The Endocrine System
Transcript of The Endocrine System
Chapter 19Chapter 19 ENDOCRINE ENDOCRINE SYSTEMSYSTEM
1.1. Compare the basic organization and function of the Compare the basic organization and function of the ES and the NSES and the NS
2.2. Describe the structural and functional organization of Describe the structural and functional organization of the hypothalamus and the pituitary and explain the hypothalamus and the pituitary and explain their relationshiptheir relationship
3.3. Discuss the locations and structures of the thyroid, Discuss the locations and structures of the thyroid, parathyroid, and adrenal glands as well as the parathyroid, and adrenal glands as well as the thymus and the endocrine part of the pancreas.thymus and the endocrine part of the pancreas.
4.4. List the hormones (and their function) produced by List the hormones (and their function) produced by these glands. these glands.
5.5. Briefly review the results of abnormal hormone Briefly review the results of abnormal hormone productionproduction
Endocrine System OverviewEndocrine System Overview
Ductless glands produce Ductless glands produce hormoneshormones
Gland may be entire Gland may be entire organ or interspersed bits organ or interspersed bits of tissueof tissue
Chemical classification of Chemical classification of hormoneshormones
Target tissues are Target tissues are identified by receptorsidentified by receptors
HypothalamusHypothalamus
Control Center for Control Center for internal environmentinternal environment
Regulates nervous and endocrine systems via 3 mechanisms:
1. ANS centers exert nervous control on adrenal medulla
2. ADH and Oxytocin production
3. Regulatory hormone production (RH and IH) controls pituitary gland directly and all other endocrine glands indirectly
Fig 19-3
Pituitary Gland (= Pituitary Gland (= Hypophysis)Hypophysis)
Structure:Structure: Infundibulum - connection to hypothalamus Infundibulum - connection to hypothalamus In the sella turcica In the sella turcica Two parts with an embryonic double originTwo parts with an embryonic double origin
Posterior Pituitary = neurohypophysisPosterior Pituitary = neurohypophysis Storage Storage shed for ADH and Oxytocin (produced in ?)shed for ADH and Oxytocin (produced in ?)
Anterior Pituitary Anterior Pituitary = adenohypophysis= adenohypophysis production of production of 7 peptide hormones, 7 peptide hormones, see fig 19.5see fig 19.5
Histology
Fig 19-4
Hypophyseal Portal System Hypophyseal Portal System
Portal systems:Portal systems: two capillary networks two capillary networks in serial arrangement in serial arrangement Advantage?Advantage?
Named after their Named after their destination: . . . destination: . . .
Portal veins:Portal veins: blood blood vessels that link two vessels that link two capillary networkscapillary networks
Fig 19-6
Thyroid GlandThyroid Gland Anterior surface of trachea Anterior surface of trachea
just inferior of thyroid just inferior of thyroid cartilage (or Adam’s apple)cartilage (or Adam’s apple)
Two lobes connected by Two lobes connected by isthmusisthmus
MicroscopicMicroscopic thyroid folliclesthyroid follicles produce thyroid hormoneproduce thyroid hormone
C Cells - produce calcitonin C Cells - produce calcitonin ((CaCa2+2+))
Fig 19-7
Thyroid Gland FunctionThyroid Gland Function
Thyroxin (T4) and triiodothyronine (T3) speed up metabolic rate
Calcitonin lowers blood Ca2+ levels
Thyroid pathologies: Hyper- and Hypothyroidism
Goiter
Exophthalmus
HyperthyroidismHypothyroidism
Slowing of mind and body
Four Parathyroid Four Parathyroid GlandsGlands
Parathyroid Parathyroid hormone (PTH; hormone (PTH; sometimes also sometimes also called called parathormone)parathormone)
Function: Function: antagonist to antagonist to CalcitoninCalcitonin
Fig 19-9
4 tiny glands embedded in the back of the 4 tiny glands embedded in the back of the thyroid (superior and inferior)thyroid (superior and inferior)
Thymus GlandThymus 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)
Adrenal or Suprarenal Adrenal or Suprarenal GlandGland
Cortex:Cortex: corticosteroid production aldosterone, cortisol, sexhormonealdosterone, cortisol, sexhormone
Medulla: modified sympathetic Medulla: modified sympathetic ganglion produces adrenaline and ganglion produces adrenaline and noradrenaline (noradrenaline (parallels sympathetic parallels sympathetic division of ANS)division of ANS)
HistologyHistology
Fig 19-10
Pancreas Part of endocrine and Part of endocrine and
digestive systems. digestive systems. (99% exocrine)(99% exocrine)
Pancreatic islets Pancreatic islets or islets of Langerhansor islets of Langerhans cells: glucagon cells: glucagon ( blood sugar levels by
stimulating liver to convert glycogen to glucose)
cells: insulin cells: insulin ( blood sugar levels by causing the cells to take up glucose for use by the mitochondria)
cells: somatostatincells: somatostatin