CHAPTER 4 - Tissues

What are tissues composed of?

Tissues are composed of groups of similar cells with a common function

• 4 Basics tissue types

  • Epithelial tissue - covering

  • Connective tissue - support

  • Muscle Tissue - movement

  • Nervouse tissue - Control

Histology

the study of tissues

Epithelial Tissue

found covering surfaces, in the lining of cavities and forms glands

• Functions:

  • as a boundary

  • Selective Barrier

  • Secretory surface

  • Protective surface

Connective Tissue

the most abundant tissue in the body

• has 3 main components

  • Cells, ground substance, fibers

    • Extracellular matrix = ground substance + fibers

• Functions:

  • Binds and supports

  • transport of substances

  • storage of energy reserves

  • source of immune responses

Connective Tissue: Cells

• Blasts - immature cells

• Cytes - mature cells

Cell Types

• Fibroblasts

• Chondroblasts

• Osteoblasts

• Adipocytes

• White blood cells

Cell Types: Mast Cells & Macrophages

• Mast cells - release heparin (anticoagulant) and histamine (dilates blood vessels)

• Macrophages - large phagocytic cells

Connective Tissue: Ground Substance

The material that fills space between cells and surrounds fibers

• consists of water, adhesion proteins and complex polysaccharides

  • Functions: supports cells, binds cells tgt, stores water, medium for exchange between cells and blood

Connective Tissue: Fibers

• Collagen fibers - long, straight fibers composed of collagen (protein)

  • the most abundant protein in the body

• Elastic fibers - thin, branched fibers composed of eleastin protein

  • found in the skin, lungs, and vessel walls

• Reticular fibers - short, thin branched networks of fibers composed of collagen and glycoprotein

Muscle Tissue

consists of cells (fibers) that contract to produce movement

• 3 types

  • Skeletal

  • Cardiac

  • Smooth

Skeletal muscle

• Has many nuclei per cell (multinucleate)

• Long, cylindrical cells

• Under voluntary control

• Attached to bones

• Peripheral nuclei

• Striations

  • Functions: Moves bones in skeleton

Cardiac Muscle

• Has one nucleus in the center per cell

• Branched, shorter fibres

• Under involuntary control (cannot be controled)

• Striations

• Found in the walls of the heart

  • Function: contracts heart to propel blood

Smooth Muscle

• One nucleus, in the center of each cell

• Short, spindle-shaped cells

• Under involuntary control

• No striations

• Found in walls of hollow organs

  • Function: to propel contents of hollow organs

Nervous tissue

The main component of the nervous system

• Brain, spinal cord & nerves

  • this regulates and control body functions

    • 2 major cell types

      • Neurons

      • Neuroglia

Nervous Tissue: Neurons

these are the nerve cells that generate and conduct nerve impulses

Nervous Tissue: Neuroglia

these nerve cells are the more numerous non-conducting cells which function in support, insulation and protection of neurons