Unit 2 - Epithelial Tissue (copy)

What is the main function of epithelial tissue in the human body?

Epithelial tissue serves as a boundary between different environments, providing protection, absorption, secretion, and sensation.

How are epithelial layers classified in terms of vascularity?

Epithelial layers are avascular but innervated, meaning they lack blood vessels but contain nerve endings.

What are the two types of glands composed of epithelial tissue?

Exocrine and endocrine glands.

What role do cilia play in the respiratory system?

Cilia move mucus and trapped particles upward towards the throat, forming a mucociliary escalator.

Describe the structure of epithelial cells in terms of orientation and layers.

Epithelial cells have a polarized structure with one surface oriented towards a cavity or external environment and the other anchored to a basement membrane.

What types of cellular junctions stabilize epithelial tissues?

Tight junctions, anchoring junctions (including desmosomes, hemidesmosomes, and adherens), and gap junctions.

What are the characteristics of tight junctions?

Tight junctions separate cells into apical and basal compartments, preventing leakage between the cells.

What is the role of desmosomes in epithelial tissue?

Desmosomes stabilize the epithelial tissue by providing strong, flexible connections between adjacent cells.

What distinguishes hemidesmosomes from other junctions?

Hemidesmosomes link epithelial cells to the extracellular matrix, such as the basal lamina, using integrins.

How does the arrangement of organelles differ in epithelial cells?

Epithelial cells have a polarized distribution of organelles and membrane-bound proteins between their basal and apical surfaces.