Respiratory System

oxygen absorption

Pulmonary Functions \n • _________________ & CO2 removal (main function) \n • Defence

Oxygen absorption & CO2 removal

Pulmonary Functions

______________;

– Ventilation (brain, muscles, airways, compliance) \n – Gas exchange across the air-blood barrier \n – Perfusion

Defence

Pulmonary Functions

__________________:

* against airborne micro-organisms
* Biotransformation, endocrine functions

Arterial blood gas; ventilation

Pulmonary disease causes failure of lung function


1. ____________________ analysis:

* decreased paO2 : hypoxemia
* increased paCO2 : hypercapnia


2. _____________ mechanics:

* airflow & volume measured using a spirometer

Forced vital capacity

Lung Function: Ventilation Mechanics \n • _____________________: total volume of exhaled air \n • FEV1: forced expiratory volume in 1 second

pulmonary edema

Major consequence of ________________

* Obstructs alveolar ventilation
* Impairs surfactant, decreases lung compliance

Compliance

_____________ = ΔV/ΔP

Bronchopneumonia

* a type of pneumonia that causes inflammation in the alveoli
* Air-borne/inhaled infection with opportunistic bacterial pathogens

sterile

The Problem of Lung Defence

* Many bacterial respiratory pathogens are carried by apparently healthy individuals
* The lungs are constantly challenged with pathogens from the nasopharynx and in inhaled particles
* The lung must remain “________” for optimal function

__Mucociliary clearance & cough__

Lung defence #1. ____________________________

* Size-dependent impacting of particles
* Trapping of particles by mucus
* Clearance of mucus to the nasopharynx
* sweep material out of lung

Innate defence proteins

Lung defence #2. __________________ & peptides from airway epithelium

* **β-Defensins**: eg. tracheal antimicrobial peptide
* Cathelicidins
* Lysozyme
* **Lactoferrin**
* Lactoperoxidase
* **Surfactant proteins** A & D
* Complement proteins

Alveolar Macrophages

Multi-layered system of lung defence. 3. ________________

* Phagocytosis of particles & bacteria
* Killing pathogens
* Recruitment of inflammatory cells
* “Housekeeping” in the alveoli

Recruited Cells

Multi-layered System of Lung Defence. 4._____________

..enhance lung defences

* Neutrophils, macrophages: phagocytosis and killing of bacteria
* B lymphocytes: antibody blocks colonization, kills bacteria, opsonization
* T lymphocytes: activate macrophages→ increased microbicidal functions

Host; infectious; environment

Predisposing causes of bacterial bronchopneumonia

_____ factors: Stress, Vaccination, Genetics

__________ Agents: Bacteria, viruses, mycoplasma

______________: Chilling, Organic dust in barn air, Air pollutants

Pulmonary carcinoma

Lung Cancer: ___________________

* malignant epithelial cancer

Human Lung Cancer

_____________________:

* #1 cause of cancer death in North America
* #2 cause of preventable mortality in North America
* Association with cigarette smoking
* Older patients, poor prognosis \n – <50% 1-year survival \n – <15% 5-year survivall

Blood air interface:

* Type I pneumocyte
* Basement membrane
* Endothelium
* __Critical for efficient gas exchange__
* __Effects on compliance__

hyaline; alveolar

Acute: ___________ membranes & ________ edema

pink membranes that line the alveoli

* damage to epi or endothelial cells

Subacute: proliferation of type II pneumocytes

* \

Chronic: Interstitial fibrosis

* \

Acute respiratory Distress syndrome

_________________________; (ARDS)

Common cause of severe respiratory disease, \n in patients hospitalized for other diseases \n • 36% mortality \n • Return to normal lung function in survivors

Pneumocytes

Acute Respiratory Distress Syndrome \n Pathogenesis: Injury to type I _____________ or endothelium

lung; pleural

Lung Cancer

* Fills function space within _______
* Impinges on a vital structure (eg bronchus)
* Erodes a blood vessel → hemorrhage
* Metastasis within _________ cavity
* Lymph node and distant metastasis
* Paraneoplastic effects

Interstitial Lung Injury

Cellular Targets in _________________

* Type I Pneumocytes
* Type II Pneumocytes
* Endothelial cells
* Alveolar Macrophages

Type I

______ Pneumocytes

* Gas exchange
* Susceptible to injury

Type II

________ Pneumocytes

* Stem cell: regeneration
* Production of surfactant
* Metabolism/detoxification

gas exchange; compliance

Blood-air interface:

* Type I pneumocyte
* Basement membrane
* Endothelium

Critical for efficient __________ \n Effects on ___________

hyaline; edema

Evolution of Alveolar Injury

Acute: _____ membranes & alveolar ________

subacute

Evolution of Alveolar Injury

___________: proliferation of type II pneumocytes

fibrosis

Evolution of Alveolar Injury

Chronic: Interstitial ___________

compliance; tidal volume

Alveolar Injury and Restrictive Lung Disease

* Obstruct oxygen exchange in alveoli
* Reduce pulmonary _____________ — stiff & inelastic
* Reduce lung capacity — reduced ____________

Acute Respiratory Distress Syndrome

_______________________ “ARDS”

* Common cause of severe respiratory disease in patients hospitalized for other diseases
* 36% mortality
* Return to normal lung function in survivor

endothelium

Acute Respiratory Distress Syndrome

Pathogenesis: Injury to type I pneumocytes or ___________

* Sepsis or endotoxemia
* Viral or mycoplasmal infection
* Aspiration of vomitus
* Trauma
* Toxins

mucociliary clearance

Large airways: trachea, bronchi - Ciliated epithelial cells

* Function: ______________
* Vulnerable to injury
* ex. Goblet cells, basal cells, mucosal glands

regeneration; inflammatory

__Small airways: bronchioles__ \n Club cells: non-ciliated, bronchiolar, epithelial cells \n Function \n – Stem cell for _____________ \n – Metabolism and detoxification of chemicals \n – Dampening of the ____________ response

viruses; toxic

Causes of Airway Disease

* _____________: eg. influenza
* Hypersensitivity disease: eg. asthma
* _______: eg. cigarette smoke pollutants

Asthma

______________

* Hyper-reactive airways → episodes of reversible bronchoconstriction leading to airway obstruction
* Inflammatory airway disease
* Triggering factors \n •Allergen exposure \n •Drug exposure \n •Exercise \n •Cold, heat, stress \n •Pollutants

Chronic Obstructive Pulmonary Disease

_____________________________

* 4th most common cause of death (Strong association with smoking) \n • Chronic bronchitis \n • Emphysema

Chronic bronchitis

_______________

* Airway irritation : “smoker’s cough”... \n ...may lead to permanent damage to airway

Emphysema

_________________ \n Destruction of alveolar wall → enlargement and dysfunction of the alveoli