Tissue Types in Biology

Study Notes

Characteristics of the Four Tissue Types

Epithelial Tissue

Matrix amount is minimal, primarily composed of basal lamina.
Lacks direct blood supply, relying on diffusion for nutrient acquisition.
Surface features include microvilli and cilia for absorption and movement.
Found covering body surfaces, lining cavities, hollow organs, and tubes, as well as forming secretory glands.
Cell arrangement varies from one to many layers, with shapes including flattened, cuboidal, or columnar.

Connective Tissue

Extensive matrix composed of varied protein fibers and ground substance, which can be liquid, gelatinous, firm, or calcified.
Cartilage is unique for having no direct blood supply.
Lacks specific surface features on cells.
Provides support for skin and organs, exists as cartilage, bone, and blood.
Cells are randomly scattered within the matrix, exhibiting irregular to round shapes.

Muscle Tissue

Minimal matrix, formed by external lamina.
Capable of generating electrical signals, force, and movement.
Lacks distinctive surface features.
Comprises skeletal muscles, hollow organs, and tubular structures.
Cells are linked in sheets or elongated bundles, shaped as elongated thin cylinders, with heart muscle cells potentially being branched.

Nerve Tissue

Matrix amount is minimal, also associated with external lamina.
Possesses the ability to generate electrical signals.
Cells do not have surface features.
Located throughout the body, with a concentration in the brain and spinal cord.
Cell arrangement can either be isolated or networked, with highly branched and/or elongated appendages.

Types of Epithelia

Exchange Epithelia

Composed of a single layer of flattened cells.
Features pores between cells for easy passage of molecules.
Found in the lungs and lining of blood vessels.

Transporting Epithelia

Single layer of columnar or cuboidal cells.
Characterized by tight junctions that prevent movement between cells, and surface area is increased by membrane folding into villi.
Located in the intestine, kidneys, and some exocrine glands.

Ciliated Epithelia

Consists of one layer, with cuboidal to columnar shaped cells.
One side is covered with cilia for fluid movement across the surface.
Found in the nose, trachea, upper airways, and female reproductive tract.

Protective Epithelia

Composed of many layers, with flattened cells on the surface and polygonal shapes in deeper layers.
Cells are tightly connected by numerous desmosomes for protection.
Located in the skin and linings of cavities that open to the environment, such as the mouth.

Secretory Epithelia

Can have one to many layers, with cell shapes ranging from columnar to polygonal.
Characterized by protein-secreting cells filled with membrane-bound secretory granules and extensive rough endoplasmic reticulum; lipid droplet-containing steroid-secreting cells showcase extensive smooth ER.
Found in exocrine glands like the pancreas, sweat, and salivary glands, as well as in endocrine glands such as the thyroid and gonads.

Description

This quiz covers the characteristics of the four main tissue types in biology, focusing on epithelial and connective tissues. It explores their matrix properties, structural features, arrangements, and locations within the body. Test your knowledge on the unique attributes that distinguish each tissue type.