Here is 18-1. More detail to follow in class
Chapter 18, part 1
The Endocrine System
Learning Objectives
Compare the major chemical classes and general mechanisms of hormones.
Describe the location and structure of the pituitary gland, and explain its structural and functional relationships with the hypothalamus.
Describe the location and structure of each of the endocrine glands.
Learning Objectives
Identify the hormones produced by each of the endocrine glands and specify the functions of those hormones.
Describe the functions of the hormones produced by the kidneys, heart, thymus, testes, ovaries and adipose tissue.
Explain how hormones interact to produce coordinated physiological responses.
SECTION 18-1 Intercellular Communication
Endocrine versus Nervous system
Nervous system performs short term crisis management
Endocrine system regulates long term ongoing metabolic
Endocrine communication is carried out by endocrine cells releasing hormones
Alter metabolic activities of tissues and organs
Target cells
Paracrine communication involves chemical messengers between cells within one tissue
SECTION 18-2 An Overview of the Endocrine System
Endocrine system
Includes all cells and endocrine tissues that produce hormones or paracrine factors
Figure 18.1 The Endocrine System
Hormone structure
Amino acid derivatives
Structurally similar to amino acids
Peptide hormones
Chains of amino acids
Lipid derivatives
Steroid hormones and eicosanoids
Figure 18.2 A Structural Classification of Hormones
Hormones can be
Freely circulating
Rapidly removed from bloodstream
Bound to transport proteins
Mechanisms of hormone action
Receptors for catecholamines, peptide hormones, eicosanoids are in the cell membranes of target cells
Thyroid and steroid hormones cross the membrane and bind to receptors in the cytoplasm or nucleus
Figure 18.3 G Proteins and Hormone Activity
Figure 18.4 Hormone Effects on Gene Activity
Control of endocrine activity
Endocrine reflexes are the counterparts of neural reflexes
Hypothalamus regulates the activity of the nervous and endocrine systems
Secreting regulatory hormones that control the anterior pituitary gland
Releasing hormones at the posterior pituitary gland
Exerts direct neural control over the endocrine cells of the adrenal medullae
Figure 18.5 Three Methods of Hypothalamic Control over the Endocrine System
SECTION 18-3 The Pituitary Gland
Hypophysis
Releases nine important peptide hormones
All nine bind to membrane receptors and use cyclic AMP as a second messenger
Figure 18.6 The Anatomy and Orientation of the Pituitary Gland
The anterior lobe (adenohypophysis)
Subdivided into the pars distalis, pars intermedia and pars tuberalis
At the median eminence, neurons release regulatory factors through fenestrated capillaries
Releasing hormones
Inhibiting hormones
