Anatomy & Physiology B&C Cheat Sheet

This cheat sheet condenses essential knowledge of the Respiratory, Digestive, and Immune systems, crucial for Science Olympiad, by focusing on anatomy, function, key processes, disorders, and high-yield comparisons.

Core Principles

Respiratory System: Air pathway from nose to alveoli, ventilation mechanics (inspiration/expiration), gas exchange principles, and major disorders like asthma and COPD.
Digestive System: Alimentary canal organs and accessory organs, mechanical vs. chemical digestion, macronutrient breakdown, and key diseases like GERD and Crohn's.
Immune System: Differentiating innate vs. adaptive immunity, primary/secondary lymphoid organs, cell types, antibody functions, hypersensitivity types, and autoimmune disorders.

Action Steps

1. Memorize the air pathway: Nose → pharynx → larynx → trachea → primary bronchi → secondary bronchi → tertiary bronchi → bronchioles → alveolar ducts → alveoli.
2. Understand ventilation: Diaphragm contraction increases thoracic volume and decreases pressure for inspiration; relaxation decreases volume and increases pressure for expiration.
3. Recall gas exchange factors: Diffusion increases with surface area and concentration gradient, and decreases with membrane thickness.
4. Identify digestive organs: Alimentary canal (mouth to anus) and accessory organs (salivary glands, liver, gallbladder, pancreas).
5. Differentiate immune responses: Innate immunity is rapid and nonspecific; adaptive immunity is slower, antigen-specific, and has memory.
6. Recognize antibody classes: IgM (first), IgG (most abundant, crosses placenta), IgA (secretions), IgE (allergies), IgD (B-cell receptor).
7. Distinguish hypersensitivity types: Type I (IgE/mast cells), Type II (antibody-cell attack), Type III (immune complexes), Type IV (T-cells).

Key Terms

Alveoli: Tiny air sacs in the lungs where gas exchange (O₂ and CO₂) occurs between air and blood.
Peristalsis: Wave-like muscle contractions that move food through the digestive tract.
Opsonization: Coating a pathogen with molecules (like C3b) to enhance phagocytosis.
MHC I: Major Histocompatibility Complex Class I; presents endogenous antigens to CD8 cytotoxic T cells.
MHC II: Major Histocompatibility Complex Class II; presents extracellular antigens to CD4 helper T cells on APCs.
Anaphylaxis: A severe, potentially life-threatening systemic allergic reaction involving IgE and mast cells.

Real World Examples

Asthma attack: Reversible airway inflammation and bronchoconstriction, treated with bronchodilators and corticosteroids.
Eating dairy products with lactose intolerance: Insufficient lactase enzyme leads to GI symptoms because lactose cannot be broken down for absorption.
Receiving an organ transplant (allograft): The recipient's immune system may recognize donor antigens as foreign, leading to rejection, managed with HLA matching and immunosuppressive drugs.

Timeline

First response (Innate): Rapid, non-specific immune response involving barriers, phagocytes, and inflammation.
First response (Adaptive): Slower, antigen-specific response involving B and T lymphocytes, with initial activation taking days.
Secondary response (Adaptive): Faster and stronger immune response due to memory B and T cells, occurring upon re-exposure to an antigen.