Heart
From NonSpiritual
As used in phrases such as "I love you from the depth of my heart", the "heart" is a metaphorical organ denoting the assumed seat of feelings in human beings. Most feelings are accompanied by secretions of various hormones and chemicals in the body, and they usually affect the operation of the physical, biological heart. For example, feelings such as anger and fear release adrenaline in the body and increase the heart-rate. Hence, it is common to feel emotional states as emanating from, or centered in, the physical heart.
Physiologically, emotions and feelings have their origin in the limbic system in the brain (especially the Amygdala).
Sometimes the word "gut", "being" or "core" is used in place of the metaphorical "heart".
