Chapter 10: The Endocrine System Essentials of human Anatomy and Physiology Fifth Edition Seeley, Stephens and Tate.
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Chapter 10: The Endocrine System
Essentials of human Anatomy
and PhysiologyFifth Edition
Seeley, Stephens and Tate
The Endocrine SystemThe Endocrine System
Slide 9.1Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Living systems require coordination and integration
Endocrine and nervous systems are the control systems of the body
Endocrine control:
Slower
Longer acting
The Endocrine SystemThe Endocrine System
Slide 9.1Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Nervous system control (later) More rapid
Short duration
The two systems are interrelated
Act to maintain homeostasis
The Endocrine SystemThe Endocrine System
Slide 9.1Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Endocrine glands vs. Exocrine glandsEndocrine glands make hormones
Hormones released into blood
Circulate throughout the body
Act only at “receptor sites” ontarget cells: very specific
The Endocrine SystemThe Endocrine System
Slide 9.1Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hormones control several major processes Reproduction Growth and development Mobilization of body defenses Maintenance of much of homeostasis Regulation of metabolism
Hormone OverviewHormone Overview
Slide 9.2Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hormones (Gr. “to set in motion”) are produced by specialized cells
Blood transfers hormones to target sites
Hormones alter the physiology of other cells
The Chemistry of HormonesThe Chemistry of Hormones
Slide 9.3Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Amino acid-based hormones
Proteins
Peptides
Amines
Steroids – made from cholesterol
Prostaglandins – made from highly active lipids
Mechanisms of Hormone ActionMechanisms of Hormone Action
Slide 9.4Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hormones affect only certain tissues or organs (target cells or organs)
Target cells must have specific protein receptors
Hormone binding influences the function of the cells
Effects Caused by HormonesEffects Caused by Hormones
Slide 9.5Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Changes in plasma membrane permeability or electrical state
Synthesis of proteins, such as enzymes
Activation or inactivation of enzymes
Stimulation of mitosis
Steroid Hormones: Mechanism of Steroid Hormones: Mechanism of Action Action (DNA or “Gene Expression”)(DNA or “Gene Expression”)
Slide 9.6Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hormones diffuse through the plasma membrane of target cells
Enter the nucleus
Bind to a specific protein within the nucleus
Steroid Hormone ActionSteroid Hormone Action
Slide 9.6Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hormone-protein complex binds to a specific site on the cell’s DNA
Activates genes that result in synthesis of new proteins
New protein influences cell function
Steroid Hormone ActionSteroid Hormone Action
Slide 9.7Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 9.1a
Nonsteroid Hormone Action: Nonsteroid Hormone Action: “Second Messenger System”“Second Messenger System”
Slide 9.8Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hormone binds to a membrane receptor
Hormone does not enter the cell
Sets off a series of reactions that activates an enzyme
Nonsteroid Hormone Action: Nonsteroid Hormone Action: “Second Messenger System”“Second Messenger System”
Slide 9.8Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Catalyzes a reaction that produces a second messenger molecule
Cyclic AMP (cAMP)
cAMP activates additional intracellular changes to promote a specific response
Nonsteroid Hormone ActionNonsteroid Hormone Action
Slide 9.9Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 9.1b
Control of Hormone ReleaseControl of Hormone Release
Slide 9.10Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hormone levels in the blood are maintained by negative feedback
A stimulus (like low hormone levels in the blood) triggers the release of more hormone
Hormone release stops once an appropriate level in the blood is reached
Hormonal Stimuli of Endocrine Hormonal Stimuli of Endocrine GlandsGlands
Slide 9.11Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Endocrine glands are activated by other hormones
Figure 9.2a
Humoral Stimuli of Endocrine Humoral Stimuli of Endocrine GlandsGlands
Slide 9.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 9.2b
Changing blood levels of certain ions stimulate hormone release
Neural Stimuli of Endocrine GlandsNeural Stimuli of Endocrine Glands
Slide 9.13Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Nerve impulses stimulate hormone release
Most are under control of the sympathetic nervous system
Figure 9.2c
Location of Major Endocrine GlandsLocation of Major Endocrine Glands
Slide 9.14Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 9.3
Pituitary GlandPituitary Gland
Slide 9.15Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Size of a grape
Hangs by a stalk from the hypothalamus
Protected by the sphenoid bone (what part??)
Has two functional lobes Anterior pituitary – glandular tissue
Posterior pituitary – nervous tissue
Hormones of the Anterior PituitaryHormones of the Anterior Pituitary
Slide 9.16Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Six anterior pituitary hormones Two affect non-endocrine targets
Four stimulate other endocrine glands (tropic [“tropic” = “feeding”] hormones)
All six are secreted by the anterior pituitary (glandular tissue)
Hormones of the Anterior PituitaryHormones of the Anterior Pituitary
Slide 9.16Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Characteristics of all anterior pituitary hormones Proteins (or peptides)
Act through second-messenger systems
Regulated by hormonal stimuli, mostly negative feedback
Hormones of the Anterior PituitaryHormones of the Anterior Pituitary
Slide 9.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 9.4
Functions of Anterior Pituitary Functions of Anterior Pituitary HormonesHormones
Slide 9.18Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Growth Hormone (GH)
Action: growth of skeletal muscles and long bones; maintains size
Target: bone and muscle
Functions of Anterior Pituitary Functions of Anterior Pituitary HormonesHormones
Slide 9.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Prolactin (PRL)
Action: Stimulates and maintains milk production following childbirth
Target: mammary tissue
Function in males is unknown
Functions of Anterior Pituitary Functions of Anterior Pituitary HormonesHormones
Slide 9.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Adrenocorticotropic hormone (ACTH) Action: Regulates endocrine activity of the
adrenal cortex
Target: Cells of adrenal cortex
Functions of Anterior Pituitary Functions of Anterior Pituitary HormonesHormones
Slide 9.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Thyroid-stimulating hormone (TSH) Action: Influences growth and activity of the
thyroid gland Target: cells of the thyroid gland
Functions of Anterior Pituitary Functions of Anterior Pituitary HormonesHormones
Slide 9.20aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Gonadotropic hormones
Target: male/female gonads
Action: Follicle-stimulating hormone (FSH)
Stimulates follicle development in ovaries
Stimulates sperm development in testes
Functions of Anterior Pituitary Functions of Anterior Pituitary HormonesHormones
Slide 9.20bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Gonadotropic hormones (continued) Luteinizing hormone (LH)
Action: Triggers ovulation in females
Causes ruptured follicle to become the corpus luteum in females
Stimulates testosterone production in males (ICSH)
Pituitary - Hypothalamus Pituitary - Hypothalamus RelationshipRelationship
Slide 9.21Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Release of hormones is controlled by the hypothalamus
Hypothalamus produces two hormones
Made by neurons
transported the posterior pituitary by neurons
Pituitary - Hypothalamus Pituitary - Hypothalamus RelationshipRelationship
Slide 9.21Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The posterior pituitary is NOT an endocrine gland Does NOT make hormones
Is NOT glandular
Only releases hormones
Hormones of the Posterior PituitaryHormones of the Posterior Pituitary
Slide 9.22Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Oxytocin Target: Smooth muscle of uterus, breast
Action:
stimulates contractions of the uterus during labor
causes milk ejection
Hormones of the Posterior PituitaryHormones of the Posterior Pituitary
Slide 9.22Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Antidiuretic hormone (ADH) Target: Kidney tubules
Action:
Inhibits urine production
In large amounts, causes increased blood pressure (vasopressin)
Hormones of the Posterior PituitaryHormones of the Posterior Pituitary
Slide 9.22bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 9.5
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