respiratory system

structure of the respiratory system

1. nasal cavity: air is warmed and filtered by mucus and hairs

2. pharynx: junction between food and air

3. larynx and trachea

4. left and right bronchi

5. lungs

6. bronchioles

7. alveoli

alveoli

sites of gas exhange

type I alveolar cells

make up the alveolar wall

type II alveolar cells

release surfactant which reduces surface tension

mediastinum

area between the two lungs where the heart is located

lobes of the right and left lungs

right: superior, middle, inferior

left: superior, inferior

pleura

protective double membrane containing pleural fluid and a lung

rate of diffusion

directly proportional to surface area and concentration gradient

inversely proportional to the distance between two solutions

diffusion

passive transport mechanism by which gas exchange in the lungs occurs

interaction of cardiovascular and respiratory systems

1. pulmonary vessels carry blood low in O₂ and high in CO₂ from the heart to the lungs

2. alveoli (high in O₂) diffuse O₂ into the capillaries and pick up CO₂ from the capillaries (high in CO₂) to be exhaled

3. oxygenated blood is returned to the heart

4. systemic circulation sends oxygenated blood throughout the body

5. cells consume oxygen and deoxygenated blood is returned to the heart

steps of ventilation

1. diaphragm and intercostals contract

2. lung volume increases and pressure decreases

3. air drawn in

4. diaphragm and intercostals relax

5. lung volume decreases and pressure increases

6. air pushed out

tidal volume

the amount of air breathed in and out during a normal breath

residual volume

CO₂ rich air left in the lungs after expiration

how is respiration controlled?

medulla oblongata monitors CO₂ levels and blood pH

(low pH = high CO₂ → increase respiration rates)

asthma

condition in which respiratory airways narrow due to swollen airways or mucus buildup

influenza

infection of the respiratory system caused by a virus

causes the body to attack infected host cells

epiglottis

prevents food from entering the trachea

conducting zone

transports air to the respiratory zone but no gas exchange occurs

nose, mouth, pharynx, larynx, trachea, bronchi, terminal bronchioles

respiratory zone

sites of gas exchange in the lungs

respiratory bronchioles and alveoli

hypoventilation

inadequate ventilation

results in high CO₂ (hypercapnia) and low O₂ (hypoxia)

makes blood pH acidic

hyperventilation

excessive ventilation

results in results in low CO₂ (hypocapnia) and hgh O₂ (hyperoxia)

makes blood pH basic