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Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 9
The Endocrine System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The Endocrine System
 Second messenger system of the body
 Uses chemical messages (hormones) that are released into
the blood
 Hormones are produced by specialized cells
 Cells secrete hormones into extracellular fluids
 Blood transfers hormones to target sites
 These hormones regulate the activity of other cells and
several major processes
 Reproduction
 Growth and development
 Mobilization of body defenses
 Maintenance of much of homeostasis
 Regulation of metabolism
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.1
The Chemistry of Hormones
 Amino acid-based
hormones
 Proteins
 Peptides
 Amines
 Steroids – made
from cholesterol
 Prostaglandins –
made from highly
active lipids
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.3
Mechanisms of Hormone Action
 Hormones affect
only certain tissues
or organs (target
cells or organs)
 Target cells must
have specific protein
receptors
 Hormone binding
influences the
working of the cells
Slide 9.4
Effects Caused by Hormones
 Changes in plasma
membrane
permeability or
electrical state
 Synthesis of
proteins, such as
enzymes
 Activation or
inactivation of
enzymes
 Stimulation of
mitosis
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.5
Steroid Hormone Action
 Diffuse through the
plasma membrane of
target cells
 Enter the nucleus
 Bind to a specific
protein within the
nucleus
 Bind to specific sites
on the cell’s DNA
 Activate genes that
result in synthesis of
new proteins
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.6
Nonsteroid Hormone Action
 Hormone binds to a
membrane receptor
 Hormone does not enter
the cell
 Sets off a series of
reactions that activates an
enzyme
 Catalyzes a reaction that
produces a second
messenger molecule
 Oversees additional
intracellular changes to
promote a specific
response
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.8
Control of Hormone Release
 Hormone levels in the
blood are maintained
by negative feedback
 A stimulus or low
hormone levels in the
blood triggers the
release of more
hormone
 Hormone release stops
once an appropriate
level in the blood is
reached
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.10
Humoral Stimuli of Endocrine Glands
 Endocrine
glands are
activated by
other
hormones
 Changing
blood levels of
certain ions
stimulate
hormone
release
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.12
Neural Stimuli of Endocrine Glands
 Nerve impulses
stimulate hormone
release
 Most are under
control of the
sympathetic nervous
system
Figure 9.2c
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.13
Pituitary - Hypothalamus
Relationship
 Release of hormones is controlled by
releasing and inhibiting hormones
produced by the hypothalamus
 Hypothlamus produces two hormones
that are transorted to neurosecretory
cells of the posterior pituitary
 The poterior pituitary is not strictly an
endocrine gland, but does release
hormones
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.21
Pituitary Gland
 Size of a grape
 Hangs by a stalk
from the
hypothalamus
 Protected by the
sphenoid bone
 Has two functional
lobes
 Anterior pituitary
– glandular
tissue
 Posterior pituitary
– nervous tissue
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.15
Hormones of the Anterior Pituitary
 Six anterior pituitary
hormones
 Two affect nonendocrine targets
 Four stimulate other
endocrine glands
(tropic hormones)
 Characteristics of all
anterior pituitary
hormones
 Proteins (or
peptides)
 Act through secondmessenger systems
 Regulated by
hormonal stimuli,
mostly negative
feedback
Slide 9.16
Functions of Anterior Pituitary Hormones
 Growth Hormone (GH)
 General metabolic hormone
 Major effects are directed to growth of skeletal
muscles and long bones
 Causes amino acids to be built into proteins
 Causes fats to be broken down for a source of
energy
 Prolactin (PRL)
 Stimulates and maintains milk production following
childbirth
 Function in males is unknown
 Adrenocorticotropic hormone (ACTH)
 Regulates endocrine activity of the adrenal cortex
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.19
Functions of Anterior Pituitary Hormones
 Thyroid-stimulating hormone (TSH)
 Influences growth and activity of the thyroid
 Gonadotropic hormones
 Regulate hormonal activity of the gonads
 Follicle-stimulating hormone (FSH)
 Stimulates follicle development in ovaries
 Stimulates sperm development in testes
 Gonadotropic hormones (continued)
 Luteinizing hormone (LH)
 Triggers ovulation
 Causes ruptured follicle to become the corpus
luteum
 Stimulates testosterone production in males
 Referred to as interstitial cell-stimulating
hormone (ICSH)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.20a
Hormones of the Posterior Pituitary
 Oxytocin
 Stimulates contractions
of the uterus during
labor
 Causes milk ejection
 Antidiuretic hormone
(ADH)
 Can inhibit urine
production
 In large amounts,
causes vasoconstriction
leading to increased
blood pressure
(vasopressin)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.22
Thyroid Gland
 Found at the
base of the
throat
 Consists of two
lobes and a
connecting
isthmus
 Produces two
hormones:
thyroid hormone
and calcitonin
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.23a
 Thyroid hormone
 Major metabolic hormone
 Composed of two active
iodine-containing
hormones
 Thyroxine (T4) –
secreted by thyroid
follicles
 Triiodothyronine (T3) –
conversion of T4 at
target tissues
 Calcitonin
 Decreases blood calcium
levels by causing its
deposition on bone
 Antagonistic to parathyroid
hormone
 Produced by C
(parafollicular) cells
Figure 9.9
Slide 9.25
Parathyroid Glands
 Tiny masses on the
posterior of the thyroid
 Secrete parathyroid
hormone
 Stimulate osterclasts
to remove calcium
from bone
 Stimulate the kidneys
and intestine to absorb
more calcium
 Raise calcium levels in
the blood
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.26
Adrenal Glands
 Two glands
 Cortex – outer
glandular region in
three layers
 Medulla – inner
neural tissue
region
 Sits on top of the
kidneys
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.27
Hormones of the Adrenal Cortex
 Mineralocorticoids (mainly aldosterone)
 Produced in outer adrenal cortex
 Regulate mineral content in blood, water, and electrolyte
balance
 Target organ is the kidney
 Glucocorticoids (including cortisone and cortisol)
 Produced in the middle layer of the adrenal cortex
 Promote normal cell metabolism
 Help resist long-term stressors
 Released in response to increased blood levels of ACTH
 Sex hormones
 Produced in the inner layer of the adrenal cortex
 Androgens (male) and some estrogen (female)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.28a
Hormones of the Adrenal Medulla
 Produces two
similar hormones
(catecholamines)
 Epinephrine
 Norepinephrine
 These hormones
prepare the body
to deal with shortterm stress
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.30
Pancreatic Islets
 The pancreas is a mixed
gland
 The islets of the pancreas
produce hormones
 Insulin – allows glucose
to cross plasma
membranes into cells
from beta cells
 Glucagon – allows
glucose to enter the
blood from alpha cells
 These hormones are
antagonists that
maintain blood sugar
homeostasis
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.32a
Pineal Gland
 Found on the third
ventricle of the brain
 Secretes melatonin
 Helps establish the
body’s wake and sleep
cycles
 May have other as-yetunsubstantiated
functions
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.34
Thymus
 Located posterior to
the sternum
 Largest in infants and
children
 Produces thymosin
 Matures some
types of white blood
cells
 Important in
developing the
immune system
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.35
Hormones of the Ovaries
 Estrogens
 Produced by Graafian follicles or the placenta
 Stimulates the development of secondary female
characteristics
 Matures female reproductive organs
 Helps prepare the uterus to receive a fertilized egg
 Helps maintain pregnancy
 Prepares the breasts to produce milk
 Progesterone
 Produced by the corpus luteum
 Acts with estrogen to bring about the menstrual cycle
 Helps in the implantation of an embryo in the uterus
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.36
Hormones of the Testes
 Interstitial cells of testes
are hormone-producing
 Produce several androgens
 Testosterone is the most
important androgen
 Responsible for adult
male secondary sex
characteristics
 Promotes growth and
maturation of male
reproductive system
 Required for sperm cell
production
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.38
Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 15
The Urinary System
Slides 15.1 – 15.20
Lecture Slides in PowerPoint by Jerry L. Cook
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Functions of the Urinary System
 Elimination of waste
products
 Nitrogenous wastes
 Toxins
 Drugs
 Regulate aspects of
homeostasis
 Water balance
 Electrolytes
 Acid-base balance in the
blood
 Blood pressure
 Red blood cell production
 Activation of vitamin D
Slide 15.1a
Organs of the Urinary system
 Kidneys
 Ureters
 Urinary bladder
 Urethra
Figure 15.1a
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Slide 15.2
Location of the Kidneys
 Against the dorsal
body wall
 At the level of T12 to
L3
 The right kidney is
slightly lower than the
left
 Attached to ureters,
renal blood vessels,
and nerves at renal
hilus
 Atop each kidney is
an adrenal gland
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Slide 15.3
Coverings of the Kidneys
 Renal capsule
 Surrounds each
kidney
 Adipose capsule
 Surrounds the
kidney
 Provides
protection to the
kidney
 Helps keep the
kidney in its
correct location
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 15.4
Regions of the Kidney
 Renal cortex –
outer region
 Renal medulla –
inside the cortex
 Renal pelvis –
inner collecting
tube
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 15.2b
Slide 15.5
Kidney Structures
 Medullary pyramids –
triangular regions of
tissue in the medulla
 Renal columns –
extensions of cortex-like
material inward
 Calyces – cup-shaped
structures that funnel
urine towards the renal
pelvis
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Slide 15.6
Nephrons
 The structural and functional
units of the kidneys
 Responsible for forming urine
 Main structures of the nephrons
include the glomerulus and renal
tubule.
 Glomerulus
 A specialized capillary bed
 Attached to arterioles on both
sides (maintains high
pressure)
 Large afferent arteriole
 Narrow efferent arteriole
 Capillaries are covered with
podocytes from the renal
tubule
 The glomerulus sits within a
glomerular capsule (the first
part of the renal tubule)
Slide 15.8
Peritubular Capillaries
 Arise from efferent
arteriole of the
glomerulus
 Normal, low pressure
capillaries
 Attached to a venule
 Cling close to the renal
tubule
 Reabsorb (reclaim)
some substances from
collecting tubes
Slide 15.12
Urine Formation Processes
 Filtration
 Reabsorption
 Secretion
Figure 15.4
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Slide 15.13
Filtration
 Nonselective passive
process
 Water and solutes
smaller than proteins
are forced through
capillary walls
 Blood cells cannot pass
out to the capillaries
 Filtrate is collected in
the glomerular capsule
and leaves via the renal
tubule
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Slide 15.14
Reabsorption
 The peritubular capillaries
reabsorb several materials
 Some water
 Glucose
 Amino acids
 Ions
 Some reabsorption is
passive, most is active
 Most reabsorption occurs
in the proximal convoluted
tubule
 Materials not reabsorbed
include urea, uric acid,
creatinine, and excess
water
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Slide 15.15
Secretion – Reabsorption in
Reverse
 Some materials
move from the
peritubular
capillaries into the
renal tubules
 Hydrogen and
potassium ions
 Creatinine
 Materials left in the
renal tubule move
toward the ureter
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Slide 15.17
Characteristics of Urine Used for
Medical Diagnosis
 Colored somewhat yellow due to the
pigment urochrome (from the
destruction of hemoglobin) and solutes
 Sterile
 Slightly aromatic
 Normal pH of around 6
 Specific gravity of 1.001 to 1.035
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Slide 15.19
Ureters
 Slender tubes attaching the kidney to the bladder
 Continuous with the renal pelvis
 Enter the posterior aspect of the bladder
 Runs behind the peritoneum
 Peristalsis aids gravity in urine transport
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Slide 15.20
Urinary Bladder
 Smooth, collapsible,
muscular sac
 Temporarily stores
urine
 Trigone – three
openings
 Two from the ureters
 One to the urethrea
 Urinary bladder wall
 Three layers of smooth
muscle (detrusor muscle)
 Mucosa made of
transitional epithelium
 Walls are thick and folded
in an empty bladder
 Bladder can expand
significantly without
increasing internal
pressure
Slide 15.21a
Urethra
 Thin-walled tube that carries urine from the bladder to the outside
of the body by peristalsis
 Release of urine is controlled by two sphincters
 Internal urethral sphincter (involuntary)
 External urethral sphincter (voluntary)
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Slide 15.23
Urethra Gender Differences
 Length
 Females – 3–4 cm (1 inch)
 Males – 20 cm (8 inches)
 Location
 Females – along wall of
the vagina
 Males – through the
prostate and penis
 Function
 Females – only carries
urine
 Males – carries urine and
is a passageway for
sperm cells
Slide 15.24a
Micturition (Voiding)
 Both sphincter muscles must
open to allow voiding
 The internal urethral
sphincter is relaxed after
stretching of the bladder
 Activation is from an
impulse sent to the spinal
cord and then back via the
pelvic splanchnic nerves
 The external urethral
sphincter must be
voluntarily relaxed
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Slide 15.25
Maintaining Water Balance
 Normal amount of
water in the human
body
 Young adult females
– 50%
 Young adult males –
60%
 Babies – 75%
 Old age – 45%
 Water is necessary for
many body functions
and levels must be
maintained
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Slide 15.26
Distribution of Body Fluid
 Intracellular fluid
(inside cells)
 Extracellular
fluid (outside
cells)
 Interstitial fluid
 Blood plasma
Figure 15.7
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 15.27
Maintaining Water Balance
 Changes in electrolyte balance causes water to move from one
compartment to another
 Alters blood volume and blood pressure
 Can impair the activity of cells
 Water intake must equal water output
 Sources for water intake
 Ingested foods and fluids
 Water produced from metabolic processes
 Sources for water output
 Vaporization out of the lungs
 Lost in perspiration
 Leaves the body in the feces
 Urine production
 Dilute urine is produced if water intake is excessive
 Less urine (concentrated) is produced if large amounts of water
are lost
Slide 15.29
 Proper concentrations of various electrolytes must be present
Regulation of Water and Electrolyte Reabsorption
 Regulation is primarily
by hormones
 Antidiuretic
hormone (ADH)
prevents excessive
water loss in urine
 Aldosterone
regulates sodium
ion content of
extracellular fluid
 Triggered by the
renninangiotensin
mechanism
 Cells in the kidneys
and hypothalamus are
active monitors
Maintaining Acid-Base Balance in Blood
 Blood pH must remain
between 7.35 and 7.45
to maintain homeostasis
 Alkalosis – pH above
7.45
 Acidosis – pH below
7.35
 Most ions originate as
byproducts of cellular
metabolism
 Most acid-base balance
is maintained by the
kidneys
 Other acid-base
controlling systems
 Blood buffers
 Respiration
Blood Buffers
 Molecules react to
prevent dramatic changes
in hydrogen ion (H+)
concentrations
 Bind to H+ when pH
drops
 Release H+ when pH
rises
 Three major chemical
buffer systems
 Bicarbonate buffer
system
 Phosphate buffer
system
 Protein buffer system
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Slide 15.34
The Bicarbonate Buffer System
 Mixture of carbonic acid
(H2CO3) and sodium
bicarbonate (NaHCO3)
 Bicarbonate ions
(HCO3–) react with
strong acids to change
them to weak acids
 Carbonic acid
dissociates in the
presence of a strong
base to form a weak
base and water
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 15.35
Respiratory System Controls of AcidBase Balance
 Carbon dioxide in the
blood is converted to
bicarbonate ion and
transported in the plasma
 Increases in hydrogen ion
concentration produces
more carbonic acid
 Excess hydrogen ion can
be blown off with the
release of carbon dioxide
from the lungs
 Respiratory rate can rise
and fall depending on
changing blood pH
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 15.36
Renal Mechanisms of Acid-Base
Balance
 Excrete bicarbonate
ions if needed
 Conserve or
generate new
bicarbonate ions if
needed
 Urine pH varies
from 4.5 to 8.0
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Slide 15.37