Antibody Function, Immune Response & Respiratory System Overview

Antibody Structure

Antibody monomer has 2 binding sites and includes variable, constant, and hinge regions

Complement Activation by Antibodies

Only IgG and IgM activate the complement system

IgG and Placenta

Only IgG antibodies cross the placenta to protect the fetus

IgM Structure and Function

IgM is a pentamer (IgM5), signals active infection, and activates the classical complement pathway

IgA Structure and Function

Dimeric IgA is found in secretions; monomeric IgA circulates in blood plasma

Immunoglobulin Classes Overview

IgG makes up 80% of serum antibodies and crosses the placenta; IgD, IgE, and IgA do not

IgE Function

IgE binds mast cells, triggers degranulation, and causes strong inflammation or allergic responses

iClicker Technical Issues

Class experienced technical difficulties with the iClicker system during questions

Antibody Mechanism of Action

Antibodies do not kill pathogens directly; they facilitate immune responses

Antibody Functions

Antibodies activate complement, neutralize pathogens, and cause agglutination (antigen-antibody complexes)

Opsonization

Opsonization enhances phagocytosis by tagging antigens with antibodies

Opsonization and Inflammation

Antibodies promote inflammation by binding mast cells and enabling degranulation

T Cell Activation Steps

Antigen presentation by dendritic cells on MHC molecules triggers T cell activation

T Cell Activation Signals

Naive T cell activation requires two signals: antigen recognition and costimulation

Safety Procedures

Maintain a clear path and wear eye protection during activities

Cytotoxic T Cell Function

Cytotoxic T cells induce apoptosis using perforin and granzymes

T Cell Antigen Recognition

T cells recognize antigens via MHC-bound peptides on cell surfaces

Respiratory System Function

The respiratory system exchanges O2 and removes CO2 via the lungs

Respiratory Zones

Conducting zone transports air; respiratory zone performs gas exchange (O2 and CO2)

Conducting Zone Anatomy

Air passes from the nose to the trachea through conducting structures

Trachea Structure

Hyaline cartilage keeps the trachea open; the epiglottis prevents food entry

Tracheal Flexibility

Muscle tissue behind hyaline cartilage allows food to pass through the esophagus

Conducting Zone Function

Warms, moistens, and cleans inhaled air before reaching the lungs

Conducting Zone Epithelium

Lined by ciliated, columnar, pseudostratified epithelial cells

Respiratory Epithelium

Pseudostratified ciliated columnar epithelium secretes mucus via goblet cells

Ciliary Escalator

Moves particles away from the respiratory zone to protect the lungs

Nasal Structure

External nose is cartilage; septum includes cartilage and bones (nasal, vomer, ethmoid)

Nasal Conchae and Meatuses

Conchae are bony protrusions; meatuses are spaces between them

Nasal Cavity Function

Conchae warm and humidify air; sinuses lighten the skull

Olfactory Pathway

Nasal → olfactory bulb → brain (allows rapid drug delivery)

Alzheimer's and Diabetes

Alzheimer's is sometimes called type 3 diabetes; insulin may help symptoms

Olfactory Mucosa Function

Warms, moistens, and filters inhaled air

Olfactory System Limitation

Dry air reduces humidification due to decreased H2O

Pharynx Function

Conducts air and food and supports sound resonance

Tonsils Function

Tonsils trap pathogens as secondary lymphoid organs

Pharynx Anatomy

Consists of nasal, oral, and laryngopharynx regions

Pharynx and Larynx Overview

Includes epiglottis, vocal cords, larynx, trachea, and esophagus divisions

Upper vs Lower Respiratory Boundary

The larynx divides upper and lower respiratory systems at the thyroid cartilage

Cricoid Cartilage Importance

Location is critical for tracheotomy to restore airway passage