Transcript Respiration - mcdowellscience

Respiration
Cambridge Biology
Let’s watch a video! But first…
• What is “respiration”?
• NOT “breathing”!
– This is the action of your lungs inhaling and
exhaling air; “ventilation.”
• Respiration = the process of breaking down
glucose to use for ENERGY
– If glucose were gasoline, then respiration would
be the engine running in your car.
• (you can’t go anywhere if the engine’s not running!)
One more thing before video:
Aerobic Respiration
Anaerobic Respiration
• Using O2 to break down
glucose
• NOT using O2
• “without air”
• “with air” ~ “with oxygen”
Aerobic Respiration
• Using O2 to break down Glucose to release
Energy for cells.
• Glucose + Oxygen  Carbon Dioxide + Water + Energy
• C6H12O6 + 6O2  6CO2 + 6H20 + Energy
But where did the Glucose come
from?
• You ate it!
• Food breaks down into glucose molecules in
the stomach (Digestion).
• These glucose molecules enter your blood in
the small intestine (Absorption).
• Blood carries the glucose molecules to
individual cells (Circulation).
But where did the Oxygen come from?
• You inhaled it (breathing).
• In your lungs, your blood takes in O2 and lets
out CO2.
• This is called Gas Exchange.
– (you’re exchanging one gas for another)
• You need LOTS of surface area to exchange
gasses quickly enough.
– Lungs have about 70 square meters of S.A.
• (about the size of a tennis court!)
How do you get so much Surface Area
in the Lungs?
• Alveoli: very tiny sacs about 0.25 mm across
• Alveoli are where Gas Exchange occurs
– Gas can only exchange through a small distance
– Blood capillary is right next to alveolus
– Gas moves through capillary wall and alveolus wall
• Distance of 0.001 mm
Alveolar Gas Exchange
Alveolar Gas Exchange
Alveolar Gas Exchange
Alveolar Gas Exchange
Pathway of Inhaled Air
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Mouth/nose
Trachea
R + L Bronchi
Bronchioles
Alveoli
Pathway of Oxygen
• Alveoli
• Pulmonary (Lung) Capillaries
• Pulmonary Vein
– The blood in this Vein is Oxygenated (!!)
– It is moving AWAY from the Lungs, but TOWARD the
Heart.
• Heart  Aorta  Arteries  Arterioles 
Capillaries  Body Cells
• Respiration (conversion to Energy) happens in the
Cell
– Now the Cell has plenty of Energy!
Pathway of Oxygen
Pathway of Oxygen
Pathway of Oxygen
Question Time!
• Where does the blood in Pulmonary Vein come
from? (Hint: it is Oxygenated)
– The Lungs
• Where is it going?
– The Heart
• Where does the blood in the Pulmonary Artery
come from? (Hint: it is Deoxygenated)
– The Heart
• Where is it going?
– The Lung
Oxygen Content of Air
Inspired Air
Expired Air
Oxygen
21.00 %
16.00 %
Carbon Dioxide
00.04 %
04.00 %
Nitrogen
78.00 %
78.00 %
Moisture Content
Variable
High
Temperature
Variable
High
How do we Breathe?
• Ventilation:
– Moving fresh air into lungs
– Moving “used” air out of lungs
• Ventilation happens because of changes in
pressure that our body creates by contracting
and relaxing muscles:
– Diaphragm
– Intercostals (“between ribs”)
• Pleural membranes keep everything airtight.
Pleural Cavity and Breathing Muscles
Lungs & Diaphragm
Inhalation
• Diaphragm contracts
– It moves DOWN because of its unique shape
• Intercostal muscles contract
– Making the ribs move UP
• Volume increases inside pleural cavity.
• Pressure decreases; creates a vacuum!
• Air from outside flows into the Lungs.
Diaphragm
Inspiration
Inspiration
Exhalation
• Diaphragm relaxes
– Now it moves back UP
• Intercostals also relax
– Ribs can move back DOWN
• Volume DECREASES
• Pressure INCREASES – like a full balloon!
• Air moves back out of the Lungs.
Inspiration / Expiration
Air Pressure in Model Lung
How do Other Animals Breathe?
• Diffusion:
– Small animals with no ventilation structure
• Gills:
– Fish
• Lungs:
– Mammals
– Birds
– Herpetiles (Reptiles + Amphibians)
• Skin:
– Amphibians
• Tracheae:
– Insects
Diffusion
• O2 and CO2 diffuse in and out of the organism
without a specialized organ
• Small size
• Large surface area
Gills
• Structures on fish that allow gas exchange
with water.
• Fish “pump” water over and through gills.
Gills in Respiration
Gills in Respiration
Lungs
• Allow gas exchange with air.
• Bird lungs are structured to allow maximum
gas exchange
– Air moves through the lungs, not in-and-out like in
mammals
Bird Respiratory System
Bird Respiration
Lungs + Skin
Tracheae
• Network of branching tubes in insects.
• Gas exchange occurs directly between
tracheae and respiring cells.
– No blood involved!
• Insects breathe in and out through spiracles.
Insect Anatomy
Insect Tracheae
Respiration WITHOUT Oxygen
• “Anaerobic Respiration”
• Many organisms respire anaerobically.
– Even humans! (sometimes)
• But Aerobic Respiration is more efficient
– It yields about 19 times as much energy from one
glucose molecule as Anaer. Resp.
Anaerobic Respiration in Yeast
• Yeast is a single-celled fungus.
• Breaks down Glucose into Ethanol and CO2
• Can be used to make alcoholic drinks and
bread
– Ethanol = alcohol
– CO2 bubbles = bread rises
Yeast: Anaerobic Respiration
Anaerobic Respiration in Humans
• Only when our muscles run out of O2
– During strenuous exercise
• We break down glucose into lactic acid to
release useable energy.
• Lactic acid is toxic!
• So, we can’t do this very long.
How do your Lungs stay Clean?
• The air we inhale contains dust and bacteria.
• Lung passages are lined with goblet cells and
cilia, which keep unwanted particles from
getting to the alveoli.
Goblet Cells + Cilia
• Goblet cells secrete mucus that traps dust and
bacteria.
• Cilia are tiny hairs that sweep the mucus up
toward the back of your throat.
• Then you swallow the mucus, along with
everything else!
– Bacteria die in your stomach’s acid and enzymes.
Goblet Cells and Cilia
Cigarette Smoke: Tar
• Damages DNA in lung cells
• This can result in lung cancer
– Lung cells divide uncontrollably into a mass called
a tumor.
• If Tar (or other harmful chemicals) get into the
blood, they can be carried to other parts of
the body and cause other types of cancer.
Cigarette Smoke: Tar
• Tar can paralyze or destroy Cilia
– Now they can’t sweep mucus out of the bronchial
tubes!
• Tar makes Goblet Cells excrete more mucus
– Mucus slides down into lungs, creating a breeding
ground for bacteria
• Excessive coughing damages lining of tubes
– Bronchitis: inflammation of bronchi
• Damage to alveolar walls hinders gas exchange
– Emphysema: difficulty getting enough O2
Cigarette Smoke
• Also contains Carbon Monoxide (CO)
• CO binds to hemoglobin in blood (just like O2)
– But it never comes off!
– So that means less places in the blood for O2
• Smokers often run short of O2 during
energetic activity.
Air Pollution: Particles
• Coarse
– 1-10 μm across
– Filtered out in airways and bronchial tubes
• Fine
– 0.1 to 1 μm across
– Not filtered out; can deposit in alveoli
• Ultrafine
– 0 to 0.1 μm across
– Can penetrate cell walls, enter bloodstream, and
travel to your brain!
Particles
Air Pollution: Sulfur Dioxide
• Gas produced from burning fossil fuels
– (industry + automobiles)
• Mixes with water and becomes sulfuric acid
(acid rain):
– SO2 + H2O  H2SO4
• SO2 turns to acid when enters your lungs and
can damage the lining and alveoli.
So… what should you do to protect
your Lungs?
• Don’t smoke!
• Try not to breathe polluted air.