Endocrinology2

Endocrinology2 - FEEDBACK CONTROL OF HORMONE...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
FEEDBACK CONTROL OF HORMONE SECRETION -Hormone secretion is precisely regulated by feedback mechanisms. E.G. an excess of hormone, or excess hormonal activity, leads to a diminution of secretion. Similarly, a deficiency of hormone leads to an increase in secretion. -Regulation by either hormonal or nonhormonal mechanisms. Non-hormonal negative feedback Figure 2.1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Hormonal feedback mechanisms -CRH: corticotopin releasing hormone -ACTH: adrenocorticotropic hormone -cortisol (glucocorticoid) Figure 2.2
Background image of page 2
(II) ENDOCRINE GLANDS AND THEIR SECRETIONS 1. Anatomic Location 2. Hormones Secreted 3. Chemical Nature of Hormones 4. Effects 5. Mechanism of Action 6. Control of Release 7. Problems 8. Treatment
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
PITUITARY GLAND Anatomy: Two distinctly different tissues. (1) adenohypophysis (a.k.a. anterior pituitary, or pars distalis) (2) neurohypophysis (a.k.a. posterior pituitary, or pars nervosa). Histologically, the anterior pituitary is endocrine tissue . The posterior pituitary is neural tissue . Figure 2.3
Background image of page 4
Signaling between the hypothalamus and the pituitary Figure 2.4 FSH: follicle stimulating hormone LH: luteinizing hormone IGF-1: insulin-like growth factor 1
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Table 3. Hypothalamic Hormones Hormone Structure Posterior pituitary hormones Arginine vasopressin Oxytocin Hypophyseotropic hormones Thyrotropin-releasing hormone (TRH) Gonadotropin-releasing hormone (GnRH) Somatostatin 1 Growth hormone-releasing hormone (GRH) Prolactin-inhibiting hormone (PIH, dopamine) Corticotropin-releasing hormone (CRH) 1 In addition to the tetradecapeptide shown here (somatostatin 14), an N-terminally extended molecule (somatostatin 28) and a 12-amino acid form (somatostatin 28 [1-12]) are found in most tissues.
Background image of page 6
Posterior Pituitary Gland [Neurohypophysis] -Outgrowth of hypothalamus connected by the pituitary stalk. -Posterior pituitary secretes oxytocin and vasopressin (a.k.a. antidiuretic hormone). -Oxytocin and vasopressin synthesized in two hypothalamic nuclei ( supraoptic nucleus and paraventricular nucleus), whose axons run down the pituitary stalk and terminate in the posterior pituitary close to capillary blood vessels. -Prohormones processed in secretory granules during axonal transport. -mature hormones liberated from the carrier molecules, neurophysins . -circulating half lives: 1-3 minutes Figure 2.5
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
-males: no known function, although secreted by posterior pituitary??? -females: two main functions, both motor. (i) parturition ; uterus extremely sensitive to oxytocin at end of pregnancy. -dilation of the uterine cervix by fetal head causes reflex release of oxytocin. -causes uterus to contract, which assists the expulsion of fetus and later of placenta. (ii) milk ejection . In lactating mother: response to the stimulus of suckling. -Oxytocin causes milk filled ducts to contract and squeeze milk out.
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/26/2011 for the course PHGY 210 taught by Professor Trippenbach during the Winter '08 term at McGill.

Page1 / 23

Endocrinology2 - FEEDBACK CONTROL OF HORMONE...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online