Respiratory System

Functions

  • Deliver air to the lungs
  • bring oxygen into the body (cells)
  • Expel carbon dioxide back into the air

Breathing Mechanism

Visceral pleura - inner membrane of lungs
Pleural cavity - cavity in between visceral pleura and parietal pleura
Parietal Pleura - outer membrane of lungs
Intercostal muscles - muscles in between the ribs (aid in respiration)
Diaphragm - muscle at bottom of lungs

Atmospheric psi 760mmHg
Psi inside lungs(intrapulmonary psi) 760mmHg
Intrapleural pressure (pressure inside the pleural cavity) - 750mmHg

  • Gases travel from higher to lower pressure

Inspiration

  • Volume in lungs increases due to constriction of muscles
  • Diaphragm contracts and moves down
  • When intrapulmonary volume increases, intrapulmonary pressure decreases
  • intrapulmonary volume and pressure have an inverse relationship
  • Air will flow in

Expiration

  • Intercostal muscles and diaphragm will relax
  • diaphragm will move up back into place
  • Intrapulmonary volume will decrease causing intrapulmonary pressure to increase

Differences between right and left

Lungs

  • each lung has an oblique fissure that separates each lobe

Primary bronchi

right

  • larger than the left lung
  • comprised of 3 lobes: superior, middle, and inferior

left

  • only has two lobes: inferior and superior

right

left

External respiration

  • dark red blood is filled with oxygen and returned to the heart
  • hemoglobin is bound to red blood cells
  • Oxygenated blood had higher psi than deoxygenated blood
  • Deoxygenated blood expels blood into the lungs from the alveoli

Internal Respiration

  • Tissue cells continuously use O2 for their metabolic activities and produce CO2
  • O2 psi is always lower in tissues than in arteries
  • O2 moves rapidly from blood into the tissues
  • At the same time, CO2 moves quickly into the blood
  • Gas exchanges that occur between blood and alveoli and between blood and tissue cells take place by simple diffusion

Volume

  • Tidal Volume: amount of air inhaled or exhaled with each breath
  • Inspiratory reserve: amount of air that can be forcefully inhaled after a normal tidal volume inspiration
  • Expiratory reserve: amount of air that can be forcefully exhaled after a normal tidal volume expiration
  • Residual volume: Amount of air remaining after forced expiration

Capacity

  • Total lung capacity: Max air contained in lungs after max inspiratory effort
  • Vital capacity: Max air that can be inspired after max inspiratory effort
  • Inspiratory capacity: Max amount of air that can be inspired after normal tidal volume expiration
  • Functional residual capacity: Volume air remaining in lungs after normal tidal volume expiration

Respiratory diseases

-COPD (Chronic Obstructive Pulmonary Disorder): Chronic Bronchitis, emphysema, and athsma

  • Lung cancer: Uncontrolled cell growth and development of tumors in the lungs
  • Pneumonia: bacterial or viral infection of the lungs
  • Seasonal flu: a viral infection; many variations, changes rapidly year to year
  • Tuberculosis: Bacterial infection in the respiratory system caused by myobacterium