A&P Tissue Flashcards: Vascular vs Avascular

Tissue Types Overview

• Four main types of tissue: epithelial, connective, muscle, and nervous.

Epithelial Tissue Characteristics

• Avascular, with no blood vessels; relies on diffusion for nutrient supply.
• Composed of closely packed cells; provides protective barriers and secretory functions.
• Capable of rapid reproduction.

Epithelial Tissue Shapes

• Squamous: Thin, flattened cells.
• Cuboidal: Cube-like cells.
• Columnar: Elongated cells.
• Transitional: Layered cells that can stretch; notably seen in urinary bladder.

Epithelial Layer Types

• Simple: Single layer of cells; allows for efficient absorption and secretion.
• Stratified: Multiple layers; provides added protection.
• Pseudostratified: Appears stratified but all cells contact the basement membrane; found in trachea.

Glandular Epithelia

• Exocrine glands: Secrete substances into ducts for external or internal destination.
• Endocrine glands: Secrete hormones directly into the bloodstream.
• Types include merocrine, apocrine, holocrine, serous, and mucous glands, each with unique secretion mechanisms.

Connective Tissue Characteristics

• Vascularity varies by type; well-vascularized tissues have a good blood supply, while avascular ones do not.
• Cells are spaced apart with a matrix in between them; supports and binds other tissues.
• Functions include support, fat storage, protection, produce blood cells, and immune responses.

Connective Tissue Cells

• -Blasts: Active, immature cells (e.g., fibroblasts, chondroblasts).
• -Cytes: Mature cells involved in maintenance (e.g., adipocytes, osteocytes).
• Mast cells: Release histamine; important in inflammatory response.
• Macrophages: Engulf debris and pathogens, key in immune defense.
• Plasma cells: B lymphocytes that produce antibodies.

Blood Components

• Leukocytes: White blood cells involved in immunity.
• Erythrocytes: Red blood cells responsible for oxygen transport.

Carcinomas

• Cancers that originate from epithelial tissues; account for about 90% of cancer cases.

Specific Tissue Types

• Loose Connective Tissue: Vascular and provides flexibility and support.
• Dense Regular Connective Tissue: Avascular, found in tendons and ligaments.
• Dense Irregular Connective Tissue: Avascular, provides structural support in various directions.
• Adipose Tissue: Vascular connective tissue that stores fat.
• Blood: Specialized connective tissue with both erythrocytes and leukocytes.