Which structure in the heart initiates action potentials that stimulate contraction of the heart at constant rate of about 100 beats per minute?
a) Cardiac accelerator nerves
b) Atrioventricular node
c) Cardiovascular center
d) Sinoatrial node
e) Bundle of His
d
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Which of the following is most likely to result from an aneurysm in a brain artery?
A) hypotension B) quadriplegia C) stroke D) myocardial infarction E) pulmonary embolism
Llamas, cats, and rabbits are called ____________ ovulators because the ovum is only released after ovulation
Fill in the blank(s) with correct word
Which of the following best describes the interaction between an enzyme and its
substrate? A) The enzyme temporarily deactivates the substrate. B) The enzyme surrounds and completely contains the substrate. C) The substrate surrounds and completely contains the enzyme. D) Part of the enzyme temporarily binds part of the substrate molecule.
Life expectancy has steadily increased in the last century, whereas life span has not
Indicate whether the statement is true or false