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
open circulatory systems
circulating fluid is contained within the body cavity
-have channel-like routes that direct where the fluid moves
closed circulatory system
made up of set of internal vessels & a heart that pumps blood to different body regions
-delivers O2 at high rates
how does increased blood pressure affect rate of blood flow?
increases it
how does increased resistance affect rate of blood flow?
decreases it
arteries
large, high-pressure vessels that move blood flow away from the heart & toward tissues
veins
large, low-pressure vessels that returns blood to the heart
arterioles
small branches of an artery
capillaries
very small blood vessels arranged in finely branched networks connecting arterioles to venules, where gases, nutrients, & waste products are exchanged by diffusion w/ surrounding tissues
venae cavae
two large veins in the vertebrate body that drain blood from the head and body into the heart
lymphatic system
a network of vessels distributed through the vertebrate body with important functions in the immune system
lymph
the fluid in the vertebrate lymphatic system in which T and B cells circulate
lymphatic vessels
merge with larger thin-walled vessels, drain the lymph into lymphatic ducts, and empty into the venous system leading to the heart
which gland releases what in response to dehydration?
posterior pituitary gland; ADH
what effect does ADH have on arteries?
causes them to constrict
what happens if blood pressure drops?
arterioles supplying the limbs maintain blood pressure to the heart, brain, and kidneys by stimulating the smooth muscle to contract
what happens if blood pressure is high?
sympathetic neurons synapsing on the smooth muscles are inhibited
vasoconstriction
the narrowing of a blood vessel by the contraction of smooth vessel, which in turn increases resistance and decreases blood flow
vasodilation
the widening of a blood vessel by the relaxation of smooth muscle, which in turn decreases resistance and increases blood flow
pulmonary circulation
circulation of the blood to the lungs
systematic circulation
circulation of the blood to the body
what adaptation made double circulation possible?
4-chambered hearts
how many chambers do fish hearts have?
2 chambers
atrium function
receives blood
ventricle function
pump blood
where does deoxygenated blood flow to in a fish?
atrium
where does blood from the atrium flow to in a fish?
ventricle
where does deoxygenated blood from the ventricle flow to in a fish?
main artery
where does blood from the main artery flow to in a fish?
the gills
where does blood from the gills flow to in a fish?
the aorta
aorta
a large artery through which oxygenated blood flows from the left ventricle of the heart to the head and body
how many chambers does an amphibian and reptile heart have?
3-chambers
t/f: in mammals, bulk flow only refers to the movement of oxygen (either into or out of the lungs and within the bloodstream).
false, bulk flow also refers to the movement of carbon dioxide
we breathe more quickly and deeply when we exercise. why does this make sense?
-we produce more co2 and increased ventilation is necessary to rid ourselves of co2
-we use more ATP and additional o2 is necessary to generate sufficient ATP
what increases the amount of oxygen that fish can extract from the surrounding seawater?
-gills with a large surface area
-ventilation of the gills with the aid of an operculum
-countercurrent exchange
-very thin lamellae
what are desirable characteristics for a gas exchange surface?
large surface area and small thickness
imagine that someone suffers a horseback riding injury and one of their ribs punctures the diaphragm. how will this injury affect the person’s breathing?
the injury will make it more difficult to increase negative air pressure in their chest cavity, making inhalation more difficult
does unidirectional airflow or tidal breathing maintain a larger concentration gradient for diffusion?
unidirectional flow
do birds receive fresh air only during inhalation?
no
what is tidal ventilation?
air moves into the lungs during inhalation and moves out of the lungs during exhalation
what percent of oxygen in the air is typically extracted by the mammalian lung when an animal is resting?
less than 25%
t/f: if a hemoglobin molecule comes into close contact with a respiring cell, the presence of CO2 in the environment will cause hemoglobin to bind to more oxygen molecules (if is not already bound to four)
false
what does a shift to the right in the hemoglobin dissociation curve mean?
the affinity of hemoglobin for O2 has decreased
how do the partial pressures of O2 in the lung, blood cells, and blood plasma compare?
pO2 red blood cell < pO2 blood plasma < pO2 lung
insects possess ___ circulatory systems
open
what function do collagen and elastin have in arteries?
they provide elastic rebound of the arterial wall to help smooth out blood flow
in the disease elephantiasis, lymph vessels become blocked because of infection with parasitic worms. which process would be impacted by this disease?
the return of interstitial fluid to the bloodstream
as fluid moves through a vessel, which factors determine the flow resistance?
-the radius of the vessel
-the length of the vessel
-the viscosity of the fluid
diffusion of materials between the blood and body tissues occurs at which of the blood vessels?
capillaries
what event occurs during systole?
both ventricles contract
atrioventricular valves separate:
the left atrium from the left ventricle and the right atrium from the right ventricle
in which of the heart chambers would deoxygenated blood be found?
right atrium and right ventricle
why is the muscular wall of the left ventricle thicker than that of the right ventricle?
the left ventricle must contract with more force in order to send blood to the body’s extremities
the initiation of the mammalian heart contraction takes place at the:
SA node
what event are the following associated with: depolarization, contraction, increased pressure, emptying
systole
what event are the following associated with: repolarization, relaxation, decreased pressure, filling
diastole
where does the blood in the right side of the heart come from?
the body
where does the blood in the right side of the heart go to?
the lungs
where does the blood on the left side of the heart come from?
the lungs
where does the blood on the left side of the heart go to?
the body
