cortical Bone)

The dense, hard outer layer of bone organized into structural units called osteons (Haversian systems).

Spongy Bone (Cancellous Bone)

A porous internal bone tissue containing trabeculae and red bone marrow, found at the ends of long bones.

Osteoblasts

Bone-forming cells that synthesize the organic matrix (osteoid) and initiate the mineralization process.

Osteocytes

Mature bone cells trapped in the matrix that act as mechanosensors to monitor and maintain the tissue.

Osteoclasts

Large, multinucleated cells that resorb (break down) bone tissue to facilitate remodeling and calcium release.

Osteogenic Cells

Undifferentiated stem cells found in bone membranes that can divide and differentiate into osteoblasts.

Osteoid

The organic bone matrix, making up roughly $30\text{--}35\%$ of bone mass, primarily composed of Type I collagen fibers.

Hydroxyapatite

Inorganic mineral salts (calcium phosphate crystals) making up approximately $65\text{--}70\%$ of bone mass, providing hardness and compressive strength.

Hematopoiesis

The production of blood cells, which occurs within the red bone marrow of spongy bone.

Osteocalcin

A hormone released by bone that helps regulate glucose levels and fat deposition.