Neurotransmitters | MCQs

Explanation

Norepinephrine is the primary neurotransmitter released by postganglionic neurons in the sympathetic nervous system.

It prepares the body for "fight or flight" responses by increasing heart rate, blood pressure, and alertness.

Explanation

Most anesthetics enhance the action of GABA (an inhibitory neurotransmitter) by increasing Cl⁻ ion influx into neurons.

This hyperpolarizes the neuron, making it less excitable and leading to unconsciousness.

Explanation

Catecholamines are amino acid-derived hormones.

They are synthesized from the amino acid tyrosine and include:

• dopamine
• norepinephrine
• epinephrine hormones.

Explanation

In multicellular organisms, chemical signaling can be categorized into three basic types:

• Paracrine signaling: This type of signaling involves the release of chemical signals, such as hormones or neurotransmitters, into the extracellular fluid, where they can bind to nearby cells. Examples include histamine release during an allergic reaction and neurotransmitters released by nerve cells.
• Autocrine signaling: In this type of signaling, cells release chemical signals that bind to receptors on their own surface, regulating their own behavior. Examples include the regulation of cell growth and division.
• Endocrine signaling: This type of signaling involves the release of hormones into the bloodstream, which are then transported to distant cells, where they bind to receptors and regulate various physiological processes. Examples include insulin regulating blood sugar levels and thyroid hormones regulating metabolism.

Explanation

Explanation