Increased cAMP as a downstream event of epinephrine and norepinephrine stimulation of the left ventricle produce PKA. Which of the following events in the cardiac muscle physiology is influenced by the increase in PKA?

A. Action potential enters from
B. Voltage-gated Ca2+ channels
C. Ca2+ induces Ca2+ release adjacent cell open. Ca2+ enters the cell through ryanodine receptor channels (RyR2)
D. Local release causes Ca2+ spark.
E. Ca2+ ions bind to troponin to initiate contraction
F. Relaxation occurs when Ca2+ unbinds from troponin
G. Ca2+ is pumped back into the sarcoplasmic reticulum for storage
H. Ca2+ is exchanged with Na+
I. Na+ gradient is maintained by the Na+/K+ ATPase

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.

Ineed to get this test done which of the following statements is correct in hour our immune system responds to a potential pathogen? a.) the skin will be the first line of defense, and then the many phagocytes in the bloodstream will attempt to consume the possible pathogen. b.) b cells will start reading the antigen code immediately and call t cells to assist in destroying the pathogen. c.) the adapted immune system will call on the innate immune system to destroy the pathogen. d.) the t-cells in the adapted immune systems are the first to recognize the pathogen

Which of the following is a period in the paleozoic era? devonian cambrian permian all of the above