A&P Lab Review: Classification of Tissues

Classification of Tissues

• Tissues are classified based on complexity: cell, tissue, organ, organ system.
• Histology is the study of tissues.

Epithelial Tissue

• Comprises cells that line body cavities and cover external surfaces.
• Functions include forming glands (endocrine and exocrine) and is classified by cell shape and arrangement.
• Typically has closely packed cells with minimal intercellular material and is avascular with a free edge.
• Exhibits high regenerative capacity, important for protection and absorption.

Types of Epithelial Tissue

• Stratified Squamous Epithelium: Provides protection; found in the epidermis of the skin.
• Transitional Epithelium: Allows for stretching; located in the urinary bladder.
• Simple Cuboidal Epithelium: Functions in absorption; found in kidney tubules.
• Simple Squamous Epithelium: Facilitates filtration; located in air sacs of the lungs.
• Simple Columnar Epithelium: Associated with secretion; located in the stomach and digestive tract.

Functional Features of Epithelial Tissue

• Specialized structures such as cilia assist in the movement of materials across cell surfaces.
• Goblet cells are unicellular glands that secrete mucus.
• Microvilli enhance absorption in the small intestine by increasing surface area.

Glandular Epithelium

• Endocrine glands are ductless and secrete hormones directly into the bloodstream.
• Exocrine glands possess ducts and secrete substances such as sweat, oil, and digestive enzymes.

Connective Tissue

• Characterized by a significant amount of extracellular matrix, which provides strength and support.
• Vascularization varies, influencing the healing process.
• Functions include protection, support, and binding other tissues together.

Types of Connective Tissue

• Dense Regular Connective Tissue: Connects muscles to bones and bones to bones.
• Adipose Tissue: Provides insulation and stores energy.
• Dense Irregular Connective Tissue: Forms fibrous joint capsules.
• Fibrocartilage: Composes intervertebral discs.
• Areolar Tissue: Serves as a soft packaging tissue with a jellylike matrix.
• Hyaline Cartilage: Forms structures like the embryonic skeleton, ribs’ costal cartilages, and the larynx.
• Elastic Cartilage: Provides flexibility in the external ear.
• Osseous Tissue: Functions as a skeletal framework, enabling muscle movement.
• Elastic Connective Tissue: Comprises large artery walls.

Muscle Tissue

• Skeletal Muscle: Voluntary, striated, multi-nucleated, and attached to bones; cylindrical in shape.
• Cardiac Muscle: Involuntary, striated, single nucleus, and forms heart walls; features intercalated discs.
• Smooth Muscle: Involuntary, single nucleus, spindle-shaped cells found in hollow organs like the bladder and stomach.

Nervous Tissue

• Neurons are specialized for communication and impulse transmission.
• Exhibit two key physiological characteristics: irritability and conductivity.
• Similar to other cells as they contain nuclei and organelles but possess long cytoplasmic processes to enhance signal transmission.

This quiz covers the classification of tissues as explored in Exercise 6 of the Anatomy & Physiology Lab. It includes definitions and hierarchical relationships among cells, tissues, organs, and organ systems, as well as specific tissue types such as epithelium.