2. Respiration
īGas exchange- also called respiration
īĄ Uptake of molecular oxygen from the environment and the
discharge of CO2
īĄ Respiration is not only exclusive to this concept; presence of
cellular respiration
īˇ Aerobic respiration
īˇ Anaerobic respiration
3. Cellular respiration
īChemical breakdown of food to yield ATP
īIs a catabolic process
īAerobic Respiration- presence of a complete redox
process due to the presence of O2
īĄ More ATP yield
īAnaerobic Respiration- absence of O2
īĄ Less ATP is produced
4. Glycolysis
īGlycolysis- process of breaking down sugar to yield
ATP
īBoth an aerobic and anaerobic process
īAnaerobic- less ATP is produced
īĄ Used by bacteria in producing energy; less efficient
īAerobic-more ATP is produced of more products
that can be broken down through oxidative
phosphorylation
9. Gas Exchange in Plants (Photosynthesis)
īCO2 is taken in while O2 is released
īFactors such as temperature, wind, humidity affect
gas exchange in plants
īDifferent plants employ different strategies in
acquiring CO2 from the environment
īPresence of C3, C4 and CAM plants
10. C3, C4 and CAM
īDifferent group of plants have different strategies in
acquiring CO2for photosynthesis
īAll pathways start from a single CO2 from the
environment
11. C3 pathway
īThe most basic among the three
īA basic 6-C compound is broken down into two 3-C
compound
ī3-C is more stable than the 6-C compound
12. C4 pathway
īC4 plants produce an intermediate 4-C compound
before converting it to the 3-C
īSpecial structure is present in producing the 4-C
compound
īĄ Bundle sheath
īEmploys spatial adaptation
13. CAM pathway
īCrassulacean acid metabolic pathway
īCommon in plants under the family Crassulaceae
īDifference to the C4 pathway is the used of temporal
adaptation
īCO2 is taken at night when the temperature is low
and the stomata are open
14.
15. Animal Respiration
īRespiration or gas exchange is necessary to support
ATP production
īMay involve both respiratory system and circulatory
system
16.
17. Animal Respiration
īRespiratory medium- oxygen source
īĄ Air for terrestrial animals
īĄ Water for aquatic animals
īˇ Oxygen in water is less concentrated compared to air
īˇ Oxygen exists in a dissolved form
īˇ Many factors affect oxygen concentration in water such as
temperature
18. Respiratory Surface
īRespiratory Surface- part of an animal where gas
exchange occurs
īGas exchange occurs entirely through diffusion
īDiffusion rate- directly proportional to the SA where
it occurs
īĄ Inversely proportional to the square to which molecules must
move
19. Respiratory Surface
īTherefore, respiratory surface have thin walls and
have a large SA
īAlso, water is needed by all living cells to maintain
its plasma membrane
īThus, respiratory surfaces are moist, dissolving first
CO2 and O2 in water
20. Respiratory Surface
īRespiratory surface structure:
īĄ Depends on the size of the organism
īĄ Depends on the organismâs habitat
īĄ Depends on its metabolic demands
īˇ Endotherm has a larger SA of respiratory surface than a similar-
sized ectotherm
21. Protists and Some Simple Animals
īGas exchange occurs at the entire length of
unicellular organisms
īSame for simple animals such as poriferans,
cnidarians and flatworms
īCell in their body is close enough to the respiratory
medium
22. More Complex Animals
īRespiratory Surface- does not have direct access to
the respiratory medium
īRespiratory surface- thin, moist epithelium
īĄ Separates the respiratory medium from blood and capillaries
23. Cutaneous Respiration
īAnimals such as earthworms and amphibians use the
entire length of their body to respire
īSkin is the respiratory organ
īShould always be moist, near bodies of water and/or
damp
īWhy?
25. The Most Common Respiratory Organs
īIf an animal lacks sufficient body SA for exchange of
gases the solution is an extensively folded respiratory
organ
īMost common are tracheal system, gills and lungs
26. Gills: Respiratory adaptations of aquatic animals
īGills- outfolding of the body suspended in water
īCan be internal or external
īShape varies
īĄ Sea stars- gills have simple shape and distributed all over the
body
īĄ Annelids- flaplike gills that extended from each segment or
long feathery gills found on the head or tail
īĄ Clams, fish- gills are found in one local region
28. Water as a respiratory medium
īAdvantage
īĄ Cell membranes of respiratory surface are always moist
īDisadvantage
īĄ Less concentration of O2
īˇ High temp, high salinity= low O2 conc
29. Ventilation
īProcess of increasing contact between the
respiratory medium and respiratory surface
īSolution to the low O2 conc in water
īWithout ventilation a region of high O2 conc and
high CO2 conc can occur
30. Ventilation
īCrayfish and lobster- use paddlelike appendages in
driving water over the gills
īFish- gills are ventilated through the passage of
water through the mouth and to the gills
īĄ May require large amount of energy
31. Fish Ventilation
īHigh volume of water is needed to ventilate the gills
thereby increasing the energy used
īArrangement of gill capillaries decrease energy use
īBlood moves opposite the direction of the water
īThe process is called countercurrent exchange
32. Countercurrent exchange
īThere exists a diffusion gradient that favors the
movement of O2 from water to blood in the
capillaries
īVery efficient: can remove up to 80% of O2 dissolved
in water
īIs also important in temperature regulation and
other physiological processes
35. Terrestrial Respiratory Structures: Tracheal
Systems and Lungs
īAir as a respiratory medium
īĄ High concentration of O2
īĄ Diffusion of O2 and CO2 is faster, ventilation is not much
needed
īĄ Partial pressure of gases dictates the rapid transfer of the two
gases involve
36. Air as a respiratory medium
īĄ When ventilation is needed, less energy is needed to pump air
īˇ Air is much lighter than water
īˇ Less volume of air is needed to obtain equal amount of O2 from
H2O
īĄ Disadvantage: Respiratory epithelium should always be moist
īˇ Solution: highly folded respiratory structure
38. Tracheal Systems
īMade up of air tubes that branch throughout the
body; not folded
īLargest tubes: called tracheae; open to the outside
īSpiracles- outside opening
īTracheoles: finer branch of tracheae, directly
connected to cell surface
39. Tracheal System
īGas exchange is through diffusion across the moist
epithelium at the terminal ends of the system
īCirculatory system is not involved
īDiffusion is enough to support cellular respiration
īLarger insects with higher energy demands ventilate
through rhythmic body movements
40. Tracheal System
īFlying insect has high metabolic demand
īWings act as bellows in pumping air through the
tracheal system
īFlight muscle cells are packed with mitochondria,
tracheal tubes supply ample amount of O2
41. Lungs
īConfined to one location
īGap between respiratory medium and transport
tissue is bridged by the circulatory system
īHave dense net of capillaries under the epithelium
that forms the respiratory surface
īEvolved in spiders, terrestrial snails, vertebrates
44. Lungs
īAmphibians small lungs, rely mainly through skin
īReptiles, birds, mammals rely mainly on their lungs
īTurtles: exception: supplement lung breathing
through epithelial surface through the mouth and
anus
īSome fish have lungs: lungfishes
īSize and complexity of lungs: correlated to an
animalâs metabolic rate
46. Mammalian Respiration
īMammalian Lung Structure: spongy, honeycombed
with moist epithelium
īBranching ducts convey air to lungs
īAir enters through the nostrils
īFiltered by hairs and cilia
īAir is warmed, humidified and sampled for odors
47. Mammalian Respiration
īAir moves from the nasal passage to the pharynx and
then to the larynx
īThe act of swallowing moves the larynx upward
tipping the epiglottis over the glottis
īGlottis- opening of the windpipe
īLarynx- adapted as voicebox
īSyrinx- vocal organ of birds
īĄ Found at the base of the trachea
īĄ Produce sound without the vocal chords found in mammals
48. Mammalian Respiration
īSound: produced when voluntary muscles stretch
and vibrate during the process
īHigh-pitched sound: tight, rapid vibration
īLow-pitched sound: less tense, slow vibration
49. Mammalian Respiration
īFrom the trachea: forks into two bronchi
īShaped like an inverted tree
īFiner branches are called bronchioles
īEpithelial lining is covered with mucus and beating
cilia
īMucus traps contaminant, while, the cilia moves this
to the pharynx where it can be swallowed
51. Ventilating the Lungs
īTerrestrial organisms also rely on ventilation
īĄ Maintains high O2 and low CO2 at the gas exchange surface
īProcess of ventilating the lungs is called breathing
īĄ Breathing- alternate process of inhalation and exhalation
īTwo types
īĄ Positive pressure breathing
īĄ Negative pressure breathing
52. Positive pressure breathing
īFrogs ventilate their lungs through positive pressure
breathing
īIn a breathing cycle:
īĄ Muscles lower the oral cavity floor (becomes enlarge and draws
air through the nostrils)
īĄ Closing of the mouth and nostril (oral cavity floor rises and
forces air into the trachea)
īĄ Air is force out/exhaled (elastic recoil of lungs and muscular
contraction of chest)
53. Negative Pressure Breathing
īWorks like a suction pump (air is pulled rather than
pushed)
īNegative pressure is produced due to action of chest
muscle
īĄ Relaxation of chest muscle pushes air; contraction pulls air in
īExpansion of lungs is possible due to its double-
walled sac
īĄ Inner sac adheres to the lungs
īĄ Outer sac adheres to the chest cavity walls
īĄ Space in between is filled with fluid
54. Surface Tension
īSurface tension- responsible for the behavior of the
lungs
īThe lungs slide past each other but cannot be pulled
separately
īThe surface tension couples the movement of the
lungs to the movement of the rib cage
55. Breathing
īInhalation- Contraction of muscles (rib muscles and
diaphragm)
īĄ Increases volume of chest cavity
īĄ Decreases alveolar air pressure
īĄ Rib cage expands (ribs pulled upward; breastbone pushed
forward)
īGas moves from an area of higher partial pressure to
low partial pressure
īAir moves from the URT to alveoli of LRT
56. Breathing
īExhalation- relaxation of muscles
īĄ Rib muscles and diaphragm relax
īĄ Lung volume is reduced
īĄ Inc in alveolar air pressure
īShallow breathing- rib muscle and diaphragm are
responsible
īDeep breathing- muscles of the back, neck and chest
are responsible
īSome animals employ visceral pump- adds to the
piston like action of the diaphragm
57. Breathing
īTidal volume- volume of air inhaled and exhaled in
each breath
īĄ Ave human tidal volume is 500 ml
īVital capacity- max tidal volume during forced
breathing
īĄ 3.4 L female; 4.8 L male
īResidual volume- air left in the lungs during
exhalation
īĄ Lungs hold more air than the vital capacity
58. Breathing
īAge or disease decrease the elasticity of the lungs
īĄ Residual volume increases at the expense of vital capacity
īĄ Max O2 conc in the alveoli decreases
īĄ Gas exchange efficiency is decreased
59. Ventilation in birds
īMore complex than mammals
īPresence of air sacs
īDo not function directly in gas exchange; acts as
bellows
īLungs and air sacs- ventilated during breathing
īPresence of parabronchi rather than alveoli
īĄ Air moves in one direction
īĄ Air is completely exchanged
īĄ Max O2 conc is higher in birds than in mammals
60. Regulation of Breathing
īBreathing â controlled by the medulla oblonagata
and the pons
īThis ensures that respiration is coordinated with
circulation
īMedulla oblongata- major control center of
breathing
īControl center in the pons works synergistic with the
control center of the medulla oblongata
61. Regulation of Breathing
īNegative feedback- helps maintain breathing
īStretch sensors- found in the lungs send impulses to
the medulla (inhibits the breathing control center)
īMedulla- monitors CO2 level of the blood
īĄ CO2 conc is detected through slight change in blood and tissue
fluid pH
īĄ Carbonic acid lowers pH
īĄ Drop in pH increases rate of rate and depth of breathing
62. Oxygen Concentration
īOxygen Concentration- have little effect to breathing
control center
īSevere depression of O2 conc stimulates O2 sensors
in the aorta and carotid arteries to send alarm
signals
īBreathing rate is increased by the control centers
īIncrease in CO2 conc is a good indicator of decrease
in O2 conc
63. Hyperventilation
īExcessive deep, rapid breathing inc CO2 conc in the
blood
īBreathing centers temporarily stops working
īImpulses to the rib muscles and diaphragm are
inhibited
īBreathing resumes when CO2 conc inc
64. Different Factors Affect Breathing
īNervous and chemical signals affects rate and depth
of breathing
īMost efficient if it works in tandem with the
circulatory system
īE.g. Exercise: inc cardiac output-inc breathing rate
īĄ Enhances O2 uptake and CO2 removal
65. Respiratory pigments: transports gases and
buffers the blood
īLow solubility of O2- problem if O2 is transported
via the circulatory system
īĄ E.g. Normal human consume 2L of O2 per minute
īĄ Only 4.5 ml of O2 can dissolve into a L of blood in the lungs
īĄ If 80% dissolved O2 would be delivered, 500 L of blood should
be pumped per minute (a ton per 2 mins)
īĄ Unrealistic!!!!
īĄ Special respiratory pigments are used
66. Respiratory Pigments
īTransports O2 instead of dissolving into a solution
īInc O2 that can be carried in the blood (~200 mL O2
per L in mammalian blood)
īDecreases cardiac output (20-25 L per min)
67. Respiratory Pigments
īBinds O2 reversibly
īĄ Loads O2 from respiratory organ; unloads in other parts of the
body
īHemocyanin- found in hemolymph of arthropods
and many mollusks
īCopper- acts as the oxygen-binding component
īHemoglobin- respiratory pigment of all vertebrates
68. Hemoglobin
īConsists of four heme subunits
īIron acts as the binding site of O2
īLoading and unloading of O2 depends on the
property of each subunits called cooperativity
īAffinity is dependent to the conformation of each
subunit
īĄ Binding of one O2 molecule to one subunit induces the inc in
affinity of other subunits
īĄ Unloading of one O2 molecule decreases the affinity of other
subunits
69. Dissociation Curves of Gases
īCooperativity of heme subunits is shown in a
dissociation curve
īSteep slope- slight change in Po2causes substantial
loading or unloading of O2
īBecause of cooperativity, slight drop in Po2causes a
relatively large inc in O2 to be unloaded
70.
71. The Bohr Shift
īA shift to the right of the oxygen hemoglobin
dissociation curve
īBrought about by increase CO2 or low blood pH
īDecrease in affinity of hemoglobin to O2
īGreater efficiency of O2 unloading
72. Carbon Dioxide transport
īHemoglobin- also transports CO2 not only O2
īĄ Assists in buffering the blood
īBlood released by respiring cells:
īĄ 7%- transported in the solution of blood plasma
īĄ 23% - bind to amino group of hemoglobin
īĄ 70% - transported in the blood in the form of carbonic acid
73. Carbon Dioxide Transport
īCO2- converted in the red blood cells into
bicarbonate
īĄ Reacts first with water to form carbonic acid (carbonic
anhydrase)
īĄ Dissociates into H+
and bicarbonate
īĄ H ions- attach to different sites in the Hb and other proteins
īĄ Bicarbonate ions- diffuse into the plasma
īĄ Movement of blood through the lungs reverses the process
favoring the conversion of bicarbonate to CO2
74. Deep-diving air breathers
īStockpile oxygen- O2 is reserved in the blood and
muscles (e.g. Weddell seal)
īHigh percentage of myoglobin
īDec heart rate and O2 consumption
ī20-min dive- O2 in myoglobin is used up
īĄ Energy is erived from fermentation rather than respiration