Nursing Entrance Exam

the nervous and endocrine systems. The hypothalamus secretes regulatory hormones – special hormones that control endocrine cells in the pituitary gland. The hypothalamus acts as an endocrine organ. Hypothalamic neurons synthesize hormones, transport them along axons within the infundibulum, and release them into the circulation at the neurohypophysis. The hypothalamus receives information about pain and stress, and it regulates the autonomic nervous system that controls body temperature, hunger, and thirst, to name a few. The hypothalamus also regulates the release of several hormones that act on other glands. • Pituitary gland: The pituitary gland is in the center of the skull and attaches to the hypothalamus. The hypothalamus controls the release or suppression of pituitary hormones. As well as having its own unique effects, it can influence the performance of the other endocrine glands. o The pituitary gland is divided into anterior and posterior lobes on the basis of function and developmental anatomy. Nine important peptide hormones are released by the pituitary gland – seven by the adenohypophysis (anterior lobe) and two by the neurohypophysis (posterior lobe).  The posterior pituitary gland tends to store oxytocin, which is used for uterine contractions, and antidiuretic hormone (ADH), which stimulates water retention. • Thyroid gland: The thyroid is located at the base of the larynx, and its middle part (the isthmus), covers the trachea’s second and third cartilaginous rings. It secretes the hormones triiodothyronine and thyroxin, both of which have an important role in controlling metabolism (including energy/ATP production) throughout the body. It also secretes calcitonin, which alters calcium levels in the blood. • Parathyroid glands: There are normally two pairs of parathyroid glands embedded in the posterior surfaces of the thyroid gland. The cells of the two adjacent glands are separated by the dense capsule that surrounds each parathyroid gland. The parathyroid cells (also termed chief cells or principal cells) produce parathyroid hormone. Like the C cells of the thyroid gland, the parathyroid cells monitor the circulating concentration of calcium ions. When the Ca2+ concentration in the blood falls below normal, the parathyroid cells secrete the parathyroid hormone (PTH), or parathormone. Without them, there is not enough calcium in the blood for the nervous system to function properly. Those who have hyperparathyroidism have demineralized bones and the calcium in their bones is released in their urine. • Adrenal or suprarenal glands: Each adrenal gland lies at roughly the level of the twelfth rib and is firmly attached to the superior portion of each kidney by a dense fibrous capsule. The adrenal glands produce three types of steroids, which are listed below. Steroid hormones are fat (lipid) hormones. o The exterior of the adrenal glands (the adrenal cortex) produces three types of hormones:  Mineralocorticoids: Control sodium and potassium levels in the body.  Glucocorticoids: Involved in metabolism and resistance to stress. One of these is cortisone, a hormone that has a variety of functions in the body.

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