the exchange of gases between body tissues and the environment
External respiratory system
where exchange of O2 and CO2 occurs between the atmosphere and the pulmonary blood flow
Internal respiratory system
gas exchange occurs between the systemic capillaries and the tissues
O2 travels in the blood towards tissues, CO2 flows away
What are the 5 steps of respiration?
ventilation, gas exchange, gas transport, gas exchange, cellular respiration
process of air moving in and out of lungs, supply alveoli with fresh O2 and remove CO2. Bulk flow
2. Gas exchange
across alveolar membrane: O2 and CO2 move down their pressure gradients into or out of alveoli. Diffusion
3. Gas transport
oxygen rich blood travels away from the lung and towards the heart, pumps it towards systemic tissues. Bulk Flow
4. Gas exchange
across capillary membranes: O2 and CO2 move down their pressure gradients into or out of the capillaries. Diffusion
5. Cellular respiration
cells in systemic tissues use up O2 and produce CO2
What is Boyles law?
At constant temp, volume of gas is inversely related to pressure
Equation for Boyle's law
Law of Partial pressures
Partial pressure of a gas is the amount of pressure that gas exerts individually
Equation of partial pressure
Px=Fx x Pb
What is Dalton's law?
Total pressure of a mixture is equal to the sum of the partial pressures of the gases in that mixture
In the atmosphere what is the pressure = to?
What is PB (barometric pressure)?
pressure of the atmosphere outside body
What is PA (alveolar pressure)?
pressure in the alveoli
What is PIP (intrapleural pressure)?
pressure of the fluid in the pleural cavity
Diaphragm and external intercostal contract, increase in throacic vol, lungs expand, increase vol (decrease pressure), air moves into lungs
To breath in...
Inspriatory muscles relax, diaphragm moves upwards, decrease in thoracic vol and lung vol, increase in intrapulmonary pressure, air moves out of lungs
To breath out...
What is surfactant?
phospholipid produced by alveolar type II cells, lowers surface tension in alveoli
How does surfactant reduce surface tension?
reduce attractive forces due to H-bonding by becoming interspersed between H2O molecules
Lack of surfactant=
stiff lungs, neonate
What is the tidal volume?
volume of air that moves in and out during normal quiet ventilation
What is the inspiratory reserve volume?
Extra 3L can be inspried if external intercostal muscles contracted too
What is the expiratory reserve volume?
Extra 1.5L can be expelled if internal intercostal muscles contracted too
What is the residual volume?
after max expiration, lungs still partially inflated
What is the function residual capacity?
when breathing quietly, breathing with 2.5L already in lungs
What is the vital capacity?
When you breathe maximally in and out, you will by inhaling and exhaling 5L
What is the total lung capacity?
If you breathe all the way in, you hold about 6L in lungs
What is the inspiratory capacity?
tidal volume + IRV