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Bio 130 Human Biology
Tidal movement of air
n Nasal cavitiesn nasopharynxn pharynxn larynxn vocal cordsn trachea
Bio 130 Human Biology
More airways
n Bronchiolesn respiratory
bronchiolesn aveoli
n can you name all the structure air passes?
Bio 130 Human Biology
The lungs
n Located in thoracic cavity above dome shaped diaphragm.
n Surrounded by a sac like membrane with fluid in it called the pleural sac.
n Alveoli (blind sacs) are surrounded by a dense capillary network and is site of gas exchange.
Bio 130 Human Biology
Factors that effect gas exchange
n Air is 21% oxygen. (partial pressure)n The pressure of air affects the amount
of oxygen available.n O2 & CO2 move from high to low
pressure.n Gas exchange occurs at the surface
which must be moist. (800sq feet of surface)
Bio 130 Human Biology
Lung capacity
n Male 4800ml Female 3800(vital capacity)
n 150ml is dead space.n 500ml is moved in and out during rest.
(tidal volume)n 350ml actull reach alveolin 1200ml of residual air is always in the
lungs and cannot be forced out. (residual volume)
Bio 130 Human Biology
The two sites of gas exchange
n In the lungsn Oxygen has a high
pressure in the lungs and flows into the blood
n Carbon dioxide has a high pressure in the blood and flows out
n In the tissuesn oxygen moves
towards the tissues
n carbon dioxide moves to the blood
Bio 130 Human Biology
Movement of gases
n Oxygenn Binds to hemoglobin
in RBC.n Hemoglobin gives
up oxygen under warm low pH conditions.
n Carbon dioxiden 23% to hemoglobin
70% bicarbonate in blood
n red blood cells convert carbon dioxide to bicarbonate
Bio 130 Human Biology
Blood Transports Gases between the Lungs and the Cells
n Most carbon dioxide is transported as bicarbonate ions
n Bicarbonate is made in the red blood cellsn Carbon dioxide and water are converted to
bicarbonate ions and hydrogen.n The hydrogen is carried by hemoglobin (no
ph change)n Bicarbonate circulates in the blood stream
and removes excess acids.
Bio 130 Human Biology
Control of respiration
n The body tries to equilibrate blood and air flow.
n Airflow can be increased by dilating bronchiole tubes.
n Increased oxygen causes blood vessels to dilate.
Bio 130 Human Biology
Regulation of Breathing: Nervous System Involvement
n Respiratory center in the medulla oblongata: establishes basic breathing pattern
n Chemical receptors: monitor carbon dioxide, hydrogen ions, and oxygen levels
n Medulla: sensitive to hydrogen ions in cerebrospinal fluid resulting from carbon dioxide in blood
Bio 130 Human Biology
Regulation of Breathing: Nervous System Involvement
n Carotid and aortic bodies: sensitive to carbon dioxide, pH, and oxygen levels
n Conscious control: resides in higher brain centers; ability to modify breath
Bio 130 Human Biology
Unusual places to breath
n When moving from high to low pressures, gases can escape into the blood, decompression sickness.
n Hypoxia is due to low oxygen pressure at high elevations.
n Carbon monoxide binds to hemoglobin better than oxygen.