40.1 Animal Hormones
HS-LS1.A: Systems of specialized cells within organisms help
them perform the essential functions of life.
Learning objectives:
1-Distinguish between the mode of action of neurotransmitter
and hormone
2-Compare and contrast the mode of action of peptide and
steroid hormones.
Compare between endocrine
and nervous system
■Animals rely on 2 systems for regulation
Endocrine system
■ductless gland which secrete
chemical signals directly into blood
●chemical
travels to target tissue
●slow, long-lasting response
Hormones release by endocrine glands
Nervous system
■system of neurons, central
nerve system
●transmits
“electrical” signal to
target tissue
●fast, short-lasting response
Neurotransmitters released by neurons
A pheromone is a chemical that an animal produces which changes the behavior of
another animal of the same species. Some describe pheromones as behavior-altering
agents. Many people do not know that pheromones trigger other behaviors in the animal
of the same species
Regulation
Why are hormones needed?
chemical messages from one body part to another
communication needed to coordinate whole body
homeostasis & regulation
●
■metabolism
■growth
■development
■maturation
■Reproduction
Hormones control processes unique to
invertebrates
Ex: metamorphosis ex: ecdysone
2004-2005
growth hormones
– An endocrine system consists of glands that
coordinate body activities through hormones.
• Carried by the bloodstream to target cells throughout the
body
●Affects 1 tissue, a few, or most tissues in body
●Or affect other endocrine glands (tropic hormones)
– Endocrine glands can be contrasted with exocrine
glands
• Endocrine glands – secrete substances directly into the
bloodstream
• Exocrine glands – secrete products into ducts, which
subsequently take them to lumens of other organs or outside
the body” Ex: salivary gland and tear glands also phermones
•
Neurosecretory: these are specialized neurons that can
also secrete hormones.
– Ex. Hypothalamus, pituitary
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Animal Hormones
• Hormones are Chemical Signals
• Pheromones
–
a chemical substance produced and released into the
environment by an animal, especially a mammal or an
insect, affecting the behaviour or physiology of others
of its species.
– Once the food runs out, the ants release a separate
pheromone that lets the ants know that the food is
gone.
6
Major Glands of The Human Endocrine System
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HYPOTHALAMUS
Releasing and inhibiting hormones:
regulate the anterior pituitary
PITUITARY GLAND
Posterior Pituitary
Antidiuretic (ADH):
water reabsorption by kidneys
Oxytocin: stimulates uterine
contraction and milk letdown
Anterior Pituitary
Thyroid stimulating (TSH):
stimulates thyroid
Adrenocorticotropic (ACTH):
stimulates adrenal cortex
Gonadotropic (FSH, LH): egg and
sperm production; sex hormone
production
Prolactin (PL): milk production
PINEAL GLAND
Melatonin: controls circadian
and circannual rhythms
Growth (GH): bone growth, protein
synthesis, and cell division
PARATHYROIDS
Parathyroid hormone (PTH):
raises blood calcium level
parathyroid glands
(posterior surface
of thyroid)
THYROID
Thyroxine (T4) and triiodothyronine
(T3): increase metabolic rate;
regulates growth and development
Calcitonin: lowers blood calcium level
THYMUS
Thymosins: production
and maturation of T
lymphocytes
ADRENAL GLAND
Adrenal cortex
Glucocorticoids (cortisol):
raises blood glucose level;
stimulates breakdown of protein
Mineralocorticoids (aldosterone):
reabsorption of sodium and
excretion of potassium
Sex hormones: reproductive organs
and bring about sex characteristics
PANCREAS
Insulin: lowers blood
glucose level and
promotes glycogen
buildup
Glucagon: raises blood
glucose level and
promotes glycogen
breakdown
Adrenal medulla
Epinephrine and norepinephrine:
active in emergency situations;
raise blood glucose level
testis
(male)
GONADS
Testes
Androgens (testosterone):
male sex characteristics
Ovaries
ovary (female)
Estrogens and progesterone:
female sex characteristics
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Different Types of Hormones
• The two major types of hormones found in living organisms
are steroid hormones and peptide hormones. These work
differently when targeting cells.
• https://www.youtube.com/watch?v=TgNwxF3aQpE
1. Steroid (lipid-based) hormones – steroid hormones are lipidbased, so they can easily pass through the phospholipid bilayer.
Once in the cell, they target receptors deep in the cytoplasm or
the nucleus. Ex. Testosterone, estrogen, aldosterone
2. Peptide (protein-based) hormones – peptide hormones are
protein-based, so they can not pass directly through the
phospholipid bilayer. These hormones must bind to a cellsurface receptor and then transmit their message into the cell.
This follows the stereotypical signal transduction pathway.
Ex. Prolactin, HGH, oxytocin, insulin, glucagon
Enter the cell by moving through the plasma membrane
rather than binding to receptor proteins
Feedback Mechanisms
https://www.youtube.com/watch
?v=plVMjqaBYIU
https://www.youtube.com/watch
?v=plVMjqaBYIU
What Happens?
• Between meals
Blood glucose lowPancreas secretes
glucagonLiver changes glycogen to
glucoseglucose sent to target tissues
• After a meal
Blood glucose highPancreas secretes
insulinGlucose goes to the Liver(Glygogen) and
goes to Target tissues
Positive feedback loops are also very important in living organisms. These are
the opposite of negative feedback. The production of a hormone causes the
continuation of a behavior. Oxytocin and prolactin are examples of hormones
that function through positive feedback.
40.2 Hypothalamus and pituitary gland.
Learning Objectives.
1-Describe the relationship between the
hypothalamus and the pituitary gland.
2-List and describe the hormones released by the
anterior and posterior pituitary gland.
3-Explain some hormones are controlled by positive
and negative feedback and give example for each.
Task 1
Explain how the hypothalamus communicates
with the endocrine system.
Task 2
List the hormones produced by the posterior
pituitary gland and provide function for each.
Task 3
List the hormones produced by the anterior
pituitary gland and provide function for each.
40.2 Hypothalamus and
Pituitary Gland
• The hypothalamus regulates internal environment
1-Acts through autonomic system ”It influences the heart
beat, blood pressure ,appetite and body temperature.
2-Also controls the glandular secretions of
pituitary gland(The master gland)
– Posterior Pituitary
• Produces antidiuretic hormone (ADH)
– Controlled by negative feedback
• Produces oxytocin
• Controlled by positive feedback
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Hypothalamus and Pituitary
Gland
• Anterior Pituitary
• Controlled by the hypothalamus, which produces
– Hypothalamic-releasing hormones
– Hypothalamic-inhibiting hormones
• Anterior pituitary hormones that affect other glands:
• Thyroid-Stimulating Hormone (TSH)
• Adrenocorticotropic Hormone (ACTH)
• Gonadotropic Hormones
• Anterior pituitary hormones that do NOT affect other
glands
• Prolactin (PRL)
• Melanocyte-Stimulating Hormone (MSH)
• Growth Hormone (GH)
20
GH
Neurosecretory: these are specialized neurons that can also
secrete hormones.
Ex. Hypothalamus, pituitary
Adrenocorticotropic hormone (ACTH) is a hormone produced in
the anterior, or front, pituitary gland in the brain. The function of ACTH
is to regulate levels of the steroid hormone cortisol, which released
from the adrenal gland. ACTH is also known as: adrenocorticotropic
hormone.
MSH stimulates the production and release of melanin by
melanocytes in skin and hair.
In females, FSH stimulates the ovarian follicle, causing an egg to
grow. It also triggers the production of estrogen in the follicle. The rise
in estrogen tells your pituitary gland to stop producing FSH and to
start making more LH. The shift to LH causes the egg to be released
from the ovary, a process called ovulation.
In men, LH stimulates testosterone production from the interstitial cells of the
testes (Leydig cells). FSH stimulates testicular growth and enhances the
production of an androgen-binding protein by the Sertoli cells, which are a
component of the testicular tubule necessary for sustaining the maturing
sperm cell.
Hypothalamus and the Pituitary
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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)
Adrenal cortex:
adrenocorticotropic
hormone (ACTH)
Bones, tissues:
growth hormone
(GH)
Ovaries, testes:
gonadotropic
hormones (FSH, LH)
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Effect of Growth Hormone
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a.
b.
a: © AP/Wide World Photos; b: © Ewing Galloway, Inc.
26
Acromegaly
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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.
27
40.3 Other Endocrine Glands and
Hormones
Learning objectives:
1- Distinguish among the function of T3 and T4
,calcitonin and parathyroid hormone.
2- Compare and contrast the mineralocorticoids and
glucocorticoids.
3- Identify the causes and major symptoms of the major
conditions associated by endocrine system.
https://www.youtube.com/watch?v=SVSBo065hmw
• Thyroid and Parathyroid Glands
• Thyroid Gland
• Attached to the trachea just below the larynx
• Composed of a large number of follicles filled with
1-Triiodothyronine (T3) and Thyroxine (T4)
• These hormones function to increase the metabolic rate by stimulating most of the body cells to
metabolize at a faster rate
• Thyroid acquires iodine to produce these compounds
2-Calcitonin
• Thyroid-induced abnormalities
–
–
–
–
–
–
–
Hypothyroidism – immune system produces antibodies that destroy the thyroid gland
Simple goiter - Poor hormone production
Cretinism - Poor thyroid development (Congenital hypothyroidism )
Myxedema - Hypothyroidism
Hyperthyroidism – over secretion of T3 or T4
Exophthalmic goiter – Hyperthyroidism
Graves disease – antibodies stimulate overproduction of T3 and T4
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cretinism
Myxedema
• Effects of Calcitonin
• Regulates blood calcium level (in part)
• Secreted by the thyroid gland when blood calcium
level rises
• Brings about deposit of calcium in the bones
31
• Parathyroid Glands
• Low calcium level in blood stimulates the release of
parathyroid hormone (PTH) by the parathyroid
glands
– Parathyroid hormone causes
• Phosphate level in blood to decrease, and
• Calcium level in blood to increase
– Insufficient production of parathyroid hormone leads to tetany
32
Regulation of Blood Calcium Level
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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.
33
Task 1
List the hormones produced by the adrenal gland and provide
function for each.
Malfunctions of the Adrenal Cortex
Task 2
List the hormones produced by the pancreas, testes , ovaries
,pineal gland and thymus gland and provide function for each.
• Adrenal Glands
• Adrenal medulla
• Produces epinephrine and norepinephrine
• Adrenal cortex
• Produces mineralocorticoids and glucocorticoids
36
Adrenal Glands
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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
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• Glucocorticoids
– Cortisol
• Raises blood glucose level
• Promotes breakdown of muscle proteins to amino
acids
• Promotes metabolism of fatty acids
• Counteracts inflammatory response
38
• Mineralocorticoids
– Aldosterone
• Promotes two renal functions:
– Absorption of sodium
– Excretion of potassium
– Atrial natriuretic hormone (ANH)
• Inhibits secretion of aldosterone
• Causes excretion of sodium ions (natriuresis)
– Renin-angiotensin-aldosterone system
• Raises blood pressure
• Angiotensin II constricts arterioles
• Aldosterone causes kidneys to reabsorb sodium (causing
water retention)
40
Regulation of Blood Pressure and
Volume
https://www.youtube.com/watch?v=bY6IWVgFCrQ
Enzyme
Hormone secreted by
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• Malfunctions of the Adrenal Cortex
• Addison disease
• Insufficient secretion of hormones by adrenal
cortex
• Dehydration, weakness, weight loss, hypotension
• Cushing syndrome
• Excessive levels of glucocorticoids
• Causes metabolism of muscle protein
42
Addison Disease
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a.
b.
a: © Custom Medical Stock Photos; b: © NMSB/Custom Medical Stock Photos
44
Cushing Syndrome
45
• Pancreas
• Made up of exocrine and endocrine tissue
– Endocrine portion of the pancreas:
• Consists of pancreatic islets
• Produce and secrete
– Insulin
» Secreted during high blood glucose level
» Stimulates uptake of glucose by cells
– Glucagon
» Secreted during low blood glucose level
» Stimulates liver to break down glycogen
– Exocrine portion of the pancreas:
• Secretes enzymes and buffers into the small intestine
46
Regulation of Blood Glucose
Level
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
insulin
Liver stores
glucose from
blood as
glycogen.
Pancreatic islet
of Langerhans
Muscle cells
store glycogen
and build protein.
After eating,
pancreas
secretes insulin
into blood.
Adipose tissue
uses glucose
from blood
to form fat.
Blood glucose
level lowers.
Homeostasis (normal blood glucose)
Before eating,
pancreas secretes
glucagon into
blood.
Liver breaks
down glycogen
to glucose.
Glucose enters
blood.
Pancreatic islet
of Langerhans
Adipose tissue
breaks down fat.
glucagon
© Peter Arnold, Inc./Alamy
47
• Diabetes Mellitus
• Inability of the body’s cells to take up glucose
as they should
• Causes blood glucose levels to be higher than
normal
• Cells must rely on other sources of energy, such
as fatty acids
• As blood glucose levels rise, glucose, along with
water, is excreted in the urine
• Results in frequent urination and a feeling of
extreme thirst
48
• Diabetes Mellitus
• Type 1 Diabetes
• Pancreas does not produce enough insulin
• Body turns to the metabolism of fat, which leads to the
buildup of ketones in the blood
• Patients must have daily insulin injections
• Type 2 Diabetes
• Patients are typically overweight and adipose tissue
produces a substance that impairs insulin receptor function
• Prevented/controlled by adhering to a low-fat diet, low-sugar
diet, and regular exercise
49
Other Endocrine Glands and
Hormones
• Testes and Ovaries
– Testes
• Produce testosterone
• Secondary sex characteristics
• Anabolic steroids mimic the effect of testosterone and
can lead to very dangerous side effects
– Ovaries
• Produce estrogen and progesterone
• Secondary sex characteristics
50
The Effects of Anabolic Steroid
Use
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balding in men and women;
hair on face and chest in
women
'roid rage–
delusions and hallucinations;
depression upon withdrawal;
violent or aggressive behavior
deepening of voice in women
severe acne
breast enlargement in men
and breast reduction in women
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
adolescents by Prematurely halting Fusion
of the growth plates
51
• Pineal Gland
– Produces melatonin
• Involved in daily sleep-wake cycle (circadian
rhythms)
– Controlled by an internal biological clock
• Thymus Gland
– Most active during childhood
– Aids in differentiation of lymphocytes
52
Melatonin Production
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a. experimental
b. winter
6 P.M.
6 A.M.
c. summer
© The McGraw-Hill Companies, Inc./ Evelyn Jo Johnson, photographer
53
• Leptin
– Secreted by adipose tissue
– Involved in feedback control of appetite
• Erythropoietin
– Produced by the kidneys
– Stimulates production of red blood cells
• Prostaglandins
– Local hormones
– Not distributed in blood
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H
ormones play important roles in regulating the lives of
many living organisms.
a. For TWO of the following physiological
responses, EXPLAIN how hormones cause the response in
plants.
- increase in height
- Adjustment to change in light
- adjustment to lack of water
b. For TWO of the following physiological
response, EXPLAIN how hormones cause the responses in
animals.
- increase in height
- adjustment to change in light
- adjustment to lack of water
10. Which of the following diagrams best represents hormones-activated gene expression?
Answer = A