Connective Tissues and Embryology Lecture 3

Vocabulary flashcards covering histology classifications, connective tissue cell and fiber types, ground substance, and early embryology germ layers based on the lecture notes.

Epithelial Tissue

Sheets of cells that cover body surfaces, line internal passageways and chambers, and produce glandular secretions.

Connective Tissue

Tissue consisting of cells and extracellular spaces that fills internal spaces, provides structural support, stores energy, and protects or binds the body.

Muscle Tissue

Tissue composed of cells capable of electrical excitation and contraction to produce active movement.

Nervous Tissue

Tissue composed of cells capable of electrical excitation that conduct electrical impulses and transmit signals throughout the body.

Matrix

The structure surrounding connective tissue cells, composed of extracellular protein fibers and ground substance.

Ground Substance

The fluid, syrupy, gel-like, or hard fluid component of the matrix containing the jelly-like glycoprotein hyaluronan secreted by fibroblasts.

Collagen Fibers

The most common and strongest thick, unbranched protein fibers in connective tissue, composed of three fibrous protein subunits wound like strands of a rope.

Reticular Fibers

Thin, individual collagen fibrils that form a tough, flexible mesh or network in connective tissue proper and the borders of epithelial tissue.

Elastic Fibers

Branching and wavy fibers made of elastin protein that allow stretch and recoil in connective tissue proper and some cartilage.

Fibroblasts

The most common cell type in connective tissue, responsible for producing all connective tissue protein fibers.

Fibrocytes

Mature fibroblasts surrounded by ground substance that can revert to fibroblasts to repair damaged connective tissue.

Mesenchymal Stem Cells

Stem cells that respond to local injury and produce fibroblasts, macrophages, or other connective tissue cells.

Mast Cells

Immune cells found near blood vessels that are related to basophils, release histamines, and stimulate local inflammation.

Plasma Cells

Immune lymphocytes (also called plasmocytes) that produce antibodies.

Adipocytes

Fat cells containing energy-storing lipid droplets.

Areolar Connective Tissue

A loose connective tissue containing all three protein fiber types and all cell types, which cushions organs, provides support, and allows independent movement.

Adipose Connective Tissue

A loose connective tissue filled with adipocytes and blood vessels that functions in energy storage, cushioning, and insulation.

Reticular Connective Tissue

A loose connective tissue filled with reticular fibers that provides a framework or scaffolding for immune cells in organs like the liver, spleen, lymph nodes, and bone marrow.

Dense Regular Connective Tissue

A dense connective tissue with parallel collagen fiber orientation that resists tension in one direction, found in tendons, ligaments, and aponeuroses.

Dense Irregular Connective Tissue

A dense connective tissue with randomly oriented collagen fibers that resists tension in many directions and provides strength in the skin dermis.

Elastic Connective Tissue

A dense connective tissue made of stacked elastic fibers that allows extreme stretch and recoil, found in the aorta and large blood vessels.

Scurvy

A condition caused by a lack of Vitamin C required to cross-link collagen fibrils, leading to tooth loss, fever, rash, bruising, fatigue, and muscle weakness.

Interstitial Fluid

Solution derived from blood plasma that bathes all the cells of the body.

Cleavage

Cell division within the zygote (fertilized egg) that ends when it contacts the uterine wall.

Blastomeres

Cells produced during the initial cell divisions of the embryo within the first couple of days.

Morula

A solid ball of embryonic cells formed by day 3 of development.

Blastocyst

A hollow ball of cells formed by day 5 that adheres to the uterine lining at day 7, containing an inner cavity (blastocoele) and an inner cell mass.

Inner Cell Mass

The group of cells within the blastocyst that differentiates to form the actual embryo.

Ectoderm

The primary germ layer that gives rise to the nervous system, epidermis of the skin and its derivatives, pituitary gland, suprarenal medullae, and specific mucous epithelia.

Mesoderm

The primary germ layer that gives rise to connective tissues, dermis, kidneys, gonads, and the skeletal, muscular, cardiovascular, and lymphatic systems.

Endoderm

The primary germ layer that gives rise to the respiratory and digestive mucous epithelia, liver, pancreas, thyroid, thymus, and urinary bladder.

Embryonic Shield

The region of embryonic development present at roughly two weeks that consists of a pair of epithelial layers: an upper ectoderm and an underlying endoderm.

Primitive Streak

A region in the embryonic shield where superficial cells migrate between the upper ectoderm and underlying endoderm to form the mesoderm.