ventilatory system

content on ventilation from exercise physiology

principle structures of the ventilatory system

nose, mouth, pharynx, larynx, trachea, bronchi, bronchioles, alveoli, lungs

functions of conducting airways

• warm and moisten air

• low resistance pathway for airflow

• defence against harmful substances that are inhaled

tidal volume

volume of air inhaled and exhaled per breath

residual volume

amount of air in lungs after max exhale

total lung capacity

volume of air in lungs after max inhalation

inspiratory reserve volume

additional air inspired over tidal volume

expiratory reserve volume

volume of air in excess of tidal volume that can be forcibly exhaled

vital capacity

max volume of air that can be exhaled after max inhalation

process of inhalation at rest

- external intercostal muscles contract, internal intercostal muscles relax, increasing thoracic cavity

- diaphragm contracts

- decreases pressure in lungs relative to atmospheric pressure

- air is sucked into lungs

process of exhalation at rest

- both sets of intercostal muscles relax

- diaphragm relaxes

- increases pressure in lungs relative to outside atmospheric pressure

- air is forced from the lungs

inhalation during exercise

accessory muscles raise ribs further to be able too inhale more air (in addition to other inhalation processes)

nervous control of ventilation

- increases as blood acidity increases (low ph) due to cO2 content in blood

detected by the respiratory centre

- increases rate and depth of ventilation

chemical control of ventilation

- lung stretch receptors receive information about increased breathing

- muscle proprioceptors receive information about increased activity

- chemoreceptors receive information about changes in blood

haemoglobin

- protein in red blood cells

- carries oxygen from lungs to body tissue

- returns carbon dioxide to lungs

- most of oxygen in blood is transported by haemoglobin

gaseous exchange

- diffusion/two way exchange

- air in lungs is high in oxygen and low in carbon

- blood going to lungs is high in carbon and low in oxygen

- oxygen diffuse from alveoli to blood

- carbon diffuse from blood into alveoli