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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
Communication in the Body
Regulation in the body is accomplished
by two systems:
-Nervous system (via electrical impulses)
-Endocrine system (via chemical signaling)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.1
Cellular Communication
Both systems are involved in cellular
communication.
Cells communicate to:
-Respond to internal and external
changes.
-Regulate gene expression
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Slide 9.1
Three Types of communication
Sometimes called cellular signaling:
via local (diffusion + nerves) or
long distance (blood vessels) mechanisms
Cellular Communication
∙ Local Signaling:
∙Paracrine:
∙Cells releasing chemicals that alter
activity in adjacent cells or themselves
(autocrine).
∙Synaptic
∙Nervous system!
∙ Distant Signaling
∙Endocrine
∙hormones
Slide 9.1
Endocrine System: communication via
hormones (chemicals)
-Release hormones that can travel via the
blood stream
-Who makes them?
∙ Endocrine glands
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.1
Thyroid
Parathyroid
Anterior and
Posterior
Pituitary Gland
Adrenal
glands
Pancreas
Testes
Or
Ovaries
FYI
∙ Other organs in your body are involved
in releasing hormones.
∙Example: small intestines and heart
∙ These are not endocrine glands though,
and their primary function is not to
release hormones.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.1
Hormones control several major
processes
-Reproduction
-Growth and development
-Mobilization of body defenses
and homeostasis
-Regulation of metabolism
-Stress response
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Slide 9.1
The Chemistry of Hormones
∙ Amino acid-based hormones
∙ Proteins
∙ Peptides
∙ Amines
∙ Steroids – made from cholesterol
∙ Prostaglandins – made from highly
active lipids
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Slide 9.3
Fig. 11-14
HORMONE
RECEPTION
RECEPTOR PROTEIN
TRANSDUCTION
CHEMICAL CHANGES IN
THE TARGET CELL
CYTOPLASM
INACTIVE
TRANSCRIPTION
FACTOR
ACTIVATED
TRANSCRIPION
FACTOR
P
DNA
RESPONSE
Gene
NUCLEUS
mRNA
Effects Caused by Hormones
Hormones can have many effects, such as:
-Changes in plasma membrane
permeability
-Stimulate the synthesis of proteins, such
as enzymes
-Activation or inactivation of enzymes
-Stimulation of mitosis: aka cell division
and repair
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.5
Hormones control
my DNA?
Yes…they are
powerful!
Regulating them is
very important.
*Control of Hormone Release
∙ Many hormone levels are regulated via
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
∙ Great example of….Homeostasis!
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.10
Stimuli of Endocrine Glands
Changing blood levels of certain ions
stimulate hormone release.
Ex. Blood calcium levels
regulates hormones
PTH and calcitonin
Figure 9.2b
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 (SNS).
Figure 9.2c
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.13
Location of Major Endrocrine Organs
Protein based
(couple exceptions)
Steroid based
(couple exceptions)
Figure 9.3
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Slide 9.14
Anterior Pituitary: master gland!
Figure 9.4
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Slide 9.17
∙ These are extreme
cases and only
treatable with a
thyroidectomy.
*Thyroid Problems: Goiter
∙ Since the hormones of
the thyroid
require iodine,
people low dietary
iodine = a
problem (goiter)
∙ The thyroid makes a part of the hormones,
but they are missing iodine.
∙ Therefore, the thyroid never gets “the
message” to stop making T3 and T4
because it works via negative feedback.
∙ This = enlargement of the thyroid.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.24
Thyroid Gland
https://www.
youtube.
com/watch?
v=0h5jM7eN
6j4
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.23b
Thyroid Gland
-Location: base of throat
-Form: two lobes and a connecting
tissue isthmus
-Produces two hormones
1. Thyroid hormone (to body tissues for
controlling growth, development, +
energy utilization)
2. Calcitonin-regulates amount of blood
calcium levels in the body
vid problesm: https://www.youtube.com/watch?v=qIn8AHHB1_o
Slide 9.23a
Thyroid Hormone: major metabolic
hormone
Often blamed for “slow metabolism and
weight problem” although often over
exaggerated.
-Controls the rate at which glucose is
metabolized or “burned” = converted to
chemical energy or lost as heat.
Targets all cells in body because they all
need energy!
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.24
Adrenal Glands:
two glands that
sit on top of the
kidneys
Regulates: concentration of
water and salts in
urine
-blood pressure
https://www.youtube.com/watch?v=06jbq3bxKE0
vid: https://www.youtube.com/watch?v=Xgq_alEB2zw
Slide 9.27
*Blood Pressure
maintenance
Stimulus: BP too low?
Keep more water in your blood- don’t pee it out
Constrict your vessels to decrease diameter
(vasoconstriction) – less space = more pressure
Stimulus: BP too high?
Pee more- get the water out of your body!
Make your vessels wider to decrease pressure
(vasodilatation)- more space= less pressure.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.28a
Adrenal Cortex: Aldosterone
Figure 9.10
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.28b
Endocrine System Control
Blood Osmolarity Feedback
osmoreceptors in
hypothalamus
ADH
increase
thirst
increased
water
reabsorption
pituitary
high
blood osmolarity
blood pressure
low
adrenal
gland
increased
water & salt
reabsorption
renin
aldosterone
angiotensin
angiotensin
ogen
Produces hormones known as
corticosteroids
Three types:
1. Mineralocorticoids (aldosterone)
2. Glucocorticoids (cortisone, cortisol)
3. Sex Hormones (androgens,
estrogens)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.28a
*Adrenal Cortex: Sex Hormones
∙ Sex hormones
∙ Produced in the inner layer of the adrenal
cortex
∙ Androgens (male) and some estrogen
(female)
∙ Produced in small amounts throughout life.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.29b
Putting it together….Why stress is BAD
∙ So what are some
symptoms of stress?
∙
Weight gain
∙
Difficulty concentrating, focusing, remembering
∙
Digestive problems
∙
Increased blood pressure
∙
Heart palpitations, chest pains
∙
Restless, insomnia
∙ WHY do those symptoms
occur?
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.30
Roles of the Hypothalamus and Adrenal
Glands in the Stress Response
L
UL
D
E
M
X
CO
RT
E
A
Figure 9.12
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.31
Pancreas: a mixed gland
-produces hormones:
1. Insulin – released from beta cells
2. Glucagon – released from alpha cells
These hormones are antagonists that
maintain blood sugar homeostasis
3vid: https://www.youtube.com/watch?v=NZ4zcrTzUjA
Slide 9.32a
Pancreatic Islets- anatomical plane?
Figure 9.13
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Slide 9.32b
Pancreatic Islets- sagittal plane!
Figure 9.13
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.32b
Pancreas: exo- and endoInsulin – released when blood
glucose levels are too high
• Communicates to cells to take glucose in,
stored in muscle and liver cells
• insulin ~ glucose goes in
• As a result, blood glucose levels
decrease
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.32a
vid:https://www.
Slide 9.33
Pancreas: exo- and endoGlucagon – released when blood
glucose levels are too low
• Communicates to cells to release
glucose, from muscle and liver cells
glucagon = glucose gone (from cells and
into blood)
• As a result, blood glucose levels
increase
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 9.32a
Endocrine System Control
Regulation of Blood Sugar
Feedback
islets of Langerhans
beta islet cells
insulin
liver stores
glycogen
body
cells take
up sugar
from blood
pancreas
liver
high
blood sugar level
(90mg/100ml)
low
triggers
hunger
liver
releases
glucose
liver
pancreas
glucago
n
islets of Langerhans
alpha islet cells
reduces
appetite
Thymus gland
Location: posterior to the sternum
Largest in infants and children;
shrinks with age.
-Major component in immune system
-Produces thymosin
-Trains and develops white blood cells (Tlymphocytes, T cells), which attack foreign
invaders to the body
http://www.innerbody.com/image_endoov/lymp04-new.html
Slide 9.35
Any Questions??
Robert Wadlow
1918-1940
8' 11"
AP Biology
2009-2010
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