Gas Exchange Flashcards
- energy from food is released by oxidative processes, usually with molecular oxygen as the terminal electron acceptor
- oxygen is taken into the body across a respiratory surface
respiration
oxidative processes that occur within cells
cellular respiration
exchange of gasses between blood and tissues
internal respiration
exchange of oxygen and carbon dioxide between the organism and its environment
external respiration
To allow diffusion of gases across an aqueous phase, respiratory surfaces must be __ and always kept __
thin
wet
lungs
aerial respiration
gills
aquatic respiration
- frequently supplements gill or lung breathing in larger animals such as amphibians and fishes
- gas exchange occur across skin or outer integument
cutaneous respiration
respire through a system of tubes called tracheae that connect to the air via spiracles that can be actively opened or closed
tracheal respiration
valvelike openings
spiracles
branching system of tubes
tracheae
smallest end channels of tracheae are fluid-filled
tracheoles
gills of an animal, most typically an amphibian, that are exposed to the environment, rather than set inside the pharynx and covered by gill slits
external gills
animal with external gills example
axolotl
the structure formed from the outgrowth of pharynx inside the body, consisting of gill slits, which is used to increase the rate of diffusion of gases and help in counter-current mechanism
internal gills
help in crawling, swimming, and respiration
parapodia
thin filamentous structures, richly supplied with blood vessels arranged so that blood flow is opposite to the flow of water
fish gills
arrangement that provides greatest possible extraction of oxygen from the water
countercurrent flow
branchial pump
- mouth
- opercular cavities
gill ventilation often assisted by the fish’s forward movement through the water with its mouth open
ram ventilation
have lungs that can be ventilated by muscle movements to produce a rhythmic exchange of air
terrestrial vertebrates
vary from simple, smooth-walled, baglike lungs of some salamanders to the subdivided lungs of frogs and toads
amphibian lungs
total surface available for gas exchange is much in lungs which are subdivided into numerous interconnecting air sacs
nonavian reptiles
contains millions of small sacs (alveoli) each intimately associated with a rich vascular network
mammalian lungs
disadvantage of lungs
- gas exchange is between blood and air only in alveoli and alveolar ducts
- dead space - volume of air in lungs that does not participate in gas exchange
- air must enter and exit through the same channel
one-cell-thick air capillaries
parabronchi
Parabronchi in birds receive nearly fresh air during both ___ and ___
inspiration
expiration
(amphibians)
action to force air into their lung
positive pressure
(amphibians)
air is pulled into the lungs by expansion of the thoracic cavity
negative pressure
upper respiratory tract
- nasal cavity
- pharynx
lower respiratory tract
- larynx
- trachea
- bronchi
- lungs
nostrils
external nares
Three (3) important changes the air undergoes in its passage to the air sacs
- filtered free from most dust and other foreign substances
- warmed to body temperature
- saturated with moisture
covers the lungs and interlobar fissures
visceral pleura
lines the inner surface of the walls of the chest
parietal pleura
“space” between the pleura
pleural cavity
lungs maintains a __ __ or the __ __ __ that keeps the lungs expanded to fill the pleural cavity, and therefore no real pleural space exits
partial vacuum or
negative intrapleural pressure
chest cavity is floored by the ___
diaphragm
- to fall below atmospheric pressure
- air rushes in through passageways to equalize pressure
intrapulmonary pressure
less active process than inspiration
normal expiration
occurs during exercise
forced expiration
neurons in ___ of the brain regulate normal, quiet breathing
medulla
- located close to the heart and the neck region
- monitor peripheral changes in blood levels of carbon dioxide and hydrogen ions and send stimulatory signals to the medulla respiratory centers if these levels rise
peripheral chemoreceptors
becomes saturated with water vapor as it travels through the air-filled passageways toward the alveoli
inspired air
___ ___ of oxygen drops and that of carbon dioxide rises
partial pressure
air from the alveoli mixes with air in the dead space to produce still a different mixture
expiration
red, iron-containing protein present in all vertebrates and many invertebrates
hemoglobin
each molecule of hemoglobin is __ __ and __ __
5% heme
95% globin
iron-containing compound giving the red color to blood
heme
colorless protein
globin
each gram of hemoglobin can carry a maximum of approx. ___ __ of oxygen
1.3 mL
How does hemoglobin bind with oxygen
when oxygen concentration is high
hemoglobin with bound oxygen
oxyhemoglobin
- a result of the effect carbon dioxide has on hemoglobins affinity for oxygen
- The rate of O2 unloading is increased in metabolically active tissues due to increased acidity
Bohr effect
A lower pH also shifts the hemoglobin saturation curve to the right and causes ___ of oxygen to active tissue
release
- blue, copper-containing protein
- crustaceans and most molluscs
hemocyanin
- green-colored, iron-containing pigment
- four families of polychaete tubeworms
chlorocruorin
- red pigment found in some polychaete worms
- although it contains iron, this metal is not present in a heme group
- oxygen-carrying capacity is poor compared to hemoglobin
hemerythrin
hydrogen ions combine with hemoglobin
deoxyhemoglobins
a chemical complex formed by carbon dioxide and hemoglobin after the release of oxygen by the hemoglobin to a tissue cell
Carbaminohemoglobin
