Download External Gas Exchange

By:
An indian and a jew
Respiratory structures are adapted for gas exchange in air or
water.
◦ External Gas exchange, creature uses their body surface
for gas exchange
◦ Gills are adapted for respiration in water
◦ Trachea and lungs are adapted for terrestrial respiration
All respiratory systems must be:
(1) Moist
(2)Thin
(3)Large in relation to the body.
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Cell respiration releases energy in the form of
ATP so that this energy can be used inside the
cell.
Cell respiration occurs in the mitochondria and
cytoplasm of cells.
Oxygen is used in this process and carbon
dioxide is produced.
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Small animals with a large body surface use this
and exchange gas externally
Is not very efficient but is good enough to support
small animals.
Hydras and worms use this.
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Gills are outward extensions of the pharynx
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Adapted by marine animals for gathering oxygen in water.
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Fish use Countercurrent exchange-O2 rich water goes in the opposite
direction of O2 poor blood.
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Concurrent Exchange- O2 rich water goes in the same direction as O2
poor blood.
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Countercurrent Exchange is more effective in extracting H2O.
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Uses much more energy than lungs.
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Tracheae- Tiny air tubes that take oxygen directly to the cells.
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Tracheoles- tinnier air tubes that branch off from Tracheae
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Walls lined with chitin for support.
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Used by bugs and other small terrestrials.
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Not very efficient
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It is fairly effective and costs
very little energy to operate
since oxygen is abundant in
the air
Uses some muscles and
pressure to easily manipulate
gases.
Actually has more surface
area than most body parts.
Is controlled by the brain.
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Respiration- The sequence of events that result in gas exchange between
the body’s cells and the environment.
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External Respiration- The gas exchange between the air and the blood
within the lungs. Blood transports oxygen from the lungs to the tissues.
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Internal Respiration- The gas exchange between the blood and the tissue
fluid. Blood then transports CO2 to the lungs.
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Ventilation- The inspiration and expiration of air. The exchange of gas
between the lungs and the atmosphere. (A.K.A Breathing)
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Inspiration-The act of moving air into the lungs.
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Expiration-The act of moving air out of the lungs.
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The Nasal Cavity takes in air.
The pharynx filters, warms, and moistens air and conducts it into
the lungs.
Air goes to the glottis (when the epiglottis is closed), then to the larynx,
and then into the trachea.
Then it splits into 2 Bronchi which enter the Lungs, and then they split
into many bronchioles with alveoli at the ends.
There is a huge capillary network in the lungs that surrounds the
alveoli for gas exchange.
Blood delivers the oxygen to the tissues and bring back CO2 to lungs.
It is involuntary and the respiratory centers in the medulla oblongata control
it. Can be influenced by nervous and chemical input.
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Is located in the medulla
oblongata and controls
respiration.
It is sensitive to H+. When the
pH decreases from an
increase in H+ it increases
our breathing rate.
It detects H+ through
receptors in the body.
Chemoreceptors called
Carotid bodies (Carotid
arteries) and Aortic bodies
(Aorta).
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It is a horizontal muscle that
divides the thoracic cavity
from the abdominal cavity.
Inspiration- It contracts and
goes down and the chest
moves up.
Expiration- It relaxes and
goes up and the chests
moves down.
Plays an important function in
maintaining pressure in the
lungs.
Inhalation:
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The external intercostal muscles contract. This moves the ribcage up and out.
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The diaphragm contracts. As it does so it moves down and becomes
relatively flat.
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Both of these muscle contractions result in an increase in the volume of the
thorax which in turn results in a drop in pressure inside the thorax.
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Pressure eventually drops below atmospheric pressure.
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Air then flow into the lungs from outside the body, through the mouth or nose,
trachea, bronchi and bronchioles.
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Air continues to enter the lungs until the pressure inside the lungs rises
to the atmospheric pressure.
Exhalation:
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The internal intercostal muscles contract. This moves the ribcage down and in.
The abdominal muscles contract. This pushes the diaphragm up, back into a dome
shape.
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Both of these muscle contractions result in a decrease in the volume of the thorax.
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As a result of the decrease in volume, the pressure inside the thorax increases.
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Eventually the pressure rises above atmospheric pressure.
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Air then flows out of the lungs to outside of the body through the nose or mouth.
Air continues to flow out of the lungs until the pressure in the lungs has fallen back to
atmospheric pressure.
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http://www.youtube.com/watch?v=dTsUyXXudvA (Breathing)
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To maintain the concentration gradients of oxygen and carbon
dioxide in the alveoli.
The body needs oxygen to make ATP via cell respiration.
The body needs to get rid of carbon dioxide, a product of cell
respiration.
Oxygen needs to diffuse from the alveoli into the blood. Carbon
dioxide needs to diffuse from the blood into the alveoli.
To do so there must be a high oxygen concentration and a low
carbon dioxide concentration in the alveoli.
A ventilation system makes this possible by getting rid of the carbon
dioxide in the alveoli and bringing in more oxygen.
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Gas exchange is the biological
process of swapping one gas
for another. (What happens in
the alveoli)
Oxygen diffuses into the
capillaries from the air in the
alveoli and carbon dioxide
diffuses out of the capillaries
and into the air in the alveoli.
It occurs in the alveoli in the
lungs.
Gases have partial pressures,
which exert pressure on other
things.
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Great numbers of them increase the surface area for gas exchange.
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Wall made up of single layer of cells and so are the walls of the
capillaries so diffusion distance is small allowing rapid gas exchange.
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Covered by a dense network of capillaries which have low oxygen and
high carbon dioxide concentrations. This allows oxygen to diffuse into
the blood and carbon dioxide to diffuse out of the blood.
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Some cells in the walls secret fluid allowing gases to dissolve. The
fluid also prevents the sides of alveoli from sticking together.
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Hemoglobin (Hb)-A special molecule that has a special part in aiding our
breathing. Commonly forms bonds with oxygen and CO2
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Oxyhemoglobin (HbO2)-Used by RBCs to carry oxygen. (Common)
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Carbonic anhydrase- is an enzyme that speeds up the breakdown of
carbonic acid and the formation of bicarbonate ions.
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Bicarbonate ion (HCO3-)-The from in which Carbon is transported in the
blood. (common)
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Carbaminohemoglobin(HbCO2)-Some carbons from bonds with
hemoglobin to form this. (Rare)
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Reduced hemoglobin-(HbH+)- maintains your body’s ph.
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Exhale: HbO2 separates when blood reaches the tissues where it
diffuses and releases the oxygen. The CO2 then either attaches
to the Hb and forms HbCO2 or CO2 combines with water to form
Carbonic acid (H2CO3) which dissolves into H+ and a
Bicarbonate ion (HCO3-).
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Inhale: The H+ and HCO3- combine into carbonic acid and form
water and CO2, which is catalyzed by carbonic anhydrase, and is
then expired. The O2 comes in and forms HbO2 with the
Hemoglobin.
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http://www.youtube.com/watch?v=QP8ImP6NCk8 (Hemoglobin)
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Bicarbonate Ion- HCO3- acts as a buffer so the blood will not get too
acidic.
The reaction is reversed when the blood reaches the lungs.
Bohr Shift: The more CO2 in the blood, the more acidic (low pH) the blood
becomes. Decreasing the pH causes hemoglobin to release its’ oxygen
easier. This is needed during exercise to supply the body with O2.
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Bronchitis-Infection of the Bronchi, treatable.
Pneumonia- Your lungs are filled with bacteria due to an infection,
treatable.
Pulmonary Tuberculosis- Caused by tubercle bacillus(a bacterium),
treatable.
Carbon Monoxide (CO)-poisonous because it forms strong bonds
with Hemoglobin and is difficult to remove, incurable.
Asthma- disorder caused by really sensitive airways, causes
spasms, incurable, treatable.
Emphysema-Damaged alveoli cause lack of oxygen, incurable,
harmful.
Lung Cancer=Some bad cellsTumorMetastasis GG.
Smoking=BAD