1What is the main purpose of lungs?
Gas exchange for oxygen and carbon dioxide
2What happens during breathing?
Ventilation (inspiration and expiration)
3What are the two branches from the trachea?
Bronchi
4What are smaller airways in lungs called?
Bronchioles
5Where does gas exchange occur?
Alveoli
6What surrounds the alveoli?
Capillaries
7What moves air in and out of lungs?
Ribcage, intercostal muscles, diaphragm
8What happens during inspiration?
Air enters due to lower pressure
9What contracts during inspiration?
Diaphragm and intercostal muscles
10What happens to the diaphragm during inspiration?
It flattens and moves downward
11What happens to the ribcage during inspiration?
It moves upwards and outwards
12What happens during expiration?
Air exits due to higher pressure
13What relaxes during expiration?
Diaphragm and intercostal muscles
14What happens to the ribcage during expiration?
It moves downwards and inwards
15Why is expiration passive?
It requires no energy
16What happens during forced expiration?
Intercostal muscles actively contract
17What is the alveolar epithelium?
Thin layer of alveolar cells
18Why is alveolar epithelium thin?
Short diffusion path for gases
19What increases diffusion speed in alveoli?
Large surface area and ventilation
20What diffuses out of the alveoli?
Oxygen (O₂)
21What diffuses into the alveoli?
Carbon dioxide (CO₂)
22What maintains the diffusion gradient?
Ventilation and blood flow
23What ensures rapid gas exchange?
Steep oxygen and CO₂ gradient
24What increases alveoli's surface area?
Numerous small sacs in lungs
25What connects alveoli to bronchioles?
Alveolar ducts
26What lines the alveoli?
Moist epithelium
27What carries oxygenated blood away?
Capillaries surrounding alveoli
28What kind of process is inspiration?
Active (requires energy)
29What kind of process is normal expiration?
Passive (no energy required)
30What happens during deep breathing?
More muscles actively used
31What happens to alveoli during ventilation?
Pressure changes allow gas flow