BIO 204 Exam 2 Study Guide: Lymphatic and Respiratory Systems

Lymphatic System

Complement Proteins and the Complement System

The complement system is a group of plasma proteins that enhance immune responses. It operates via three pathways:

• Classical Pathway: Activated by antibodies bound to antigens.

• Alternative Pathway: Activated directly by pathogen surfaces.

• Lectin Pathway: Activated by mannose-binding lectin attaching to pathogen carbohydrates.

These pathways converge to promote opsonization, inflammation, and cell lysis.

Primary vs. Secondary Immune Response

• Primary Response: First exposure to antigen; slower, produces fewer antibodies.

• Secondary Response: Subsequent exposure; faster and stronger due to memory cells.

Mast Cell Activation and Sensitization

Mast cells are immune cells that release histamine and other mediators during allergic reactions. Sensitization occurs when IgE antibodies bind to mast cells, priming them for activation upon subsequent antigen exposure.

Cells of Innate Immunity and Their Function

• Neutrophils: Phagocytose bacteria and debris.

• Macrophages: Engulf pathogens and present antigens.

• Natural Killer (NK) Cells: Destroy virus-infected and tumor cells.

• Dendritic Cells: Antigen presentation to T cells.

Cells of Adaptive Immunity and Their Function

• B Lymphocytes: Produce antibodies (humoral immunity).

• T Lymphocytes: Include helper T cells (activate other immune cells) and cytotoxic T cells (destroy infected cells).

Classes of Immunoglobulins/Antibodies

• IgG: Most abundant; crosses placenta.

• IgM: First produced in response; pentamer structure.

• IgA: Found in mucosal areas and secretions.

• IgE: Involved in allergic reactions.

• IgD: Functions mainly as a B cell receptor.

Consequences of Lymph Node Removal

Removal can lead to lymphedema (swelling due to fluid accumulation) and increased risk of infection.

Thymus Function

The thymus is the site of T cell maturation and selection, ensuring self-tolerance.

Spleen Function

The spleen filters blood, removes old red blood cells, and mounts immune responses to blood-borne antigens.

Lymph Node Function

Lymph nodes filter lymph, trap pathogens, and facilitate immune cell activation.

Red Bone Marrow Function

Red bone marrow is the site of hematopoiesis, producing all blood cells including lymphocytes.

Lymphocytes

Lymphocytes are white blood cells central to adaptive immunity, including B and T cells.

Lymphatic Trunks and Ducts

Lymphatic trunks collect lymph from regions and drain into major ducts:

• Thoracic Duct: Drains most of the body.

• Right Lymphatic Duct: Drains right upper quadrant.

Neutrophil Characteristics

• Most abundant leukocyte.

• Short-lived, highly phagocytic.

• First responders to infection.

Major Histocompatibility Complexes (MHC) and Their Purpose

• MHC I: Present on all nucleated cells; present endogenous antigens to cytotoxic T cells.

• MHC II: Present on antigen-presenting cells; present exogenous antigens to helper T cells.

Lymph Node Anatomy

• Cortex: Contains follicles with B cells.

• Medulla: Contains T cells and macrophages.

• Afferent/Efferent Vessels: Lymph enters via afferent and exits via efferent vessels.

Lymphatic System Table

Structure	Function
Lymph Node	Filters lymph, immune activation
Spleen	Filters blood, immune response
Thymus	T cell maturation
Red Bone Marrow	Blood cell production
Lymphatic Ducts	Drain lymph into venous system

Interferon

Interferons are cytokines that inhibit viral replication and activate immune cells.

Leukotrienes

Leukotrienes are inflammatory mediators derived from arachidonic acid, promoting chemotaxis and bronchoconstriction.

Interleukins

Interleukins are cytokines that mediate communication between immune cells.

Pyrogens

Pyrogens induce fever by acting on the hypothalamus.

Perforins

Perforins are proteins released by cytotoxic T cells and NK cells to create pores in target cell membranes.

Humoral vs. Cellular Immunity

• Humoral Immunity: Mediated by B cells and antibodies.

• Cellular Immunity: Mediated by T cells.

Allergic Reactions and Anaphylactic Shock

Allergic reactions involve IgE-mediated mast cell activation. Anaphylactic shock is a severe, systemic allergic response causing vasodilation and airway constriction.

Respiratory System

Functions of the Respiratory System

• Gas exchange (O2 and CO2)

• Regulation of blood pH

• Voice production

• Olfaction

• Protection from pathogens

Upper vs. Lower Respiratory Infections

• Upper: Affect nose, pharynx, larynx (e.g., common cold).

• Lower: Affect trachea, bronchi, lungs (e.g., pneumonia).

Changes in Intrapulmonary Pressure During Ventilation

Intrapulmonary pressure decreases during inspiration and increases during expiration, facilitating airflow.

Types of Epithelium Throughout the Respiratory System

• Pseudostratified ciliated columnar: Nasal cavity, trachea.

• Simple squamous: Alveoli.

• Stratified squamous: Oropharynx, laryngopharynx.

Types of Breathing Patterns

• Apnea: Absence of breathing.

• Bradypnea: Slow breathing.

• Dyspnea: Difficulty breathing.

• Tachypnea: Rapid breathing.

Factors That Affect Lung Compliance

• Elasticity of lung tissue

• Surface tension (surfactant reduces tension)

• Chest wall flexibility

Boyle's Law

Boyle's Law describes the relationship between pressure and volume in the lungs:

$P_1 V_1 = P_2 V_2$

As volume increases, pressure decreases (and vice versa).

Henry's Law

Henry's Law states that the amount of gas dissolved in a liquid is proportional to its partial pressure:

$C = k P$

Where C is concentration, k is solubility constant, and P is partial pressure.

Dalton's Law

Dalton's Law states that total pressure of a mixture of gases is the sum of the partial pressures of individual gases:

$P_{total} = P_1 + P_2 + P_3 + \ldots$

Surfactant

Surfactant is a substance produced by type II alveolar cells that reduces surface tension, preventing alveolar collapse.

CO2 Transport Equation

Carbon dioxide reacts with water to form carbonic acid, which dissociates:

$\mathrm{CO_2} + \mathrm{H_2O} \leftrightarrow \mathrm{H_2CO_3} \leftrightarrow \mathrm{H^+} + \mathrm{HCO_3^-}$

Lung Cancer

Lung cancer is characterized by uncontrolled cell growth in lung tissues, often linked to smoking.

Emphysema

Emphysema involves destruction of alveolar walls, reducing surface area for gas exchange and causing breathlessness.

Tuberculosis

Tuberculosis is a bacterial infection (by Mycobacterium tuberculosis) causing granuloma formation in lungs.

AIDS

AIDS (Acquired Immunodeficiency Syndrome) is caused by HIV, leading to severe immune deficiency.

Lung Volumes and Capacities

• Tidal Volume (TV): Air moved per breath.

• Inspiratory Reserve Volume (IRV): Extra air inhaled after normal inspiration.

• Expiratory Reserve Volume (ERV): Extra air exhaled after normal expiration.

• Residual Volume (RV): Air remaining after maximal exhalation.

Lung capacities are combinations of volumes:

• Vital Capacity (VC): $VC = TV + IRV + ERV$

• Total Lung Capacity (TLC): $TLC = VC + RV$

Hemoglobin Saturation

Hemoglobin saturation refers to the percentage of hemoglobin molecules bound to oxygen. It is influenced by partial pressure of oxygen, pH, and temperature.

Hypoventilation vs. Hyperventilation

• Hypoventilation: Decreased ventilation, leading to increased CO2 and acidosis.

• Hyperventilation: Increased ventilation, leading to decreased CO2 and alkalosis.

Obstructive vs. Restrictive Pulmonary Disease

• Obstructive: Difficulty exhaling (e.g., asthma, emphysema).

• Restrictive: Reduced lung expansion (e.g., fibrosis).

Spleen Anatomy

• White Pulp: Lymphocyte-rich, immune function.

• Red Pulp: Blood filtration, removal of old RBCs.

Additional info: Academic context was added to clarify immune cell functions, respiratory laws, and disease mechanisms for completeness and exam preparation.