Question

stimulation of the beta - 1 receptors on heart muscle cells results in all of the following except

○ decreased oxygen use.

○ increased contraction force.

○ increased atp production.

○ increased heart rate.

○ increased metabolic rate.

Explanation:

When beta - 1 receptors on heart muscle cells are stimulated, the heart rate increases (positive chronotropic effect), the force of contraction increases (positive inotropic effect). An increase in heart rate and contraction force leads to an increase in metabolic rate (more energy is needed for the increased work of the heart) and an increase in ATP production (to meet the energy demands). Also, since more ATP is produced (through processes that consume oxygen, like aerobic respiration), oxygen use increases, not decreases.

Answer:

decreased oxygen use.