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Gas exchange
Mrs. Jackie Maldonado
Respiratory system
Composed Trachea- branches into
two bronchiBronchi- branches into
many bronchiolesBronchioles- end up in a
sac called alveolilungs
Features of alveoli for gas exchange
Large surface area provided by millions of alveoli in the lung
Short distance for gases to travel, due to fact that the walls of the alveolus and the blood capillary are made on one cell layer each.
The moist surfaces of alveoli allow the gases to dissolve in water and then pass in and out between the alveoli and the capillaries
Features of alveoli for gas exchange
Network of capillaries surrounding the alveolus, ensuring constant blood flow
Concentration gradient of gases between the alveoli and the capillaries is very high which allows fast diffusion of gases
Concentration of gases an explanation
Oxygen concentration is high in the alveoli which contain oxygen from the atmosphere while in the blood is low (used in respiration)
Carbon dioxide is high in the blood due to respiration and low in the alveoli.
Only 4% of oxygen is used in each breath from 20% inhale
Features of alveoli for gas exchange
Hemoglobin in the red blood cells has high affinity to oxygen and so it combines with a great speed
RBC are large in size compared with the diameter of the capillaries allowing efficient loading and unloading of gases
The need for a ventilation system
Ventilation system
Needed to maintain a high concentration of oxygen in the alveoli and low CO2.
Produced by changes in pressure in the chest cavity carry byDiaphragmIntercostals muscles
Mechanism of ventilation Inspiration or inhale
Diaphragm contracts and flattens
Intercostal muscles also contract and pull the ribcage outward and forward
The chest cavity become larger and the pressure smaller
The air rushes from the atmosphere into the lungs, moving from higher to lower pressure
Mechanism of ventilation
Exhale or expirationThe diaphragm relaxes, becoming dome
shaped, The intercostal muscles relaxRibs move downward and backwardChest cavity decrease in volume and the
pressure increases.Air is pushed out of the lungs into the
atmosphere moving from higher to lower pressure
What is the difference between breathing and cell respiration?
Cell respirationProcess that occurs inside the cell
which results in the production of ATP Breathing
Mechanical process that causes ventilation maintaining high O2 and low CO2 in the blood
How does exercise improve the functioning of the heart and lungs?
Strengthens and enlarges muscles Heart rate increases sending more blood to
the working muscles, increasing cardiac output
Cardiac output= stroke volume X heart rate
Stroke volume= volume of blood ejected by the ventricles in one beat.
How does exercise improve the functioning of the heart and lungs?
After training the heart rate would not increase much because the heart is stronger and the stroke volume is more
Before training our breathing rate increases as well as our tidal volume
Tidal volume- volume of inhale air in each breath In athletes they increase cardiac output by
increasing stroke vl. and not heart rate and increase their ventilation by increasing their tidal vl and not breathing rate
Why does breathing rate increase during exercise?
To provide more O2 and glucose to the muscles for the process of respiration and to remove carbon dioxide which increase acidity of blood
How does breathing rate increase with exercise?
Respiration rate in muscles increases as well as CO2 levels and pH decreases
pH decreases affect chemosensors located at the aorta and carotid arteries.
Chemosensors send messages to the respiratory centers in the brain stem which in turn send messages to the breathing apparatus.
These muscles contract and relax faster increasing breathing rate.
Health problems associated with gas exchange
Lung cancer Tuberculosis Asthma Emphysema
Asthma
Results from allergy to chemicals (allergens) which irritate trachea and bronchi
Cause constriction of bronchioles thus small tidal volume
Could lead to dead Increases by seasons
Asthma
Emphysema Caused by smoking Substances in smoke stop
the beating of cilia so that air particles enters to the air passages
Results in coughing resulting in walls of the alveoli breaking apart Less surface area less gas
exchange
Could also results in dead