GAS EXCHANGE

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GAS EXCHANGE
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GAS EXCHANGE

• As you recall, all the cells of organisms carry
  out aerobic cellular respiration in order to
  release energy from food.
• Remember?
• C6H12O6 O2 CO2 H2O
  ATP
• (glucose) (oxygen) (carbon
  dioxide) (water) (energy)

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C6H12O6 O2 CO2 H2O
ATP(glucose) (oxygen)
(carbon dioxide) (water) (energy)

• Oxygen is needed for this process.
• Carbon dioxide is released from this system.
• To survive, organisms must take in oxygen and
  expel carbon dioxide from their bodies.
• This is accomplished through a process called
• GAS EXCHANGE

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• Review of the eight life processes
• Respiration
• Reproduction
• Regulation
• Growth
• Excretion
• Nutrition
• Transport
• Synthesis

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VOCABULARY

• Respiration the process of releasing chemical
  energy stored in foods
• Gas exchange the physical methods that organisms
  have for obtaining oxygen from their surroundings
  and removing excess carbon dioxide
• Respiratory surface surface through which gas
  exchange occurs between an organism and its
  environment

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Characteristics of a Respiratory Surface

1. Thin walled for diffusion
2. Must be moist (oxygen and carbon dioxide are
   dissolved in solution)
3. Must be in contact with the source of oxygen
4. Must be in contact with the transport system so
   gases can get to all cells

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Gas exchange occurs by diffusion

• As cells use up the oxygen from cellular
  respiration, the concentration of oxygen in the
  cell is low
• The capillaries carry oxygen rich blood from the
  respiratory surface so the concentration of
  oxygen in the blood is high.
• Therefore oxygen diffuses from the blood to the
  cells (high to low concentration)

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Therefore oxygen diffuses from the blood to the
cells (high to low concentration)
O2
O2
O2
O2
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Gas exchange occurs by diffusion

• The cells build up carbon dioxide as a waste
  product of cellular respiration
• The blood has a low concentration of carbon
  dioxide
• Therefore the carbon dioxide diffused from the
  cells to the blood
• (high to low concentration)

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Therefore the carbon dioxide diffused from the
cells to the blood (high to low concentration)
CO2
CO2
CO2
CO2
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The greater the surface area of the respiratory
surface, the greater the rate of gas exchange.
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Protists have direct exchange between the cell
and the environment

• Multicellular organisms have specialized organs
  and organ systems for gas exchange.

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PROTISTSDiffusion directly through the cell
membrane
CO2
CO2
o2
o2
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HYDRA

• Diffusion directly from the environment to the
  cells of the gastrovascular cavity and into the
  endoderm
• Diffusion directly from the fresh water into the
  cells of the ectoderm

CO2
O2
CO2
O2
O2
CO2
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GRASSHOPPER

• Blood does not carry gases
• System of branching tubes carry air to the cells
• Air enters 10 pair of openings called spiracles
• Tracheal tubes branch into smaller tubes and into
  fluid filled ends where there can be contact with
  the body cells
• Here oxygen and carbon dioxide can diffuse
• Air is pumped in and out of tracheal system by
  muscle contraction
• Air sacs (connected to tubes) help pump air in
  and out

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GRASSHOPPER
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EARTHWORM

• Skin is the respiratory surface
• Skin is thin and specialized cells secrete mucus
• Just beneath the skin is a large number of
  capillaries
• Capillaries pick up oxygen and carry it to all
  the cells
• Oxygen is deposited and carbon dioxide gets
  picked up and returned to the skin
• If the skin dries out they suffocate
• If there is flooding rain they drown

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EARTHWORM
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MULTICELLED ANIMALS

• air breathers (air is 21 oxygen)
• must keep the respiratory surfaces moist
• must have respiratory surfaces extending inside
  to protect surfaces and decrease water loss by
  evaporation
• most have respiratory pigments in the blood to
  allow the blood to carry more gases than water
• hemoglobin is the most common respiratory pigment

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MULTICELLED ANIMALS

• water breathers (water has less than 1 oxygen)
• less oxygen available and oxygen diffuses more
  slowly in water
• therefore large amounts of water must pass over
  the respiratory surface

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GAS EXCHANGE IN GILLS

• Gas exchange organ of water living organisms are
  gills
• As water passes over, oxygen diffuses across to
  the blood vessels
• A great deal of water must pass over them

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ORGANISM ORGAN WHERE GAS EXCHANGE TAKES PLACE ADAPTATIONS OR SPECIALIZED STRUCTURES FUNCTION OF SPECIAL STRUCTURES
PROTISTS (AMOEBA and PARAMECIUM)
HYDRA
EARTHWORM
GRASSHOPPER
Cell membrane
none
Endoderm to gastrovascular (cell
membrane) Ectoderm to fresh water
none
Cell secrete mucus to keep skin moist
Specialized cells Blood
Skin
Hemoglobin so blood carries more O2 than water
Where diffusion of gases occurs
Spiracles to tracheal tubes to
air sacs
Air sacs
Body movements squeeze air sacs and help move air
in and out of the body
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General Structure

• Lungs fill a large part of the chest cavity
• Chest and abdomen are separated by the diaphragm
• Lungs are enclosed by the pleura

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Structures

• The Nose
• Air enters through the nostrils
• Mucous membrane and cilia trap small particles of
  bacteria and dust
• Blood vessels are close to the surface
• The nose
• Filters air
• Moistens air
• Warms air

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The Pharynx

• The throat common passage from the nose and the
  mouth

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The Larynx

• The voice box is made of cartilage
• Contains two pair of vocal cords
• Controlled vibrations make a variety of sounds
• The epiglottis blocks the larynx from food during
  swallowing

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The Trachea

• 12 cm long and 2.5 cm wide
• Kept open by horseshoe shaped rings of cartilage
• Ciliated mucous membranes push particles up into
  the throat
• Smoking stops cilia from moving and increases
  production of mucous

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Bronchi

• Two cartilage ringed tubes that branch off the
  trachea to the lungs
• Cilia lines the tubes
• Branch into the bronchial tubes in the lungs

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Bronchioles (tiny tubes)

• The smallest branches of the bronchial tubes that
  lead to the alveoli

BRONCHIOLE
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The Alveoli

• Tiny air chambers one cell thick
• Walls are moist and surrounded by capillaries
• Site of gas exchange or external respiration
• 300,000,000 alveoli
• 70 square meters of surface area (40 xs the
  surface area of the skin)

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Fill in the diagram on page 10. in the packet

1. Nose
2. Nasal passage
3. Pharynx
4. Epiglottis
5. Larynx
6. Esophagus
7. Trachea
8. Lung (or pleura)
9. Pleura
10. Bronchi

1. Bronchioles
2. Diaphragm
3. Alveoli (air sacs)
4. Capillaries (blood vessels)
5. Capillary beds
6. Bronchioles
7. Alveoli

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RESPIRATORY SYSTEM PARTS AND FUNCTIONS

• Nose
• Air enters
• Hair filters out dust, dirt, and bacteria
• Nasal chamber
• Warms and moistens air
• Pharynx (throat)
• Passage to the trachea
• Epiglottis
• Flap that closes over trachea
• Keeps food and liquid out of the lungs
• Esophagus
• Tube to the stomach

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RESPIRATORY SYSTEM PARTS AND FUNCTIONS

• Trachea (wind pipe)
• Tube that carries air from the pharynx to the
  bronchi
• Ciliated and has cartilage rings
• Bronchi (2 bronchi)
• Short tubes from the trachea into the right and
  left lungs
• Bronchioles
• Tiny tubes
• Carry air from the bronchi to the alveoli
• Lung
• Main organ of respiration
• Contains tiny air sacs (alveoli) and capillaries

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RESPIRATORY SYSTEM PARTS AND FUNCTIONS

• Diaphragm
• Muscle below the chest cavity
• Moves down with inhalation (contracts)
• Moves up with exhalation (relaxes)
• Capillaries
• Surrounds the alveoli
• SITE OF GAS EXCHANGE
• Alveoli
• Air sacs
• SITE OF GAS EXCHANGE

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• THE FOUR PHASES
• OF
• HUMAN RESPIRATION

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THE FOUR PHASES OF HUMAN RESPIRATION

• I. BREATHING
• II. EXTERNAL RESPIRATION
• III. INTERNAL RESPIRATION
• IV. CELLULAR RESPIRATION

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I. BREATHING

• Movement of air into and out of the lungs
• Inhalation
• Ribs up and out
• Diaphragm pulls down
• Air rushes in
• Exhalation
• Ribs relax and drop down
• Diaphragm moves up
• Air pushed out
• No muscles in the lungs, they are elastic and air
  is moved due to pressure changes
• Breathing controlled by
• Respiratory center in the brain
• Sensors in the aorta and other arteries that
  sense gas levels

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II. EXTERNAL RESPIRATION

• Exchange of oxygen and carbon dioxide between
  lungs (alveoli) and blood
• Air flow moves with the concentration gradient

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III. INTERNAL RESPIRATION

• Exchange of oxygen and carbon dioxide between
  blood and tissues (body cells)
• Exchange by diffusion

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Exchange of oxygen and carbon dioxide between
blood and tissues (body cells)Exchange by
diffusion
III. INTERNAL RESPIRATION
O2
O2
CO2
CO2
O2
O2
CO2
CO2
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IV. CELLULAR RESPIRATION

• Using oxygen, the cells release energy (ATP) from
  food (glucose)

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TRANSPORT OF GASES IN BLOOD

• Oxygenated blood must be transported from the
  lungs to all the cells of the body

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TRANSPORT OF OXYGEN

• Hemoglobin (Hb) carries O2 on red blood cells
• Hb O2 oxyhemoglobin (HbO2) with a loose bond
• CO has a stronger bond with hemoglobin than O2
  therefore cigarette smokers blood carries less
  O2 than non-smokers blood

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TRANSPORT OF CARBON DIOXIDE

• 70 carried by water
• CO2 H2O H2CO3
• H2CO3 H HCO3
• 20 carried by hemoglobin
• Hb CO2 HbCO2
• 10 dissolves in plasma

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PHASES OF RESPIRATION
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• BREATHING AIR ? EXT. RESP ? TRANSPORT ? INT.
  RESP ? CELL RESP
• ALVEOLI CAPILLARY CAPILLARY
  TISSUES
• O2 in / CO2 out BLOOD AEROBIC RESP

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BREATHING AIR ? O2 in / CO2 out
EXT. RESP ? ALVEOLI CAPILLARY
TRANSPORT ?
INT. RESP ? CAPILLARY TISSUES
? CELLULAR RESPIRATION
BLOOD FLOW
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BREATHING
INHALATION
EXHALATION
INHALE EXHALE DIAPHRAGM C
ONTRACTS / MOVES DOWN RELAXES / MOVES UP RIB
CAGE UP AND OUT DOWN AND IN SIZE OF CHEST
CAVITY INCREASES DECREASES AIR MOVEMENT INTO
LUNGS OUT OF LUNGS PRESSURE LOWER IN
LUNGS HIGHER IN LUNGS
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DISEASES OF THE RESPIRATORY SYSTEM
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ASTHMA

• Chronic inflammation of the bronchi
• Response to irritants with shortness of breath,
  coughing, and wheezing
• Treated with medications and inhalers

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Asthma
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BRONCHITIS

• Inflammation of the lining of the lower
  respiratory passages (bronchi and bronchioles)
• Mucus production increases and impairs breathing
• Risk of lung infection (pneumonia) increases

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Chronic Bronchitis
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EMPHYSEMA

• Alveoli enlarge as the walls between the alveoli
  break down (airways collapse)
• Chronic inflammation causes lungs to lose
  elasticity
• It takes a large amount of energy just to breath
• Over inflation of the lungs leads to a
  permanently expanded barrel chest

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emphysema lungs
A normal lung
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PNEUMONIA

• Infection in the lungs
• Caused by
• Bacteria (treatable with antibiotics)
• Virus
• fungus

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Pneumonia
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LUNG CANCER

• Accounts for 1/3 of all cancer deaths in the
  United States
• Second-hand smoke is the third leading cause of
  preventable death in America
• Many have no symptoms in the early stages
• Increased incidence associated with smoking (8
  out of 10 lung cancers are caused by smoking)

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Lung Cancer