Body Tissues and Epithelia Quiz

Body Tissues

• Composed of groups of similar cells.
• Four primary tissue types: Epithelial, Connective, Muscular, Nervous.

Simple Epithelia

• Functions include absorption, secretion, filtration, and act as selective barriers.
• Generally thin, focusing on exchange rather than protection.
• Types:
  • Simple Squamous Epithelium: Forms membranes for rapid diffusion; found in air sacs of lungs and capillary walls; contributes to serous membranes of body cavities.
  • Simple Cuboidal Epithelium: Common in glandular ducts and kidney tubules; covers ovarian surfaces.
  • Simple Columnar Epithelium: Lines digestive tract; contains goblet cells for mucus production; can be ciliated or nonciliated.
  • Pseudostratified Columnar Epithelium: Appears layered but is a single layer; involved in absorption and secretion.

Stratified Epithelia

• Primarily provides protection.
• Types:
  • Stratified Squamous Epithelium: Most common; surface cells are squamous, with deeper cells being cuboidal or columnar; found in esophagus, mouth, vagina, and skin.
  • Stratified Cuboidal Epithelium: Rare, found in large gland ducts.
  • Stratified Columnar Epithelium: Also rare, located in some gland ducts.
  • Transitional Epithelium: Modified stratified epithelium; lines urinary bladder and ureters; cells can change shape.

Types of Connective Tissue

• Loose Connective Tissue: Fibers loosely arranged, includes areolar, reticular, and adipose tissue.
  • Areolar Tissue: Most abundant type; contains various cells and fibers in a semi-fluid ground substance.
  • Reticular Tissue: Features a net-like arrangement of fibers.
  • Adipose Tissue: Specialized for fat storage with fewer fibers.
• Dense Connective Tissue: Packed with fibers, little ground substance; includes dense regular and irregular connective tissues.
  • Dense Regular Connective Tissue: Contains parallel collagen fibers; often called white fibrous tissue.
  • Dense Irregular Connective Tissue: Has irregularly arranged fibers providing strength from multiple directions.
  • Elastic Connective Tissue: Dominated by elastic fibers, allowing stretch and recoil.

Cartilage

• Extracellular matrix with collagen and elastic fibers in gel-like ground substance.
• Chondroblasts secrete fibers; turn into chondrocytes in lacunae (spaces).
• Types of cartilage:
  • Hyaline Cartilage: Most common, with fine collagen fibers; smooth surface for joint movement.
  • Elastic Cartilage: Contains dense elastic fibers, allowing flexibility.
  • Fibrocartilage: Dense with thick collagen fibers, providing tensile strength; found in intervertebral discs.

Bone

• Organized in layers (lamellae); consists of collagen fibers, ground substance, and inorganic salts.
• Osteocytes: Mature bone cells located in lacunae; communicate via canaliculi (small canals).
• Types:
  • Compact Bone: Features osteons, structural units centering on a central canal.
  • Spongy Bone: Lattice-like arrangement called trabeculae; contains larger spaces.

Blood

• Composed of red blood cells, white blood cells, platelets, and plasma.
• Plasma acts as the extracellular matrix.

Muscle Tissue

• Highly vascularized, consisting mainly of elongated muscle fibers capable of contraction.
• Types:
  • Skeletal Muscle: Voluntary control, striated appearance.
  • Cardiac Muscle: Involuntary control, striated, found in heart.
  • Smooth Muscle: Involuntary, non-striated, found in walls of hollow organs.

Nervous Tissue

• Forms the brain, spinal cord, and nerves; very cellular.
• Comprises:
  • Neurons: Responsible for transmitting information.
  • Neuroglia: Supportive cells aiding neuron functionality; include various types serving diverse roles in the nervous system.