THE RESPIRATORY

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THE RESPIRATORY CARDIOVASCULAR SYSTEMS
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ANNOUNCEMENTS

• Exam 3 Is Tues. Dec 6th
• Extended office hours Mon. Dec 5th
• Room 454 BS Bldg.
• From noon 4pm
• Practice Exam posted by Wed.
• Approximate Grade Cutoffs

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CELLULAR RESPIRATION

• To Produce ATP, Animals Must Obtain O2 and
  Eliminate CO2

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CELLULAR RESPIRATION

• In the process of producing ATP, animal cell
  mitochondria consume O2 and produce CO2
• If animal is deprived of O2, death results
• If CO2 builds up in tissues, disease-like
  symptoms appear

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CELLULAR RESPIRATION
Air or Water
Blood
Mitochondria
Circulatory system
Environment
Cell
Respiratory surface
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FUNCTIONS OF RESPIRATION

• Aids in vocalizations
• Enhances return of venous blood to heart
• Rids body of excess heat and water
• Adjusts acid-base balance of body
• Gas exchange

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GAS BEHAVIOR

• Atmosphere composed of a mixture of gases
• The presence of a gas in mixture is expressed as
  partial pressure (Px)
• Gas laws explain movement of gases in respiratory
  system
• Ex Gases move from high to low
• pressure

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DALTONS LAW

• Total pressure in system is sum of individual
  partial pressures
• Ptotal Pa Pb Pc
• PATM 760mmHg

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BOYLES LAW

• Pressure (P) and volume (V) are inversely related
• (P1 V1) (P2 V2)
• As V decreases,
• P increases
• As V increases,
• P decreases

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RESPIRATORY ORGANS

• Respiratory Organs
• Provide increased surface area for gas diffusion
• Organs evolved to maximize diffusion rate
• Required by some organisms for gas exchange
• Large animals
• Animals with high metabolic rates
• Vary in form depending on animals environment

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RESPIRATORY ORGANS IN AQUATIC ENVIRONMENTS

• The Gill
• Outgrowths of
• body surface used
• for gas exchange
• Diverse structures in aquatic invertebrates
• Internal or external
• Fish have similar gill
• structure

External gills
Internal gills
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THE FISH GILL
water flows In through mouth
water flows over gills, then out

• Located at either side of head
• Consist of slits at back of mouth
• Highly vascularized
• Mechanics include
• opening and closing mouth and flap of skin
  covering gills
• Countercurrent exchange

Mouth open
Lid closed
Lid open
Mouth closed
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lid open
mouth closed
lid closed
mouth open
water flows In through mouth
FISH GILL
water flows over gills, then out
surface for gas exchange
gill arch
filament of gill
direction of water flow
direction of blood flow
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RESPIRATORY ORGANS IN DRY ENVIRONMENTS

• The Tracheal System
• Some insects have series of tubes branching
  throughout the body
• Transport air from opening
• in body surface to tissues
• Spiracles

trachea (internal tube)
spiracle (opening at body surface)
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RESPIRATORY ORGANS IN DRY ENVIRONMENTS

• The Tracheal System
• Tubes narrow to fluid filled tips
• Allow diffusion of gases into tissue
• Tubes often sandwiched between muscles
• Mechanisms for air movement
• Gas exchange can take place without circulatory
  system

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branching of trachea
trachea (internal tube)
spiracle (opening at body surface)
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RESPIRATORY ORGANS IN DRY ENVIRONMENTS

• DEMO!

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RESPIRATORY ORGANS IN DRY ENVIRONMENTS

• Lungs
• Moist, internal structures used for gas exchange
• Found in
• Amphibians
• Lizards
• Birds
• mammals
• A few fish invertebrates

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LUNGS
AMPHIBIAN (salamander still rather like fishes,
early amphibians)
AMPHIBIAN (frog only adults are adapted to
dry habitats)
MAMMAL (human adapted to dry habitats)
REPTILE (lizard adapted to dry habitats)
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MAMMALIAN RESPIRATORY ANATOMY

• Path of Air Into Lungs
• Naval cavity (oral cavity)
• Pharynx (throat)
• Larynx (voice box)
• Trachea (windpipe)
• Bronchi
• Bronchiole
• Alveoli

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THE ALVEOLI

• Tiny sacs increase surface area
• for gas exchange
• Provides interface between air and blood
  (pulmonary capillaries)
• Interface is 1/200th of thickness of a piece of
  paper!

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THE ALVEOLI
Human lungs contain approximately 150 million
alveoli!
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THE MAMMALIAN LUNG

• Mechanics of Ventilation
• Lungs are stuck to thoracic cavity wall
• As a result, lungs never deflate completely
• When thoracic cavity expands or recoils, so do
  lungs

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MECHANICS OF VENTILATION

• Mechanics of Ventilation
• Ventilation is result of
• Pressure gradients
• Mechanical events
• Muscle contraction and relaxation
• Inspiration
• An active, energy requiring event!
• Expiration
• A passive event

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INWARD BULK FLOW OF AIR
OUTWARD BULK FLOW OF AIR
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MECHANICS OF VENTILATION

• INHALATION
• Diaphragm external intercostals contract
• Diaphragm moves downward
• Rib cage lifts up and out
• Volume of thoracic cavity increases
• Pressure inside cavity decreases (below ATM)
• Gases move down partial pressure gradient, into
  lungs
• Inspiration ceases when Patm Pintrapulmonary

AIR FLOWS IN
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PRESSURES

• Atmospheric Pressure (ATM)
• Combined pressure of all atmospheric gases
• 760 mmHg at sea level
• Intrapulmonary Pressure
• Pressure inside all the alveoli

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MECHANICS OF VENTILATION

• EXHALATION
• Diaphragm and intercostals relax (recoil)
• Diaphragm moves upwards
• Rib cage moves down and in
• Volume of thoracic cavity decreases
• Pressure inside cavity increases (above ATM)
• Air flows down pressure gradient, out of lungs
• Air movement ceases when Pintrapulmonary Patm

Air flows out
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EXHALATION
INHALATION
Diaphragm
Muscles contract, volume increases, pressure
inside falls, so air flows in.
Muscles relax, volume decreases, pressure
inside rises, so air flows out.
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AIR FLOW IN LUNGS

• Factors Effecting Air Flow in Lungs
• Pressure gradients
• Resistance to flow
• (which is influenced by)
• Length of airways (constant)
• Viscosity of air (constant)
• Radius of tubes

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AIRWAY RESISTANCE

• Trachea and Bronchi
• Rigid structures
• 90 of airway resistance
• Constant sources of resistance
• Except when mucus accumulates in airways

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AIRWAY RESISTANCE

• Bronchioles
• 10 of resistance
• Source of variable resistance since airways dont
  have fixed diameter
• Bronchoconstriction
• Increased resistance to air flow
• Bronchodilation
• Decreased resistance to air flow

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GAS EXCHANGE AT THE LUNGS

• Movement of gases can be explained using partial
  pressure gradients

• In venous blood traveling past alveoli
• PO2 40 mmHg
• PCO2 46 mmHg
• In alveoli of the lungs
• PO2 100 mmHg
• PCO2 40 mmHg

O2 moves from lungs into blood CO2 moves from
venous blood into lungs ? exhaled
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GAS EXCHANGE AT THE TISSUES

• Cells of tissue
• PO2 lt 40 mmHg
• PCO2 gt 46 mmHg

Arterial blood reaching tissues PO2
100 mmHg PCO2 40 mmHg

• O2 moves into cells of tissue, where its used
  for cellular respiration
• CO2 moves from tissues into circulation, where
  its carried to lungs to be
• exhaled (as waste)

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Partial Pressure Gradients Explain Movement of
Gases Through Circulation
alveolar sacs
PO2
PCO2
cells of body tissue
more than 45
less than 40
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RESPIRATORY PIGMENTS

• O2, CO2 and H use respiratory pigments to
• move through blood
• Hemoglobin is the main
• respiratory pigment in mammals

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RESPIRATORY PIGMENTS

• Hemoglobin (Hb) is Composed of
• Four globin (protein) subunits
• Each subunit centered around heme grp.
• Each heme grp. has a central iron atom (Fe)
• Each Fe2 binds one O2 molecule

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HEMOGLOBIN

• Cooperative Binding
• Each Hb molecule can bind four O2 molecules
• Once first O2 molecule binds, Hb changes shape
• Further binding of O2 molecules more favorable

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OXYGEN TRANSPORT IN BLOOD

• 98 O2 in a given volume of
  blood is transported inside RBCs
• Bound to hemoglobin (Hb)
• Hb O2 ?? Hb-O2 (Oxyhemoglobin)
• Reversible, weak reaction

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FACTORS THAT EFFECT BINDING TO Hb

• Greater Hb-O2 Binding Takes Place Under Certain
  Conditions
• Increased PO2
• Basic pH (low CO2 and H concentration)
• Low temperatures

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OXYHEMOGLOBIN DISSOCIAITION CURVE

• Hb Binding Affinity for O2 Is
• Altered By Changes In
• pH
• Bohr Effect
• CO2 levels
• Temperature

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OXYHEMOGLOBIN DISSOCIAITION
CURVE

• Some Special Situations
• Carbon Monoxide Poisoning (CO)
• Fetal Curve
• Exercise

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CARBON DIOXIDE TRANSPORT IN BLOOD

• CO2 Transported Three Ways in Blood
• 7 dissolved in plasma
• 93 diffuses into RBC where
• 23 binds to Hb
• Carbaminohemoglobin
• Hb
  CO2 ?? Hb-CO2
• 70 converted to bicarbonate (HCO3-) protons
• 
  (H)

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CARBON DIOXIDE TRANSPORT IN BLOOD

• AT TISSUES
• Tendency towards acidic pH and/or high PCO2
• Hb releases O2
• Most CO2 diffuses into RBC where
• 23 binds to Hb
• Rest undergoes reaction

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CARBON DIOXIDE TRANSPORT IN BLOOD

• AT TISSUES
• Conversion of CO2 to bicarbonate (HCO3 ) and H
  depends on presence of carbonic anhydrase (CA)
• CA Enzyme in RBCs
• CO2 H2O??H2CO3??H HCO3-

CA
CA
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ACID BASE BALANCE

• Buildup of CO2 results in acidic blood
• Condition known as acidosis
• Loss of too much CO2 results in basic blood
• Condition known as alkalosis

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ACID BASE BALANCE

• Rate and depth of ventilation can both cause and
  repair imbalances in blood pH

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ALKALOSIS

• Hyperventilation
• Increased rate of breathing
• Results in increase intake of O2
• Also increase expiration of CO2 (decrease CO2
  in blood)
• Depletes bodys supply of CO2 (decreased H)
• Condition called alkalosis

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ACIDOSIS

• Hypoventilation
• Decrease in rate or depth of breathing
• Less CO2 exhaled
• Results in acidic blood
• Condition known as acidosis