MAJOR ENDOCRINE GLANDS III. Pituitary Gland and Hypothalamus …

III. Pituitary Gland and Hypothalamus… B. Pituitary Gland *Location *Number Hormones: Lobes *Anterior Lobe (6): (adenohypophysis) *Posterior Lobe (2): (neurohypophysis) *Infundibulum Hypophyseal Tract: Posterior Pituitary - *Neurohormones made where: Hypophseal Portal Veins Infundibulum Figure 9.3

Hormones released by Posterior Pituitary into capillary beds ADH= full name: i) *Target: ii) *Stimulus: iii) Inhibition: increasing body water and blood pressure iv) *Effect: v) Regulation: Humoral; Negative Feedback via Hypothalaamus osmoreceptors that sense H2O

v) … Via hypothalamus osmoreceptors that sense H2O concentration 1. Posterior Pituitary … v) … Via hypothalamus osmoreceptors that sense H2O concentration b. Oxytocin *Target: *Stimulus: Inhibition: reduced Pressure on Cervix and lack of suckling *Effect: Regulation: neural factors; from pressure and stretch receptors; Positive Feedback

1. Posterior Pituitary… Hormones … b. Oxytocin …

2. Anterior Pituitary Hormones i) Two categories of Hormones Non-stimulating Hormones Stimulating Hormones

2. Anterior Pituitary … a. Overview … ii) *Stimulus: Releasing & Inhibiting hormones of hypoth. iii) 2 of the Ant. Pit Hormones go directly to target organs and NOT to another Endocrine Gland = Non- stimulating Hormones Hypothalamus Hormone  Ant. Pituitary Hormone  Target Organ iv) 4 of the Anterior Pituitary Hormones: act as the hormonal stimulus for other Endocrine Glands = Stimulating hormones Hypothalamus Hormone Anterior Pituitary Stimulating Hormone  Endocrine Gland which releases its hormone  Target Organ v) Regulation: Hormonal; Via Negative Feedback– usually the last hormone in the chain inhibits production of the Pituitary Hormone and/or Hypothalamus Hormone

b. Non-stimulating Hormones Hypothalmic hormone  non-stimulating hormone  target i) Growth Hormone *Target: Stimulation: Daily cycle set by Hypothalamus with peak production during adolescence Inhibition: High levels of GH *Effect (Action): *Bones and Skeletal Muscles: *Metabolic Effects: Regulation: Hormonal; Negative Feedback. GH - feedback to Hypothalamus

i) Growth hormone … Regulation … GH Stimulating Hormone and GH inhibiting Hormone from Hypothalamus *DISORDERS: Students Please do the following Pituitary dwarfism Gigantism age 16 age 33 age 9 age 52

2. Anterior Pituitary … e. Non-stimulating Hormone … ii) Prolactin (PRL) *Target: Breasts *Stimulus: End of Pregnancy & Infant Suckling Inhibition:. Not pregnant and no suckling *Effect: Causes milk production Regulation: Hormonal; Negative Feedback Prolactin Inhibiting Hormone (PIH) = Dopamine: NO STIMULATING HORMONE When a woman is NOT pregnant Prolactin Inhibiting Hormone is high and release of Prolactin is mostly inhibited If a woman is pregnant and ready to give birth and an infant is suckling PIH is low and prolactin is released and milk production occurs.

i) Thyroid-Stimulating Hormone = Thyrotropin 2. Anterior Pituitary … Hypo. Releasing Hormone  Pit. Stimulating Hormone  Endocrine Gland  final Hormone c. Stimulating Hormones = Tropic Hormones– Cause growth Function: cause another Endocrine Gland to release its hormone i) Thyroid-Stimulating Hormone = Thyrotropin *Target: Stimulus/Inhibition: no distinct stimulus as is continuously produced *Effect (Action): Regulation: Hormonal; via Thyroid Releasing Hormone of hypothalamus and levels of Thyroid Hormone: Releasing Hormone  Stimulating Hormone  Thyroid Hormone Negative Feedback

*Effect (Action): Cause Adrenal Gland to release ? f. Stimulating Hormones of Ant. Pit. ii) Adrenocorticotropic Hormone (corticotrophin)= ACTH is a Stimulating Hormone *Target: *Stimulation: *Inhibition: *Effect (Action): Cause Adrenal Gland to release ? Regulation: Hormonal; Negative Feedback via Corticotropin Releasing Hormone (CRH) from the Hypothalamus which stimulates its release increasing Glucocorticoid Hormones feedback to inhibit the Pit and Hypo Hormones CRH  ACTH  Adrenal Gland  Glucocorticoid Hormones Negative Feedback

f. Stimulating Hormones iii) Gonadotropins: FSH and LH (1) FSH = Follicle-Stimulating Hormone *Target: Gonads Stimulation: Puberty and Sexual Maturity Inhibition: Childhood *Action: Stimulates production of gametes in both sexes. *Synergistic w/ LH in what? Regulation: Low levels of Gonadal Hormones (Testosterone, Estrogen, and Progesterone) stimulate High levels of Gonadal Hormones inhibit hypothalamus from releasing Gonadotropin Releasing Hormone (GnRH) GnRH  FSH and LH  Gonadal Hormones Negative Feedback

f. Stimulating Hormones iii) Gonadotropins: … LH = Lutenizing Hormone *Target: Stimulus: Inhibition: *Action: *Stimulates production of what? *In women triggers what? *Synergistic w/ FSH in ? *Causes secretion of what? Regulation: Stimulation: GnRH Inhibition: High Testosterone, Estrogen, and Progesterone: im women only if not pregnant

IV. Thyroid Gland B. Thyroid Hormone, Thyroxine (T3) Overview *Location & Structure: 2. Microscopic View: *Follicles b) Parafollicular cells: B. Thyroid Hormone, Thyroxine (T3) 1. Active forms: T4 & T3 Production *Required Element? *Other parts produced where?

Stimulation: in infants, exposure to cold; needed constantly IV. Thyroid Gland … Follicle Colloid B. Thyroxine … *Target: Stimulation: in infants, exposure to cold; needed constantly Inhibition– see Regulation *Effects (Actions): *Metabolic Rate affected how? *Growth affected how? 4. Regulation: Release: Thyroxine Releasing Hormone from Hypothalamus  Throxine Stimulating Hormone from Pituitary  Thyroid Gland  Thyroxine Inhibition: increasing Thyroxine

C. Calcitonin (insignificant in humans) *Gland Produced at? - Cells = IV. Thyroid Gland … C. Calcitonin (insignificant in humans) *Gland Produced at? - Cells = Target: Actions at Pharmacological Doses Regulation: Humoral; Negative Feedback; - Via changes in Blood Calcium

V. Parathyroid Glands & Parathyroid hormone A. *Location: B. *Target: C. Effect (Actions) *Osteoclasts: Reabsorption of Ca+ *Vitamin D: D. Regulation: Humoral; Negative Feedback Release: When blood Ca+2 low Inhibition: increasing Ca+2 blood levels

Thyroid and Parathyroid Thyroid Gland Parathyroid Gland

VI. Adrenal Glands A. Overview 1. Location: Parts a. Adrenal Cortex Tissue: Hormones: Corticosteroids Made from Cholesterol *3 Layers: List b. Adrenal Medulla Tissue: Hormones: Catecholamines

Parts & Layers of Adrenal Gland Hormones Layers = Capsule = Zona Glomerulosa = Zona Fasiculata Adrenal Cortex = Zona Reticularis

B. ADRENAL CORTEX 1. Zona Glomerulosa a. Hormone: Mineralocorticoids– mostly Aldosterone b. *Target: Juxtaglomerular Complex c. Effect: Long-term Stress Response Reabsorption of Na+ Excretion of K+ Indirectly causes water reabsorption and increased blood pressure d. Regulation: humoral & hormonal Decreased Na+ and increased K+ Kidney: Renin-Angiotensin- Aldosterone Mechanism

2. Glucocorticoids a. *Layer: b. Cortisol (significant amounts) i) Target: Body Cells ii) Effect: Long-term Stress Response Gluconeogenesis Increased blood fatty acids and amino acids (so glucose for brain) iii) Stimulus: Stress iv) Regulation: Hormonal; Negative Feedback CRH (hypo)  ACTH (ant. pit.) Cortisol Inhibition: rising Cortisol levels

Hormone: weak Androgens– levels normally low and insignificant Adrenal Glands … 3. Gonadocorticoids *Layer: Hormone: weak Androgens– levels normally low and insignificant C. Adrenal Medulla 1. Cells of: Chromaffin Cells = Modified Sympathetic Ganglionic neurons 2. Hormones: Catecholamines = epinephrine & norepinephrine Target: Lung bronchi, blood vessels, and heart Effect (Actions): short-term stress “Fight or Flight” see diagram on next slide. when sympathetic N.S. activated, it sends impulses via preganglionic neurons to adrenal medulla

Adrenal Medulla … ‘fight or flight’ … Short term Stress Hypothalamus Nerve impulses Short-term stress response Spinal cord Adrenal medulla Preganglionic sympathetic fibers Catecholamines (epinephrine and norepinephrine) 1. Increased heart rate 2. Increased blood pressure 3. Liver converts glycogen to glucose and releases glucose to blood 4. Dilation of bronchioles 5. Changes in blood flow patterns, leading to increased alertness and decreased digestive and kidney activity 6. Increased metabolic rate Figure 9.13, step 5

VII. Pancreas A. Location: B. *Hormones/Cells: β  make? α  make? C. Target: Body Cells and Liver D. Effects: Insulin Glucagon E. Stimulus: blood glucose levels F. Regulation: Humoral via Negative Feedback G. Disorders: Diabetes Mellitus— Type I and Type II Insulin producers Glucagon producers Students Do

X. Hormones Secreted by Organs IX. Gonads & Placenta A. Ovaries – produce: steroid hormone 1. Estrogens 2. Progesterone B. Testes – produce: Produce androgens (testosterone) X. Hormones Secreted by Organs Kidneys Erythropoietin Renin  Angiotensin II HEART 1. Atrial Natriuretic Peptide (ANP) Gastrointestinal Tract 3

END of PPT