1.5

Tissue Organization

Epithelial tissue

Tissues that cover the body's outer and inner surfaces, and form glandular tissue. They are classified based on shape (squamous, cuboidal, columnar) and arrangement (simple, stratified, pseudostratified).

Connective tissue

Tissue that produces the extracellular matrix supporting and connecting other tissues. It includes connective tissue proper and specialized connective tissue like cartilage, bone, and blood cells.

Muscle tissue

Tissue responsible for movement by contracting. It consists of thin (actin) and thick (myosin) filaments and includes skeletal, cardiac, and smooth muscle types.

Nervous tissue

Tissue used for communication between peripheral tissues and the central nervous system, comprising neurons for communication and glial cells for support.

Tight junctions

Found in epithelial tissue, these junctions prevent fluid entry into intercellular spaces by connecting neighboring cells tightly.

Adhering junctions

Form strong adhesions between cells to prevent cell separation.

Gap junctions

Join neighboring cell membranes by creating channels in the cytoplasm of each cell.

Atrophy

Decrease in the size of an organ or tissue due to a decrease in cell mass, caused by disuse, lack of stimulation, or aging.

Hypertrophy

Increase in the size of an organ or tissue due to enlarged cells, often in response to increased workload.

Hyperplasia

Increase in the size of an organ or tissue due to an increase in the number of cells, seen in glandular proliferation during pregnancy.

Metaplasia

Replacement of one differentiated tissue by another in response to chronic irritation or inflammation, like in Barrett esophagus.

Dysplasia

Abnormal cellular growth leading to cells varying in size, shape, and organization, often a precursor to cancer.

Free radicals

Highly reactive chemical species with unpaired electrons that can damage cells and tissues.

Hypoxia

Low oxygen delivery to tissues leading to decreased ATP production and cellular injury.

Disruption of intracellular calcium homeostasis

Rise in intracellular calcium levels activating enzymes and causing damaging effects.

Apoptosis

Programmed cell death eliminating worn-out, excess, or genetically damaged cells, crucial for normal physiologic processes.

Necrosis

Cell death in living tissues triggering an inflammatory response, leading to different types like coagulative, liquefactive, caseous, and gangrenous necrosis.