respiration Flashcards
What is the problem with respiration?
gas exchange is necessary to support ATP production in cellular respriation
–> O2 must diffuse into the organism from the environment CO2 much diffuse out
What are the key considerations that are needed to be taken into account when talking about respiration?
respiratory surface area
distance across which the molecule must diffuse
How do gills work?
internal or external vascularized membrane
ventelated by the flow of water over them
O2 diffusion aided by countercurrent exchange
What is the Tracheal system?
internal network of air tubes
cells are supplied directly
system can be ventilated by body movements, while compress and expand tracheoles
What are Lungs?
localized respiratory organs
subdivided infolding of body surface
Bird lungs are different how?
inflatable air sacs associated with rigid lungs
How are Human lungs different?
internal sacs; inflatable
The human respiratory system
Trachea
bronchi and alveoli
- trachea branches into two primary bronchi
- bronchi branch repeatedly into bronchioles
- tiniest bronchioles end as alveloi (air sacs)
- alveoli are the sites of gas exchange
- why alveoli are good gas exchangers
(thin epithelium, millions of alveoli, total surface area = 100m^2 in human) - alvioli and surface tension
(alveolar epithelium moist(lined by film of water)
(solution to the problem: the film is not just water; it has a surfacant (surface-acting agent) the reduces surface tension
what is the mechanism of ventilation and negative pressure breathing
diaphragm contracts, moves down –> thorasic volume increase
cohesion of pleural fluid –> parietal pleura (lining inside chest) sticks to vesceral pleura (lining around lungs)
lungs volume incrase , pressure decrease –> air rushes in
exhalation - the reverse of the above processes
what do the respiratory pigments do?
what are they?
bind and transport gases
help buffer the blood
special proteins that transport most of the oxygen in blood (hemocyanin and hemoglobin)
hemocyanin (in arthropods and many molluscs, O2 bound to copper)
Hemoglobin is found in what? and what is its structure?
in almost all vertebrates
in red blood cells
four subunits (four polypeptide chains), each with a heme group –> hemeglobin can bind four O2 molecules
O2 bound to iron
Why is Hemoglobin needed to carry O2?
because O2 alone has a low solubility in blood
heme alone would carry CO2 not O2
what else does hemoglobin also bind?
CO2 bound to amino groups (not O2 binding sites)
H+ attached to carious sites
Bisphosphoglycerate (BPG): important regulator for the affinity of hemoglobin for oxygen
Cooperative binding and release
binding of oxygen to one hemoglobin subunit–> remaining subunits change shape slightly –> their affinity for oxygen increases
release of O2 by one subunit –> remaining subunits follow suit as conformational change lowers their affinity for oxygen
What is a Bohr shift?
a drop in pH lowers the affinity of hemoglobin for O2
What is Daltons Law?
in a mixture of gases, the total pressure is the sun of the pressure each gas would exert is it were present alone
Gas exchange between tissues and blood
how does O2 diffues?
O2 diffuses down the PO2 gradient
from alveolar spaces into lung capillaries
from systemic capillaries to tissue
Gas exchange between tissues and blood
How does CO2 diffues?
CO2 diffuses down the PCO2 gradient
from tissue to systemic capillaries
from lung capillaries to alveolar spaces
CO2 transport
7% of CO2 transported in solution
23% binds to multiple amino groups of hemoglobin
70% tranported as bicarbonate ions
Buffering substances in blood?
carbonic acid- bicarbonate system
phosphates
proteins
Fetal gas exchange
what is the adult and fetal hemoglobins?
adult: alpha2beta2
fetal: alpha2gamma2
how to hold your breath a long time?
have a lot of blood; store some in the spleen
have a lot of muscle myoglobin
don’t work too hard
respiratory adaptation of diving mammals
weddel seals in antarctica can remain underwater for 20-60 mins
elephant seals can dive to 1500 m and remain underwater for 2 hours
