Transcript The Respiratory System

The Respiratory System
Group Members:
Abby Ridley-Kerr
Lia Kato
Sasha Yovanovich
Shelby LaRosa
The Relationship of the Respiratory
Surface and the Transport System
• The respiratory
system collects O2
and pumps it
throughout the body.
• Then it expels the
remaining CO2 left
over after gas
exchange.
Characteristics of a Respiratory
Surface
• Thin and has a large surface area.
• All living cells bathed in water maintaining
plasma membranes.
• To supply O2 and expel CO2.
• Gills, Tracheae, and Lungs are the most
common respiratory surfaces.
Terrestrial Animals and Internal
Surfaces
• Terrestrial animals have internal
respiratory systems because they are
more complex animals which cannot
supply enough O2 by merely using
external cells.
Countercurrent Exchange in Fish
• Countercurrent
exchange is
evidenced in fish.
• The blood gains
oxygen as it moves
through the capillary.
• It simultaneously
obtains water allowing
for a greater transfer
of oxygen.
How is countercurrent in fish an
adaptive value?
• The fish has adapted
to its aqueous habitat
by using both the
surrounding water
and blood flow to gain
oxygen.
Features of Tracheal Tubes and
Lungs
• Lungs are adapted for gas exchange
because they have a large surface area
and a dense network of capillaries
• The trachea is adapted for gas exchange
because it has C-shaped rings of cartilage
that maintain its shape. Also, it forks into
two bronchi, one leading to each lung.
Human Respiratory System
Alveoli
• Alveoli- are air sacs at
the tip of the
bronchioles; they are
sufficient enough to
carry out gas
exchange for the
entire body
Partial Pressure and Gas
Exchange
•
•
A gas always diffuses from a region of higher partial pressure to a
region of lower partial pressure.
1. Blood arriving at the lungs via the pulmonary arteries has a lower PO and
a higher PCO than the air in the alveoli. As blood enters capillaries, CO2
diffuses from the blood to the air in the alveoli. O2 in the air dissolves in the
fluid that coats the epithelium and diffuses into the blood.
2. When the blood leaves the lungs in the pulmonary veins, its PO has been
raised and its PCO has been lowered. After returning to the heart, this blood
is pumped through the systemic circuit.
3. In the tissue capillaries, gradients of partial pressure favor the diffusion
of O2 favor the diffusion of O2 out of the blood and CO2 into the blood. This
is because cellular respiration removes O2 from and adds CO2 to the
interstitial fluid.
4. After the blood unloads O2 and loads CO2, it is returned to the heart and
pumped to the lungs again, where it exchanges gases with air in the alveoli.
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Breathing Regulation
• Breathing is regulated by automatic
mechanisms which insures that the work
of the respiratory system in coordinated
with the cardiovascular system and
metabolic demands for gas exchange.
• These automatic mechanisms include, the
medulla, pH levels, carotid arteries, the
aorta, and the diaphragm.
Breathing Regulation
Medulla
• The medulla sets the basic breathing
rhythm, sends impulses to the diaphragm
and rib muscles to stimulate contraction
pH Level
• Changes in pH trigger either increased
depth and rate of breathing or decreased
rate of breathing
Carotid Arteries
• Carotid arteries detect changes in blood
pH and send nerve impulses to the
medulla
• It also detects changes in oxygen levels in
the blood
Aorta
• The aorta detects
changes in blood pH
and CO2 levels
Diaphragm
• The diaphragm
contracts and causes
inhalation
Adaptive Values of Hemoglobin
• Hemoglobin is an iron containing protein in
red blood cells that reversibly binds
oxygen.
• It can bind not only to oxygen but also to
nitric oxide.
• The nitric acid relaxes the capillary walls
and allows them to expand, aiding in the
deliver of oxygen to all cells.
Dissociation Curves
of Hemoglobin
Hydrogen ions affect the
conformation of hemoglobin—a
drop in pH shifts the oxygen
dissociation curve toward the right.
At a given PO2, hemoglobin gives
up more O2 at pH 7.2 than at pH
7.4 , the normal pH of human
blood. The pH decreases in very
active tissues because the CO2
produced by respiration reacts
with water, forming carbonic acid.
Hemoglobin then releases more
O2 , which supports the increased
cellular respiration in the active
tissues.
Oxygen Circulation and
Hemoglobin
• When the tissues rest, the body is at
normal metabolism.
• So when O2 is consumed in cellular
respiration it causes a relatively large
increase in the amount of O2 the blood
unloads.
pH Reduction and Oxygen Release
Path of CO2
1.
Carbon dioxide produced by body tissues diffuses into the
interstitial fluid and the plasma.
2.
Over 90% of the CO2 diffuses into red blood cells, leaving only
7% in the plasma as dissolved CO2.
3.
Some CO2 is picked up and transported by hemoglobin.
4.
However, most CO2 reacts with water in red blood cells,
forming carbonic acid (H2CO3), a reaction catalyzed by
carbonic anhydrase contained within red blood cells.
5.
Carbonic acid dissociated into a bicarbonate ion (HCO3-) and a
hydrogen ion (H+).
6.
Hemoglobin binds most of the H+ from H2CO3, preventing the
H+ from acidifying the blood and thus preventing the Bohr shift.
7.
Most of the HCO3- diffuses into the plasma where it is carried
in the bloodstream to the lungs.
8.
In the lungs, HCO3- diffuses from the plasma into red blood
cells, combining with H+ releasing from the bloodstream and
forming H2CO3.
9.
Carbonic acid is converted back into CO2 and water.
10. CO2 formed from H2CO3 is unloaded from hemoglobin and
diffuses into the interstitial fluid.
11. CO2 diffuses into the alveolar space, from which it is expelled
during exhalation. The reduction of CO2 concentration in the
plasma drives the breakdown of H2CO3 into CO2 and water in
the red blood cells (see step 9), a reversal of the reaction that
occurs in the tissues (see step 4).
THE END!!!!