Nursing Preparation Study Guide

Nursing Preparation Study Guide 3. The Coordination of Activities of the Nervous and Endocrine Systems: The hypothalamus coordinates neural and endocrine activities by inhibiting or stimulating endocrine cells in the pituitary gland through the production of regulatory hormones. These hormones are produced at the tuberal area and are released into local capillaries for transport to the adenohypophysis. 4. The Secretion of Two Hormones: The hypothalamus secretes two hormones – antidiuretic hormone (ADH) and oxytocin (OT). Antidiuretic hormone (ADH, also called vasopressin) is produced by the supraoptic nucleus, and it restricts water loss at the kidneys. Oxytocin (OT) stimulates smooth muscle contractions in the prostate gland in males and in the uterus and mammary glands of females. It is produced by the paraventricular nucleus. These hormones are transported along axons that pass through the infundibulum to the neurohypophysis. There, the hormones are released into the blood for distribution throughout the body. 5. The Production of Emotions and Behavioral Drives: Specific hypothalamic centers produce sensations that lead to conscious or subconscious changes in behavior. For example, stimulation of the feeding center produces the sensation of hunger, while stimulation of the thirst center produces the sensation of thirst. These unfocused “impressions” originating in the hypothalamus are called drives. The conscious sensations are only part of the hypothalamic response. For instance, the thirst center also orders the release of ADH by neurons in the supraoptic nucleus. 6. Coordination between Voluntary and Autonomic Functions: When a dangerous or stressful situation arises, the heart rate and respiratory rate increase, leading the body to prepare for an emergency. The hypothalamus makes these autonomic adjustments. 7. The Regulation of Body Temperature: The preoptic area of the hypothalamus coordinates the activities of other CNS centers and it regulates other physiological systems tomaintain normal body temperature. If body temperature drops, the preoptic area sends instructions to the vasomotor center, which is an autonomic center located in the medulla oblongata; it controls blood flow by regulating the diameter of the peripheral blood vessels. In response, the vasomotor center decreases the blood supply to the skin, thus reducing the rate of heat loss. 8. The Control of Circadian Rhythms: The suprachiasmatic nucleus coordinates daily cycles of activity that are linked to the 24-hour day-night cycle. This nucleus receives input from the retina of the eye, and its output adjusts the activities of other hypothalamic nuclei, the pineal gland, and the reticular formation.

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