Which of the following correctly lists the sequence of structures that a cardiac action potential follows in order to excite normal contraction of the heart?
a) Bundle of His, Purkinje fibers, Atrioventricular (AV) node
b) Sinoatrial (SA) node, Purkinje fibers, AV node, Bundle of His
c) Purkinje fibers, AV node, SA node, Bundle of His
d) SA node, AV node, Bundle of His, Purkinje fibers
e) Bundle of His, SA node, AV node, Purkinje fibers
d
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Metabolism is defined as ________.
A. the removal of wastes produced by chemical reactions B. the taking in of nutrients C. all the chemical reactions occurring in an organism that support life D. the breakdown of substances into simpler forms
Which white blood cells are first to arrive at the site of a wound to begin infection control?
A) basophils B) eosinophils C) neutrophils D) monocytes
Why is it important to precisely regulate the pH of blood or other body fluids?
A) Blood functions as an excellent solvent. B) Blood and other body fluids have a very high heat capacity. C) Dehydration synthesis of large molecules occurs. D) Hydrogen ions are extremely reactive. E) Some organic molecules have polar covalent bonds.
What is true about somatic reflexes?
A) They help prepare the body for "fight-or-flight." B) We are not usually aware of them. C) They activate skeletal muscle. D) They are important in regulating digestion and blood pressure.