64 gas exchange_akira

Akira nakama

• Our lungs, heart and blood vessels collaborate to ensure that body cells are well supplied with Oxygen and give up carbon dioxide.

• Body needs oxygen to process aerobic cell respiration.

• In aerobic respiration Chemical bond within glucose molecule are sequentially broken to release energy. Much energy stored in body is in form of ATP.

• This aerobic respiration requires Oxygen molecules and six carbon of glucose are released as a carbon dioxide as a waste.

• In daily life we are continuously inhale air to the lung and exhale the carbon dioxide out. This cycle is called ventilation.

• The air stays in lung for only brief moment but that brief second is enough for diffusion of gas

• Oxygen in lung tissue diffuses into the blood stream.• The movement of the gas is also called gas exchange

and there are two locations where gas exchange occurs.

• In lungs oxygen moves from air to the lungs in to the blood stream.

• In capillary bed oxygen diffuse out of the blood stream and into the body cell and carbon dioxide diffuses out of the body cell into capitally bed.

• There are some organisms without ventilations system such as amoeba. These organisms do not require ventilation system as long as they are in environment with higher concentration of air compare to concentration of oxygen inside body.

• Other reason for ventilation is concentration of the respiratory gases within the lungs encourages the diffusion of each gas in a direction that is beneficial to the body.

• The air first enter trachea• Then your right and left primary bronchi • Then smaller and smaller branches of

bronchi• Then very small braches called bronchi• Finally, the air enters the small air sacs in the

lungs called alveoli

• Alveoli in the lungs are found as clusters at the ends of the smallest bronchioles. This has appearance that is very similar to a brunch of grapes.

• There are 300 million alveoli in each of the lungs

• Each cluster of alveoli has a surrounding capillary bed.

• The blood entering these capillary beds comes from the right ventricle via the pulmonary arteries.

• The blood in pulmonary arteries is relatively low in oxygen and high in carbon dioxide

• While this blood is in the capillary bed surrounding a cluster of alveoli, oxygen diffuses from the air in each alveolus across two cell membrane.

• One of the two cell membranes is the single cell membrane making up the wall of the alveolus and the second is the single cell membrane making up the wall of the capillary

• Carbon dioxide diffuses in the opposite direction through the same two cell membranes. As long as organism breathe and refresh the gases within alveoli, the concentration gradients of these two gases will ensure diffusion of each gas in the direction described previously.

• http://www.youtube.com/watch?v=d-f3RL0KiUg&feature=related

Adaptation Advantage

Spherical shape of alveoli Provides a large surface area for respiratory gases to diffuse through

Flattened, single cell thickness of each alveolus

Prevents respiratory gases from having to diffuse through more cell layer

Most inner lining of alveolus Allows for efficient diffusion

Associated capillary bed nearby Respiratory gases do not have to diffuse far to reach single cell thick capillaries

• Each time organism breath, a fairly complex series of events occurs within.

• The mechanism of breathing is based on the inverse relationship between pressure and volume.

• An increase in volume will lead to a decrease in pressure.

• Volume will do the opposite and whatever pressure does.

• The lungs are located within thoracic cavity • The thoracic cavity is closed to the outside air,

which lungs have only one opening to the outside air, which is trachea

• 1.The diaphragm contracts and at the same times the abdominal muscle and intercostals muscles help to raise the rib cage. Collectively, these action act to increase the volume of the thoracic cavity.

• 2.After Thoracic cavity has increased its volume, the pressure inside the cavity decreases. This leads to less pressure pushing on the passive lung tissue.

• 3.The lungs tissue increase its volume because there is less pressure exerted on it

• 4.This leads to a decrease in pressure inside of the lungs, also known as a partial vacuum

• 5.Air comes in through open mouth or nasal passages to counter the partial vacuum with in the lungs.

• Alan Damon. “Higher Level Biology.“Gas exchange, Pearson.2007. 2010.10.17

• Michael Kent.”Advanced Biology.”Oxford publish. Oxford. 2007.2010.10.17

• Gaseous Exchange in Human Beings . India: TutorVista Global Pvt. Ltd, 2010. Print.