Respiratory System

• ventilation• external respiration• transport• internal respiration• cellular respiration

Respiration is the process of exchanging gases between the atmosphere and body cells. Consists of the following events:

Organs of the Respiratory System

Upper Respiratory Tract

Mucous in Respiratory Tract

Cilia move mucus and trapped particles from the nasal cavity to the pharynx

Sinuses

Air-filled spaces in maxillary, frontal, ethmoid, and sphenoid bones

Vocal Cords

Trachea

Cross section of trachea Wall of trachea

Tracheostomy

Performed to allow air to bypass an obstruction within the larynx

Bronchial Tree

Alveoli

Diffusion Across Respiratory Membrane

Location of Lungs

Transverse Section of Lungs

19-15

Lungs at Rest

When lungs are at rest, the pressure on the inside of the lungs is equal to the pressure on the outside of the thorax

Air Movements

• Moving the plunger of a syringe causes air to move in or out• Air movements in and out of the lungs occur in much the same way

Inspiration

• Intra-alveolar pressure decreases to about 758mm Hg as the thoracic cavity enlarges• Atmospheric pressure forces air into the airways

Maximal Inspiration

Thorax at end of normal inspiration

Thorax at end of maximal inspiration• aided by contraction of sternocleidomastoid and pectoralis minor muscles

Expiration

• due to elastic recoil of the lung tissues and abdominal organs

Maximal Expiration

• contraction of abdominal wall muscles• contraction of posterior internal intercostal muscles

Pneumothorax

Respiratory Volumes

• tidal volume – volume moved in or out during a normal breath

• inspiratory reserve volume – volume that can be inhaled during forced breathing in addition to tidal volume

• expiratory reserve volume – volume that can be exhaled during forced breathing in addition to tidal volume

• residual volume – volume that remains in lungs at all times

Respiratory Volumes and Capacities

This chart will be given to you on the test!!!

Respiratory Capacities

• inspiratory capacity = TV + IRV• functional residual capacity = ERV + RV• vital capacity = TV + IRV + ERV• total lung capacity = VC + RV

•You do not have to memorize these because you can use the previous chart on the test

Clinical Terms on pgs. 764-765

•Bronchitis•Hyperventilation•Pleurisy•Pneumothorax•Rhinitis•Sinusitis•Tracheotomy

Clinical Application

The Effects of Cigarette Smoking on the Respiratory System

• cilia disappear• excess mucus produced• lung congestion increases lung infections• lining of bronchioles thicken• bronchioles lose elasticity• emphysema fifteen times more common• lung cancer more common• much damage repaired when smoking stops