Tissues

Matrix: jelly-like material between cells of tissues.

Four major types of tissues:

1. Epithelial tissue

2. Connective tissue

3. Muscle tissue

4. Nervous tissue

Epithelial Tissue:

• Types of cells:

  • Squamous

  • Cuboidal

  • Columnar

• Simple Epithelial tissue (1 layer):

  • Simple squamous (lungs)

  • Simple cuboidal (kidneys)

  • Simple columnar (small intestine)

• Stratified epithelial tissue (2+ layers):

  • Stratified cuboidal (sweat glands)

  • Pseudostratified ciliated columnar (trachea)

Integumentary Tissue:

• Epidermis: outer layer of skin

• Dermis: below epidermis

Connective Tissue:

• Most abundant type, includes:

  • Connective tissue proper (fibrous)

  • Cartilage

  • Bone

  • Blood

• Types of Connective Tissue Proper:

  • Loose fibrous (adipose, areolar, reticular)

  • Dense fibrous (collagen fibers):

    • Regular (tendons connect muscle to bone, ligaments connect bone to bone)

    • Irregular (dermal layer of skin)

• Cartilage:

  • Hyaline (costal cartilage)

  • Elastic (outer ear)

  • Fibrocartilage (between vertebrae)

• Bone:

  • Compact (outer shaft)

  • Cancellous (spongy, contains marrow)

• Blood:

  • Liquid: plasma

  • Solid: red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes)

Muscle Tissue:

• Functions: movement

• Types:

  • Skeletal (attached to bone, voluntary, multinucleated, striated)

  • Cardiac (heart, involuntary, mono-nucleated, striated with intercalated disks)

  • Smooth (lines organs, involuntary, mono-nucleated, non-striated)

Nervous Tissue:

• Functions: Control and communication

• Neurons:

  • Cell body, Axon (carries impulses away), Dendrites (carries impulses toward)

• Neuroglia: Supports cells

Tissue Repair:

• Bottom layer of cells divides and moves to surface:

• Regeneration: Original function restored (e.g., healing cuts)

• Regenerative Capacity:

  • Regenerate well: Epithelia, bone

  • Moderate: smooth muscle, tendons/ligaments

  • Cannot regenerate: Cardiac muscle, nervous tissue (fibrosis).

• Regeneration

  • destroyed tissue replaced by SAME TYPE of tissue

  • Original function restored

  • Example- healing cut in the skin

  • Regeneration very well - Epithelial tissues, bone

  • Regeneration moderately - smooth muscle, tendons/ligaments

  • Cannot regenerate- cardiac muscle, nervous tissue

  fibrosis

  • destroyed tissue replaced by connective tissue (original function lost)