Amy, a high-strung teenager, was suddenly startled by a loud bang that sounded like a gunshot. Her heartbeat accelerated rapidly. When she realized that the noise was only a car backfiring, she felt greatly relieved but her heart kept beating heavily for several minutes more. What hormone was released into her bloodstream that is causing this response

Catecholamines, endothelins, glucocorticosteroids and thyroid hormones.

Explanation:

Catecholamines, endothelins, glucocorticosteroids and thyroid hormones are the type of hormones that is released into the bloodstream that causes increase of heart rate. Stress and anxiety is responsible for the raising of your heart rate. It may also increases when you're very happy or upset. People who have severe obesity can have a slightly faster pulse as compared to normal people.

a, i am pretty sure.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation: