Transcript 18-01_pptlect

Anatomy & Physiology
SIXTH EDITION
Chapter 18, part 1
The Endocrine System
PowerPoint® Lecture Slide Presentation prepared by
Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Frederic H. Martini
Fundamentals of
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.
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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.
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SECTION 18-1
Intercellular Communication
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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
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SECTION 18-2
An Overview of the Endocrine System
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Endocrine system
• Includes all cells and endocrine tissues that
produce hormones or paracrine factors
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Figure 18.1 The Endocrine System
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Figure 18.1
Hormone structure
• Amino acid derivatives
• Structurally similar to amino acids
• Peptide hormones
• Chains of amino acids
• Lipid derivatives
• Steroid hormones and eicosanoids
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Figure 18.2 A Structural Classification of
Hormones
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Figure 18.2
Hormones can be
• Freely circulating
• Rapidly removed from bloodstream
• Bound to transport proteins
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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
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Figure 18.3 G Proteins and Hormone Activity
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Figure 18.3
Figure 18.4 Hormone Effects on Gene Activity
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Figure 18.4
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
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Figure 18.5 Three Methods of Hypothalamic
Control over the Endocrine System
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Figure 18.5
SECTION 18-3
The Pituitary Gland
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Hypophysis
• Releases nine important peptide hormones
• All nine bind to membrane receptors and use
cyclic AMP as a second messenger
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Figure 18.6 The Anatomy and Orientation of the
Pituitary Gland
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Figure 18.6a, b
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
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