Pituitary Gland Hypothalamus Hypothalamus and Pituitary Gland The
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Pituitary Gland & Hypothalamus
Hypothalamus and Pituitary Gland • The hypothalamus and pituitary gland work together to control other endocrine glands. • They are connected by the infundibulum. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Pituitary Gland • Master Gland – Controls growth & activity of the Thyroid Gland, Adrenal Gland, Gonads, & Liver • “Middleman” between the brain (CNS) and the peripheral endocrine organs • Pituitary hormones act on endocrine and nonendocrine tissue • Located outside the blood-brain barrier
Pituitary Gland • Anterior lobe (adenohypophysis) – Comprises 75% of the weight of the pituitary gland – Secretes 7 hormones. • Posterior lobe (neurohypophysis) – Made of neural tissue – Releases two hormones/neuropeptides made by the hypothalamus. 1. Oxytocin 2. Vasopressin/ADH Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Hypothalamus • Secretes releasing and inhibiting hormones that control the release of hormones by the pituitary gland. • They reach the pituitary gland via the hypophyseal portal system.
Hypophysiotropic Hormones Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Hypophyseal Portal System Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Anterior Pituitary - Trophic Hormones 1. 2. 3. 4. 5. 6. 7. Human Growth Hormone - h. GH Thyroid-Stimulating Hormone - TSH Follicle-Stimulating Hormone - FSH Luteinizing Hormone - LH Prolactin - PRL Adrenocorticotropic Hormone - ACTH Melanocyte-Stimulating Hormone - MSH
Human Growth Hormone (h. GH/GH) a. k. a. Somatotropin • Most abundant AP hormone • Produced by somatotrophs • Account for majority of cells present in AP • 1° - acts on liver (IGF) • GHRH stimulates; SST/GHIH inhibits
h. GH Feedback Loops Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Thyroid-Stimulating Hormone (TSH) a. k. a. Thyrotopin • Produced by thyrotrophs • 1°- acts on thyroid (T 3/T 4). In mammals thermogenesis • Stimulated by TRH
Follicle-Stimulating Hormone (FSH) a. k. a Follitropin • Produced by gonadotrophs • Specifically, FSH-gonadotroph • 1°- in men: promotes spematogenesis; in women: follicular growth (estrogen/progesterone) • Stimulated by Gn. RH
Luteinizing Hormone (LH) a. k. a. Lutropin • Produced by gonadotrophs • Specifically, LH-gonadotroph • 1° - in men: acts on testes (testosterone); in women: acts on ovaries (ovulation/CL) Stimulated by Gn. RH
Prolactin (PRL) • Produced by lactotrophs • A. k. a. mammotrophs • PRL increases during pregnancy and reaches maximal values at parturition • Milk production in post-partum women • Stimulated by nursing infant
Adrenocorticotropic Hormone (ACTH) a. k. a. Corticotropin • Produced by corticotrophs • 1° action- stimulates steroid biosynthesis within the adrenal cortex; cortisol • Stimulated by CRH • High cortisol = Cushings Disease • Low cortisol = Addisons Disease
Melanocyte-Stimulating Hormone (MSH) a. k. a. Melanotropin • Produced by corticotrophs • Disperse melanin pigment in melanocytes in the skin • Not secreted in large amounts by AP
Credit: Dr. Michael Ormsbee, Florida State University
Hypothalamus and A. P. Negative feedback loops control the secretions of: • Thyrotrophs • TSH • Gonadotrophs • LH, FSH • Corticotrophs • ACTH, MSH Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Posterior Pituitary • The posterior pituitary gland does not synthesize any hormones. • It stores and releases from axon terminals two hormones: – oxytocin (OT) – anti-diuretic hormone (ADH)/vasopressin • Axons from the neurosecretory cells form the hypothalamohypophyseal tract. Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Hypothalamus and Post. Pituitary Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Posterior Pituitary - ADH • Antidiuretic hormone (ADH)/vasopressin – Amount secreted varies with blood osmotic pressure. – Its function is to decrease urine output. – Osmoreceptors (neurons) in the hypothalamus monitor blood osmotic pressure. ↑ blood volume causes ↓ ADH secretion ↓ blood volume causes ↑ ADH secretion Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
ADH Feedback Loop Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Posterior Pituitary - Oxytocin • The “cuddle” or “love” hormone • Active during parturition and post-partum Stretching of cervix = ↑↑ oxytocin release Results in ↑ smooth muscle contractions of uterus After birth – responsible for milk letdown/ejection Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
- Hyposecretion of prolactin
- Hypothalamus and pituitary gland connection
- Embryonic development of pituitary gland
- Pituitary gland and pineal gland spiritual
- Thyoid gland
- Hypophyseal fossa and pituitary gland
- Hypophyseal fossa and pituitary gland
- Hypophyseal fossa and pituitary gland
- Endocrine organ
- Normal pituitary gland
- Division of pituitary gland
- Pituitary gland anatomical relations
- Hyperfunction of the pituitary gland in preadolescence
- Morphology of pituitary gland
- Posterior pituitary blood supply
- Blood supply of pituitary gland
- Prolactin hormones
- Pituitary gland hormones
- Brainstem glioma
- Where is kidney pain felt diagram
- Tuberculum impar
- Subdivision of pituitary gland
- Pituitary gland thyroid
- Anterior pituitary
- The embryonic origin of the anterior pituitary gland is
- Pituitary gland disorders