After the effector cell has being stimulated by acetylcholine (ACh), what enzyme stop the stimulation and allows the effector membrane to repolarize?

A) Increased intraocular pressure: Sympathomimetic drugs stimulate the sympathetic nervous system and promote "fight or flight" responses, often resulting in vasoconstriction and other effects. Some sympathomimetics, especially those that affect alpha-adrenergic receptors, can lead to increased intraocular pressure, which is a concern in conditions like glaucoma.

B) Decreased blood pressure: Sympathomimetic drugs generally increase blood pressure by stimulating alpha and beta receptors that cause vasoconstriction and increased heart rate. In contrast, drugs that would decrease blood pressure are usually parasympathomimetics or other agents designed to block sympathetic responses.

C) Decreased heart rate: Sympathomimetic drugs typically increase heart rate by stimulating beta-1 adrenergic receptors in the heart. These drugs are used in situations requiring increased cardiac output or to counteract bradycardia. Decreased heart rate would typically occur with parasympathomimetic drugs or medications that block sympathetic activity (e.g., beta blockers).

D) Increased respiration: Sympathomimetic drugs can increase respiratory rate by promoting bronchodilation through beta-2 adrenergic receptor activation in the lungs. However, "increased respiration" as a general effect is not as specific or consistent as the other cardiovascular and ocular effects of these drugs. The primary and most prominent physiological change would be related to the cardiovascular effects.

A) The blood cells will migrate to the bone marrow:
While the bone marrow is responsible for producing red blood cells, dehydration and hypertonicity of the blood would not cause the red blood cells to migrate to the bone marrow. Migration of blood cells typically refers to white blood cells moving toward sites of infection or inflammation, not a response to dehydration.

B) The red cells will precipitate out of circulation:
Red blood cells do not precipitate out of circulation due to dehydration or hypertonic conditions. Instead, dehydration causes a shift in water balance that leads to changes in the shape and function of the red blood cells. Precipitation of cells is not a physiological response in this context.

C) They will swell and eventually rupture:
In conditions of hypertonicity, where the concentration of solutes (such as sodium) in the blood is higher than normal, red blood cells actually shrink, not swell. When blood is hypertonic, water moves out of the red blood cells into the extracellular space to balance the osmotic pressure, leading to cell shrinkage. Cells only swell in hypotonic conditions, when water moves into the cell.

D) The cells will shrink and shrivel, decreasing their oxygen-carrying ability:
When the body becomes dehydrated, the blood becomes hypertonic (more concentrated), leading to a shift of water out of the red blood cells to try to balance the osmotic gradient. As a result, the red blood cells shrink and shrivel. This shrinkage can impair their ability to carry oxygen effectively, as the cells may become more rigid and less flexible, making it difficult for them to navigate through small blood vessels and perform gas exchange in the lungs and tissues.