A client primary care provider prescribed a B-adrenergic receptor blocker. Which of the following therapeutic effects do the client and care provider likely seek?

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.

A) Pupil constriction: Pupil constriction (miosis) is primarily mediated by the parasympathetic nervous system through muscarinic receptors, not nicotinic receptors. Nicotinic receptors, when stimulated, affect skeletal muscle contraction, not the size of the pupils.

B) Muscle contraction: Nicotinic receptors are located on skeletal muscle cells and are responsible for mediating muscle contraction when activated. When a drug stimulates nicotinic receptors, the expected outcome is muscle contraction, as these receptors play a critical role in neuromuscular transmission.

C) Increase GI motility: While nicotinic receptors are involved in muscle contraction, they are not the primary mediators of gastrointestinal motility. Muscarinic receptors, which are part of the parasympathetic nervous system, primarily control GI motility. Stimulating muscarinic receptors would lead to increased motility, but not nicotinic receptors.

D) Decrease in heart rate: A decrease in heart rate is typically associated with the stimulation of muscarinic receptors, particularly those that influence the parasympathetic nervous system (vagal tone). Nicotinic receptor activation does not directly influence heart rate; in fact, their stimulation is more related to skeletal muscle contraction.