Biology Chapter 7: The Lymphatic System Flashcards

Lymphatic System Overview

• Comprises lymphatic vessels and organs.
• Performs essential functions including absorbing excess interstitial fluid and dietary fats, producing lymphocytes, and fighting pathogens.

Lymphatic Vessels

• Similar to cardiovascular veins, featuring valves.
• Lymph movement is aided by skeletal muscle contractions.

Lymphatic Ducts

• Two primary ducts:
  • Thoracic duct (larger), drains into the left subclavian vein.
  • Right lymphatic duct (smaller), drains into the right subclavian vein.

Lymphatic Organs

• Two categories: primary organs (red bone marrow, thymus) and secondary organs (lymph nodes, spleen, tonsils).

Specific Lymphatic Organs

• Red Bone Marrow: Site for blood cell production and maturation of B cells.
• Thymus: Bilobed organ where immature T cells mature; produces Thymosin, which aids T cell maturation.
• Spleen: Filters blood, removes pathogens and old red blood cells via macrophages.
• Lymph Nodes: Located along lymphatic vessels, filter lymph, and are abundant in neck, armpit, and groin; contain compartments filled with immune cells.
• Tonsils: Located in the pharynx; function similarly to lymph nodes.
• Peyer Patches: Found in intestinal walls and appendices; contribute to immune defense.

Immunity

• Protection against foreign substances, pathogens, and cancer cells.

Innate Immunity

• Acts as the first responder without specific recognition; does not depend on prior pathogen exposure.

Nonspecific Defenses

• Include physical and chemical barriers, inflammatory response, and protective proteins.

Physical and Chemical Barriers

• First line of defense includes:
  • Physical: Skin and mucous membranes.
  • Chemical: Acidic secretions and enzymatic secretions.

Inflammatory Response

• The second line of defense involving neutrophils and macrophages.
• Classic symptoms include redness, heat, swelling, and pain, all triggered by histamine release.

Complement System

• A series of plasma proteins labeled by the letter C followed by numbers.
• Amplifies inflammatory response and assists in pathogen destruction.

Interferons

• Produced by virally infected cells to alert neighboring cells of viral presence.

Adaptive Immunity

• Activated upon pathogen exposure; provides protection against cancer.
• Relies on distinguishing "self" from "nonself" and functions through B cells and T cells.

Mechanisms of Adaptive Immunity

• Two pathways:
  • Cell Mediated: T cell dependent.
  • Antibody Mediated: B cell dependent (also known as humoral immunity).

B Cells and Antibody Mediated Immunity

• B cell receptors (BCR) bind to antigens, leading to proliferation into plasma and memory cells.

Antibody Structure

• Y-shaped proteins composed of variable (antigen binding site) and constant regions (classification).

Types of Antibodies

• IgG: Major antibody in blood; crosses placenta; activates complement and enhances phagocytosis.
• IgM: Largest antibody; first produced during infection; agglutinates cells.
• IgA: Predominantly found in secretions (saliva, breast milk); prevents pathogen attachment to epithelial cells.
• IgD: Found on immature B cells; indicates readiness for activation.
• IgE: Associated with allergic responses and parasitic worm protection.

Functions of Antibodies

• Include neutralizing pathogens and attracting white blood cells for enhanced immune response.

Test your knowledge of the lymphatic system with these flashcards covering key terms and functions. Learn about the anatomy, roles, and importance of lymphatic vessels and organs. Ideal for biology students looking to reinforce their understanding of this crucial system.