Endocrine System

Endocrine System - THE ENDOCRINE SYSTEM ASSIGNED READING:...

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Unformatted text preview: THE ENDOCRINE SYSTEM ASSIGNED READING: PAGES 638-675 IN SALADIN 5TH EDITION TYPES OF INTERCELLULAR COMMUNICATION 1. Gap junctions: through cytoplasm 2. Neurotransmitters: through synaptic cleft 3. Paracrines: through interstitial fluid 4. Hormones: through the blood PRINCIPLES OF HORMONE COMMUNICATION 1. Hormones are released by endocrine glands (endocrine cells, neuroendocrine glands) 2. Hormones are picked up by the blood Fenestrated capillaries abundant 1. Hormones travel throughout body 2. Hormones diffuse out of capillaries 3. Hormones stimulate Target cells Target cells Endocrine cells Hormone in bloodstream Your average capillary Fenestrated capillary 1 2 3 4 5 ANATOMY OF HYPOTHALAMUS AND PITUITARY Forms floor and walls of third ventricle of the brain Regulates primitive functions of the body (water balance, thermoregulation, sex drive, and childbirth and various autonomic functions) Many of its functions carried out by pituitary gland: Posterior pituitary Unmyelinated nerve fibers Glial cells (pituicytes) Anterior pituitary ANATOMY OF HYPOTHALAMUS AND PITUITARY Suspended from hypothalamus by a stalk: the infundibulum housed in sella turcica of sphenoid bone Composed of two structures with independent origins and separate functions adenohypophysis (anterior lobe; pars distalis) arises from the pharynx during development glandular epithelium neurohypophysis (posterior lobe; pars nervosa) outgrowth of the brain nervous tissue: hypothalamo-hypophyseal tract POSTERIOR PITUITARY HORMONES Produced in hypothalamus transported by hypothalamo-hypophyseal tract to posterior lobe releases hormones when hypothalamic neurons are stimulated ADH (antidiuretic hormone) increases water retention thus reducing urine volume and prevents dehydration Control of ADH release: High osmolality (salt concentration) in blood detected by osmoreceptors in hypothalamus Third ventricle of brain Hypothalamohypophyseal tract Stalk (infundibulum) Posterior lobe Anterior lobe Optic chiasm Nuclei of hypothalamus: Paraventricular nucleus Supraoptic nucleus Oxytocin Antidiuretic hormone Pineal gland Cerebral aqueduc Mammillary body Anterior Posterior Floor of hypothalamus POSTERIOR PITUITARY HORMONES Produced in hypothalamus transported by hypothalamo-hypophyseal tract to posterior lobe releases hormones when hypothalamic neurons are stimulated OT (oxytocin) stimulate uterine contractions and propulsion of semen during orgasm stimulates labor contractions during childbirth stimulates flow of milk during lactation (letdown) Promotes emotional bonding Control of OT release: Neuroendocrine reflex : cerebral cortex initiates hormone release Third ventricle of brain Hypothalamohypophyseal tract Stalk (infundibulum) Posterior lobe Anterior lobe Optic chiasm Nuclei of hypothalamus: Paraventricular nucleus Supraoptic nucleus Oxytocin Antidiuretic hormone Pineal gland Cerebral aqueduc Mammillary body Anterior Posterior Floor of hypothalamus ANTERIOR PITUITARY HORMONES...
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Endocrine System - THE ENDOCRINE SYSTEM ASSIGNED READING:...

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