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AP BIOLOGY

VIEWS: 11 PAGES: 5

									AP Biology                                             Name: _________________________________
Ch. 42 – Gas Exchange

Why do we need a respiratory system?
Need ______ in
     for aerobic cellular respiration
             makes __________________!
Need ______ out
     waste product from ___________________________

What is Gas Exchange?
__________ & _________ exchange between ____________________ & ____________________
What is REQUIRED for Gas Exchange Organs?

_______________________________ MEMBRANES
_______________________________ SURFACE AREA
Also, are OFTEN associated with an intimate connection to a ________________________ system
     LOTS of __________________ with ___________________ to pick up O2 and drop off CO2

Why Moist Membranes??
Moisture maintains __________________________________ structure
Gases _________________ only when _______________________ in ____________________________
Why large surface area?
_____________________________ rate of gas exchange
     CO2 & O2 move across cell membrane by __________________________________
           rate of ____________________ is proportional to _____________________________

Gas exchange surfaces occur in many forms…
    Single cell
    Amphibian
    Echinoderm
    Insect
    Fish
    Land Vertebrate


WATER TO LAND TRANSITION
VERY important to watch…
PROBLEMS with gas exchange on land that do not exist in water (and vice versa…)
     Especially in VERTEBRATES…
WATER vs. AIR as _____________________________________________
Water
     Holds __________________ oxygen than air
     Harder to _____________________________
            Movement across the respiratory surface
            Water is __________________________ than air
     Does keep respiratory organs nice and ____________________, though!
Air
     Holds ___________________ oxygen than water
     __________________________ to ventilate
     __________________________________ the respiratory surface!!

Organisms living in _____________________…
Have no worries about keeping respiratory surface _____________________
     As a result, respiratory organs are commonly found on the ___________________ of the body
DO have worries about
     extracting enough oxygen from water
             ______________________________in fish maximizes oxygen extracted from environment…
     Moving _____________________ water across respiratory surface

Organisms living on _______________________…
MUST find solution to keeping respiratory surface ______________________
     Solution is to keep organs protected from air on the________________________ of the body
     Also bathed in ________________________________
No worries about
     available oxygen
     ventilation

Evolution of gas exchange structures
Aquatic organisms
___________________systems with lots of _______________________ __________________ to aquatic
environment

Terrestrial organisms
_____________________ , __________________________ respiratory tissues with lots of ________________

Gas Exchange in Water: _____________________
    _______________________ epithelium – ________________ for gases to diffuse through
    Highly _____________________________ - __________________________ surface area
    Lots of _________________________________

Counter current exchange system
     ______________carrying gas flows in one direction, ____________ flows in ______________ direction

How counter current exchange works
     Blood & water flow in opposite directions
            maintains ___________________________ over whole length of gill capillary
            maximizing _______ transfer from ________________ to ___________________

Gas Exchange on Land
Advantages of terrestrial life
      air has many advantages over water

               ___________________ concentration of O2
              O2 & CO2 diffuse much ____________________ through air
              respiratory surfaces exposed to air do not have to be _____________ as thoroughly as gills
              air is much ___________________ than water & therefore much easier to pump
              expend ________________________ energy moving air in & out
Disadvantages
      keeping large respiratory surface moist causes high ______________________________
             reduce water loss by keeping lungs___________________________

Terrestrial adaptations

In ___________________________ - _____________________ tubes and spiracles
      Trachea - air _______________ branching throughout body
      ______________________ – openings to environment
      Gas exchanged by diffusion across moist cells directly lining ends of the tracheae
             _______ connection to open _________________________ system

In Vertebrates - ______________________

______________ – hollow grape-like air sacs
Gas exchange across ________ epithelium of millions of 2alveoli

       total surface area in humans ~_______________ m

______________________________ breathing
Breathing due to changing pressures in lungs
air flows from _________________pressure to __________________ pressure - _____________ flow

_____________________air instead of pushing it

Diaphragm _______________, increases___________________ ; decreases ___________________, air

 rushes _________.

Mechanics of breathing
Air enters nostrils
      ______________________ by hairs, warmed & humidified
      sampled for odors
________________  _______________________  _______________________ (vocal cords) 
________________________ (windpipe)  ________________________  _________________________
___________________________________ (_____________________)
Epithelial lining covered by ______________________ & thin film of ___________________________
      mucus traps ____________________, ____________________, particulates
beating cilia move mucus _______________________________ to pharynx, where it is _________________



_____________________________breathing control
________________________sets rhythm & ________________ moderates it
coordinate respiratory, cardiovascular systems & metabolic demands
Nerve sensors in walls of aorta & carotid arteries in neck detect ______ & _______ in blood
Medulla monitors blood
Monitors ____________ level of blood
      measures __________ of blood
      CO2 + H2O  ___________________ (______________________ _______________)
            if pH ____________________ then _________________________ depth & rate of breathing &
             excess CO2 is ___________________________ in exhaled air

Breathing and Homeostasis
Homeostasis
     keeping the internal environment of the body _______________________________
     need to balance O2 in and CO2 out
     need to balance energy (ATP) production
Exercise
     breathe faster
            need more ATP

             bring in more O2 & remove more CO2
Disease
     poor lung or heart function = breathe faster
            need to work harder to bring in O2 & remove CO2

Diffusion of gases
________________________________ & _____________________drives movement of gases into & out of
blood at both lungs & body tissue

Hemoglobin
Why use a carrier molecule?
    O2 _____________ _________________ enough in H2O for animal needs
    blood alone could ____________ provide enough O2 to animal cells
    __________________________ in insects = ______________________ (bluish/greenish)
    __________________________ in vertebrates = ______________________ (reddish)

________________________________ binds O2
      ______________________ O2 at _____________ or __________________ &
      _____________________ at ________________________________

Cooperativity in Hemoglobin
Binding O2
      binding of O2 to _______ subunit causes __________________________ to other subunits
      _______________________________ change
              ______________________________ attraction to O2
Releasing O2
      when _______ subunit ____________________ O2, causes ____________________to other subunits
      ___________________________change

             ________________________________ attraction to O2
Bohr Shift – encouraging oxygen to be released when needed….

      __________ in pH _________________ affinity of Hb for O2
      active tissue (producing ___________) lowers blood _______& induces Hb to release more ______
   
      ____________________ in temperature lowers affinity of Hb for O2
      active muscle produces _____________

Transporting CO2 in blood
Dissolved in ___________________________ as _________________________________ ion
Releasing CO2 from blood at lungs
       ___________________ CO2 ________________ at lungs allows CO2 to diffuse _________ of blood

       ________ lungs

Adaptations for pregnancy
Mother & fetus exchange O2 & CO2 across ________________________ tissue
Fetal hemoglobin (HbF)
HbF has ____________________________attraction to O2 than Hb
      Mom’s blood has____________ % O2 by time blood reaches placenta
      _____________ Hb must be able to bind O2 with greater attraction than __________________ Hb

								
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