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prepared by
Betsy C. Brantley
Valencia College
CHAPTER
10
The
Endocrine
System
© 2013 Pearson Education, Inc.
Chapter 10 Learning Outcomes
• Section 1: Hormones and Intercellular Communication
• 10.1
• Explain the classification of hormones, identify key functions of
hormones secreted by organs of the endocrine system, and list
organs with secondary endocrine functions.
• 10.2
• Compare the mechanism of action for nonsteroid and steroid
hormones.
• 10.3
• Describe how the hypothalamus controls other endocrine
organs.
© 2013 Pearson Education, Inc.
Chapter 10 Learning Outcomes
• Section 2: Endocrine Organs
• 10.4
• Describe the location and structure of the pituitary gland, and
identify pituitary hormones, their target tissues, and functions.
• 10.5
• Describe the location and structure of the thyroid gland, identify
the hormones it secretes, and list the effects of thyroid
hormones on peripheral tissues.
• 10.6
• Describe the location and structure of the parathyroid glands,
identify the hormone they produce, and list the effects of
parathyroid hormone on peripheral tissues.
© 2013 Pearson Education, Inc.
Chapter 10 Learning Outcomes
• 10.7
• Describe the location, structure, and general functions of the
adrenal glands, identify the hormones produced by the adrenal
cortex and the adrenal medulla, and list the effects of each
hormone.
• 10.8
• Identify the location and structure of the pancreas, identify key
pancreatic cells, and the hormones they produce, specify the
functions of each hormone, and summarize blood glucose
homeostasis.
• 10.9
• Identify the location of the pineal gland, and identify the
functions of melatonin.
© 2013 Pearson Education, Inc.
Chapter 10 Learning Outcomes
• 10.10
• CLINICAL MODULE Define diabetes mellitus, explain Type 1
and Type 2 diabetes, list clinical problems caused by diabetes
mellitus, and identify treatment for each type.
• 10.11
• Define the stress response and summarize the events for each
phase.
© 2013 Pearson Education, Inc.
Intercellular Communication (Section 1)
• Coordination of cellular activity requires
communication between cells
• Most common type of communication uses
chemical messengers
• Messengers released into interstitial fluid and blood
• Communication between neighboring cells by diffusion
of messengers
• Communication over greater distances coordinated by
nervous and endocrine systems
© 2013 Pearson Education, Inc.
Intercellular Communication by the Endocrine and Nervous Systems
Cell Type
Endocrine
glandular cells
Neurons
© 2013 Pearson Education, Inc.
Transmission
Through the
bloodstream
Across synaptic
clefts
Chemical
Messengers
Effects
Hormones
Long-term
communication
Neurotransmitters
Short, quick
communication
Figure 10 Section 11
The Endocrine and Nervous Systems
(Section 1)
• Features in common
• Release chemicals that bind to specific receptors
• Share some of same chemical messengers (e.g.,
norepinephrine, epinephrine)
• Regulate messenger activity by negative feedback
• Common goal to preserve homeostasis
© 2013 Pearson Education, Inc.
Chemical Messengers (Section 1)
• Endocrine – hormones
• Transported in bloodstream to target cells
• Target cells need appropriate receptors
• Provides long-term communication (growth and
development)
• Nervous – neurotransmitters
• Transported by diffusion across synaptic cleft
• Limited to specific area
• Target cells need appropriate receptors
• Provides short, quick communication (reflexes)
© 2013 Pearson Education, Inc.
Chemical Categorization of Hormones (10.1)
•
Hormones divided into three groups based on
chemical structure
1. Amino acid derivatives
2. Peptide hormones
3. Lipid derivatives
© 2013 Pearson Education, Inc.
Amino Acid Derivatives (10.1)
•
Small molecules related to amino acids
1. Derivatives of tyrosine
•
Thyroid hormone
•
Catecholamines (e.g., epinephrine)
•
Sources of tyrosine include meat, dairy, and fish
2. Derivatives of tryptophan
•
Melatonin
•
Sources of tryptophan include turkey, chocolate, oats,
bananas, dried dates, milk, cottage cheese, and peanuts
© 2013 Pearson Education, Inc.
Peptide Hormones (10.1)
•
Chains of amino acids
•
Most synthesized as prohormones
•
Inactive molecules converted to active before or after
secretion
1. Glycoproteins
•
More than 200 amino acids long with carbohydrate side
chains
2. Short polypeptides/small proteins
•
Large and diverse group
•
Short chain polypeptides, 9 amino acids long
•
Small proteins up to 198 amino acids long
© 2013 Pearson Education, Inc.
Two Classes of Lipid Derivatives (10.1)
1. Eicosanoids
•
Derived from arachidonic acid
•
Coordinate cellular activities and affect enzymatic processes
•
Prostaglandins involved in coordinating local cellular activities
2. Steroid hormones
•
Derived from cholesterol
•
Released by reproductive organs
•
Androgens by testes
•
Estrogen and progesterone by ovaries
•
Released by adrenal cortex (corticosteroids) and kidneys
(calcitriol)
•
Bound to specific transport proteins
•
Remain in circulation longer than peptide hormones
© 2013 Pearson Education, Inc.
Structural classification of hormones
Amino Acid Derivatives
Derivatives of Tyrosine
Thyroid Hormones
Thyroxine (T4)
Catecholamines
Epinephrine
Peptide Hormones
Glycoproteins
Includes:
Thyroid-stimulating hormone
(TSH), Luteinizing hormone
(LH), Follicle-stimulating
hormone (FSH), and several
other hormones
Short Polypeptides/
Small Proteins
Includes:
Antidiuretic hormone (ADH),
oxytocin (OXT), growth
hormone (GH), prolactin
(PRL), and several other
hormones
Lipid Derivatives
Eicosanoids
Prostaglandin E
Aspirin suppresses the
production of
prostaglandins.
Steroid Hormones
Estrogen
Sources of tyrosine
include meat, dairy, and fish.
Derivative of Tryptophan
Melatonin
Turkey is a well known
source of tryptophan. Other
sources include chocolate, oats,
bananas, dried dates, milk,
cottage cheese, and peanuts.
© 2013 Pearson Education, Inc.
Figure 10.1
11
Primary Endocrine System Organs (10.1)
• Hypothalamus
• Pituitary gland
• Thyroid gland
• Parathyroid glands
• Adrenal glands
• Pancreas (pancreatic islets)
© 2013 Pearson Education, Inc.
Secondary Endocrine Organs (10.1)
• Contain tissues that secrete hormones, but
endocrine functions are secondary
• Heart hormones
• Regulate blood volume
• Thymus hormones
• Stimulate and coordinate immune response
• Digestive tract hormones
• Coordinate digestive system functions, glucose
metabolism, and appetite
© 2013 Pearson Education, Inc.
Secondary Endocrine Organs (10.1)
• Adipose tissue hormones
• Regulate appetite and fat metabolism
• Kidney hormones
• Regulate blood cell production and rates of calcium and
phosphate absorption by intestinal tract
• Gonadal hormones
• Affect growth, metabolism, and sexual characteristics
• Coordinate activities of organs in reproductive system
© 2013 Pearson Education, Inc.
Structural classification of hormones
Pineal Gland
Hypothalamus
Organs with
Secondary
Endocrine
Functions
Pituitary Gland
Thyroid Gland
Heart
Parathyroid
Glands
Thymus
Adrenal Glands
Digestive tract
Pancreas
(Pancreatic
Islets)
Adipose tissue
Kidneys
Testis
Gonads
Ovary
© 2013 Pearson Education, Inc.
Figure 10.1
22
Module 10.1 Review
a. Define endocrine system.
b. Describe the structural classification of
hormones.
c. Name the primary organs of the endocrine
system and those organs and tissues with
secondary endocrine functions.
© 2013 Pearson Education, Inc.
Nonsteroid Hormones Mechanism (10.2)
• Bind to receptors on plasma membrane
• Activate G proteins
• Use second messenger
• Intracellular intermediate alters enzyme activity in cell
• Often high-energy compounds like cyclic-AMP (cAMP)
• Nonsteroid hormones include:
• Lipid soluble (eicosanoids) with receptors on inner
surface of membrane
• Not lipid soluble (catecholamines, peptide hormones)
with receptors on outer surface of membrane
© 2013 Pearson Education, Inc.
Nonsteroid hormones and second messenger mechanism
Nonsteroid
hormone
(first messenger)
Plasma
membrane
1
Binding of hormone
to plasma membrane
receptor
2
G protein
activated
3
4
CYTOPLASM
Second messenger
system activated
Cellular enzyme
activity changed
Target cell
response
NUCLEUS
Nuclear
envelope
Nuclear
pore
© 2013 Pearson Education, Inc.
DNA
Figure 10.2 111 24
Steroid Hormones Mechanisms of Action (10.2)
• Pass directly through target cell's plasma
membrane
• Lipid soluble
• Bind to receptors in cytoplasm and nucleus
• Affect gene activity and protein synthesis
© 2013 Pearson Education, Inc.
Steroid hormone mechanism
1
Steroid hormone
Diffusion through
membrane lipids
Target cell response
Alteration of cellular
structure or activity
6
2
Receptor
Translation and
protein synthesis
Binding of
hormone to
cytoplasmic
or nuclear
receptors
creates a
hormonereceptor
complex.
5
4
Receptor
Nuclear
pore
Nuclear
envelope
© 2013 Pearson Education, Inc.
Transcription and
mRNA production
3
Gene
activation
Binding of
hormone-receptor
complex to DNA
Figure 10.2 221 24
Module 10.2 Review
a. Describe two mechanisms of hormone action.
b. Which type of hormone binds to a plasma
membrane receptor and why?
c. Which type of hormone diffuses across the
plasma membrane and binds to receptors in the
cytoplasm?
© 2013 Pearson Education, Inc.
Hypothalamus Control (10.3)
•
Integrates activities of nervous and endocrine
systems through three mechanisms
1. Synthesis and transport of two hormones to posterior
pituitary
•
Antidiuretic hormone (ADH)
•
Oxytocin (OXT)
2. Secretion of regulatory hormones to anterior pituitary
•
Releasing hormone (RH)
•
Inhibiting hormone (IH)
3. Autonomic centers
© 2013 Pearson Education, Inc.
Posterior Lobe of the Pituitary Gland (10.3)
• ADH and oxytocin
• Synthesized in hypothalamus
• Released into circulation from posterior lobe of pituitary
gland
© 2013 Pearson Education, Inc.
Anterior Lobe of the Pituitary Gland (10.3)
• Regulatory hormones carried to anterior lobe by
hypophyseal portal system
• Releasing hormone stimulates secretion of hormone
from anterior lobe
• Inhibiting hormone prevents secretion of hormone from
anterior lobe
• Hormones from anterior lobe control:
• Thyroid gland
• Adrenal cortex
• Reproductive organs
© 2013 Pearson Education, Inc.
Autonomic Centers (10.3)
• Exert direct neural control over endocrine cells in
adrenal medulla
• Active when sympathetic division stimulated
• Adrenal medulla responds by releasing
epinephrine (E) and norepinephrine (NE)
© 2013 Pearson Education, Inc.
Three mechanisms of hypothalmic control over endocrine function
1
Antidiuretic
hormone and
oxytocin are
synthesized
by hypothalamic neurons.
2
Regulatory and
inhibitory hormones
target the anterior
lobe of the pituitary
gland.
3
Autonomic centers
exert direct neural
control over
endocrine cells in
the adrenal
medullae.
HYPOTHALAMUS
Preganglionic
motor fibers
Hypophyseal
portal system
Anterior lobe of
pituitary gland
Hormones from anterior lobe
of the pituitary gland target
the thyroid, adrenal cortex,
and reproductive organs.
© 2013 Pearson Education, Inc.
Adrenal cortex
Adrenal medulla
Posterior lobe
of pituitary
gland
ADH and oxytocin are
released into circulation
from posterior lobe of
the pituitary gland.
Adrenal gland
Upon direct neuronal
stimulation, the adrenal
medullae secrete epinephrine
and norepinephrine into the
circulation.
Figure 10.3 11
Module 10.3 Review
a. Identify the three mechanisms by which the
hypothalamus integrates neural and endocrine
function.
b. Define regulatory hormone.
c. Contrast releasing hormones with inhibiting
hormones.
© 2013 Pearson Education, Inc.
Primary Endocrine Organs (Section 2)
• Pituitary gland
• Secretes multiple hormones regulating activities of
adrenal cortex, thyroid gland, reproductive organs, and
melatonin production
• Thyroid gland
• Affects metabolic rate and calcium levels in body fluids
• Adrenal glands
• Hormones involved with mineral balance, metabolic
control, and resistance to stress
• Adrenal medulla releases E and NE in response to
sympathetic activation
© 2013 Pearson Education, Inc.
Primary Endocrine Organs (Section 2)
• Pineal gland
• Secretes melatonin
• Affects reproductive function and circadian rhythm
• Parathyroid glands
• Secrete hormone important for regulating calcium ion
concentration in body fluids
• Pancreas (pancreatic islets)
• Secrete hormones regulating glucose uptake and
utilization
© 2013 Pearson Education, Inc.
Primary Endocrine Organs (Section 2)
• Pituitary gland, parathyroid gland, pineal gland,
pancreatic islets, some adrenal hormones
• Exert effects through second messenger systems
• Primarily impact enzyme activities
• Thyroid hormones and other adrenal hormones
• Primarily alter genetic activities
• Effects take longer to appear
© 2013 Pearson Education, Inc.
Primary endocrine organs
Pituitary Gland
Pineal Gland
Thyroid Gland
Parathyroid
Glands
Adrenal Glands
© 2013 Pearson Education, Inc.
Pancreas
(Pancreatic
Islets)
Figure 10 Section 2
The Pituitary Gland as a Master Gland (10.4)
• Small, oval gland
• Nestled within sella turcica, depression in
sphenoid
• Releases nine important peptide hormones
• Seven secreted by the anterior pituitary
• Two released from the posterior pituitary (made by the
hypothalamus)
• All bind to membrane receptors
• All use same second messenger
© 2013 Pearson Education, Inc.
Pituitary hormones and their targets
HYPOTHALAMUS
Floor of
hypothalamus
Hormones of the Posterior Lobe of the
Pituitary Gland
Optic chiasm
Fold of dura
mater
Anterior lobe
of the pituitary
gland
ADH
OXT
Antidiuretic hormone (ADH),
also known as vasopressin
Oxytocin (okytokos,
swift birth), or OXT
Posterior lobe
of the pituitary
gland
Kidney
Hormones of the Anterior Lobe of the Pituitary Gland
Gonadotropins
(FSH and LH)
TSH
ACTH
GH
Adrenocorticotropic
Thyroidhormone (ACTH)
stimulating
hormone (TSH)
Thyroid
gland
© 2013 Pearson Education, Inc.
Adrenal
gland
Folliclestimulating
hormone
(FSH)
Ovary
Luteinizing
(LOO-tē-in-ī-zing)
hormone
(LH)
Testis
Growth
hormone (GH)
Uterus
PRL
MSH
Prolactin
(pro-, before
+ lac, milk)
(PRL)
Melanocytestimulating
hormone
(MSH)
Muscular
and
skeletal
systems
Figure 10.4
Anterior Lobe of the Pituitary Gland (10.4)
•
Secretes seven hormones called tropic
hormones
•
1.
2.
3.
4.
5.
6.
7.
"Turn on" other endocrine glands or support functions
of other organs
TSH
ACTH
FSH
LH
GH
PRL
MSH
© 2013 Pearson Education, Inc.
Anterior Pituitary Gland Hormones (10.4)
1. Thyroid-stimulating hormone (TSH)
•
Also called thyrotropin
•
Targets thyroid gland
•
Triggers release of thyroid hormones
2. Adrenocorticotropic hormone (ACTH)
•
Also called corticotropin
•
Targets cells of adrenal cortex
•
Triggers release of steroid hormones
•
© 2013 Pearson Education, Inc.
Specifically hormones affecting glucose metabolism
Anterior Pituitary Gland Hormones (10.4)
•
Gonadotropins regulate the activities of the
gonads
•
•
Gonads are organs (testes and ovaries) that produce
reproductive cells and hormones
Gonadotropins include FSH and LH
3. Follicle-stimulating hormone (FSH)
•
Females
•
•
•
Males
•
•
Promotes ovarian follicle development
Stimulates secretion of estrogen
Promotes maturation of sperm
Inhibited by inhibin, released by cells in testes and
ovaries
© 2013 Pearson Education, Inc.
Anterior Pituitary Gland Hormones (10.4)
4. Luteinizing hormone (LH)
•
•
Females
•
Induces ovulation
•
Promotes secretion of estrogen and progestins
Males
•
Stimulates production of sex hormones (androgens) by
interstitial cells
•
© 2013 Pearson Education, Inc.
Testosterone most important androgen
Anterior Pituitary Gland Hormones (10.4)
5. Growth hormone (GH)
•
•
•
Stimulates cell growth and reproduction
Accelerates rate of protein synthesis
Epithelia and connective tissues
•
•
•
Stimulates stem cell divisions and differentiations
Adipose tissue
•
Stimulates break down of triglycerides into fatty acids
•
Glucose-sparing effect when tissues use fatty acids
instead of glucose to generate ATP
Liver
•
© 2013 Pearson Education, Inc.
Stimulates breakdown of glycogen reserves
Anterior Pituitary Gland Hormones (10.4)
6. Prolactin (PRL)
•
Stimulates mammary gland development
•
Stimulates milk production by mammary glands in
pregnancy and nursing period
7. Melanocyte-stimulating hormone (MSH)
•
Stimulates melanocytes of skin to increase production
of melanin
•
Portion of anterior lobe that produces this is virtually
nonfunctional in adults
© 2013 Pearson Education, Inc.
Hormones of the anterior lobe of the pituitary gland
Hormones of the Anterior Lobe of the Pituitary Gland
Gonadotropins
(FSH and LH)
ACTH
TSH
GH
Adrenocorticotropic FollicleThyroidLuteinizing
hormone (ACTH)
stimulating (LOO-tē-in-ī-zing)
stimulating
hormone
hormone
hormone (TSH)
(FSH)
(LH)
Thyroid
gland
© 2013 Pearson Education, Inc.
Adrenal
gland
Ovary
Testis
PRL
Growth
Prolactin
hormone (GH) (pro-, before
+ lac, milk)
(PRL)
MSH
Melanocytestimulating
hormone
(MSH)
Muscular
and
skeletal
systems
Figure 10.4
Posterior Lobe of the Pituitary Gland (10.4)
•
Contains axons of hypothalamic neurons
•
Releases two hormones
1. Antidiuretic hormone (ADH) or vasopressin
2. Oxytocin (OXT)
© 2013 Pearson Education, Inc.
Posterior Pituitary Gland Hormones (10.4)
1. Antidiuretic Hormone (ADH) or vasopressin
•
Released in response to:
•
•
•
•
•
Neurosecretory neurons stimulated by osmoreceptors
Primary function to decrease water loss at kidneys
•
•
•
Rise in solute concentration in blood
Fall in blood volume
Decreased blood pressure
Resulting water retention reduces electrolyte
concentration in extracellular fluid
Also causes vasoconstriction, helping raise blood
pressure
Alcohol inhibits ADH release
© 2013 Pearson Education, Inc.
Posterior Pituitary Gland Hormones (10.4)
2. Oxytocin (OXT)
•
In women, stimulates smooth muscle contraction in
wall of uterus
•
•
Stimulates contraction of cells in mammary glands
•
•
Promotes labor and delivery
Promotes ejection of milk
Find increased levels in both sexes during sexual
arousal and orgasm
© 2013 Pearson Education, Inc.
Hormones of the posterior lobe of the pituitary gland
Hormones of the Posterior Lobe of the
Pituitary Gland
ADH
OXT
Antidiuretic hormone
(ADH), also known as
vasopressin
Oxytocin (okytokos,
swift birth), or OXT
Kidney
© 2013 Pearson Education, Inc.
Uterus
Figure 10.4
Module 10.4 Review
a. Name the two lobes of the pituitary gland and the
cellular sources of their secreted hormones.
b. Identify the nine pituitary hormones and their
target tissues.
c. In a dehydrated person, how would the amount
of ADH released by the posterior pituitary
change?
© 2013 Pearson Education, Inc.
Thyroid Gland (10.5)
• On anterior surface of trachea
• Inferior to thyroid cartilage
• Two lobes connected by narrow isthmus
• Variable size depending on:
• Heredity
• Environmental factors
• Nutritional factors
• Average weight 34 g
• Deep red color from extensive blood supply
© 2013 Pearson Education, Inc.
The thyroid gland
Thyroid
cartilage
Right lobe of
thyroid gland
Isthmus of
thyroid gland
Internal jugular vein
Left lobe of
thyroid gland
Common
carotid artery
Simple cuboidal
epithelium
of follicle
Thyroglobulin
in colloid
Trachea
Outline of
clavicle
Outline of
sternum
Thyroid
follicle
C (clear)
cells
Section of thyroid gland LM x 260
© 2013 Pearson Education, Inc.
Figure 10.5
1 – 2
Thyroid Follicles (10.5)
• Thyroid gland filled with thyroid follicles
• Hollow spheres lined with simple cuboidal epithelium
• Colloid in cavity
• Viscous fluid containing dissolved proteins
• Follicular cells synthesize thyroglobulin
• Contains amino acid tyrosine
• Iodide ions added to form thyroid hormones
• Thyroglobulin-hormone complex stored in follicle
© 2013 Pearson Education, Inc.
Parafollicular Cells (10.5)
• In thyroid gland, cells outside follicles
• Large, pale, clear cells called C (clear) cells or
parafollicular cells
• Produce calcitonin (CT)
• Helps regulate calcium ion concentrations in body fluids
© 2013 Pearson Education, Inc.
Histological organization of thyroid gland
Simple cuboidal
epithelium
of follicle
Thyroglobulin
in colloid
Thyroid
follicle
C (clear)
cells
Section of thyroid gland LM x 260
© 2013 Pearson Education, Inc.
Figure 10.5
2
Thyroglobulin (10.5)
•
Thyroglobulin broken down by follicular cells into two
hormones released into bloodstream
1. T3 (triiodothyronine) with three iodide ions
2. T4 (thyroxine) with four iodide ions
•
About 75 percent thyroid hormones attached to transport
proteins
•
Thyroid-binding globulins (TBGs)
•
Release thyroid hormones gradually
•
More than a week's supply of thyroid hormone in
bloodstream bound to transport proteins
© 2013 Pearson Education, Inc.
Thyroid Hormone Transport (10.5)
• Transported across plasma membrane
• Primarily by carrier-mediated processes
• Inside cell
• Bind to receptors on mitochondria and within the
nucleus
• Increase rate of ATP production
• In nucleus, activate specific genes or changes rate of
transcription
• Affect concentration of enzymes and so metabolic
activities of cell
© 2013 Pearson Education, Inc.
Mechanism of thyroid hormone entry and action in a cell
Thyroid-binding globulin
Thyroid hormone (T3 and T4)
1
Carrier-mediated
transport across the
plasma membrane
Target cell response
Increased
Receptor
Alteration of cellular
structure or
enzymatic activity
production
6
2
Binding to receptors
at mitochondria and
within the nucleus.
Mitochondria
respond by
increasing ATP
production.
Translation and
protein synthesis
5
Transcription and
mRNA production
Receptor
4
Gene activation
3
© 2013 Pearson Education, Inc.
Binding of
hormone-receptor
complex to DNA
Figure 10.5
4
Effects of Thyroid Hormones on Peripheral
Tissues (10.5)
•
Raise metabolic rate
•
•
In children, may raise body temperature, oxygen, and
energy
Increase heart rate and force of contraction
•
Generally raise blood pressure
•
Increase sensitivity to sympathetic stimulation
•
Maintain normal sensitivity of respiratory centers
to changes in oxygen and carbon dioxide
concentrations
© 2013 Pearson Education, Inc.
Effects of Thyroid Hormones on Peripheral
Tissues (10.5)
•
Stimulate red blood cell formation
•
Enhancing oxygen concentration
•
Stimulate activity in other endocrine tissues
•
Accelerate turnover of minerals in bone
© 2013 Pearson Education, Inc.
Module 10.5 Review
a. Name the three hormones secreted by the
thyroid gland.
b. List five effects that thyroid hormones have on
peripheral tissues.
c. After a thyroidectomy (surgical removal of the
thyroid gland), symptoms of decreased thyroid
hormone concentrations take about a week to
appear. Why?
© 2013 Pearson Education, Inc.
Parathyroid Glands (10.6)
• Four parathyroid glands
• Embedded in posterior surface of thyroid gland
• Shaped like small peas
• Total weight 1.6 g
• Covered by capsule of thyroid gland
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The parathyroid glands
Thyroid gland
Parathyroid
glands
Blood vessel
Dense fibrous
capsule
Parathyroid gland
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LM x 94
Thyroid
follicles
Figure 10.6
1 – 2
Two Parts to the Parathyroid (10.6)
1. Parathyroid cells
•
Produce parathyroid hormone (PTH)
•
Secreted in response to low calcium concentrations in
blood
2. Oxyphils
•
No known function
© 2013 Pearson Education, Inc.
Calcium Ion Balance (10.6)
• Calcitonin lowers blood calcium; PTH raises blood calcium
• PTH primary regulator of circulating calcium ion
concentration
• Increases calcium reabsorption in kidneys
• Increases calcitriol production
• Increases calcium absorption from digestive system
• Causes release of calcium from bone
• Elevated calcium levels are rare
• Removal of thyroid gland (and calcitonin) seldom affects balance
• Can give calcitonin if needed for disorders that raise calcium levels,
causing excessive bone formation
© 2013 Pearson Education, Inc.
Slide 1
Rising levels of blood calcium
Homeostatic regulation of calcium ion concentrations
HOMEOSTASIS
DISTURBED
Rising calcium
levels in blood
HOMEOSTASIS
© 2013 Pearson Education, Inc.
Figure 10.6
3
Slide 2
Rising levels of blood calcium
Homeostatic regulation of calcium ion concentrations
Thyroid gland
produces
calcitonin
HOMEOSTASIS
DISTURBED
Rising calcium
levels in blood
HOMEOSTASIS
© 2013 Pearson Education, Inc.
Figure 10.6
3
Slide 3
Rising levels of blood calcium
Homeostatic regulation of calcium ion concentrations
Thyroid gland
produces
calcitonin
Increased
excretion
of calcium
by kidneys
Calcium
deposition
in bone
HOMEOSTASIS
DISTURBED
Rising calcium
levels in blood
HOMEOSTASIS
© 2013 Pearson Education, Inc.
Figure 10.6
3
Slide 4
Rising levels of blood calcium
Homeostatic regulation of calcium ion concentrations
© 2013 Pearson Education, Inc.
Thyroid gland
produces
calcitonin
Increased
excretion
of calcium
by kidneys
Calcium
deposition
in bone
HOMEOSTASIS
RESTORED
HOMEOSTASIS
DISTURBED
Blood calcium
levels decline
Rising calcium
levels in blood
HOMEOSTASIS
Figure 10.6
3
Slide 5
Rising levels of blood calcium
Homeostatic regulation of calcium ion concentrations
Thyroid gland
produces
calcitonin
Increased
excretion
of calcium
by kidneys
Calcium
deposition
in bone
HOMEOSTASIS
RESTORED
HOMEOSTASIS
DISTURBED
Blood calcium
levels decline
Rising calcium
levels in blood
HOMEOSTASIS
Normal blood
calcium levels
(8.5–11 mg/dL)
HOMEOSTASIS
DISTURBED
Falling calcium
levels in blood
© 2013 Pearson Education, Inc.
Figure 10.6
3
Slide 6
Rising levels of blood calcium
Homeostatic regulation of calcium ion concentrations
Thyroid gland
produces
calcitonin
Increased
excretion
of calcium
by kidneys
Calcium
deposition
in bone
HOMEOSTASIS
RESTORED
HOMEOSTASIS
DISTURBED
Blood calcium
levels decline
Rising calcium
levels in blood
HOMEOSTASIS
Normal blood
calcium levels
(8.5–11 mg/dL)
HOMEOSTASIS
DISTURBED
Falling calcium
levels in blood
Parathyroid
glands secrete
parathyroid
hormone (PTH)
© 2013 Pearson Education, Inc.
Figure 10.6
3
Slide 7
Rising levels of blood calcium
Homeostatic regulation of calcium ion concentrations
Thyroid gland
produces
calcitonin
Increased
excretion
of calcium
by kidneys
Calcium
deposition
in bone
HOMEOSTASIS
RESTORED
HOMEOSTASIS
DISTURBED
Blood calcium
levels decline
Rising calcium
levels in blood
HOMEOSTASIS
Normal blood
calcium levels
(8.5–11 mg/dL)
HOMEOSTASIS
DISTURBED
Falling calcium
levels in blood
Parathyroid
glands secrete
parathyroid
hormone (PTH)
© 2013 Pearson Education, Inc.
Increased reabsorption of calcium
by the kidneys
Calcium release
from bone
Increased calcitriol
production causes
Ca2+ absorption
from digestive
system
Figure 10.6
3
Slide 8
Rising levels of blood calcium
Homeostatic regulation of calcium ion concentrations
Thyroid gland
produces
calcitonin
Increased
excretion
of calcium
by kidneys
Calcium
deposition
in bone
HOMEOSTASIS
RESTORED
HOMEOSTASIS
DISTURBED
Blood calcium
levels decline
Rising calcium
levels in blood
HOMEOSTASIS
Normal blood
calcium levels
(8.5–11 mg/dL)
HOMEOSTASIS
DISTURBED
Falling calcium
levels in blood
Parathyroid
glands secrete
parathyroid
hormone (PTH)
© 2013 Pearson Education, Inc.
HOMEOSTASIS
RESTORED
Blood calcium
levels increase
Increased reabsorption of calcium
by the kidneys
Calcium release
from bone
Increased calcitriol
production causes
Ca2+ absorption
from digestive
system
Figure 10.6
3
Effects of Parathyroid Hormone on Peripheral
Tissues (10.6)
•
Mobilizes calcium from bone by affecting
osteoblast and osteoclast activity
•
PTH inhibits osteoblasts
•
•
•
•
•
Reduces rate of calcium deposition in bone
Osteoclast activity erodes bone matrix
Plasma calcium levels rise
Enhances reabsorption of calcium by kidneys
Stimulates formation and secretion of calcitriol at
kidneys
•
Calcitriol enhances calcium and phosphate absorption
by the digestive system
© 2013 Pearson Education, Inc.
Module 10.6 Review
a. Describe the locations of the parathyroid glands.
b. Explain how parathyroid hormone raises blood
calcium levels.
c. Increased blood calcium levels would result in
increased secretion of which hormone?
© 2013 Pearson Education, Inc.
Adrenal Glands (10.7)
• Pyramid-shaped gland
• On superior border of each kidney
• Only anterior surface is covered with parietal
peritoneum
• Rich blood supply
• Outer cortex region and inner medulla region
• Cortex yellow from stored lipids
© 2013 Pearson Education, Inc.
The adrenal gland
Capsule
Adrenal cortex
Adrenal
medulla
Right adrenal
gland
Adrenal
arteries
Left adrenal
gland
Right
kidney
Left
kidney
Abdominal aorta
Inferior vena cava
© 2013 Pearson Education, Inc.
Figure 10.7
1
1– –24 2
Adrenal Hormones (10.7)
• Adrenal cortex
• Produces more than two dozen steroid hormones called
corticosteroids
• Affect genes in target cells, resulting in changes in
enzymes and cellular metabolism
• Adrenal medulla
• Produces epinephrine and norepinephrine
• Responds to sympathetic activation
© 2013 Pearson Education, Inc.
The adrenal gland and its hormones
The Adrenal Hormones
Region/
Zone
Capsule
Adrenal cortex
Adrenal
medulla
Right adrenal Adrenal
gland arteries
Right
kidney
Left adrenal
gland
Left
kidney
Abdominal aorta
Inferior vena cava Adrenal gland LM x 250
© 2013 Pearson Education, Inc.
Hormones
Primary
Targets
Hormonal
Effects
Regulatory
Control
Increased renal
reabsorption of
Na+ and water;
accelerates
urinary loss of K+
Stimulated by
renin-angiotensin
system; inhibited
by opposing
hormones
Capsule
ADRENAL CORTEX
Outer zone
of the
adrenal
cortex
Mineralocorticoids
(MCs),
primarily
aldosterone
Kidneys
Large,
central
zone of
the adrenal
cortex
Glucocorticoids,
primarily
cortisol
Increase
glucose
and glycogen
formation and
reduces
inflammation
Skin, bones, Adrenal androgens stimulate
and other
the development
tissues, but
of pubic hair in
minimal
boys and girls
effects in
normal adults before puberty.
Most cells
Narrow
zone
bordering
each
adrenal
medulla
Androgens
ADRENAL
MEDULLA
Epinephrine Most cells
(E) and
norepinephrine (NE)
Epinephrine and
norepinephrine
increase cardiac
activity, blood
pressure, glycogen
breakdown, and
blood glucose
levels.
Stimulated by
ACTH
Stimulated by
ACTH
Epinephrine and
norepinephrine
secretion is stimulated by sympathetic
preganglionic fibers
during sympathetic
activation.
Figure 10.7
Zones of the Adrenal Cortex (10.7)
• Outer zone
• Secretes mineralocorticoids (MCs), primarily
aldosterone
• Central zone
• Secretes glucocorticoids (GCs), primarily cortisol
• Involved in glucose-sparing effect and anti-inflammatory
effect
• Also secretes corticosterone, which liver converts to
cortisone
• Inner zone bordering adrenal medulla
• Secretes androgens that can be converted to estrogens
© 2013 Pearson Education, Inc.
The Adrenal Hormones
Region/
Zone
Hormones
Primary
Targets
Hormonal
Effects
Regulatory
Control
Capsule
ADRENAL CORTEX
Outer zone Mineraloof the adre- corticoids
(MCs),
nal cortex
primarily
aldosterone
Adrenal gland
© 2013 Pearson Education, Inc.
Kidneys
Increased renal
reabsorption of Na+
and water; accelerates urinary loss of
K+
Stimulated by reninangiotensin system;
inhibited by opposing hormones
Large, central zone of
the adrenal
cortex
Glucocorticoids,
primarily
cortisol
Most cells
Increase glucose
and glycogen
formation and
reduces inflammation
Stimulated by
ACTH
Narrow
zone
bordering
each
adrenal
medulla
Androgens
Skin, bones,
and other
tissues, but
minimal
effects in
normal adults
Adrenal androgens
stimulate the
development of
pubic hair in boys
and girls before
puberty.
Stimulated by
ACTH
ADRENAL
MEDULLA
Epinephrine
(E) and
norepinephrine (NE)
Most cells
Epinephrine and
Epinephrine and
norepinephrine
norepinephrine secreincrease cardiac
tion is stimulated by
activity, blood pres- sympathetic preganglisure, glycogen break- onic fibers during
down, and blood
sympathetic
glucose levels.
activation.
LM x 250
Figure 10.7
3
Module 10.7 Review
a. Identify the two regions of an adrenal gland, and
cite the hormones secreted by each.
b. Identify the target tissue for aldosterone.
c. How would elevated cortisol levels affect blood
glucose levels?
© 2013 Pearson Education, Inc.
The Pancreas (10.8)
• In abdominopelvic cavity between inferior border
of stomach and proximal portion of small intestine
• About 20–25 cm long
• Weighs 80 g
• Has both exocrine and endocrine functions
• Exocrine pancreas is 99 percent of organ's volume
• Forms clusters (pancreatic acini) around small ducts
• Secretes enzymes through ducts to digestive tract
© 2013 Pearson Education, Inc.
Pancreatic structures
Body of
Small intestine
(duodenum) Pancreatic pancreas
duct
© 2013 Pearson Education, Inc.
Lobule
Figure 10.8
11 24
The Endocrine Pancreas (10.8)
• Pancreatic islets (or islets of Langerhans)
• Small groups of cells among exocrine cells
• Roughly 2 million pancreatic islets in pancreas
• Alpha cells
• Produce hormone glucagon
• Raises blood glucose levels
• Beta cells
• Produce hormone insulin
• Lowers blood glucose levels
© 2013 Pearson Education, Inc.
Pancreatic islet surrounded by pancreatic exocrine cells
Alpha cells produce
glucagon
Pancreatic
acini
Capillaries
Beta cells produce
insulin
Pancreatic islet
© 2013 Pearson Education, Inc.
Figure 10.8
21 24
Insulin and Glucagon (10.8)
• Primary hormones regulating blood glucose levels
• Rising blood glucose levels triggers beta cells
• Insulin lowers blood glucose levels
• Increases rate of glucose uptake and utilization by cells
• Increases rate of glycogen synthesis in skeletal muscle
and liver
• Dropping blood glucose levels triggers alpha cells
• Glucagon raises blood glucose levels
• Increases rate of glycogen breakdown and glucose
release by liver
© 2013 Pearson Education, Inc.
Slide 1
The regulation of blood glucose concentrations
HOMEOSTASIS
DISTURBED
Rising blood
glucose levels
HOMEOSTASIS
© 2013 Pearson Education, Inc.
Figure 10.8
31 24
Slide 2
The regulation of blood glucose concentrations
Beta cells
secrete
insulin.
HOMEOSTASIS
DISTURBED
Rising blood
glucose levels
HOMEOSTASIS
© 2013 Pearson Education, Inc.
Figure 10.8
31 24
The regulation of blood glucose concentrations
Beta cells
secrete
insulin.
HOMEOSTASIS
DISTURBED
Rising blood
glucose levels
Slide 3
Increased rate of glucose
transport into cells
(throughout the body)
Increased rate of glucose
utilization and ATP
generation (throughout
the body)
Increased conversion of
glucose to glycogen (in
liver and skeletal
muscle)
Increased amino acid
absorption and protein
synthesis (throughout
the body)
Increased triglyceride
synthesis (in adipose
tissue)
HOMEOSTASIS
© 2013 Pearson Education, Inc.
Figure 10.8
31 24
The regulation of blood glucose concentrations
Beta cells
secrete
insulin.
HOMEOSTASIS
DISTURBED
Rising blood
glucose levels
Slide 4
Increased rate of glucose
transport into cells
(throughout the body)
Increased rate of glucose
utilization and ATP
generation (throughout
the body)
Increased conversion of
glucose to glycogen (in
liver and skeletal
muscle)
HOMEOSTASIS
Increased amino acid
RESTORED
absorption and protein
synthesis (throughout
Blood glucose
the body)
levels decrease
Increased triglyceride
synthesis (in adipose
tissue)
HOMEOSTASIS
© 2013 Pearson Education, Inc.
Figure 10.8
31 24
The regulation of blood glucose concentrations
Beta cells
secrete
insulin.
HOMEOSTASIS
DISTURBED
Rising blood
glucose levels
Slide 5
Increased rate of glucose
transport into cells
(throughout the body)
Increased rate of glucose
utilization and ATP
generation (throughout
the body)
Increased conversion of
glucose to glycogen (in
liver and skeletal
muscle)
HOMEOSTASIS
Increased amino acid
RESTORED
absorption and protein
synthesis (throughout
Blood glucose
the body)
levels decrease
Increased triglyceride
synthesis (in adipose
tissue)
HOMEOSTASIS
Normal blood
glucose levels
(70–110 mg/dL)
HOMEOSTASIS
DISTURBED
Falling blood
glucose levels
© 2013 Pearson Education, Inc.
Figure 10.8
31 24
The regulation of blood glucose concentrations
Beta cells
secrete
insulin.
HOMEOSTASIS
DISTURBED
Rising blood
glucose levels
Slide 6
Increased rate of glucose
transport into cells
(throughout the body)
Increased rate of glucose
utilization and ATP
generation (throughout
the body)
Increased conversion of
glucose to glycogen (in
liver and skeletal
muscle)
HOMEOSTASIS
Increased amino acid
RESTORED
absorption and protein
synthesis (throughout
Blood glucose
the body)
levels decrease
Increased triglyceride
synthesis (in adipose
tissue)
HOMEOSTASIS
Normal blood
glucose levels
(70–110 mg/dL)
HOMEOSTASIS
DISTURBED
Falling blood
glucose levels
Alpha cells
secrete
glucagon
© 2013 Pearson Education, Inc.
Figure 10.8
31 24
The regulation of blood glucose concentrations
Beta cells
secrete
insulin.
HOMEOSTASIS
DISTURBED
Rising blood
glucose levels
Slide 7
Increased rate of glucose
transport into cells
(throughout the body)
Increased rate of glucose
utilization and ATP
generation (throughout
the body)
Increased conversion of
glucose to glycogen (in
liver and skeletal
muscle)
HOMEOSTASIS
Increased amino acid
RESTORED
absorption and protein
synthesis (throughout
Blood glucose
the body)
levels decrease
Increased triglyceride
synthesis (in adipose
tissue)
HOMEOSTASIS
Normal blood
glucose levels
(70–110 mg/dL)
HOMEOSTASIS
DISTURBED
Falling blood
glucose levels
Alpha cells
secrete
glucagon
© 2013 Pearson Education, Inc.
Increased breakdown
of glycogen to glucose
(in liver, skeletal
muscle)
Increased breakdown
of fat to fatty acids
(in adipose tissue)
Increased synthesis
and release of glucose
(in liver)
Figure 10.8
31 24
The regulation of blood glucose concentrations
Beta cells
secrete
insulin.
HOMEOSTASIS
DISTURBED
Rising blood
glucose levels
Slide 8
Increased rate of glucose
transport into cells
(throughout the body)
Increased rate of glucose
utilization and ATP
generation (throughout
the body)
Increased conversion of
glucose to glycogen (in
liver and skeletal
muscle)
HOMEOSTASIS
Increased amino acid
RESTORED
absorption and protein
synthesis (throughout
Blood glucose
the body)
levels decrease
Increased triglyceride
synthesis (in adipose
tissue)
HOMEOSTASIS
Normal blood
glucose levels
(70–110 mg/dL)
HOMEOSTASIS
DISTURBED
HOMEOSTASIS
RESTORED
Falling blood
glucose levels
Alpha cells
secrete
glucagon
© 2013 Pearson Education, Inc.
Blood glucose
levels increase
Increased breakdown
of glycogen to glucose
(in liver, skeletal
muscle)
Increased breakdown
of fat to fatty acids
(in adipose tissue)
Increased synthesis
and release of glucose
(in liver)
Figure 10.8
31 24
Module 10.8 Review
a. Identify two important types of cells in the
pancreatic islets and the hormones produced by
each.
b. The secretion of which hormone lowers blood
glucose concentrations?
c. How do rising glucagon levels affect the amount
of glycogen stored in the liver?
© 2013 Pearson Education, Inc.
The Pineal Gland (10.9)
• Part of epithalamus
• In posterior portion of roof of third ventricle
• Contains neurons, neuroglia, and secretory cells
• Secretory cells produce melatonin
• Rate of melatonin production influenced by visual
pathway
• Highest production at night
• Lowest production during daylight hours
© 2013 Pearson Education, Inc.
The pineal gland
Melatonin-secreting
cells Pineal Gland
© 2013 Pearson Education, Inc.
LM x 450
Figure 10.9
11 24
Functions of Melatonin in Humans (10.9)
•
Inhibit reproductive functions
•
In some mammals, slows maturation of sperm,
oocytes, and reproductive organs by reducing rate of
GnRH secretion
•
May play role in timing human sexual maturation
•
Blood levels decline at puberty
•
Pineal tumors eliminating melatonin cause premature
puberty
© 2013 Pearson Education, Inc.
Functions of Melatonin in Humans (10.9)
•
Effective antioxidant
•
•
May protect CNS neurons from free radicals
•
Nitric oxide, hydrogen peroxide
•
Generated in active neural tissue
Set circadian rhythms
•
Daily changes in physiological processes following a
regular day-night pattern
•
Result of cyclical pineal activity
© 2013 Pearson Education, Inc.
Module 10.9 Review
a. Describe the location of the pineal gland.
b. How would longer hours of daylight, as during the
summer, affect the production of melatonin?
c. List the three functions of melatonin.
© 2013 Pearson Education, Inc.
Diabetes Mellitus (10.10)
• Endocrine disorder characterized by high blood
glucose levels (hyperglycemia)
• Kidney reabsorption overwhelmed, so glucose in urine
(glycosuria)
• Urine volume increases (polyuria)
• Disrupts metabolic activities throughout body
• Cells shift to lipids and proteins as energy source
• By-products (ketone bodies) can cause diabetic
ketoacidosis
© 2013 Pearson Education, Inc.
Type 1 Diabetes Mellitus (10.10)
• Type 1 (insulin dependent) diabetes
• Pancreatic beta cells do not produce enough insulin
• Patients must have daily injections or continuous
infusions of insulin to live
• 5–10 percent of diabetes cases
• Often develops in childhood
© 2013 Pearson Education, Inc.
Type 2 Diabetes Mellitus (10.10)
• Type 2 (non-insulin dependent) diabetes
• Most common form of diabetes mellitus
• May produce normal amounts of insulin
• Body cells do not respond properly
• Insulin resistance
• Associated with obesity
• Exercise and diet can be effective treatment
• Medications can also alter rates of glucose synthesis
and release by liver
© 2013 Pearson Education, Inc.
Diabetes Mellitus and related clinical problems
Diabetes Mellitus
Type 1 (insulin dependent) Diabetes
© 2013 Pearson Education, Inc.
Type 2 (non-insulin dependent) Diabetes
Figure 10.10
Diabetes Mellitus – Clinical Problems (10.10)
• Diabetic retinopathy
• Partial or complete blindness from proliferation of capillaries and
hemorrhaging at retina
• Increased risk of heart attack
• From increased blockages in cardiac circulation
• Diabetic nephropathy
• Degenerative changes in kidneys can lead to kidney failure
• Diabetic neuropathy
• Damage to nerves from abnormal blood flow to neural tissue
• Damage to peripheral tissues (ulceration, infection)
• From reduced blood flow to distal portions of limbs
© 2013 Pearson Education, Inc.
Diabetes Mellitus and related clinical problems
Clinical Problems Caused by
Diabetes Mellitus
Diabetic retinopathy
Increased risk of heart attack
Diabetic nephropathy
Diabetic neuropathy
Reduced blood flow to distal portions of
limbs, damaging peripheral tissues
© 2013 Pearson Education, Inc.
Figure 10.10
Module 10.10 Review
a. Define diabetes mellitus.
b. Identify and describe the two types of diabetes
mellitus.
c. Describe three clinical problems caused by
diabetes mellitus.
© 2013 Pearson Education, Inc.
Stress Response (10.11)
• Any condition that threatens homeostasis is a form
of stress
• May be physical or emotional
• Several mechanisms in body to oppose specific
disruption
• Body also has general response to stress
• Pattern of hormonal and physiological adjustments
called stress response or general adaptation
syndrome (GAS)
© 2013 Pearson Education, Inc.
Three Stages of Stress Response (10.11)
1. Alarm phase
2. Resistance phase
3. Exhaustion phase
© 2013 Pearson Education, Inc.
Alarm Phase (10.11)
•
"Fight or flight"
•
Immediate response directed by sympathetic
nervous system
1. Energy reserves mobilized, primarily as glucose
2. Body prepares through "fight or flight" responses
•
Epinephrine dominant hormone
•
Causes generalized sympathetic activation
© 2013 Pearson Education, Inc.
Resistance Phase (10.11)
• If stress is longer than a few hours, body moves into the
second phase (resistance phase)
• Glucocorticoids are the dominant hormones with help from
epinephrine, GH, and thyroid hormone
• Energy demands are still higher than normal
• Neural tissue has high demand for energy
• Glycogen reserves that were adequate in alarm phase are
nearly exhausted
• Body's metabolic reserves are mobilized and tissue
metabolism is shifted away from glucose where possible
© 2013 Pearson Education, Inc.
Exhaustion Phase (10.11)
• Lipid reserves can maintain resistance phase for
weeks or months
• When reserves are depleted, body enters third
phase (exhaustion phase)
• Mineral (Na+, K+) imbalances are involved causing
neuron and muscle fiber malfunction
• Without immediate corrective action, organ
systems fail causing death
© 2013 Pearson Education, Inc.
Slide 1
General adaptation syndrome
Alarm Phase (“Fight or
Flight”)
Brain
Adrenal
medulla
Epinephrine,
norepinephrine
Sympathetic
stimulation
General
sympathetic
activation
Immediate Short-Term
Responses to Crises
• Mobilize glycogen and
lipid reserves to form
glucose
• Increase mental
alertness
• Increase energy use by
all cells
• Change circulation
patterns
• Reduce digestive activity
and urine production
• Increase sweat gland
secretion
• Increase heart rate and
respiratory rate
© 2013 Pearson Education, Inc.
Figure 10.11
1
Slide 2
General adaptation syndrome
Alarm Phase (“Fight or
Flight”)
Brain
Resistance Phase
Sympathetic
stimulation
Brain
Adrenal
medulla
Epinephrine,
norepinephrine
General
sympathetic
activation
Immediate Short-Term
Responses to Crises
• Mobilize glycogen and
lipid reserves to form
glucose
• Increase mental
alertness
• Increase energy use by
all cells
• Change circulation
patterns
• Reduce digestive activity
and urine production
• Increase sweat gland
secretion
• Increase heart rate and
respiratory rate
© 2013 Pearson Education, Inc.
Reninangiotensin
system
Sympathetic
stimulation
ACTH
Pancreas
Adrenal
cortex
Mineralocorticoids
Glucagon Growth
(with ADH) Glucocortichormone
oids
Long-Term Metabolic
Adjustments
• Mobilize remaining energy
reserves: Adipose tissue
releases lipids; skeletal
muscle releases amino acids
• Conserve glucose:
Peripheral tissues (except
neural) break down lipids to
obtain energy
• Raise blood glucose
concentrations: Liver
synthesizes glucose from
other carbohydrates,
amino acids, and lipids
• Conserve salts and water;
lose K+ and H+
Figure 10.11
1
Slide 3
General adaptation syndrome
Alarm Phase (“Fight or
Flight”)
Brain
Resistance Phase
Sympathetic
stimulation
Brain
Adrenal
medulla
Epinephrine,
norepinephrine
General
sympathetic
activation
Immediate Short-Term
Responses to Crises
• Mobilize glycogen and
lipid reserves to form
glucose
• Increase mental
alertness
• Increase energy use by
all cells
• Change circulation
patterns
• Reduce digestive activity
and urine production
• Increase sweat gland
secretion
• Increase heart rate and
respiratory rate
© 2013 Pearson Education, Inc.
Reninangiotensin
system
Exhaustion Phase
Sympathetic
stimulation
ACTH
Pancreas
Adrenal
cortex
Mineralocorticoids
Glucagon Growth
(with ADH) Glucocortichormone
oids
Long-Term Metabolic
Adjustments
• Mobilize remaining energy
reserves: Adipose tissue
releases lipids; skeletal
muscle releases amino acids
• Conserve glucose:
Peripheral tissues (except
neural) break down lipids to
obtain energy
• Raise blood glucose
concentrations: Liver
synthesizes glucose from
other carbohydrates,
amino acids, and lipids
• Conserve salts and water;
lose K+ and H+
Factors That Can Trigger
the Exhaustion Phase
• Exhaustion of lipid reserves
and the breakdown of
structural proteins as the
body’s primary energy
source, damaging vital
organs
• Infections that develop due
to suppression of
inflammation and the
immune response, a
secondary effect of the
glucocorticoids that are
essential to the metabolic
activities of the resistance
phase
• Cardiovascular damage
from the ADH and
aldosterone- related
elevations in blood pressure
and blood volume
• Inability of the adrenal
cortex to continue
producing glucocorticoids,
which results in a failure to
maintain acceptable blood
glucose concentrations
• Failure to maintain adequate
fluid and electrolyte balance
Figure 10.11
1
Module 10.11 Review
a. List the three phases of the stress response.
b. Describe the resistance phase.
c. During which phase of the stress response is
there a collapse of vital systems?
© 2013 Pearson Education, Inc.