Endocrine System Cerebral cortex
Hypothalamus
Releasing Hormones
Anterior Pituitary Glucose Low Ca2+ ACTH TSH
Adrenal Low Blood Pressure Thyroid Pancreas Parathyroid gland
Aldosterone Cortisol T3/T4 Insulin PTH
Target tissue Pituitary Gland Hypothalamus
Pituitary Stalk Hypothalamic Axons
Anterior Pituitary Posterior Pituitary Axon termini release Cluster of hormome- hormones secreting cells Anterior Pituitary Posterior Pituitary
• Growth Hormone (GH) • Oxytocin • Adrenocorticotrophic Hormone • Vasopressin (ACTH) • Thyroid-Stimulating Hormone (TSH) • Prolactin • Leutenizing Hormone (LH) • Follicle-Stimulating Hormone (FSH) Pituitary
Optic Chiasm Hypothalamus
Pituitary Stalk
Posterior Pituitary
Anterior Pituitary Anterior Pituitary
Acidophil
Basophil
Chromophobe Capillary
Reticulin Fibers Hypothalamus hormones that regulate release of pituitary hormones
• Growth Hormone Releasing Hormone (GHRH) -> GH
• Corticotropin Releasing Hormone (CRH) -> ACTH
• Thryotropin Releasing Hormone (TRH) -> TSH
• Gonadotropin Releasing Hormone -> FSH and LH Hypothalamus
1. Neurons synthesize hormone-releasing hormones
2. Neurons release hormone- releasing hormones into primary capillary plexus.
Portal Vein
3. Hormone-releasing hormones diffuse out of secondary plexus to stimulate acidophils and basophils. Anterior Pituitary
4. Hormones from acidophils and basophils diffuse into secondary plexus and distribute throughout the body. Anterior Pituitary Fenestrated Endothelium
Somatotroph
Secretory Granule Hypothalamus
Pituitary Stalk Hypothalamic Axons
Anterior Pituitary Posterior Pituitary Axon termini release Cluster of hormome- hormones secreting cells Posterior Pituitary
Herring Body
Pituicyte Blood Vessel Posterior Pituitary Fenestrated Endothelium
Capillary Lumen
Axon Terminus Adrenal Glands Adrenal Gland
Medulla Cortex
Reticularis Fasciculata Glomerulosa Zona Glomerulosa
Trabecula
Fasciculata Glomerulosa Capsule Zona Fasciculata
Fasciculata
Glomerulosa Cortisol Pathway T4/T3 Pathway
CRH TRH Hypothalamus
Corticotroph Thyrotroph
Pituitary Cell
Throphic Hormone ACTH TSH Negative Feedback Negative Feedback
Target Cell Adrenal Glands Thyroid Hormone Cortisol T4/T3 Corticosterone CH2OH Aldosterone CH2OH H C O C O
CH3 O C HO Glomerulosa HO
Cholesterol CH3 CH3 Cells
O O
17 α-Hydroxylase
CH2OH Cortisol C O CH3 OH HO
CH3
O
11 β-Hydroxysteroid dehydrogenase (HSD)
CH2OH
Cortisone C O CH3 OH O
CH3
Reticularis
Fasciculata Adrenal Medulla
Medulla
Reticularis Thyroid Thyroid
C-cell
Colloid
Principle Cell OH OH OH OH Colloid Conjugation OH OH O O O O OH Iodination 2 OH CH 2 OH OH OH OH CH CH2 CH CH 2 2 2 CH2 CH 2 CH
CH2 CH2 CH2 CH2 Thyroglobulin secretion I0 - I Cl- Principle Cell TPO
Endocytic Vesicle
Lysosome T3 T4
T3 T4
Interstitium Na+ I- Cortisol Pathway T4/T3 Pathway
CRH TRH Hypothalamus
Corticotroph Thyrotroph
Pituitary Cell
Throphic Hormone ACTH TSH Negative Feedback Negative Feedback
Target Cell Adrenal Glands Thyroid Hormone Cortisol T4/T3 Parathyroid Parathyroid
Oxyphil Cell
Chief Cells Endocrine Pancreas Endocrine Pancreas
Exocrine Pancreas
Islet of Langerhans Glucose Membrane ATP-binding depolarization Calcium-binding closes channel Insulin open channel triggers fusion Ca+ Interstitium
Cytosol K+
PO3
Glucokinase ATP
Glycolysis TCA Cycle
CO2 H2O