SEHS 11 ventilatory system

ventilation pathway

nasal cavity- oral cavity- pharynx- larynx- trachea- bronchi- bronchioles- alveoli

Pharynx

‘throat’: carries air, food, fluid down from the nose and mouth

muscular tube

larynx

‘Voice box’

air from Pharynx -> trachea

cartilage (also contains vocal chords)

trachea

‘Windpipe’, tube carrying air from larynx to lungs

rings of cartilage lined inside by mucous membrane

bronchi

Large tubes connect trachea to both lungs

Singular: bronchus

Made of cartilage, lined by mucous membrane + smooth muscle to control airflow.

Alveoli

Air sack in the lungs: respiration here (exchange)

bronchioles

Air passages branching from bronchi

respiration

Process; the exchange of oxygen and carbon dioxide

diaphram

Muscle separates chest and abdominal cavities

Principle muscle of respiration

active ventilation

Requires muscle contraction

Inhaling cus your diaphragm contracts; pulls down, and rib muscles expand the chest to draw air in.

passive ventilation

without muscle effort, relaxation of muscles

Exhale at rest; usually passive. Diaphragm and chest muscles relax, and the lungs naturally recoil, pushing air out.

External intercostal muscles

Muscles between the ribs that elevates the thoracic cavity; facilitating inhalation

thoracic cavity

space within the rib cage (w/ vital organs)

Internal intercostal muscles

When more active, these kick in and support above by contracting.

Abdominal muscles also support the diaphragm during exercise.

ventilation rate

BPM breaths/min. Usually measured as ‘resting rate’

(CVs to measure; action, time, age)

Tidal volume

Volume air passing through (respiratory pathway) between inhalation and exhalation at rest.

vital capacity

Volume air passing between max. inhalation/exhalation.

Expiratory reserve volume (there’s also IRV btw)

ERV

Volume of forcefully exhaled air after a normal exhalation.

residual volume

needs to be air or the lungs collapse; tissue sticks, can’t undo

total lung capacity

total

Boyle’s law

higher volume; lower pressure

(increased thoracic cavity volume = lower pressure than atmosphere)

Diffusion

the movement of solute particles from a region of high to low concentration

(eg. air to lungs)