praccy exam 3 Flashcards
a mutation in the Ca2+ binding region of calmodulin will most likely result in ____
myosin cannot interact with actin
Fish-hunting snails inject toxins into their victims that block acetylcholine receptors at the neuromuscular junction and cause muscle paralysis. The toxin is most likely binding to ___
ligand-gated Na+ channels
Ca2+ binding to the TnC subunit permits the transition of thin filament from the ____
blocked to closed state
In skeletal and cardiac muscles, Ca2+ is stored in the _____
sarcoplasmic reticulum
Fine-tuning force generation by triggering action potentials before the muscle can fully relax is an example of _____
twitch summation
muscles with predominately ____ fibers are more resistant to lactic acid buildup
slow
Isometric contraction occurs when there is ____
no change in muscle length
Cardiac output can be increased by ____
-increased venous return
-increased heart rate
-increased stroke volume
-increased end-diastolic volume
the greatest diameter and lowest pressure in a blood vessel would be found in the ____
vena cava
Frank-starling mechanism where muscle length determines force generation. Physiologically the cardiac muscle present in the _____ of the force-length relationship
ascending limb
ventricular filling is complete immediately after the
p wave
which of the following blood vessels carries oxygenated blood back to the heart
pulmonary veins
The threshold for rapid depolarization in autorhythmic cardiac cells is reached by the activity of the ____
hyperpolarization cyclic nucleotide (HCN) gated Na+ channels
the autonomic nervous system can ____ heart rate by causing ____ of the membrane potential of pacemaker cells
decrease, greater hyperpolarization
in the pressure-volume loop, the end-diastolic volume is most directly indicative of _____
preload
Type 2 pneumocytes produce surfactant which lowers the surface tension of the lungs. Where are type 2 pneumocytes located?
in the alveoli
Which of the following conditions affecting the binding between oxygen and hemoglobin would decrease the affinity and make more oxygen available in the plasma
decrease pH
during expiration ________
the intrapulmonary pressure is greater than atmospheric pressure
The gas law which most directly relates to the fact that the greater partial pressure of the gas in contact with a liquid, the greater the amount of gas dissolved is called _____
henrys law
if an enzyme in blood enhances the binding of oxygen to hemoglobin, how would you expect the O2 dissociation curve to change?
the curve shifts to the left
the principle or law that state the unloading of oxygen facilitates the carrying of carbon dioxide on hemoglobin is called _____
Haldane effect
Central chemoreceptors which respond to increased H+ are located in the _____
medulla
an infection in what would indicate that the respiratory zone has been affected
alveolar sac
the muscles involved in the normal quiet expiration are
diaphram
most of the carbon dioxide in the blood is carried as HCO3- (bicarbonate ion):
dissolved in plasma
during the oxygenation of blood, oxygen binds to a(n) _____ atom in the middle of the porphyrin ring
iron
