Homeostasis: The Endocrine System Chapter 10 Pages 473 - 481

Hormones

Endocrine System endocrine system – hormones – Greek origins: to excite / set in motion

Joseph van Mering & Oscar Minkowski removed pancreas from dogs Hormone Discovery - 1889 Joseph van Mering & Oscar Minkowski removed pancreas from dogs rapid weight loss fatigued ants gathered around urine pancreas related to regulating body sugars

Hormones are specific to target cells How do they know where to go? Hormone Roles Hormones are specific to target cells How do they know where to go? target cells have ____________ for hormones Two hormone types: steroid hormones protein hormones

1. Steroid Hormones Made from cholesterol Not soluble in water Diffuse from cell of origin (through membranes) Carried through blood by protein carriers (globulins) Diffuse into target cell Often moves into nucleus to affect transcription

Steroid Hormone Action To demonstrate the classical signalling mechanism of action of estrogen...

Steroid Hormone Action -estrogen may also exert its effects through non-classical estrogen receptor mechanisms. binding area

2. Protein Hormones Short peptide sequences Water soluble Transported from cell of origin by secretory vacuoles Carried dissolved in blood Attach to surface receptors of target cells Activates enzymes to make other internal signals

Protein Hormone Action ATP R cyclic AMP + PPi To demonstrate the classical signalling mechanism of action of estrogen... other enzymes

Glands

A series of organs, called glands, that: The Endocrine Glands A series of organs, called glands, that: Also includes organs from other systems that produce hormones for example:

The Endocrine Glands

Produces hormones that act on the __________ Hypothalmus Part of the brain Produces hormones that act on the __________ Releasing hormones Example: Inhibiting hormones

Pituitary Gland “Master gland” that controls many of the other glands Two parts: Anterior and posterior Hormones:

Pituitary Gland

Growth hormone Controls : Problems can lead to dwarfism or giantism

Thyroid and Parathyroid Found in the front of the throat Hormones: Thyroxine: Calcitonin: Parathyroid hormone (PTH):

Thyroid and Parathyroid Thyroxine: Increases : Essential for : Contains 4 iodine atoms Lack of iodine in diet, causes this hormone to be overproduced and to build up in the thyroid Disorder called goiter

Thyroid and parathyroid Important for the control of calcium levels Calcium is found in the: Bone Blood

Control of calcium levels

Adrenal Gland Located on the kidneys Hormones: Epinephrine and Norepinephrine: Aldosterone: Cortisol: