Module D Flashcards
what is respiratory system ?
The respiratory system is the network of organs and tissues that help you breathe. It includes your airways, lungs, and blood vessels.
The conducting zone
consists of all of the structures that provide passageways for air to travel into and out of the lungs
= Warming & humidifying process
= Removal of debris & pathogens
the respiratory zone
is deep inside the lungs and is made up of the respiratory bronchioles as well as it is involves in gas exchange.
types of pressure in and around the lungs
pleural pressure - pressure of fluid within the space between the lungs and chest wall. Normally negative, creating an action effect.
alveolar pressure - pressure of air inside the alveoli, negative during inspiration , positive during expiration.
what are the mechanics of breathing
Inspiration - Alveolar pressure is negative resulting in pressure gradients that result in air flow into the lungs.
Expiration - Alveolar pressure rises above atmospheric pressure, becoming positive, resulting in a pressure gradient that results in airflow out of the lungs.
lung movement occurs via:
- When you breathe in, or inhale, your diaphragm contracts and moves downward.
This increases the space in your chest cavity, and your lungs expand into it.
what is lung compliance
pulmonary or lung compliance, is a measure of the lung’s ability to stretch and expand.
what are the determinants of lungs compliance
Two factors determine lung compliance –
1) elasticity of the lung tissue
2) surface tensions at air water interfaces.
what is surface tension
Surfaces tension is the tension of the surface film of a liquid cause by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area
what is the 1 determinants of lungs compliance
Elastic forces of lung tissue - determinants d by ration of elastin and collagen fiber
what is the 2 determinants of lung compliances
Surface tension of fluid lining the alveoli
- On the inside of the alveoli , surface water is attempting to contract , which collapses the alveoli
- In the alveoli, this tendency is reduced by the presence of surfactant.
what is ventilation
Volume of air breathed in 1 minutes is known as the minute ventilation
VE = VT * Bf
where V T = Tidal Volume And B F = Breathing Frequency
describe the alveolar ventilation.
Alveolar ventilation is the exchange of gas between the alveoli and the external environment. It is the process by which oxygen is brought into the lungs from the atmosphere
what is dead spaces
Dead space is the volume of air that is inhaled and does not take part in the gas exchange because reaches alveoli that are not perfused.
V A =(VT –VD )* Bf
Gas exchange
During gas exchange oxygen moves from the lungs to the bloodstream. At the same time carbon dioxide passes from the blood to the lungs
factors influencing gas diffusion
1- thickness of the alveolar repertory membrane
2- membrane surface area
3- diffusion coefficient of the gas
4- partial pressure differences on either side of membrane
Partial pressure
Partial pressure is the force exerted by a gas. Partial pressure is extremely important in predicting the movement of gases.
what is the Diffusing capacity (of the respiratory membrane)
Volumes of a gas that will diffuse through the respiratory membrane for a particle pressure differences of 1 mmHg
what is ventilation -perfusion ratio
Matching of the alveolar ventilation with the perfusion of the alveolar capillaries (with blood) expresses as VA/Q.
- For ‘optimal’ gas exchange, all alveoli would receive sufficient ventilation and alveolar blood flow.
how is oxygen (O2) carried in the blood?
Hemoglobin- 4 proteins chains (2 alpha- 2 beta) each containing a a haem group and ion atom
what is a hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of almost all vertebrates
- Hemoglobin in blood carries oxygen from the lungs or gills to the rest of the body
- oxygen is primarily transport via hemoglobin
transport of O2 within the circulation.
- Oxygen transport within the human body occurs through both convection and diffusion.
- Oxygen diffuses from both the alveoli into the
pulmonary capillaries and the systemic capillaries into the tissues
facts about hemoglobin
1- normal values are
= Males 13-18 g/dL (per 100 ml of blood)
= females 12-16 g/dL
2- 97% of O2 in blood is bound to hemoglobin
= Hb will also bind carbon monoxide and nitric oxide.
3- depending on which country you are in, you may see it spelt as hemoglobin
Diffusion of oxygen
From the alveoli , the oxygen from the air you breathe enters your blood in blood vessels.
- This process is called oxygen diffusion
- Once your blood is oxygenated it carries oxygen throughout your body.
alveoli
The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out.
what are the mechanisms of transport of C02 (carbon dioxide)
1-Co2 in dissolves state(5-10%)
2 transported as bicarbonate ion (HCO3) ( 70%)
3- As carbaminohemoglobin (CO2 HB) (20-25%)
= in combination with hemoglobin
3 ways of carbon dioxide is transport
1 - Bicarbonate
2- Carbamino haemoglobin
3- Dissolved state
Factors that influenced O2 dissociation
1- Increase H+ (ions)
2- Increased CO2 (carbon dioxide)
3- Increased temperature
Factors that influence CO2 dissociation
Bohr effect shows that when PCO2 (The partial pressure of carbon dioxide) is highest O2 dissociation from Hb (offloading) increases.
- The reverse is also true
- The Haldane effect states that greater binding of O2 with Hb, increases the release of CO2
