Lecture 2: Mechanics Of Respiration Flashcards
What are the 4 goals of the respiratory system?
- Distribute air and blood flow for gas exchange
- Provide oxygen to cells in body tissues
- Remove carbon dioxide from body
- Maintain constant homeostasis for metabolic needs
What are the four functional events of respiration?
- Mechanics of pulmonary ventilation
- Diffusion of O2 and CO2 between alveoli and blood
- Transport of O2 and CO2 to and from tissues
- Regulation of ventilation and respiration
What is EXTERNAL respiration?
- Mechanics of breathing
- Movement of gases into and out of body
- Gas transfer from lungs to tissues of body
- Maintain body cellular homeostasis
What is INTERNAL respiration?
- Intracellular oxygen metabolism
- Cellular transformation
- Krebs cycle—aerobic ATP generation
- Mitochondria and O2 utilization
What is the main purpose of ventilation?
To maintain an optimal composition of alveolar gas
Alveolar gas acts as a ___ ___ ___ between the ___ and ___.
- stabilizing buffer compartment
- between the environment and pulmonary capillary blood
How does alveolar gas act as a stabilizing buffer compartment? (3 things)
- Oxygen is constantly removed from alveolar gas by blood
- Carbon dioxide continuously added to alveoli from blood
- O2 replenished and CO2 removed by process of ventilation, by simple diffusion
What provides the stable alveolar environment?
The two ventilation phases—inspiration and expiration
Breathing is the act of ___
Creating inflow and outflow of air between the atmosphere and the lung alveoli
How much does the lung weigh?
- 1.5% of body weight
- 1 kg in 70 kg adult
Alveolar tissue is ___ of lung weight
60%
Alveoli have ___
Very large surface area—40x the external body surface area
___ diffusion pathway for gases
Short
What does the short diffusion pathway for gases permit?
Permits rapid and efficient gas exchange into blood—only 1.5 micrometers between the air and alveolar capillary RBC (very thin layer)
What is the blood volume in the lung?
500 mL (10% of total blood volume)
Respiratory muscles generate ___ to inflate and deflate the lungs
Force
What are two things that impede ventilation?
Tissue elastance and resistance
What are two other factors that alter lung volumes?
- Distribution of air movement within the lung, resistance within the airway
- Overcoming surface tension within alveoli
Air flow requires ___
A pressure gradient
Air flows from ___ to ___ pressures
High to low
During inspiration, alveolar pressure is ___
Sub-atmospheric, allowing air flow into the lungs
During expiration, alveolar pressure is ___
Higher than atmospheric pressure, allowing airflow out of the lungs
What generates changes in alveolar pressure?
Changes in pleural pressure
Inspiration is the ___ phase of the breathing cycle
ACTIVE phase