gland

(noun)

An organ that synthesizes a substance, such as hormones or breast milk, and releases it, often into the bloodstream or into cavities inside the body or on its outer surface.

Related Terms

Examples of gland in the following topics:

  • The Endocrine System

    • Melatonin: comes from the pineal gland; affects circadian rhythm and sleep cycles.
    • There are eight major endocrine glands, each with a different function.
    • Pituitary gland: the "brain" of the endocrine system; regulates all seven of the other glands and secretes growth hormone.
    • Pineal gland: regulates biorhythms and mood, and stimulates the onset of puberty.
    • The hypothalamic-pituitary-adrenal axis (HPA or HTPA axis) is a complex set of direct influences and feedback interactions among the hypothalamus, the pituitary gland, and the adrenal glands.

  • The Endocrine System and Stress

    • The hypothalamic-pituitary-adrenal (HPA or HTPA) axis is a complex set of direct influences and steroid-producing feedback interactions among the hypothalamus, the pituitary gland, and the adrenal glands.
    • This causes a negative feedback cycle in which the steroids inhibit the hypothalamus and the pituitary gland, and it also causes the adrenal gland to produce the hormones epinephrine (also known as adrenaline) and norepinephrine.

  • Biopsychology

    • Descartes suggested, for example, that the pineal gland, a midline unpaired structure in the brain of many organisms, was the point of contact between mind and body.
    • Descartes suggested that the pineal gland was the point of contact between mind and body.

  • How the Body Responds to Stress

    • The main physiological structure involved in this response is known as the HPA (hypothalamic–pituitary gland–adrenal gland) axis.
    • The hypothalamic–pituitary–adrenal axis (HPA axis) is a complex set of direct influences and feedback interactions among three endocrine glands: the hypothalamus, the pituitary gland, and the adrenal glands.
    • The HPA system reacts within a person's brain, and it releases the hormone cortisol from the adrenal gland when a person is exposed to a stressor.

  • Physical Development in Adolescence

    • During this time, both the adrenal glands and the sex glands mature—processes known as adrenarche and gonadarche, respectively.
    • During puberty, the adolescent's hormonal balance shifts strongly towards an adult state; the process is triggered by the pituitary gland, which secretes a surge of hormonal agents into the blood stream and initiates a chain reaction.
    • Both sexes experience development of pubic and underarm hair, as well as increased development of sweat glands.

  • Biology of Emotion

    • It is regulated by the hypothalamus and controls our internal organs and glands, including such processes as pulse, blood pressure, breathing, and arousal in response to emotional circumstances.
    • When activated, the sympathetic nervous system (SNS) controls the endocrine glands to prepare the body for emergency action.
    • SNS activation causes the adrenal glands to produce epinephrine (also known as adrenaline), which results in the "fight-or-flight" response.

  • Basic Principles of Classical Conditioning

    • When a dog sees food, the visual and olfactory stimuli send information to the brain through their respective neural pathways, ultimately activating the salivation glands to secrete saliva.

  • The Central Nervous System (CNS)

    • This data is then sent back through the spinal cord to muscles and glands for motor output.

  • Sexual Dysfunction and Disease

    • Other factors include back injuries, enlarged prostate gland, problems with blood supply, and nerve damage (as in spinal cord injuries).
    • Diseases such as diabetic neuropathy, multiple sclerosis, tumors, and tertiary syphilis may also have an impact, as can failure of various organ systems (such as the heart and lungs), endocrine disorders (thyroid, pituitary, or adrenal gland problems), and hormonal deficiencies (low testosterone, other androgens, or estrogen).

  • Biology of Sexual Behavior

    • One of the reasons for the importance of the hypothalamus is its relation to the pituitary gland, which secretes the hormones that are produced in the hypothalamus.
    • Several important sexual hormones are secreted by the pituitary gland.