NUR 0013 1st Edition Lecture 3Outline of Last Lecture I. Membrane bound receptorsOutline of Current Lecture Current LectureII. Tropic horomesa. Secreted by the Anterior Pituitary b. 4 in total: TSH, AcTH, FSH, LHIII. Posterior pituitary secreting hormonesa. ADH- water regulationb. Oxytocin – contractions near birth, milk secretion IV. Hypothalamic Pituitary Axesa. 1. HPT, 2 HPA, HPGV. Thyroid Glanda. Secretes Calcitonin – osteoblast and TH- metabolic activityVI. Parathyroid Glanda. PTH- osteoclast activity to increase calcium levels in the bloodVII. Adrenal Glanda. Adrenal medulla (Amino acid)b. Adrenal Cortex (Steriod)i. zona glomerulosa- outermost layer. secretes mineralcorticoidsii. zona fasiculata- middle layer secretes glucocorticoids (cortisol)iii. zona reticularis- innermost layer. Secretes gonadocorticoidsLecture 3 The following anterior pituitary hormones fall into the category of tropic hormones.Tropic hormones - hormones whose targets are other endocrine glands. (4 of the 6 are)3. Thyroid Stimulating Hormone (TSH)structure - glycoproteinThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.target - thyroid glandresponse - increase thyroid hormone productionSecretion regulated by TRH.Part of the HPT axis.4. Adrenocorticotropic Hormone (ACTH)structure - peptidetarget - adrenal cortexresponse - increased glucocorticoid hormone secretionACTH, lipotropins, beta-endorphins and MSH are all derived from a precursor molecule found in the anterior pituitary called propriomelanocortin.Secretion directed by release of CRH.Part of the HPA axis5. Follicle Stimulating Hormone (FSH) – a gonadotropin structure – glycoproteintarget - follicles in ovaries, seminiferous tubulesresponse - follicle maturation and estrogen secretion in ovaries, and sperm cell production in malesSecretion controlled by GnRH6. Luteinizing Hormone (LH) – a gonadotropinstructure – glycoproteintarget - ovaries and testesresponse - ovulation and progesterone production in ovaries testosterone synthesis and support for sperm cell production.Secretion controlled by GnRH.C. Hormones of the Posterior Pituitary1. Antidiuretic Hormone (ADH) – a.k.a. vasopressinstructure - small peptidetarget – kidneyresponse - causes the nephrons to reabsorb water based upon the potency of the signal.  Clinically- if there is an ADH deficiency copious urination can lead to diabetes insipidus. – casues extssive thirst and constant peeing Alchohol is an ADH inhibitor 2. Oxytocinstructure - small peptidetarget - uterus and mammary glandsresponse - causes uterine contractions and milk ejection. Acts in a positive feedback loop during labor.Aka The “Love” hormone.Question:Surgical removal of the posterior pituitary causes marked symptoms, but gradually these symptoms fade and hormone production returns to normal, why?- because the posterior pituitary is made up of neurons and after a while it is able to reconnect itself D. Hypothalamic Pituitary AxesHPTHypothalmyus secretes TRH (thyroid releasing hormone) – sends message to Anterior Pituitary to secrets TSH (thyroid stimulating hormone)- gets sent to the thyroid gland whichmakes TH (thyroid hormone)HPAHypothalmys secretes CRH- sends to the anterior pituitary which secretes AcRH – which gets sent to the Adrenal gland which makes Cortisol ( a steriord hormone) HPGHypothalmus secretes GnRH- which is sent to Anterior pituitary- which secrets (LH) or (FSH) which then gets sent the testies or ovaries- which produce estrogen or progesterone, or testosterone Note: Be able to describe how each of these three are controlled in a negative feedback fashion. Example: too much TH will inhibit TRH and TSH secretion. Too much cortisol will inhibit CRH and AcTH. And too much Estrogen, progesterone, testosterone will inhibit FSH and LH secretion E. Thyroid Gland – most metabolically active endocrine in the body 1. Structure 2 lobes connected by an isthmus, inferior to larynx.  Histologically the gland is composed of rings of follicular cells filled with thyroglobulin. anterior surface - secretes TH, and calcitonin posterior surface - 4 small lobes known as the parathyroid glands2. Thyroid hormone (TH) – synthesized in follicular cells  TH actually made up of 2 hormones T3 (more active) and T4 structure - amino acid target - most cells in the body response - increases basal metabolic rate, essential for normal growth. Clinical–hypothyroidism (cretinism and myexedema) and hyperthyroidism (Grave’s disease).3. Synthesis and transport It is the only endocrine gland that can produce and store large amounts of its hormone product for long periods of time. T3 is much more metabolically active at target tissues so most T4 is converted by enzymes at the target tissue. Transport is generally by thryoxine binding globulin, which is a protein that stabilizes the TH hormones while they are being shuttled to their targets.4. Calcitonin – produced by parafollicular cells. structure - polypeptide target - bone response - decreases osteoclast activity and increases the rate at which bone cells take up calcium – It has a bone sparing effect.F. Parathyroid Gland1. Anatomy - imbedded in the back of the thyroid gland(4)2. Parathyroid Hormone (PTH) structure - peptide target - bone, kidneys, small intestine response - raise levels of blood calcium by breaking down bone, causes reabsorbtion of calcium by kidney, and causes intestines to absorb more calcium through the actions of vitamin D.Question:Predict the consequences of inadequate intake of calcium on PTH secretions and target tissues. ANSWER: PTH secretion goes up. Constant PTH secretion can cause brittle bones (osteoporosis )AdrenalsG. Adrenal Glands1. Anatomy sits on top of the kidneys. composed of an epithelial cortex layer and a neuronal medulla2. Cortex Hormones – arise from 3 strata zona glomerulosa- outermost layer. secretes mineralcorticoidszona fasiculata- middle layer secretes glucocorticoids (cortisol)zona reticularis- innermost layer. Secretes gonadocorticoidsMineralcorticoids aldosterone - controls nephron tubule permeability, and reabsorbs salts based on need, thus water will follow the salt back in by osmosis. structure - steroid target - nephrons of kidney  response - sodium ion reabsorption and postassium ion