Chapter 23 - Respiratory System Flashcards
respiratory system
- exchange of gases
- moves air to and from exchange surfaces of lungs
mucus
along respiratory tracts
Respiratory defense system
nose removes large particles
Mucous cells and mucous glands
produces mucous to cover exposed surfaces
cilia
gather mucus, trapped debris, microorganisms toward pharynx to be swallowed
Alveolar macrophages
eat small particles that reach lungs
Bronchioles
– Bronchioles branch into terminal bronchioles
– Bronchioles have no cartilage
• Dominated by smooth muscle
autonomic nervous system
– Controls bronchioles diameter by regulating smooth muscle
– Controls airflow in lungs
bronchodilation
– Caused by sympathetic activation
– Enlarges diameter of airway
– Reduces resistance to airflow
bronchoconstriction
- Parasympathetic activation
– Reduces diameter of airway - Histamine release (allergic reactions)
Alveolar cell layer
pneumocytes type I -thin walls -site of gas exchange -monitored by macrophages pneumocytes type II -produces surfactant
surfactant
– Oily secretion
– phospholipids + proteins
– Coats alveolar surface and reduces surface tension
respiratory distress syndrome
– Alveoli collapse after each exhalation
– Caused by inadequate amounts of surfactant due to injury or genetic abnormalities
Pneumonia
– Inflammation of lung tissue
– Causes fluid to leak into alveoli
– Compromises function of blood air barrier
Gas exchange across blood air barrier is quick and efficient
– Because distance for diffusion is short
– And O2 and CO2 are small and lipid soluble
Blood pressure in pulmonary circuit
– Lower than that in systemic circuit
– Pulmonary vessels are blocked by blood clots, fat, or air bubbles
pulmonary embolism
A blocked branch of pulmonary artery that stops
blood flow to lobules or alveoli
external respiration
exchange of O2 and CO2 with external environment
