1. Lecture on Endocrine System Overview

2. Objectives…
Compare the basic organization and function of the ES and the NS
Describe the structural and functional organization of the hypothalamus and the pituitary and explain their relationship
Discuss the locations and structures of the thyroid, parathyroid, and adrenal glands as well as the thymus and the endocrine part of the pancreas.
List the hormones (and their function) produced by these glands.
Briefly review the results of abnormal hormone production

3. Endocrine System Overview
Ductless glands produce hormones
Gland may be entire organ or interspersed bits of tissue
Chemical classification of hormones
Target tissues are identified by receptors

4. Hypothalamus Control Center for internal environment
Regulates nervous and endocrine systems via 3 mechanisms:
ANS centers exert nervous control on adrenal medulla
ADH and Oxytocin production
Regulatory hormone production (RH and IH) controls pituitary gland directly and all other endocrine glands indirectly
Fig 19-3

5. Pituitary Gland (= Hypophysis)
Structure:
Infundibulum - connection to hypothalamus
In the sella turcica
Two parts with an embryonic double origin
Posterior Pituitary = neurohypophysis Storage shed for ADH and Oxytocin (produced in ?)
Anterior Pituitary = adenohypophysis production of 7 peptide hormones, see fig 19.5
Histology
Fig 19-4

6. Hypophyseal Portal System
Portal systems: two capillary networks in serial arrangement Advantage?
Named after their destination: . . .
Portal veins: blood vessels that link two capillary networks
effect
that RHs and IHs released from the hypothalamus
go immediately without dilution to their target.
Fig 19-6

7. Fig 19-7
Thyroid Gland
Anterior surface of trachea just inferior of thyroid cartilage (or Adam’s apple)
Two lobes connected by isthmus
Microscopic thyroid follicles produce thyroid hormone
C Cells - produce calcitonin (Ca2+)

8. Thyroid Gland Function
Thyroxin (T4) and triiodothyronine (T3)  speed up metabolic rate
Calcitonin  lowers blood Ca2+ levels
Thyroid pathologies: Hyper- and Hypothyroidism
Goiter
Exophthalmus

9. Hypothyroidism
Hyperthyroidism
Slowing of mind and body

10. Four Parathyroid Glands
4 tiny glands embedded in the back of the thyroid (superior and inferior)
Parathyroid hormone (PTH; sometimes also called parathormone)
Function: antagonist to Calcitonin
Fig 19-9

11. Thymus Gland
Inside thoracic cavity immediately posterior to sternum above the heart
Most active in infancy and childhood - Largest just before puberty
Thymosin - enhances lymphocyte production and competence. (important for immune system)

12. Adrenal or Suprarenal Gland
Cortex: corticosteroid production aldosterone, cortisol, sexhormone
Medulla: modified sympathetic ganglion produces adrenaline and noradrenaline (parallels sympathetic division of ANS)
Histology
Fig 19-10

13. Pancreas The End Pancreatic islets or islets of Langerhans
Part of endocrine and digestive systems (99% exocrine)
Pancreatic islets or islets of Langerhans
 cells: glucagon ( blood sugar levels by stimulating liver to convert glycogen to glucose)
 cells: insulin ( blood sugar levels by causing the cells to take up glucose for use by the mitochondria)
 cells: somatostatin
The End