Connective Tissue Review: Fibers, Cells, and Tissue Types

Vocabulary-style flashcards covering connective tissue components, cells, blood, and cartilage/bone types mentioned in the notes.

Collagen fibers

Provide the most strength in connective tissue; thick bundles that can run parallel or in different directions; resist pulling forces; common in tendons and ligaments.

Reticular fibers

Smaller, collagen-like fibers that are not as big or strong as collagen; form supportive networks in loose connective tissue and organ capsules (e.g., lymph nodes, spleen); stained with silver.

Elastic fibers

Elastic fibers give tissues elasticity and the ability to stretch and recoil; prominent in flexible tissues like the arterial walls.

Ground substance

The gel-like extracellular matrix that fills spaces between cells and fibers in connective tissue; supports cells and allows diffusion.

Fibroblast

Active connective tissue cell that lays down collagen and ground substance; prodominant in matrix formation; can be thought of as a builder.

Fibrocyte

Mature, less active form of the fibroblast; maintains collagen in the extracellular matrix.

Myofibroblast

Fibroblast-like cell with some smooth muscle characteristics; enhances repair, for example in periodontal ligaments after injury.

Pericyte

Fixed cell associated with capillaries; can act as endothelial or smooth muscle cell to help repair capillaries when damaged.

Macrophage

Garbage cell of connective tissue; phagocytoses dead cells and debris; derived from monocytes; can be fixed or wandering.

Mast cell

Found near blood vessels; contains histamine and heparin in granules; promotes inflammation and allergic responses; degranulation can release these mediators.

Histamine

Chemical released by mast cells that causes vasodilation and increased vascular permeability, contributing to inflammation and allergy symptoms.

Heparin

Anticoagulant found in mast cell granules; helps prevent blood clotting.

Melanocyte

Fixed cell that produces melanin pigment; provides UV protection; often located at the border between connective tissue and epithelium.

Adipocyte

Fat cell; stores triglycerides; adipose tissue; distribution varies by species and body region.

Plasma cell

Differentiated B cell that produces antibodies; generates five classes of immunoglobulins and can give rise to memory B cells.

Lymphocyte

White blood cell responsible for specific immunity; can differentiate into plasma cells or memory cells; includes B and T cells.

Immunoglobulin (Ig)

Antibody; five classes: IgA, IgD, IgE, IgM, IgG; produced by plasma cells and B cells.

B cell (B lymphocyte)

White blood cell that differentiates into plasma cells to produce antibodies and can form memory cells.

Monocyte

White blood cell that migrates into tissues and becomes a macrophage; part of the agranulocyte group.

Leukocyte

White blood cell; general term encompassing all immune cells.

Agranulocyte

White blood cells without visible granules; includes lymphocytes and monocytes.

Granulocyte

White blood cells with granules; includes neutrophils, eosinophils, and basophils.

Erythrocyte

Red blood cell; carries oxygen via hemoglobin.

Platelet

Cell fragment derived from a megakaryocyte; forms a plug to stop bleeding and supports clot formation.

Plasma

Liquid component of blood containing proteins; transports nutrients, wastes, and hormones.

Blood (as connective tissue)

The only liquid connective tissue; consists of plasma and formed elements (erythrocytes, leukocytes, platelets).

Agranulocytes vs. Granulocytes

Agranulocytes lack granules (e.g., lymphocytes, monocytes); granulocytes have granules (e.g., neutrophils, eosinophils, basophils).

Neutrophil

Granulocyte; first responder to infection; phagocytoses bacteria.

Eosinophil

Granulocyte involved in defense against parasites and in allergic responses; contains red/orange granules.

Basophil

Granulocyte with granules rich in histamine and heparin; plays a role in inflammation and allergic reactions.

Hyaline cartilage

Cartilage type formed by chondroblasts; found at joint surfaces and in tracheal rings; smooth, glassy appearance.

Chondroblast

Cell that actively secretes cartilage matrix and becomes a chondrocyte.

Elastic cartilage

Cartilage containing elastic fibers; flexible; found in external ear, auditory canal, and epiglottis.

Fibrocartilage

Cartilage rich in collagen; very tough and acts as a shock absorber; found in intervertebral discs and knee menisci.

Menisci

Fibrocartilage pads in the knee that cushion the joint and distribute load.

Bone types: cancellous (spongy) bone

Light, porous bone found at the ends of long bones; contains trabeculae and bone marrow.

Bone types: dense (compact) bone

Heavy, solid bone with tightly packed matrix; provides strength and protection.

Tendon/Ligament composition

Made predominantly of collagen fibers arranged in parallel; provide strong resistance to pulling forces and connect bone to muscle (tendon) or bone to bone (ligament).