Ch. 4 - The Tissue Level of Organization.pdf

Tissue

Groups of similar cells that perform a specific function in the body.

Histology

The study of tissues.

Epithelial tissue

Covers exposed surfaces, lines internal passageways, and forms glands.

Connective tissue

Fills internal spaces, supports other tissues, transports materials, and stores energy.

Muscle tissue

Specialized for contraction, includes skeletal, cardiac, and smooth muscle.

Nervous tissue

Carries electrical signals from one part of the body to another.

Epithelia

Layers of cells covering internal or external surfaces.

Glands

Structures that produce fluid secretions.

Polarity

Refers to the presence of an apical surface and a basal surface in epithelial tissue.

Avascularity

The condition of having no blood vessels, as seen in epithelial tissue.

Cell junctions

Connections between cells that facilitate communication and adhesion.

Desmosomes

Cell junctions that mechanically bind cells together.

Tight junctions

Cell junctions that prevent the passage of materials between cells.

Gap junctions

Intercellular connections that allow for rapid communication between cells.

Simple epithelium

A single layer of cells.

Stratified epithelium

Multiple layers of cells.

Squamous epithelium

Thin and flat epithelial cells.

Cuboidal epithelium

Square-shaped epithelial cells.

Columnar epithelium

Tall, slender rectangle-shaped epithelial cells.

Goblet cells

Unicellular glands that secrete mucus.

Exocrine glands

Glands that discharge secretions through ducts onto epithelial surfaces.

Endocrine glands

Glands that release hormones directly into the bloodstream.

Merocrine secretion

Secretory method where products are released via exocytosis.

Apocrine secretion

Secretory method that involves shedding cytoplasm.

Holocrine secretion

Secretory method where cells burst to release their contents.

Fibroblasts

Most abundant cell type in connective tissue proper, responsible for secreting proteins.

Adipocytes

Fat cells that store energy in the form of fat.

Collagen fibers

Strong, straight, unbranched fibers that provide structural support.

Elastic fibers

Fibers that can stretch and return to their original length.

Cartilage

Supporting connective tissue that absorbs shock and provides protection.

Bone

Calcified connective tissue that supports weight and resists shattering.

Mucous membranes

Membranes that line passageways with external connections and produce mucus.

Serous membranes

Membranes that line closed body cavities and secrete serous fluid.

Cutaneous membrane

The skin that covers the body.

Skeletal muscle

Striated, voluntary muscle responsible for body movements.

Cardiac muscle

Striated, involuntary muscle found only in the heart.

Smooth muscle

Non-striated, involuntary muscle found in hollow organs.

Neurons

Nerve cells specialized for conducting electrical impulses.

Neuroglia

Supporting cells in nervous tissue that maintain structure and function.

Inflammation

The body's response to injury characterized by redness, heat, swelling, pain, and loss of function.

Regeneration

The process of restoring tissue to normal function after injury.

Mast cells

Cells that release chemicals during inflammation.