5.1

Question 1

What are the four primary types of tissue?

Answer 1

Epithelial, connective, muscle, and nervous

Question 2

What are the four characteristics of epithelial tissue?

Answer 2

• Polarity - Epithelial cells have distinct apical (top) and basal (bottom) surfaces.
• Cellular Junctions - Cells are tightly connected with minimal extracellular matrix.
• Avascularity - No blood vessels; rely on connective tissue for nutrients.
• Innervation - Most are innervated, except in some areas like the stomach and intestines.

Question 3

What are the four types of cellular junctions?

Answer 3

• Tight Junctions - Form an impenetrable seal between cells to prevent leaks (e.g., bladder, digestive tract).
• Desmosomes - Strong, Velcro-like connections that provide mechanical strength (e.g., skin, heart, uterus).
• Hemidesmosomes - Half-desmosomes that anchor epithelial cells to the basement membrane.
• Gap Junctions - Tubular channels allowing direct cell-to-cell communication (e.g., heart, smooth muscle).

Question 4

What is histology?

Answer 4

Histology is the study of the microscopic structures of tissues and organs.

Question 5

List 8 functions performed by epithelial cells.

Answer 5

(1) Protect, cover, and line other tissues
(2) Filter biochemical substances
(3) Absorb nutrients
(4) Provide sensory input
(5) Manufacture secretions
(6) Manufacture excretions
(7) Diffusion
(8) Acts as an interface layer that separates and defines the beginning and ending of different types of tissues (movement of materials)

Question 6

How does the basement membrane act as a partial barrier between the epithelial cell and the underlying connective tissue?

Answer 6

The basement membrane acts as a partial barrier by allowing the diffusion of oxygen, nutrients, and waste between epithelial cells and the underlying connective tissue while providing structural support.

Question 7

Why do some epithelial cells have cilia and microvilli? What role do they play? Where are the cells with these specialized surfaces found in the body?

Answer 7

Some epithelial cells have microvilli to increase surface area for absorption and secretion (e.g., intestines, urinary tract). Others have cilia to move materials efficiently (e.g., trachea moves mucus, uterine tube moves ova).