The mental health nursing instructor is talking with the class about depression. what deficiency does the instructor explain will result in depression?

A) Norepinephrine: Norepinephrine is a potent vasoconstrictor primarily used in cases of shock to increase blood pressure by constricting blood vessels. However, it does not have a vasodilatory effect on renal blood vessels. Instead, it tends to decrease renal perfusion due to its strong vasoconstrictor properties, which could worsen renal insufficiency.

B) Dopamine: Dopamine is a catecholamine that has a dose-dependent effect on various receptors. At low doses, dopamine specifically acts on dopaminergic receptors in the kidneys, leading to vasodilation of renal blood vessels, which can improve renal perfusion. This makes it particularly useful in treating shock when there is concern about renal insufficiency or reduced kidney function.

C) Acetylcholine: Acetylcholine is a neurotransmitter of the parasympathetic nervous system, not a catecholamine. It is involved in promoting various physiological effects such as slowing the heart rate and stimulating digestive processes, but it does not have a specific role in vasodilation of renal blood vessels or shock management.

D) Enkephalin: Enkephalins are endogenous peptides involved in the regulation of pain and stress responses. They do not have a direct effect on vasodilation of renal blood vessels. Enkephalins are not typically used to treat shock or manage renal insufficiency.

A) Central nervous system (CNS), memory, and cognition: Myasthenia gravis (MG) primarily affects the neuromuscular junction, causing muscle weakness, not directly the central nervous system. While cognitive function may be affected in some patients due to fatigue or medication side effects, it is not the main system affected by MG.

B) Cardiovascular system and postural muscles: Myasthenia gravis primarily affects skeletal muscles, especially those responsible for voluntary movements like facial muscles, swallowing, and respiratory muscles. While MG can lead to general weakness, it does not typically affect the cardiovascular system directly.

C) Respiratory system and facial muscles: This is the correct answer. Myasthenia gravis primarily affects the voluntary muscles, particularly those controlling eye movements, facial expressions, swallowing, and breathing. The respiratory system is vulnerable due to weakness of the diaphragm and intercostal muscles, which can lead to respiratory distress in severe cases. Facial muscles are commonly affected, leading to symptoms like ptosis (drooping eyelids) and difficulty smiling or speaking.

D) Gastrointestinal system (GI) and lower extremity muscles: Although myasthenia gravis can cause generalized muscle weakness, it is not typically associated with the gastrointestinal system. The primary impact is on the voluntary muscles, such as those in the face, throat, and respiratory system. Lower extremity muscles can be affected, but the respiratory and facial muscles are more commonly involved.