Lab 4: Respiratory system

Muco-ciliary escalator

1. Cilia projecting from cell surface

2. Goblet cells secrete mucus

3. Mucus moves upward by coordinated movement of cilia. Functions as an efficient filter for dust particles

Structure of trachea

• Cartilage rings are there to maintain open airways, when there is a drastic pressure change

• ‘C’ shape allows food to move down the Esophagus

What helps keel alveoli and bronchioles open

• Alveoli carry residual air, keeping the alveoli and bronchioles open

• Lung recoil

Ventilation

the bulk flow of air between the atmosphere and the respiratory zone (alveoli)

What law does the pressure in the thoracic cavity follow

Boyle’s law of gases: P1V1 = P2V2

• P1 = Atmospheric pressure (constant*)

• V1 = Atmospheric volume (constant)

• P2 = Pressure within the alveolar

• V2 = Volume within the alveolar

Air flow is controlled by

changing the pressure in the lungs

How does inspiration occur

• Active mechanism that expands the thoracic cavity by contracting the inspiratory muscles

• lung volume increases, pressure in lungs lowers below atmospheric pressure

• air flows into lungs until an equilibrium is

  reached

How does expiration occur

• PASSIVE mechanism by relaxing the inspiratory muscles, allowing the lungs to RECOIL (due to elasticity)

• thoracic cavity shrinks

• lungs volume decreases which compresses the gas within the lungs to a pressure higher than the atm pressure

• air flows out of lungs until an equilibrium is reached

Tidal volum

air flowing through the airways at rest

Inspiratory reserve volume

Expiratory reserve volume

Vital capacity

Residual volume