7.3 Control of Hormone Release Flashcards
Describe a simple endocrine reflex (what does an endocrine cell sense, how does it respond, what does the response act like and serve as and why?.
an endocrine cell that directly senses a stimulus and responds by secreting a hormone. The hormone acts as the output signal and usually serves as a negative feedback signal to turn off the reflex.
How does parathyroid hormone (PTH) use a simple endocrine reflex?
Parathyroid cells monitor plasma calcium levels. When calcium levels drop, PTH is secreted to increase calcium levels. Increased calcium levels then act as a negative feedback signal to stop PTH secretion.
What are neurohormones (where are neurohormones released and where are they released from, what are examples)?
Neurohormones are chemical signals released into the blood by neurons. Examples include catecholamines, hypothalamic neurohormones from the posterior pituitary, and those that control anterior pituitary hormone release.
what triggers insulin to be released (3)?
Insulin can be released in response to increased blood glucose levels (simple endocrine reflex) or through signals from the nervous system or digestive hormones (complex endocrine reflex).
What are the two parts of the pituitary gland?
the anterior pituitary (adenohypophysis) and the posterior pituitary (neurohypophysis).
What neurohormones are stored and released by the posterior pituitary?
oxytocin and vasopressin (ADH).
What is the hypothalamic-pituitary portal system (what does it consist of, what are the components connected by, what is the purpose of this set up)?
a special circulatory system consisting of two sets of capillaries connected by portal veins, allowing hypothalamic neurohormones to directly reach the anterior pituitary without dilution.
What are the six hormones secreted by the anterior pituitary? PTGFL
prolactin (PRL), thyrotropin (TSH), adrenocorticotropin (ACTH), growth hormone (GH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
When does a long-loop negative feedback occur in endocrine pathways?
when a hormone secreted by a peripheral endocrine gland feeds back to suppress the secretion of its anterior pituitary and hypothalamic hormones.
When do short-loop feedback mechanisms occur, what do ultra-short-loop feedback mechanisms involve?
Short-loop feedback occurs when a pituitary hormone inhibits hypothalamic hormone secretion. Ultra-short-loop feedback involves a hormone acting on the cell that secreted it, often as an autocrine or paracrine signal.
