BSN 1-F Chapter 4: Tissues

Glands

• Glands are secretory organs that release substances onto surfaces, into cavities, or into the bloodstream.
• Composed mainly of epithelial tissue supported by connective tissue.
• Exocrine glands have ducts and can have single or multicellular structures.
• Exocrine secretions can occur via:
  • Merocrine: exocytosis of secretory products.
  • Apocrine: pinching off of gland cell fragments.
  • Holocrine: shedding of entire cells.
• Endocrine glands are ductless, secreting hormones directly into the bloodstream.
• Simple exocrine glands have a single, non-branched duct; compound glands have multiple branched ducts.
• Tubular glands are tube-shaped; acinar glands are sac-like; tubuloacinar and tubuloalveolar combine features.

Connective Tissue

• Connective tissue is a diverse tissue type present in every organ.
• Composed of cells separated by abundant extracellular matrix, differing from epithelia.
• Major functions include enclosing and separating tissues, supporting and connecting parts, storing compounds, cushioning, insulating, and protecting.

Connective Tissue Cells

• Specialized cells in connective tissue create the extracellular matrix.
• Osteoblasts build bone; osteocytes maintain bone; osteoclasts break down bone.
• Fibroblasts form fibrous connective tissue; fibrocytes maintain it.
• Chondroblasts form cartilage; chondrocytes maintain cartilage.
• Immune system cells present include white blood cells (macrophages and mast cells).

Extracellular Matrix

• Composed of protein fibers, ground substance, and fluid.
• Ground substance is shapeless and contains non-fibrous molecules and proteoglycans, which trap water.
• Structure of the matrix dictates the functional characteristics of connective tissue.

Types of Connective Tissue

• Two main types: embryonic and adult connective tissue.
• By eight weeks of development, most embryonic connective tissues mature into adult types.
• Loose connective tissue features a lacy network with abundant ground substance; includes areolar, adipose, and reticular types.
• Adipose tissue consists of adipocytes for lipid storage.

Muscle Tissue

• Muscle tissue is responsible for contraction and movement, utilizing contractile proteins.
• Three types of muscle tissue:
  • Skeletal: Striated, attached to skeleton, enables voluntary movement.
  • Cardiac: Forms heart muscle, responsible for pumping blood, involuntary.
  • Smooth: Non-striated, found in hollow organs, controls involuntary functions.

Tissue Membranes

• Membranes are thin layers of tissue covering structures or lining cavities.
• Composed of epithelial tissue overlaying connective tissue.
• Four types of membranes:
  • Cutaneous: External skin surface.
  • Mucous: Lines cavities open to the exterior; includes layers for protection and secretion.
  • Serous: Lines closed cavities; does not open to the outside; secretes serous fluid for lubrication.
  • Synovial: Lines joints; made of modified connective tissue, producing synovial fluid for smooth joint movement.

Nervous Tissue

• Comprises the brain, spinal cord, and nerves, coordinating body activities.
• Made up of neurons (conducting action potentials) and glial cells (supporting cells).
• Neurons consist of a cell body, dendrites, and an axon.

This quiz focuses on Chapter 4 of the BSN 1-F curriculum, covering the concept of glands and specifically exocrine glands. It will assess your understanding of the functions and classifications of these secretory organs. Prepare to explore the essential roles glands play in the human body.