Week 5 (Exam 2): Respiratory System & Gas Exchange; Cardiovascular System Flashcards
what do eukaryotic cells use O2 for?
to metabolize organic molecules for ATP production, giving off CO2 as a by-product
gas exchange
the transport of gases such as O2 & CO2 between an organism & its environment
diffusion
the net movement of molecules from a region of higher concentration —> a region of lower concentration
what distances is diffusion ineffective over?
distances over 100 mm
what is partial pressure?
the fractional concentration of a gas relative to other gases present multiplied by the total pressure of the gas mixture
bulk flow
the physical movement of fluids, either a liquid or gas, as a result of pressure differencs
-ventilation & circulation
ventilation
the movement of an animal’s respiratory medium - water or air - past a specialized respiratory surface
circulation
the movement of a specialized body fluid in animals that carries oxygen & CO2 & nutrients & waste products through the body
circulatory fluid
hemolymph in invertebrates & blood in vertebrates
how does resistance affect flow rate?
if resistance doubles, flow rate is halved
what is the first step of gas transport & exchange?
ventilation by bulk flow
what does ventilation by bulk flow entail?
breathing moves air (containing O2) into the lungs and air (containing CO2) out
second step of gas transport & exchange
diffusion across the respiratory surface
what does diffusion across the respiratory surface entail?
O2 diffuses from the lung into the blood & CO2 diffuses out of the blood into the lungs
what is the third step of gas transport & exchange
circulation by bulk flow
what does circulation by bulk flow entail
O2 & CO2 are transported by the circulatory system to & from cells
fourth step of gas transport & exchange
diffusion between blood & cells
what does diffusion between blood & cells entail
O2 diffuses from the blood into the cells & CO2 diffuses out of the cells into the blood
what are lungs
internal organs that perform gas exchange in terrestrial vertebrates
what is the trachea
an internal system of tubes that branch from openings along the abdominal surface into smaller airways, directing oxygen to & removing CO2 from respiring tissues
lamullae
a thin, sheetlike structure spread along the length of each gill filament
capillaries
very small blood vessels
how does blood flow through capillaries?
in a direction opposite to the flow of water past the gills
-countercurrent flow
spiracles
openings in the exoskeleton on either side of an insect’s abdomen through which gases are exchanged
hemoglobin
an iron-containing molecule specialized for oxygen transport
what makes up the cellular fraction of blood?
red blood cells with hemoglobin
hematocrit
the fraction of red blood cells within the blood of vertebrates
solubility
the ability of a substance to dissolve in a solvent
how does hemoglobin affect the amount of O2 in the blood?
it increases it by binding to O2 and removing it from solution
what are hemoglobins produced by?
red blood cells
where do hemoglobins reside?
red blood cells that lack a nucleus
path of O2 regarding hemoglobin
O2 diffuses into the blood —> diffuses into the red blood cells —> binds to the heme group in hemoglobin —> removes O2 from solution (keeping the O2 partial pressure of the red blood cell below that of blood plasma —> O2 diffuses into other cells
oxygen dissociation curve
the curve that results when blood partial pressure of O2 is plotted against the percentage of O2 bound to hemoglobin
-as partial pressure of O2 rises, hemoglobin binds to O2 with increasing binding affinity
cooperative binding
the increase in binding affinity with additional binding of oxygen
how does oxygen consumption affect the local O2 partial pressure?
reduces it in the cell & surrounding tissues to 40 mmHg or less
myoglobin
a monomer that contains 1 heme group
which molecule has a greater affinity for O2: myoglobin or hemoglobin?
myoglobin
which kinds of cells store large amounts of myoglobin?
red muscle cells that depend on aerobic respiration to produce ATP