The Endocrine System: Endocrine Glands and Hormone Actions

Endocrine Organs Figure 6.1 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Hypothalamus and Pituitary Gland Figure 6.2a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Neural Connection to Posterior Pituitary Figure 6.3 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Hormones of Posterior Pituitary Antidiuretic hormone (ADH or vasopressin) Paraventricular nucleus Water balance and osmolarity Oxytocin Supraoptic nucleus Milk ejection Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Hypothalamic-Pituitary Portal System Links two capillary beds Exchange between blood and tissue occurs in capillaries Figure 6.4 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Tropic Hormones Tropic Hormones of Hypothalamus and Anterior Pituitary Figure 6.5 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Control of Hypothalamic Tropic Hormone Release Neural input Hormonal Negative feedback Circadian rhythm Suprachiasmatic nucleus of hypothalamus Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Negative Feedback Loops Anterior pituitary Endocrine gland Tropic hormone 1 secretion Target cell response Hypothalamus Hormone 3 secretion Tropic hormone 2 Long loop negative feedback Short loop Figure 6.6 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Feedback Control: Thyroid Thyroid gland Thyrotropin releasing hormone (TRH) secretion Thyroid stimulating hormone (TSH) secretion Thyroid hormone secretion Anterior pituitary Target cell response Hypothalamus Long loop negative feedback Figure 6.7 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Pineal Gland Glandular tissue in brain Secretes melatonin Function unknown May be involved in circadian rhythms Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Pineal Gland Figure 6.2a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Thyroid and Parathyroid Glands Figure 6.8 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Adrenal Glands Figure 6.9a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Adrenal Glands Figure 6.9b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Hormones of the Adrenal Gland: Adrenocorticoids Mineralocorticoids (aldosterone) Secreted from zonae glomerulosa Regulates sodium and potassium levels Glucocorticoids (cortisol) Secreted from zonae fasciculata and reticularis Regulates body’s response to stress Regulates metabolism Sex hormones (androgens) Regulate reproductive function Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Anatomy of the Pancreas Figure 6.10a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Anatomy of the Pancreas Figure 6.10b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Acinar and duct cells secrete fluid and enzymes into digestive tract Exocrine Pancreas Acinar and duct cells secrete fluid and enzymes into digestive tract Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Endocrine Pancreas Islets of Langerhans Alpha cells: glucagon Beta cells: insulin Delta cells: somatostatin F cells: pancreatic polypeptide Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Gonads Male—testes Female—ovaries Testosterone Androstenedione Estradiol Progesterone Placenta of pregnant female Estrogens and progesterone Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Neural Control of Hormone Release Figure 6.11 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Humoral Control of Hormone Figure 6.12 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Anatomy of the Pancreas Figure 6.10 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Hormonal Control by a Circadian Rhythm Neural control of circadian rhythm Suprachiasmatic nucleus of the hypothalamus Hormonal control of circadian rhythm Melatonin Resets daily cycle based on light stimulus All tropic hormones of hypothalamus affected by circadian rhythm from suprachiasmatic nucleus Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Transport of Hormones Hydrophilic hormones Hydrophobic hormones Peptides, catecholamines Dissolved in plasma Hydrophobic hormones Steroids, thyroid hormones Bound to carrier proteins Only free hormone can bind to receptor Only free hormone can be metabolized Longer half-life Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Rate of Hormone Metabolism Sites of hormone metabolism Target cell Blood Liver Lipophilic hormones can be stored in adipose tissue Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

IV. Abnormal Secretion of Hormones Hormone levels must be kept in balance Pathologies Hyposecretion: too little Hypersecretion: too much Abnormal Tissue Responsiveness Normal hormone levels Tissue responds inappropriately Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Primary versus Secondary Secretion Disorders Abnormality in endocrine organ secreting hormone Secondary Abnormality in tropic hormone Hypothalamic tropic hormone Anterior pituitary tropic hormone Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Abnormal Secretion: Thyroid Abnormal thyroid gland Regulation inadequate Excess thyroid hormone (TH) secretion (a) Primary hypersecretion of thyroid hormones Thyrotropin releasing hormone (TRH) secretion Thyroid stimulating hormone (TSH) Anterior pituitary START HERE Hypothalamus Negative feedback Figure 6.13a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

Abnormal Secretion: Thyroid Secondary hypersecretion of thyroid hormones Thyroid gland Excess thyroid hormone (TH) secretion Thyrotropin releasing hormone (TRH) secretion stimulating hormone (TSH) secretion Abnormal anterior pituitary START HERE Hypothalamus Regulation inadequate Negative feedback Figure 6.13b, step 5 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.