Hypothalamus Adenohypophysis (Anterior Pituitary) Neurohypophysis (Posterior Pituitary) Vascular connection Releasing/Inhibiting hormones Neural connection Hormones released from neurons Tropic Hormones: TSH, ACTH, LH, FSH, MSH Second Tier Endocrine Glands thyroid gland, adrenal gland, musculoskeletal tissue and breast* Plus GH and Prolactin* Thyroid hormones, Corticosteroids, Sex hormones, Melanin ADH, Oxytocin Negative Feedback via hormone levels Negative Feedback via physiological responses Direct control of adrenal medulla Epinephrine (adrenaline) gonads, melanocytes Non-hypothalamic control: Parathyroid glands - calcium levels Pancreatic Islet cells - calcium levels Parafollicular cells of thyroid - calcium levels Hypothalamic -Pituitary Control

Hypothalamus Neural connection Neurohypophysis (posterior pituitary) Hormones released from neurons. Vascular connection Releasing and inhibiting hormones Adenohypophysis (anterior pituitary) Tropic hormones – control other glands The connection of the hypothalamus and pituitary involves neurons and blood vessels which travel lo the pituitary through the infundibulum. 4

Tropic hormones FSH, LH, ICSH, TSH, ACTH GH*, Prolactin* Negative feedback through Hypothalamus Adenohypophysis hypothalamus Second Tier Gland Gonads, thyroid, adrenal cortex, other tissues* Second Hormones 5

6 Neurohypophysis (posterior pituitary) Hormones released from hypothalamic neurons ADH, Oxytocin Hypothalamus

Supraoptic nuclei 1 o capillaries (Anterior pituitary) TSH, ACTH Paraventricular nuclei Hypothalamus Infundibulum Ventral nuclei Pituitary (Hypophysis) Most travel to posterior pituitary Adenohypophysis FSH,LH, MSH GH PRL Hypophyseal portal system Neurohypophysis (Posterior pituitary) ADH, oxytocin 2 o capillaries 3

Hormone Chart GLANDHORMONETARGETACTION Adeno- hypophysis Tropic hormones Second tier glands Activation of glands Follicle stimulating hormone FSH ovariesFollicle dev. estrogen secretion testesspermatogenesi s 11

GLANDHORMONETARGETACTION Leuteinizing HormoneLH, ovaries Completion of Meiosis I, ovulation, Corpus luteum, Progesterone & estrogen secretion a.k.a.ICSH, Interstitial Cell Stimulating Hormone testes interstitial cells testosterone secretion 12

GLANDHORMONETARGETACTION Controlledby TRH Thyroid stimulating hormone TSH Thyroid gland Gland development secretionof T4 and T3 Controlled By CRH Adrenal cortico- tropic hormone ACTH Adrenal cortex Secretionof most corticosteroids (exceptgonado- corticoids) 13

GLANDHORMONETARGETACTION Stimulated by GHRH Inhibited by GHIH (Somatatropin Growth hormone GH (Somato- tropin) Musculo- skeletal tissues Normal growth And maintenance Anabolic for proteins Catabolic for fats Prolactin (luteotropin) Mammary glands Milk Production 14

Postitive stimulus from aerobic and muscle-building exercise Action Insulin-like growth Liver at al. factor lipolysis Mechanism of Growth Hormone Figure 17.6 Hypothalamus GHRH or GHIH Adenohypophysis Growth hormone growthgeneral growth Anti-insulin effects plasma glucose Insulin-like growth factor Somatomedin (IGF 1 ) Musculoskeletal Protein synthesis Negative feedback 15

Stimulated by PRH in response to estrogen and progesterone in pregnancy, suckling after birth. HORMONE Prolactin (luteotropin) TARGET Mammary glands ACTION Milk production GLAND Inhibited by PIH 17

GLANDHORMONETARGETACTION Neuro- hypophysis Oxytocin released by positive feedback cycle Uterine smooth muscle Labor Mammary tissue Ejectionofmilk ADH (vasopressin) Kidney collecting tubules water reabsorption 18

GLANDHORMONETARGETACTION Thyroid follicular cells T4 (95%) (thyroxine) And T3 Most tissue (except brain, spleen, gonads) basal Metabolic rate BMR Thyroid para- follicular cells calcitoninBone tissue (children) mineral uptakeand growth 19

TSH Thyroid hypophysis energy demanding activities Adeno- Target cell follicular cells T4 & T3 TRH Hypothalamus + stimulus Mechanism of Thyroid Control Negative feedback BMR T4 T3 inside target Diffuse into target cells 21

The most important hormone for Ca homeostasis. 1) Increases absorption of Ca 2)Increases reabsorption of Ca+2 3)By the kidneys 3) Increases osteoclastic activity in bones blood calciumParathormone GI, kidneys, (PTH) skeleton ACTIONTARGETHORMONEGLAND Parathyroid glands The parathyroid gland consists of small bean-like glands embedded in the posterior portion of the thyroid. They secrete parathyroid hormone (parathormone, PTH) which is the hormone responsible for calcium homeostasis. The parathyroid glands respond to lowering blood calcium levels by secreting PTH. PTH uses several sources to raise blood calcium levels: 27

Mechanism of PTH Action 3131 Negative feedback 1) Increases absorption of Ca +2 by activating more Vit D 3 2) Increases reabsorption of Ca +2 in the kidneys. 3) Increases osteoclastic activity in bones 2 Figure

testosterone, HORMONE Corticosteroids: Mineralcorticoids e.g. aldosterone Glucocorticoids e.g. cortisol TARGET kidneys Liver, muscle, connective, ACTION Electrolyte balance, Na + reabsorption Gluco- neogenesis Gonadocorticoids e.g. sex hormones Gonads and other tissues estrogen Complement gonadal secretion GLAND Adrenal cortex Controlled by ACTH 29

Sympatho- mimetic Sympathetic receptors The catecholamines ACTIONTARGETHORMONEGLAND Adrenal Medulla e.g. epinephrine 34

plasma glucose etc. plasma glucose, etc, Muscle, fat, liver, et al. Liver, fat cells Insulin  cells  cells ACTIONTARGETHORMONEGLAND 35 Pancreas Absorptive phase hormone: storage of foodstuffs uptake of glucose and amino acids into cells for metabolism and storage: glycogenesis and lipogenesis Glucagon Post-absorptive phase hormone to replace glucose used in metabolism glycogenolysis and lipolysis

and sperm production 2 o sex characteristics Preparation for pregnancy 2 o sex characteristics Other body tissues Uterus Other body tissues Estrogen and progesterone Ovaries ACTION Development TARGET Testes HORMONE Testosterone GLAND Testes 41

ACTION Diurnal cycle regulation TARGET Hypothalamus HORMONE Melatonin (secreted during darkness) GLAND Pineal gland “Third Eye” SAD – seasonal affective disorder due to insufficient light stimulation. 42