Respiration The hows and whys of a breath. The Tidal movement of air

Respiration

The hows and whys of a breath

The Tidal movement of air

Bio 130 Human Biology

Tidal movement of air

n Nasal cavitiesn nasopharynxn pharynxn larynxn vocal cordsn trachea


More airways

n Bronchiolesn respiratory

bronchiolesn aveoli

n can you name all the structure air passes?


Human Respiratory System. Putting it all together

Figure 10.1


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.


Respiratory Cycle

Figure 10.9


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)


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)


Measurement of Lung Capacity

Figure 10.10a


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


Question

n What is pulmonary surfactant?


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


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.


Relative gas concentrations, be able to figure out where the gas will go


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.


Regulation of Breathing

Figure 10.13


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


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


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.


Disorders of Respiratory System

n Reduced air flow: asthma, emphysema, bronchitis

n Infections: pneumonia, tuberculosis, botulism

n Lung cancern Congestive heart failuren Cystic fibrosis

Documents

Respiration The hows and whys of a breath. The Tidal movement of air