Ch 40- Endocrine System
• 2.E.2: Timing and coordination of physiological
events are regulated by multiple mechanisms.
(40.1-3)
2
ENDOCRINE SYSTEM
• Endocrine (composed of glands and hormones) and
nervous systems act to control body functions.
• Endocrine reactions are MUCH slower than neural
reactions.
• Gland- a group of specialized cells that make and
secrete fluid (chemicals), called hormones that relay
messages to target organs.
Exocrine glands
• secrete products into
ducts (pancreas, gall
bladder, sweat gland)
Endocrine glands secrete product into bloodstream, no
ducts.
5
Endocrine glands
1. Pituitary Gland- “master gland”, but controlled by the
Hypothalamus (part of brain), which also regulates
internal environment. Pituitary releases hormones
that control female reprod. cycle, excess water loss,
growth, & pain perception (endorphins).
Pituitary Gland
 Divided into Posterior and Anterior Pituitary.
 Anterior
 Thyroid-stimulating Hormone (TSH)- tells thyroid to produce thyroxin
 Growth Hormone- promotes growth of muscles and metabolism; too
much GH in adult- Acromegaly; too little in child- pituitary dwarf
 FSH & LH- control the menstrual cycle
 Prolactin- milk production
 Posterior
 Antidiuretic Hormone (ADH)- water retention in kidneys
 Oxytocin- stimulate mammary glands and uteran lining
 Endocrine glands
7
Hypothalamus and the Pituitary
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
hypothalamus
1. Neurosecretory cells produce
hypothalamic-releasing and
hypothalamic-inhibiting hormones.
2. These hormones are secreted into
a portal system.
1. Neurosecretory cells produce ADH
and oxytocin.
optic
chiasm
2. These hormones move down
axons to axon endings.
portal system
4. The anterior pituitary secretes
its hormones into the bloodstream,
whereby they are then delivered to
specific cells, tissues, and glands.
3. When appropriate, ADH and
oxytocin are secreted from axon
endings into the bloodstream.
Posterior pituitary
Kidney tubules:
antidiuretic
hormone (ADH)
Smooth muscle
in uterus:
oxytocin
3. Each type of hypothalamic
hormone either stimulates or
inhibits production and secretion
of an anterior pituitary hormone.
Mammary glands:
oxytocin
Anterior pituitary
Mammary glands:
prolactin (PRL)
Thyroid:
thyroid-stimulating
hormone (TSH)
Bones, tissues:
growth hormone
(GH)
Adrenal cortex:
adrenocorticotropic
hormone (ACTH)
Ovaries, testes:
gonadotropic
hormones (FSH, LH)
8
Effect of Growth Hormone
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a.
b.
a: © AP/Wide World Photos; b: © Ewing Galloway, Inc.
9
Acromegaly
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Age 9
Age 16
Age 33
Age 52
From Clinical Pathological Conference, "Acromegaly, Diabetes, Hypermetabolism, Proteinura and Heart Failure", American Journal of Medicine, 20 (1956) 133. Reprinted with permission from
Excerpta Medica Inc.
Human Mutants: Mutation Giant
10
Endocrine Glands
2. Thyroid- Regulates metabolism (T3 and T4), body
temp, growth and assists in calcium regulation
(calcitonin). Need iodine in diet for proper function
or get a goiter.
Endocrine Glands
3. Parathyroid- Regulates mineral regulation, Ca+
absorption (Parathyroid hormone- PTH), works with
calcitonin in thyroid.
Animation
Please note that due to differing
operating systems, some animations
will not appear until the presentation is
viewed in Presentation Mode (Slide
Show view). You may see blank slides
in the “Normal” or “Slide Sorter” views.
All animations will appear after viewing
in Presentation Mode and playing each
animation. Most animations will require
the latest version of the Flash Player,
which is available at
http://get.adobe.com/flashplayer.
Regulation of Blood Calcium Level
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
calcitonin
Thyroid gland
secretes
calcitonin
into blood.
Bones
take up Ca2+
from blood.
Blood Ca2+
lowers.
Homeostasis (normal blood Ca2+)
Blood Ca2+
rises.
Parathyroid
glands
release PTH
into blood.
activated
vitamin D
parathyroid
hormone
(PTH)
Intestines
absorb Ca2+
from digestive
tract.
Kidneys
reabsorb Ca2+
from kidney
tubules.
Bones
release Ca2+
into blood.
14
Endocrine Gland
4. Adrenal- (top of kidneys; renal= kidney)
Release adrenaline (epinephrine) in response to short term
stress; low blood sugar.
Fight or Flight
Release Glucocorticoids response to long term stress.
Adrenal Glands
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
stress
hypothalamus
spinal cord
(cross section)
neurosecretory
cells produce
hypothalamicreleasing
hormone
path of nerve
impulses
epinephrine
Glucocorticoids
Protein and fat metabolism
instead of glucose
breakdown.
neuron
cell body
sympathetic fibers
Stress Response:
Long Term
anterior
pituitary
secretes
ACTH
ACTH
Reduction of inflammation;
immune cells are
suppressed.
Mineralocorticoids
Sodium ions and water
are reabsorbed by kidney.
norepinephrine
Blood volume and
pressure increase.
Stress Response:
Short Term
Heartbeat and blood
pressure increase.
glucocorticoids
Blood glucose level rises.
mineralocorticoids
Muscles become
energized.
adrenal medulla
adrenal cortex
16
Endocrine Glands
5. Pancreas- both exo- & endocrine gland. Secretes insulin
(α-cells) & glucagon (β-cells),
which are important in
regulating blood sugar. Not
enough insulin results in high
blood sugar, called Diabetes
Mellitus.
↑ bld sugar- release insulin
↓ bld sugar- release glucagon
Animation
Please note that due to differing
operating systems, some animations
will not appear until the presentation is
viewed in Presentation Mode (Slide
Show view). You may see blank slides
in the “Normal” or “Slide Sorter” views.
All animations will appear after viewing
in Presentation Mode and playing each
animation. Most animations will require
the latest version of the Flash Player,
which is available at
http://get.adobe.com/flashplayer.
Endocrine Glands
6. Gonads- Produce sex hormones & stimulates
secondary sex characteristics. Release is
controlled by pituitary.
Release estrogen & progesterone.
Release testosterone.
The Effects of Anabolic Steroid Use
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
balding in men and women;
hair on face and chest in
women
deepening of voice in women
breast enlargement in men
and breast reduction in women
'roid mania–
delusions and hallucinations;
depression upon withdrawal
severe acne
high blood cholesterol and
atherosclerosis; high blood
pressure and damage to heart
liver dysfunction
and cancer
kidney disease and
retention of fluids,
called "steroid bloat"
reduced testicular
size, low sperm count,
and impotency
in women, increased
size of ovaries;
cessation of ovulation
and menstruation
stunted growth in
youngsters by prematurely halting fusion
of the growth plates
20
Endocrine Glands
7. Pineal gland- stimulated by optic cues. Releases
melatonin to promote sleep, an example of
circadian rhythm (routines controlled by
hormones)
Melatonin Production
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a. experimental
b. winter
6 P.M.
6 A.M.
c. summer
© The McGraw-Hill Companies, Inc./ Evelyn Jo Johnson, photographer
22
Chemical Signals
• Pheromones
– Chemical signals that work at a distance between
individuals (released by 1 individual affects
another).
• Hormones
– Chemical signals that work within an individual
between organs, or locally between adjacent cells
23
Animation
Please note that due to differing
operating systems, some animations
will not appear until the presentation is
viewed in Presentation Mode (Slide
Show view). You may see blank slides
in the “Normal” or “Slide Sorter” views.
All animations will appear after viewing
in Presentation Mode and playing each
animation. Most animations will require
the latest version of the Flash Player,
which is available at
http://get.adobe.com/flashplayer.
Target Cell Concept
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
nontarget cell
receptors
target cells
hormone
capillary
25
Hormones
1. Steroids- made of lipids. Released by adrenal &
gonads. Act inside cells by activating RNA. Causes
protein formation. Stored in adipocytes. Estrogen,
progesterone
Hormones
2. Peptide- proteins, very diverse. Attach to receptor
on outside of cell and initiate a secondary messenger
(cAMP). (insulin, glucagon, epinephrine)
Peptide Hormone
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
capillary
1. Hormone binds to a
receptor in the plasma
membrane.
peptide hormone
(first messenger)
activated
enzyme
receptor protein
2. Binding leads to
activation of an
enzyme that changes
ATP to cAMP.
plasma
membrane
ATP
cAMP
(second messenger)
3. cAMP activates an
enzyme cascade.
4. Many molecules of
glycogen are broken
down to glucose,
which enters the
bloodstream.
glucose
(leaves cell
and goes
to blood)
glycogen
28
Steroid Hormone
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
steroid
hormone
1. Hormone diffuses
through plasma
membrane because
it is lipid soluble.
plasma
membrane
cytoplasm
nuclear
pore
nucleus
2. Hormone binds
to receptor inside
nucleus.
protein
DNA
receptor
protein
mRNA
3. Hormone-receptor
complex activates
gene and synthesis
of a specific mRN
molecule.
ribosome
mRNA
4. mRNA moves to
ribosomes, and protein
synthesis occurs.
29
Animation
Please note that due to differing
operating systems, some animations
will not appear until the presentation is
viewed in Presentation Mode (Slide
Show view). You may see blank slides
in the “Normal” or “Slide Sorter” views.
All animations will appear after viewing
in Presentation Mode and playing each
animation. Most animations will require
the latest version of the Flash Player,
which is available at
http://get.adobe.com/flashplayer.
Animation
Please note that due to differing
operating systems, some animations
will not appear until the presentation is
viewed in Presentation Mode (Slide
Show view). You may see blank slides
in the “Normal” or “Slide Sorter” views.
All animations will appear after viewing
in Presentation Mode and playing each
animation. Most animations will require
the latest version of the Flash Player,
which is available at
http://get.adobe.com/flashplayer.