Chapter5.I_b0077d34f88dd251d5e9529a6f9568ee

Tissues

Overview of Animal Tissues

  • Group of cells with similar structures performing particular functions.

  • Originates from common embryonic tissues.

Types of Animal Tissues

  1. Epithelial Tissue

  2. Muscle Tissue

  3. Connective Tissue

  4. Neural Tissue

Epithelial Tissue

  • Definition: Sheet of cells covering internal/external surfaces, forming a continuous layer without intercellular matrix.

  • Regeneration: High regenerative capacity throughout life.

  • Location: Covers body surfaces, lines cavities (skin, mouth, alimentary canal, lungs).

  • Function: Primarily protective.

Types of Epithelial Tissue

  1. Squamous Epithelium

    • Thin, flattened cells; protective.

    • Location: Blood vessels, skin, inner lining of the mouth.

  2. Cuboidal Epithelium

    • Cube-like cells with round nuclei.

    • Location: Glands, kidneys; secretory and absorptive functions.

  3. Columnar Epithelium

    • Pillar-like cells with basal nuclei.

    • Location: Alimentary canal; mainly secretory.

  4. Ciliated Columnar Epithelium

    • Cells with cilia aiding movement.

    • Location: Oviducts, respiratory passages.

  5. Glandular Columnar Epithelium

    • Long, pillar-like cells for secretion.

    • Location: Exocrine glands.

  6. Stratified Epithelium

    • Cells in layers; upper cells do not divide.

    • Location: Skin, conjunctiva, vagina (keratinized and non-keratinized types).

Muscular Tissue

  • Definition: Comprised of muscle cells (fibers) that can contract and relax for movement.

  • Contractile Proteins: Actin and myosin enable contraction.

Types of Muscular Tissue

  1. Striated Muscle

    • Voluntary movement; cylindrical shape; multinucleated.

    • Location: Limbs, body wall, tongue.

  2. Non-Striated Muscle

    • Involuntary movement; spindle-shaped; uninucleated.

    • Location: Urinary bladder, vessels.

  3. Cardiac Muscle

    • Involuntary; branched cells with intercalated discs; abundant mitochondria.

    • Location: Heart.

Connective Tissue

  • Definition: Connects and supports other tissues and organs in the body.

Types of Connective Tissue

  1. Skeletal/Supportive (Bone, Cartilage)

    • Cartilage: Flexible support in joints, nose; non-vascular.

    • Bone: Hard tissue providing shape, support, protection, and storing minerals.

  2. Loose Connective Tissue (Areolar, Adipose)

    • Areolar: Binds skin to underlying tissues; contains fibroblasts/mast cells.

    • Adipose: Stores fat; consists of adipocytes (white and brown fat).

  3. Dense Connective Tissue (Tendons, Ligaments)

    • Tendons: Connect muscle to bone; made of collagen fibers.

    • Ligaments: Connect bone to bone; elastic and flexible.

  4. Fluid Connective Tissue (Blood, Lymph)

    • Blood: Carries nutrients, oxygen, and cells (RBCs, WBCs, platelets).

    • Lymph: Composed of WBCs and plasma; aids in immunity and nutrient transport.

Neural Tissue

  • Definition: Composed of neurons and glial cells; forms the nervous system.

  • Neurons: Functional units with cell bodies, axons, and dendrites; conduct nerve impulses.

  • Function: Conduction of nerve impulses throughout the body.

Summary

  • Animal tissues are classified into epithelial, muscular, connective, and neural types, each serving specific functions to maintain body structure and function.