Reset Help Example: Rising potassium levels cause aldosterone release Hormone release caused by neural input Example: Stress causes corticotropin- releasing hormone (CRH) release from the hypothalamus Hormonal Stimuli Hormone release caused by another hormone Involves tropic hormones The most common type of stimulus for hormone release by the major endocrine glands Humoral Stimuli Hormone release caused by altered levels of certain critical ions or nutrients Terminated by negative feedback by the regulated substance Not terminated by negative feedback Terminated by negative feedback by a hormone Example: Luteinizing hormone causes testosterone release Neural Stimuli
The Correct Answer and Explanation is:
Matching the types of hormonal inhibition with examples:
- Hormonal Stimuli
- Definition: Hormonal stimuli refer to the release of hormones in response to other hormones. This often involves tropic hormones that stimulate the release of other hormones from their target glands.
- Example: Luteinizing hormone (LH) causes testosterone release from the testes. In this case, the release of LH is triggered by a previous hormone and leads to the secretion of another hormone (testosterone).
- Neural Stimuli
- Definition: Neural stimuli are the release of hormones triggered by nerve impulses, which are typically associated with stress or certain environmental factors.
- Example: Stress causes the release of corticotropin-releasing hormone (CRH) from the hypothalamus. This is a neural stimulus because the nerve signals related to stress trigger hormone release from the hypothalamus.
- Humoral Stimuli
- Definition: Humoral stimuli refer to the release of hormones in response to changes in the levels of certain ions or nutrients in the blood. This is the most common stimulus for hormone release by major endocrine glands.
- Example: Rising potassium levels cause aldosterone release from the adrenal cortex. In this case, the body’s response to changes in blood potassium levels triggers the release of aldosterone.
Explanation of Each Mechanism:
- Hormonal Stimuli: This type of hormone release relies on one hormone stimulating the release of another. Tropic hormones like LH and TSH (thyroid-stimulating hormone) are key examples of hormonal stimuli. They are critical for the regulation of reproductive hormones (like testosterone or estrogen) and thyroid hormones, among others.
- Neural Stimuli: Neural stimuli involve direct communication between the nervous system and the endocrine glands. The hypothalamus, as seen in the example of CRH release, is highly involved in the stress response. These stimuli are often associated with acute responses like fight or flight, where the body needs rapid adjustments.
- Humoral Stimuli: The term “humoral” refers to the fluids or nutrients in the bloodstream. Hormones like aldosterone, insulin, and parathyroid hormone are often released in response to nutrient or ion levels in the blood. The regulation of blood glucose, calcium, and potassium is key to maintaining homeostasis. Negative feedback mechanisms usually terminate these processes, ensuring that hormone levels remain within optimal ranges.
