1. Which of the following is a humoral stimulus for hormone release? (LOOK Up Answer)
2. Which hormone is secreted by adipose tissue and helps suppress your appetite? Leptin
The Endocrine System: Hypothalamus and Pituitary


Are you hot right now? Cold? Maybe you're like Goldilocks and are just right. What
about your height? Are you tall? Average? Short? Maybe your metabolism is lightning
fast and you're always hungry, or maybe it's a bit slow and you stay full longer. All of
these—regardless of which one you identify with—are regulated by the endocrine
system.
What is the endocrine system? It's a network of glands throughout the body that regulate
certain body functions, including body temperature, metabolism, growth, and sexual
development.
Though there are many glands, today we’ll focus on just two: the hypothalamus and the pituitary
gland.
Image from Human Anatomy Atlas.
Hormone Reaction Regulation

It’s no secret your brain is one busy place—neurons move at incredible speeds, synapses
are constantly firing, blood is pumping, and glands are producing hormones. These
glands, specifically the hypothalamus and pituitary, are working all the time to keep your
body running at optimal performance. Every hormone the endocrine system releases
follows a basic set-up: a signal is received, hormones are secreted, and the target cell
undergoes changes to its basic functions.
Hypothalamus

The almond-sized hypothalamus is located below the thalamus and sits just above the
brainstem. All vertebrate brains have a hypothalamus. Its primary function is to maintain
homeostasis (stability of the internal environment) in the body.
Image from Human Anatomy Atlas.
The hypothalamus links the nervous and endocrine systems by way of the pituitary gland. Its
function is to secrete releasing hormones and inhibiting hormones that stimulate or inhibit (like
their names imply) production of hormones in the anterior pituitary. Specialized neuron clusters
called neurosecretory cells in the hypothalamus produce the hormones Antidiuretic Hormone
(ADH) and Oxytocin (OXT), and transport them to the pituitary, where they're stored for later
release.
Think of the hypothalamus as the pituitary's older sibling—it not only controls the actions of the
pituitary but it secretes at least nine hormones to the pituitary's seven.
Pituitary Gland

Attached to the hypothalamus, the pituitary gland is a pea-sized, reddish-gray body that
stores hormones from the hypothalamus and releases them into the bloodstream. The
pituitary consists of an anterior lobe and a posterior lobe, each of which have distinct
functions.
Image from Human Anatomy Atlas.
Pituitary: Anterior Lobe (Adenohypophysis)
The anterior lobe (or adenophyophosis) secretes hormones that regulate a wide variety of bodily
functions. There are five anterior pituitary cells that secrete seven hormones:
Secrete human growth hormone (hGH), aka somatotropin, which stimulates
Somatotrophs tissues to secrete hormones that stimulate body growth and regulate
metabolism.
Secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH),
which both act on the gonads. They stimulate the secretion of estrogen and
Gonadotrophs
progesterone, maturation of egg cells in the ovaries, and stimulate sperm
production and secretion of testosterone in the testes.
Lactotrophs
Secrete prolactin (PRL), which initiates milk production in the mammary
glands.
Secrete adrenocorticotropic hormone (ACTH), which stimulates the adrenal
Corticotrophs cortex to secrete glucocorticoids (like cortisol). Also secretes melanocytestimulating hormone (MSH).
Thyrotrophs
Secrete thyroid-stimulating hormone (TSH), which controls secretions of the
thyroid gland.
This table represents the types of hormones secreted by the cells of the anterior pituitary.
Name
Target Area
Function
Human-growth hormone
Tissues
(hGH)
Stimulates tissue growth in the liver, muscles,
bones, as well as protein synthesis, tissue repair,
and elevation of blood glucose levels.
Thyroid-stimulating
hormone (TSH)
Thyroid gland
Stimulates thyroid gland to secrete thyroid
hormones.
Follicle-stimulating
hormone (FSH)
Ovaries and
testes (gonads)
Stimulates development of oocytes (immature
egg cells) and secretion of estrogen in females;
stimulates sperm production in the testes in
males.
Luteinizing hormone
(LH)
Ovaries and
testes (gonads)
Stimulates secretion of estrogen and
progesterone, including during ovulation, in
females; stimulates testes to produce testosterone
in males.
Prolactin (PRL)
Mammary
glands
Stimulates milk production.
Adrenocorticotropic
hormone (ACTH)
Adrenal cortex
Stimulates secretion of glucocorticoids (cortisol)
by the adrenal cortex during the body’s response
to stress.
Melanocyte-stimulating
hormone (MSH)
Brain
When in excess, can cause darkening of the skin;
may influence brain activity (its exact role
unknown—there is very little MSH in humans).
Pituitary: Posterior Lobe (Neurohypophysis)
While the anterior lobe shoulders most of the work in producing hormones, the posterior lobe
stores and releases only two: oxytocin and antidiuretic hormone (ADH), or vasopressin.
Name
Trigger
Function
Oxytocin (OT),
aka the "love"
drug
Secretes in response to uterine
distention and stimulation of the
nipples.
Stimulates smooth muscle
contractions of the uterus during
childbirth, as well as milk ejection
in the mammary glands.
Antidiuretic
hormone (ADH),
or vasopressin
Secretes in response to dehydration, Decreases urine volume to conserve
blood loss, pain, stress; inhibitors of water, decreases water loss through
ADH secretion include high blood
volume and alcohol.
sweating, raises blood pressure by
constricting arterioles.
How does the hypothalamus regulate the release of hormones from the anterior pituitary gland?
It secretes releasing and inhibiting hormones that travel through the blood to the anterior
pituitary gland.
It sends nerve impulses along axons that release hormones within the anterior pituitary gland.
It sends nerve impulses to the glandular cells of the anterior pituitary.
How does the hypothalamus regulate the release of hormones from the anterior pituitary gland?
Check answer)
A. It secretes releasing and inhibiting hormones that travel through the blood to the
anterior pituitary gland.
B. It sends nerve impulses along axons that release hormones within the anterior pituitary
gland.
C. It sends nerve impulses to the glandular cells of the anterior pituitary.
D. It releases Na+ to trigger hormone release by the anterior pituitary cells.
Which hormone is released by nerve impulses?

epinephrine
Hormones of Non-Endocrine Organs:
1. Heart
 ANP
 BNP
 CNP
2. Kidneys




Renin
b. Erythropoietin
c. Convert angiotensinogen into angiotensin
d. Convert calcidiol to calcitriol
3. Liver



Somatomedins (IGF-1)
Angiotensinogen
Converts vitamin D into calcidiol
4. GIT
Several hormones are produced within the GIT. Examples include:






Gastrin
CCK
Secretin
VIP
GIP
Somatostatin
5. Placenta
Placenta produces several hormones. These include:





hCG
Estrogens
Progesterone
hCS
Relaxin
f. Placental PTHrp
6. Pineal gland

Pineal gland produces melatonin.
Hormones of Heart:
Two of the natriuretic peptides are secreted by the cardiomocytes which are the muscle cells of
atria and ventricles containing secretory granules. The secretion is due to:
1. Increased intake of NaCl
2. Increased ECF volume
Atrial natriuretic peptide (ANP) has also been isolated from the brain tissue.
Brain natriuretic peptide (BNP) is present more in the human heart especially ventricle but also
occurs in the brain.
C-type natriuretic peptide (CNP) is present mainly in the brain, pituitary, kidneys and very little
in the heart.
Actions:
I.
ANP and BNP act mainly on the kidneys to increase sodium excretion. (Injection of CNP
has similar effects.
Mechanism of Action:
1. Dilatation of afferent arterioles and relaxation of mesangial cells increases
the glomerular filtration rate.
2. Inhibition of Na+ reabsorption in the renal tubules occurs.
3. Increased capillary permeability leads to extravasation of fluid and a decrease in blood
pressure.
4. The relaxation of vascular smooth muscles in arterioles and venules occurs (CNP has
more dilatory effect than ANP or BNP).
5. Inhibition of rennin secretion and counteract pressure effects of catecholamines and
angiotensin II take place.
Pineal Gland:
II.
Pineal gland secretes melatonin. This is a timing device to keep internal events
synchronized. Nerves from the visual pathways enter the pineal gland. Melatonin
production is highest at night and lowest during the day (circadian rhythm). It plays no
role in regulation of skin color.
Functions:
1. Controls sexual activity in humans
2. Melatonin acts on gonads (in humans it inhibits the onset of puberty by inhibiting
gonads)
3. Controls sexual activities in animals by regulating seasonal fertility.
4. Inhibits reproductive functions- i.e. in animals, longer nights mean more melatonin as
occurs during winter, so is an indication that it is not the time to reproduce.
5. Protects against damage by free radicals.
The duration of melatonin secretion each day is directly proportional to the length of night.
Placental Hormones:
III.
hCG:
Human chorionic gonadotropin maintains the corpus luteum for the five and a half weeks. It is
similar to LH and exhibits TSH like activity. It stimulates the secretion of testosterone by
developing testes in XY embryos.
IV.
Estrogen
Estrogen stimulates the growth of myometrium and helps the duct development in mammary
glands. It inhibits GnRH and PRL and promotes uterine sensitivity to oxytocin.
V.
Progesterone:
Progesterone suppresses the uterine contractions and GnRH. It causes formation of cervical
mucus plug to prevent uterine contamination. It helps in development of alveolar tissue in
mammary glands.
VI.
hCS:
Human chorionic somatomammotropin is similar to GH and PRL and cause shunting of greater
quantities to glucose and free fatty acids to the fetus. It causes lipolysis and sparing of glucose in
mother thus has diabetic-like effect. It helps to prepare the mammary glands.
Relaxin:
VII.
Relaxin softens the cervix and loosens the connective tissue between the pelvic bones.
Placental PTHrp:
Placental PTHrp increases the maternal Ca++ and mobilizes Ca++ from maternal bones.
VIII.
nervous system
-pathway
-messenger
-effects
-neurons directly affect target cells
-neurotransmitters
-immediate/short-lasting (unless repetitive)
endocrine system
-pathway
-messenger
-effects
-bloodstream (no close contact with target)
-hormones
-seconds to hours, longer-lasting
IX.
X.
XI.
paracrine signals

cells secrete chemicals into extracellular fluid that affect nearby different types of cells
autocrine signals

cells secrete chemicals into extracellular fluid that affect the same type of cell
endocrine glands

-pituitary
-hypothalamus
-thyroid
-parathyroid
-thymus
-pancreas
-pineal
-adrenal
-ovaries/testes
function of endocrine glands


regulate other cell types through the production/secretion of hormones
do endocrine glands have ducts NO
groups of endocrine organs

primary and secondary
primary endocrine organs

-only endocrine functions
-anterior pituitary gland
-thyroid gland
-parathyroid glands
-adrenal cortices
-endocrine pancreas
-thymus
secondary endocrine organs

-both endocrine and other functions
-testes/ovaries
-hypothalamus
-pineal gland
-adrenal medulla
neuroendocrine organs

-hypothalamus, pineal gland, adrenal medulla
-consist of nervous tissue, but secrete neurohormones
neurohormones

chemicals that act as hormones
hormones

-chemicals that regulate some function of other cells
how can hormones travel through the body

-in the blood
-bound to hydrophilic protein molecule
what causes a hormone to stop circulating in the blood?

it must be taken up by target cell or broken down and deactivated
what determines the amount of any particular hormone in the blood at a given time

-the rate at which the hormone is removed from the blood
-the amount of hormone secreted
fast and slow removal of hormones from the blood

-fast: reactions catalyzed by enzymes
-slow: kidneys(urine), liver(broken down by enzymes)
paraneoplastic syndrome

-hormone secretion from cancer cells (usually lung/gastrointestinal cancer)
-fluid, calcium, and sodium homeostasis imbalances
hormone receptors

-specific shape that specific hormones bind to (even at low concentrations)
-embedded in plasma membrane or cytosol/nucleus of target cell
if a hormone receptor is in the target cell's cytosol what must be said of the hormone

it is likely hydrophobic because it must pass through the phospholipid bilayer
where are hormone receptors of hydrophilic hormones

-the surface of cells
-the receptor is often associated with other proteins (ion channels, enzymes, peripheral
proteins)
up-regulation

-process where a cell produces more receptors in response to a higher level of a hormone
in the blood
down-regulation

-prolonged exposure to a high level of a hormone results in a cell decreasing the amount
of correlating receptors
what do down/up -regulation allow cells

cells have tighter control over how they interact with hormones
classes of hormones

-amino acid-base
-steroids
amino acid-base hormones

-one/more amino acids
-hydrophilic
-amine hormones: single amino acids
-peptide hormones: several amino acids
-protein hormones: complete proteins
steroid hormones

-cholesterol derivatives with core of hydrocarbon rings
-hydrophobic
what type of hormone is an exception to the rule of acid-base hormones being hydrophilic?

thyroid hormones
second-messenger system

hydrophilic hormone binds to receptor in the plasma mem
2. receptor activates a peripheral protein
3. peripheral protein activates an enzyme
4. enzyme catalyzes a formation of a second messenger
5. 2nd messenger activates series of events in cell that changes its activities
signal amplification

in second-messenger systems a single hormone can bind a receptor and lead to the
formation of hundreds of second messengers that activate/inhibit molecules that create
events in cells
adenylate cyclase-cAMP system

-second messenger system: G-protein activates enzyme-adenylate cyclase which
catalyzes formation of second messenger cyclic adenosine monophosphate (cAMP) from
ATP= changes in cell
protein kinase function

enzymes that catalyze the transfer of a phosphate group from ATP to another molecule
(phosphorylation)
hormone receptor complex

-formed when a hydrophobic hormone binds to an intracellular receptor
-generally interacts with DNA (changing the rate of synthesis of 1/more specific protein)
effects of hormone actions

-stimulating secretion from an endocrine/exocrine cell
-activating/inhibiting enzymes
-stimulating/inhibiting mitosis/meiosis
-opening/closing ion channels and/or altering its mem potential
-activating/inhibiting transcription of genes that code for RNA or proteins (gene
expression)
what can initiate hormone secretion

hormonal, humoral, or neural stimulation
hormonal stimulus

-some endocrine cells increase/decrease secretion in response to other hormones
-Ex: hypothalamus regulates secretion from the anterior pituitary gland
humoral stimulus

-many endocrine cells respond to the concentration of a certain ion/molecule in
blood/extracellular fluid (glucose)
-Ex: pancreas releases insulin in response to high blood glucose
neural stimulus

-respond to signals from the nervous system
-Ex: adrenal medulla releases neurohormones (epinephrine/nor) in response to
stimulation of sympathetic nervous system
hormone secretion by negative feedback loop

-stimulus: regulated variable leaves normal range
-receptors on endocrine cells detect change (glucose/Ca in blood/body temp)
-control center: increase/decrease secretion (same as receptor)
-effector: hormone triggers response in target
-return= decreases effector response
complementary actions of hormones

different hormones affect different target cells to accomplish a common goal
synergist hormones

different hormones act on the same cell for the same effect = more pronounced effects
antagonist hormones

hormones act on the same target cells and have the opposite effects
Endocrine

endocrine cell
Transported by blood
distant cell location
different types
Paracrine





Tissue Cell
paracrine chemical secreted
transported in extracellular fluid.
Near cell
Different type
Autocrine





Specialized cell
Autocrine chemical
Transported extracellular fluid
Same cell or near cell
Same cell or cell type
Hormones arouse cellular or alter cellular activity
•
•
•
Hormones arouse cells or alter cellular activity
Typically, one or more of the following occurs:
1. Change plasma membrane permeability or membrane potential by
opening or closing ion channels
2. Activate or inactivate enzymes
3. Stimulate or inhibit cell division
4. Promote or inhibit secretion of a product
5. Turn on or turn off transcription of certain genes
Direct gene activation
1. Steroids diffuse through the plasma membrane of target cells
2. Once inside the cell, the hormone enters the nucleus
3. Then, the hormone binds to a specific protein within the nucleus
4. Hormone-receptor complex binds to specific sites on the cell’s D N A
5. Certain genes are activated to transcribe messenger R N A
6. New proteins are synthesized
Slides 10-16 chapter 9 slides
•
Second-messenger system
1. Hormone (first messenger) binds to a membrane receptor
2. Activated receptor sets off a series of reactions that activates an
enzyme
3. Enzyme catalyzes a reaction that produces a second-messenger
molecule (such as cyclic A M P, known as c A M P)
4. Oversees additional intracellular changes to promote a specific
response in the target cell
slides 18-22 chapter 9
The stimuli that activate endocrine glands fall into three major categories



Hormonal
Humoral
Neural
Humoral stimuli


Changing blood levels of certain ions and nutrients stimulate hormone release
Humoral indicates various body fluids, such as blood and bile



Examples:
Parathyroid hormone and calcitonin are produced in response to changing levels of blood
calcium levels
Insulin is produced in response to changing levels of blood glucose levels
Stimuli for Control of Hormone Release



Hormone levels in the blood are maintained mostly by negative feedback
A stimulus or low hormone levels in the blood trigger the release of more hormone
Hormone release stops once an appropriate level in the blood is reached
Neural stimuli


Nerve fibers stimulate hormone release
Most are under the control of the sympathetic nervous system
Examples:

Sympathetic stimulation of the adrenal medulla to release epinephrine and norepinephrine
The Major Endocrine Organs





Some glands have purely endocrine functions
Anterior pituitary, thyroid, adrenals, parathyroids
Endocrine glands are ductless glands
Hormones are released directly into blood or lymph
Other glands are mixed glands, with both endocrine and exocrine functions (pancreas,
gonads)
Pituitary gland


Pea-sized gland that hangs by a stalk from the hypothalamus in the brain
Protected by the sella turcica of the sphenoid bone
Has two functional lobes



Anterior pituitary—glandular tissue
Posterior pituitary—nervous tissue
Often called the “master endocrine gland”
Posterior pituitary



Oxytocin
Stimulates contractions of the uterus during labor, sexual relations, and breastfeeding
Causes milk ejection (let-down reflex) in a breastfeeding woman
Posterior pituitary




Antidiuretic hormone (A D H)
Inhibits urine production (diuresis) by promoting water reabsorption by the kidneys
Urine volume decreases, blood pressure increases
In large amounts, causes constriction of arterioles, leading to increased blood pressure
(the reason why A D H is known as vasopressin)
Six anterior pituitary hormones



Two hormones affect nonendocrine targets
Growth hormone
ProlactinAlcohol inhibits A D H secretion
Four are tropic hormones




Follicle-stimulating hormone
Luteinizing hormone
Thyrotropic hormone
Adrenocorticotropic hormone
All anterior pituitary hormones:




Are proteins (or peptides)
Act through second-messenger systems
Are regulated by hormonal stimuli
Are regulated mostly by negative feedback
Growth hormone (G H)





General metabolic hormone
Major effects are directed to growth of skeletal muscles and long bones
Plays a role in determining final body size
Causes amino acids to be built into proteins
Causes fats to be broken down for a source of energy
Prolactin (P R L)


Stimulates and maintains milk production following childbirth
Function in males is unknown
Gonadotropic hormones







Regulate hormonal activity of the gonads
Follicle-stimulating hormone (F S H)
Stimulates follicle development in ovaries
Stimulates sperm development in testes
Luteinizing hormone (L H)
Triggers ovulation of an egg in females
Stimulates testosterone production in males
Thyrotropic hormone (T H), also called thyroid-stimulating hormone (T S H)



Influences growth and activity of the thyroid gland
Adrenocorticotropic hormone (A C T H)
Regulates endocrine activity of the adrenal cortex
Hangs from the roof of the third ventricle of the brain



Secretes melatonin
Believed to trigger the body’s sleep/wake cycle
Believed to coordinate the hormones of fertility in humans and to inhibit the reproductive
system until maturity occurs
Found at the base of the throat, inferior to the Adam’s apple




Consists of two lobes and a connecting isthmus
Follicles are hollow structures that store colloidal material
Produces two hormones
Thyroid hormone

Calcitonin
Thyroid hormone






Major metabolic hormone
Controls rate of oxidation of glucose to supply body heat and chemical energy
Needed for tissue growth and development
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 calcium deposition on bone


Antagonistic to parathyroid hormone
Produced by parafollicular cells found between the follicles
A seesaw in balance represents calcium
homeostasis of blood a 9 to 11 milligrams per 100 milliliters. When the seesaw falls on one side
it represents a stimulus of falling blood calcium ion levels, which causes the parathyroid glands
to release parathyroid hormone, P T H. The parathyroid glands are posterior to the thyroid. An
increase in P T H, cause osteoclasts to degrade bone matrix and release calcium ions into blood,
which brings back calcium homeostasis. When the seesaw goes up, it represents a stimulus of
blood calcium levels going up, which causes the thyroid gland to release calcitonin which
stimulates calcium salt deposit in bone and returns calcium homeostasis.
THYMUS



Located in the upper thorax, posterior to the sternum
Largest in infants and children
Decreases in size throughout adulthood
Produces a hormone called thymosin


Matures some types of white blood cells
Important in developing the immune system
Hormones of the adrenal cortex



Release of aldosterone is stimulated by:
Humoral factors (fewer sodium ions or too many potassium ions in the blood)
Hormonal stimulation (A C T H)
Renin and angiotensin II in response to a drop in blood pressure
Aldosterone production is inhibited by atrial natriuretic peptide (A N P), a hormone produced by
the heart when blood pressure is too high
Decreased sodium ions, or increased potassium ions
in blood have a direct stimulation effect on the adrenal gland. Decreased sodium ions, or
increased potassium ions in blood, as well as decreased blood volume and or blood pressure
cause the kidneys to release Renin, which indirectly stimulates via angiotensin 2 the adrenal
cortex. Stress causes the hypothalamus to release corticotropin releasing hormone, which causes
the anterior pituitary to release adrenocorticotropic hormone. A C T H stimulates the adrenal
cortex. When the adrenal cortex is stimulated by the A C T H, its mineralocorticoid producing
part enhances secretion of aldosterone which targets the kidney tubules. That causes increased
absorption of sodium ions and water, and increased potassium excretion, which causes increase
blood volume and pressure. An increase in the blood pressure or volume, causes the heart to
release atrial natriuretic peptide, which has an inhibitory effect on the adrenal cortex.
Hormones of the adrenal cortex



Glucocorticoids (including cortisone and cortisol)
Produced by middle layer of adrenal cortex
Promote normal cell metabolism



Help resist long-term stressors by increasing blood glucose levels (hyperglycemic
hormone)
Anti-inflammatory properties
Released in response to increased blood levels of A C T H
Hormones of the adrenal cortex




Sex hormones
Produced in the inner layer of the adrenal cortex
Small amounts are made throughout life
Most of the hormones produced are androgens (male sex hormones), but some estrogens
(female sex hormones) are also formed
Estrogens





Stimulate the development of secondary female characteristics
Mature the female reproductive organs
With progesterone, estrogens also:
Promote breast development
Regulate menstrual cycle
Pancreas






Located in the abdomen, close to stomach
Mixed gland, with both endocrine and exocrine functions
The pancreatic islets (islets of Langerhans) produce hormones
Insulin—produced by beta cells
Glucagon—produced by alpha cells
These hormones are antagonists that maintain blood sugar homeostasis
Insulin





Released when blood glucose levels are high
Increases the rate of glucose uptake and metabolism by body cells
Effects are hypoglycemic
Glucagon
Released when blood glucose levels are low
Stimulates the liver to release glucose to blood, thus increasing blood glucose A seesaw in
balance represents normal blood glucose of about 90 milligrams per 100 milliliters. When
the seesaw goes down on one side, it represents a stimulus of decreased blood glucose level
as in after skipping a meal. The low blood sugar level causes the glucagon releasing cells of
pancreas to become activated and release glucagon into the bloodstream. It causes the liver
to break down glycogen stores and release glucose to the blood. Blood glucose rises the
homeostatic set point, stimulus for glucagon release diminishes. When the seesaw goes up on
the other side, it represents a stimulus of increased blood glucose level such as after eating
four jelly doughnuts. The elevated blood sugar level cause the insulin secreting cells of the
pancreas to become activated and release insulin into the blood. Insulin causes uptake of
glucose from blood to be enhanced in most body cells, blood glucose falls to homeostatic set
point, stimulus for insulin release diminishes. Levels
A seesaw in balance represents normal blood glucose of about 90 milligrams per 100 milliliters.
When the seesaw goes down on one side, it represents a stimulus of decreased blood glucose
level as in after skipping a meal. The low blood sugar level causes the glucagon releasing cells of
pancreas to become activated and release glucagon into the bloodstream. It causes the liver to
break down glycogen stores and release glucose to the blood. Blood glucose rises the
homeostatic set point, stimulus for glucagon release diminishes. When the seesaw goes up on the
other side, it represents a stimulus of increased blood glucose level such as after eating four jelly
doughnuts. The elevated blood sugar level cause the insulin secreting cells of the pancreas to
become activated and release insulin into the blood. Insulin causes uptake of glucose from blood
to be enhanced in most body cells, blood glucose falls to homeostatic set point, stimulus for
insulin release diminishes.
Gonads


Produce sex cells
Produce sex hormones
Ovaries



Female gonads located in the pelvic cavity
Produce eggs
Produce two groups of steroid hormones
Testes



Male gonads suspended outside the pelvic cavity
Produce sperm
Produce androgens, such as testosterone
Estrogens





Stimulate the development of secondary female characteristics
Mature the female reproductive organs
With progesterone, estrogens also:
Promote breast development
Regulate menstrual cycle
Progesterone



Acts with estrogen to bring about the menstrual cycle
Helps in the implantation of an embryo in the uterus
Helps prepare breasts for lactation
Testes





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
Other organs that are generally nonendocrine in function also secrete hormones




Stomach
Small intestine
Kidneys
Heart
Placenta





Produces hormones that maintain pregnancy
Some hormones play a part in the delivery of the baby
Produces human chorionic gonadotropin (h C G) in addition to estrogen, progesterone,
and other hormones
Human placental lactogen (h P L) prepares the breasts for lactation
Relaxin relaxes pelvic ligaments and pubic symphysis for childbirth
In the absence of disease, efficiency of the endocrine system remains high until old age
Decreasing function of female ovaries at menopause leads to such symptoms as osteoporosis,
increased chance of heart disease, and possible mood changes
Efficiency of all endocrine glands gradually decreases with aging, which leads to a generalized
increase in incidence of:




Diabetes mellitus
Immune system depression
Lower metabolic rate
Cancer rates in some areas
hormone


mediator molecule
released in one part of the body
regulates activity of cells in other parts of the body
exocrine glands



secrete products into ducts
empty onto skin surface
or lumen of hollow organ
secretions: mucus, sweat, oil, earwax

saliva, digestive enzymes
endocrine glands





secretions enter interstitial fluid
diffuse into bloodstream
NO duct
secretions called hormones
regulate metabolic &
physiological activities
organs and tissues
containing cells that secrete hormones
include:



pituitary
thyroid
parathyroids















adrenals
pancreas
testes
ovaries
pineal
thymus
adipose
heart
hypothalamus
kidneys
liver
placenta
small intestines
stomach
skin
endocrine system

all endocrine glands and hormone-secreting cells
endocrinology the science of the
structure and function & disorders
of the endocrine system
hormones influence target cells

by chemically binding to receptors
Review slides 7-13 chapter 18 slides
lipid soluble hormones



steroid hormones
thyroid hormones
gas (nitric oxide)
water soluble hormones



amine hormones
peptide & protein hormones
eicosanoid hormones
transport proteins - synthesized in liver
lipid-soluble hormones
temporarily water soluble
while bound to transporter proteins
Slides 19-22 chapter1slides
response of target cell to hormone depends on



hormone concentration
abundance of hormone receptors
influences exerted by other hormones
permissive effect





one hormone
only has an effect
if the target cell has (had)
simultaneous or recent exposure
to a second hormone
synergistic effect




the effect of
two hormones working together
is greater than the sum of
the individual hormones acting alone
antagonistic effect



one hormone
opposes action of
another hormone
hormone secretion is regulated by


signals from the nervous system
chemical changes in the blood other hormones
hGH - human growth hormone
(somatotropin)
TSH - thyroid-stimulating hormone
(thyrotropin)
FSH - follicle-stimulating hormone
LH - luteinizing hormone
PRL - prolactin
ACTH - adrenocorticotropic hormone
MSH - melanocyte-stimulating
Hormone
hGH-human growth hormone (somatotropin)


target - several tissues
stimulates secretion of insulin like growth factorsgeneral body growth
regulates

aspects of metabolism
gigantism

due to excessive hGH secreted by pituitary tumor
acromegaly

excessive growth of body after closure of epiphyses
due to excessive

hGH secretion by pituitary tumor
dwarfism and failure of puberty


hGH deficiency
LH, FSH deficiency
TSH - thyroid stimulating hormone (thyrotropin)

target - thyroid
controls


thyroid gland
secretions and activities
FSH - follicle stimulating hormone
LH - luteinizing hormone
target - ovaries and testes

stimulates secretion of estrogens & progesterone



maturation of oocytes
secretion of testosterone
sperm production
male with atrophy of genitalia


lack of LH & FSH
due to pituitary failure
PRL - prolactin

target - mammary glands

effects
initiates milk production in mammary glands
galactorrhea

due to excessive prolactin from pituitary tumor
ACTH - adrenocorticotropic hormone (corticotropin)
target

adrenal cortex
stimulates

secretion of glucocorticoids
MSH - melanocyte-stimulating hormone

exact role in human’s unknown
OT - oxytocin




target - uterus & breast & brain
enhances contraction uterine muscle
stimulates milk ejection response
enhances affection and trust between mother & child and between partners
ADH - antidiuretic hormone (vasopressin)




target - kidneys, sweat glands & arterioles
kidneys return more water to blood (vs. urine)
decreases perspiration
raises BP - constricts arterioles
because of its location
near the optic chiasm

a pituitary tumor may cause bitemporal hemianopsia
slide 53 chapter 18
iodide trapping
thyroid normally contains most of body iodide
synthesis of thyroglobulin (TGB)
tyrosine
T1
T2
TGB
T3
pinocytosis and digestion of colloid
TGB is broken down releasing T3 and T4
secretion of thyroid hormones (T3 and T4) into blood
control of thyroid hormone secretion
high blood [iodine]
suppresses release of thyroid hormones
conditions that increase ATP demand
cold environment
hypoglycemia
high altitude
pregnancy
increase secretion of thyroid hormones
actions of thyroid hormones

most body cells have receptors for thyroid hormones
thyroid hormones stimulate


use of cellular O2 to produce ATP
synthesis of additional Na+/K+ pumps which use more ATP
as cells make and use more ATP more heat is given off
actions of thyroid hormones - continued
thyroid hormones increase
protein synthesis
use of glucose & fatty acids for ATP production
lipolysis
cholesterol excretion
thyroid hormones enhance some actions of catecholamines
(norepinephrine & epinephrine)
by up regulating β receptors
result: increased heart rate, more forceful heartbeats
increased blood pressure
together with hGH & insulin



thyroid hormones
accelerate body growth particularly nervous tissue
deficiency of thyroid hormones during fetal development, infancy, or childhood
causes


stunted growth
severe mental retardation
together with hGH & insulin

thyroid hormones accelerate body growth
particularly nervous tissue
deficiency of thyroid hormones
during fetal development, infancy, or childhood
causes
stunted growth
severe mental retardation
diffuse hyperthyroidism
,
Grave s disease
exopthalmos, goiter
perspiration, facial flushing
shortness of breath
loss of weight
increased appetite
nervousness, excitability
restlessness
emotional instability
warm velvety skin
palpitation, rapid pulse
tachycardia
hyperthyroidism




tension in face
sweatiness of skin
exopthalmos
lid retraction
hyperthyroidism due to













hyperfunctioning thyroid adenoma
nodular goiter
less perspiration, flushing
less weight loss
marked short of breath
nervousness, excitability
restlessness, emotional
instability, insomnia
no exophthalmos
less skin warmth
marked tachycardia
fibrillation common
heart failure common
myxedema - low thyroid hormone
due to deficiency
in thyroid gland or pituitary
cretin = individual who suffers from
congenital absence of thyroid hormone
changes as in myxedema


decreased skeletal growth& maturation
marked retardation
calcitonin



hormone produced by parafollicular cells of thyroid gland
can decrease blood calcium
inhibits osteoclasts
PTH - parathyroid hormone - parathormone

target - bone, kidneys

regulates blood levels

Ca2+

Mg 2+

HPO42-
PTH
2+
2-
increases number & activity of osteoclasts (Ca , HPO )
4
2+
2+
decreases Ca & Mg loss in urine
2-
increases HPO
4
loss in urine
promotes kidney formation of calcitriol
(active form of vitamin D )
increases GI absorption of
2+
Ca
2+
Mg
2-
HPO
4
acute hypocalcemia
as occurs after
accidental removal of
parathyroid glands
during thyroid surgery
hyper-parathyroidism
kidney stones
bone disease
due to
demineralization
other signs
& Symptoms
chronic
hypoparathyroidism
mental lassitude
personality changes
sleepiness
blurring of vision
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Drag each label to the appropriate location
on the diagram of a homeostasis pathway.
...
What is the mechanism of action of lipidsoluble hormones?
activation of genes, which increases protein
synthesis in the cell
After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex
do?
acts as a transcription factor and binds to
DNA, activating a gene
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Drag each label to the appropriate location on the diagram of a homeostasis
pathway.
What is the mechanism of action of lipid-soluble hormones?
activation of genes, which increases protein synthesis in the cell
After a lipid-soluble hormone is bound to its intracellular receptor, what does the
hormone complex do?
acts as a transcription factor and binds to DNA, activating a gene
Which hormone's receptor is always bound to DNA, even when the receptor is empty?
thyroid hormone
What keeps intracellular receptors from binding to DNA before a hormone binds to the
receptor?
chaperone proteins (chaperonins)
Each receptor has two binding sites. The chaperone protein blocks the DNA binding site
until a hormone binds at the hormone binding site.
Most water-soluble hormones exert their effects through the second messenger cyclic
AMP (cAMP). This activity will test your understanding of the events that occur during
cAMP signaling.
Drag the events of cAMP signaling in the correct sequence from left to right.
Which of the following enzymes are important in the deactivation of cAMP and
termination of signaling?
phosphodiesterase
What type of hormones bind to receptors located on the cell membrane?
water-soluble hormones, such as insulin and epinephrine
Which intracellular substance degrades cAMP, thus inactivating the response to a
hormone?
phosphodiesterase
Growth factor hormones, such as insulin, bind to which type of receptor?
tyrosine kinase receptors
Which is the correct order of events for hormones activating Gs proteins?
activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of
ATP to cAMP
Which second messenger causes the release of calcium from the endoplasmic
reticulum?
IP3
Which of the following adrenergic receptors increase cAMP levels?
β receptors
These receptors are coupled to adenylate cyclase by Gs receptors that increase cAMP.
The amplification of the signal from a water-soluble hormone is achieved through an
increase in _______.
cAMP in the cytoplasm
Many cAMP can be generated as a second messenger to amplify the signal in response
to hormone binding.
Water-soluble hormones affect target cells by binding to __________.
plasma membrane receptors
How do endocrine hormones reach their target cells?
Select the best answer.
Hormones are transported through the blood stream to target cells.
What is the role of activated protein kinases?
Select the best answer.
Phosphorylate proteins.
Cyclic AMP is degraded by __________.
phosphodiesterase
Phosphodiesterase degrades cyclic AMP into AMP.
Complete the Concept Map to describe one major mechanism by which hormones act
on their target tissues.
Drag the appropriate labels to their respective targets
What do steroids and amino acid-based hormones have in common?
Steroids and amino acid-based hormones are secreted by endocrine glands.
What is the role of the protein kinases in a cell?
When activated, they phosphorylate other proteins, including other enzymes.
Which of the following is a characteristic of thyroid hormone?
Thyroid hormone is lipid soluble.
How do steroid hormones and thyroid hormone affect change in their target cells?
The hormone passes through the cell membrane and activates intracellular receptors
that enter the nucleus to activate genes.
What tropic hormone stimulates cortisol from the adrenal gland?
adrenocorticotropic hormone (ACTH)
What is the function of the ventral hypothalamic neurons?
control secretion of thyroid stimulating hormone (TSH)
Insulin-like growth factors (IGFs) are intermediary hormones stimulated by which of the
following hormones?
GH (growth hormone)
GH stimulates IGFs from the liver. IGFs are required for the growth effect of GH on
bone and skin.
Which of the following hormones is regulated by a neuroendocrine ("letdown") reflex?
oxytocin
Suckling of the infant (or stretching of the uterus) increases release of oxytocin, which
causes the milk let-down effect (or increased uterine contractions).
Where is antidiuretic hormone (ADH), also known as vasopressin, synthesized?
hypothalamus
ADH is synthesized mainly in the supraoptic nucleus of the hypothalamus. It is stored in
the posterior pituitary in axon terminals.
What is the most important regulatory factor controlling the circulating levels of thyroid
hormone?
negative feedback
Complete the Concept Map to list and describe the chief effects of anterior pituitary
hormones.
Drag the appropriate labels to their respective targets.
Which of the following hormones has the greatest effect on the overall metabolic rate?
TSH
If the anterior pituitary failed to produce LH appropriately, what might be the result?
lowered levels of testosterone or ovarian hormones
The anterior pituitary gland does NOT produce __________.
thyroid hormone
The anterior pituitary produces TSH to stimulate thyroid hormone release in the thyroid.
Which endocrine gland produces cortisol?
adrenal gland
Focus your attention on the section called Posterior Pituitary on the left side of Focus
Figure 16.1.Drag and drop the correct identification labels to the appropriate target in
the figure.
Again, focus your attention on the section called Posterior Pituitary on the left side of
Focus Figure 16.1.
Drag and drop the correct identification labels to the appropriate target in the figure.
Answers may be used once or not at all.
Focus your attention on the section called Posterior Pituitary on the left side of Focus
Figure 16.1.Match each description to its appropriate structure.
1. Supraoptic nucleus of hypothalamus: nucleus located in a more inferior location
that synthesizes mainly the neurohormone ADH
2. Paraventricular nucleus of hypothalamus: nucleus located in a more superior
location that synthesizes mainly the neurohormone oxytocin
3. Axon termini of posterior pituitary: stores neurohormones ADH and
oxytocin and site of release of neurohormones into the blood capillary supplied
by the inferior hypophyseal artery
4. Tract in infundibulum: transports neurohormones to termini in posterior
pituitary/hypophysis
Focus your attention on the section called Anterior Pituitary on the right side of Focus
Figure 16.1.Drag and drop the labels to their appropriate location.
Focus your attention on the section called Anterior Pituitary on the right side of Focus
Figure 16.1.Match each structure at the left to its appropriate function at the right.
1. Hypophyseal portal veins: blood vessels of the hypophyseal portal system that join
two capillary beds
2. Superior hypophyseal artery: supplies the primary plexus
3. Secondary capillary plexus: site that receives the blood and hormones from the
primary plexus and into which hormones such as GH, TSH, and ACTH are secreted
4. Primary capillary plexus: site into which releasing hormones or inhibiting hormones
are secreted
5. Hypothalamus neurons: location of synthesis of releasing hormones (RH), such as
GHRH, TRH, CRH, and GnRH; or inhibiting hormones (IH), such as GHIH and PIH
Hypothalamus neurons returned
The pathway to release of neurohormones follows a series of steps. Arrange the
phrases from left to right to create the correct pathway for the neurohormone ADH from
synthesis to release. Not all phrases will be used.
Focus your attention again on the entire Focus Figure 16.1.Trace a releasing
hormone from its synthesis through its pathway to stimulation of anterior pituitary
hormones. Begin with the site of releasing hormone (RH) or inhibiting hormone (IH)
synthesis. Arrange the phrases from left to right to create the correct pathway. Not all
phrases will be used.
This diagram shows how the body keeps blood glucose at a normal level.
Drag each label to the appropriate location on the diagram.
When blood glucose levels are high
The pancreas releases insulin.
A liver cell responds to insulin by
Taking in glucose and converting it to glycogen.
What cells in the body respond to glucagon by breaking down glycogen and releasing
glucose?
Liver cells.
Body cells that respond to insulin include
Liver cells, as well as most other cells of the body.
When blood glucose levels are low
The pancreas releases glucagon, which eventually causes blood glucose levels to
increase.
The body's tendency to maintain relatively constant internal conditions is called
homeostasis
Read each sentence and decide whether it describes type 1 diabetes, type 2 diabetes,
or both.
Drag the terms on the left to the appropriate blanks on the right to complete the
sentences.
1. In type 2 diabetes, target cells do not respond normally to insulin.
2. In type 1diabetes, no insulin is produced.
3. In both type 1 and type 2diabetes, glucose levels remain higher than normal.
The images show the events that occur in your body after you eat a sugary snack. Put
the events in the correct sequence.
Drag each image to the appropriate location in the sequence.
1. Blood glucose becomes high.
2. Pancreas increases insulin.
3. Insulin binds to receptors on target cells.
4. Cells take in glucose.
5. Blood glucose returns to normal.
The diagram shows the steps in the homeostasis pathway that occur when blood
glucose levels fall.
Drag each label to the appropriate location on the diagram.
1. Low blood glucose
2. Cells in the pancreas
3. Glucagon
4. Liver cells
5. Glycogen breakdown; glucose released into blood
Glucose is stored in the human body as _______.
glycogen
Which hormone stimulates the breakdown of polymerized glucose?
glucagon
Glucose remains in the bloodstream as a result of _______.
type 1 and type 2 diabetes mellitus
Excess glucose can be found in the urine _______.
when the transport maximum for reabsorption in the kidney tubules is exceeded, as a
result of type 1 diabetes or as a result of type 2 diabetes
Diabetes mellitus is a disease of sugar balance. In type 1 diabetes, the body's immune
system gradually destroys the cells that produce insulin. In type 2 diabetes, the body's
cells become less responsive to the hormone insulin.Insulin plays a vital role in
carbohydrate metabolism. What is its role?
Choose the answer that best describes the role of insulin.
Insulin is needed for cells to pick up glucose from the blood; without insulin, more
glucose will remain in the blood.
Insulin and glucagon release from the pancreas is a vital part of the negative feedback
loop that regulates blood glucose levels. Let's review how insulin and glucagon release
change in response to plasma glucose levels and how that helps keep plasma glucose
constant.
Drag the labels onto the figure to create a flow chart of how insulin and glucagon
release change in different circumstances to keep blood glucose within a normal
range.
You are working in the free clinic when Father X comes in. You know him well; he is a
type 2 diabetic who keeps his sugar under control with diet and exercise but is often in
the clinic with homeless patients from the shelter he runs in the Episcopalian church
down the block.On this visit, Father X has brought in a thin man in his twenties named
Joe. Joe appears confused and lethargic. He is breathing heavily and has a strong fruity
odor. Father X tells you he is concerned about Joe because last night Joe was up every
half-hour or so to use the bathroom and get water. Father X knows these are signs of
diabetes, so he wants to get Joe checked out. He also tells you that Joe has not been
drinking; they have a breathalyzer at the shelter, and Joe tested clean when he checked
in the night before.Joe's blood pressure is a little low at 95/60 mm Hg and his heart rate
is a little high at 96 bpm. When you take his pulse, you notice that his skin is dry and
"tents" up when pinched −− a sign of dehydration. His respirations are more rapid than
normal, 25 breaths/min, and heavy. His blood glucose is elevated at 320 mg/dL. His
urine also contains glucose, and has a lower pH than normal. When you take his history
he tells you that type 1 diabetes runs in his family.Many of Joe's signs and symptoms
can be related to the loss of glucose in his urine. Normally, urine does not contain
glucose. When plasma glucose levels are elevated, however, some of the glucose from
the plasma passes into the urine. Apply the principle of osmosis to explain why Joe was
getting up all night to use the bathroom and why he has low blood pressure and signs of
dehydration.
The frequent urination is happening because when glucose moved into his urine, water
also followed it. This removed water from his plasma, decreasing his blood volume and
dehydrating him.
You have explained Joe's dehydration and low blood pressure. But he had some other
unusual signs and symptoms. Let's look again:Joe appears confused and lethargic. He
is breathing heavily and has a strong fruity odor. His respirations are more rapid than
normal, 25 breaths/min, and heavy. His blood glucose is elevated at 240 mg/dL. His
urine also has a lower pH than normal.Insulin does not explain these problems. They
are due to a hormone from the alpha cells of the pancreas −− glucagon. This hormone
is released in response to many stimuli, including the sympathetic nervous system. Let's
apply the functions of glucagon to explain why Joe has a low urine pH and a fruity odor.
Drag the steps of the pathway into the proper positions.
One of the more experienced nurses says it is easy to spot a patient with ketoacidosis
because of his/her heavy breathing. Why would somebody with ketones and fatty acids
in his/her blood breathe heavily?
Choose the best answer.
Joe's heavy breathing is a response to the acid in his blood. By exhaling more, he will
remove CO2 from his blood and bring the blood's pH up.
The doctor wants to give Joe an insulin injection, but Joe is unwilling to take it. He tells
you that his little sister was on insulin and died in the night after taking her shot. How
could insulin hurt somebody with diabetes?
Choose the best explanation.
Giving too much insulin can lower plasma glucose levels until the brain and heart do not
get enough glucose to function properly.
Nocturnal hypoglycemia, or low plasma glucose at night, is common in insulindependent diabetics. Dead-in-bed syndrome, however, is very rare. What causes it?
One hypothesis is that when the blood glucose drops too far, the heart ceases to beat
effectively. For this reason, a diabetic on insulin will carefully monitor blood glucose and
watch for any signs of hypoglycemia. The insulin dosage before going to bed may be
lower than during the day.
Joe is becoming more confused and uncoordinated. When he tries to get up to leave
the examination room, he stumbles and falls down. He is semiconscious and breathing
even more heavily. One of the aides says he needs some orange juice, right away.
"That's just the wrong thing to do," the doctor answers. "Don't you see his heavy
breathing and smell the ketones on his breath? Give him the insulin, stat!" Who is right?
The doctor is right −− Joe's plasma glucose is elevated, so he cannot have
hypoglycemia.
Drag the appropriate labels to their respective targets on the adrenal gland.
Which of the following hormones is a part of the rapid response (rather than the
prolonged response) to stress?
epinephrine
Epinephrine is part of the immediate or rapid response to stress. Epinephrine is
released from the adrenal medulla as a result of the increase in the sympathetic
nervous system. In fact, the chromaffin cells in the adrenal medulla act like modified
postganglionic neurons.
In response to stress, which of the following changes would happen?
decreased insulin secretion
Insulin decreases plasma glucose and during stress we need an increase in plasma
glucose as well as other body fuels. Therefore, insulin secretion would be decreased, in
turn increasing plasma glucose.
Which of the following are symptom(s) of pheochromocytoma?
heart palpitations
Yes, due to the increase in epinephrine, heart rate would be increased and you would
feel like your heart was pounding or racing.
Choose which condition has all of the following symptoms: hypertension,
hyperglycemia, and a "moon face."
Cushing's disease
A patient with Cushing's would have hypertension, increased blood glucose, and an
unusual fat distribution on the face, known as a "moon face." These symptoms are due
to increased levels of cortisol and can also be seen in patients after long periods of
steroid treatment.
What hormone also aids the stress response by promoting water retention and acting as
a vasoconstrictor?
ADH (vasopressin)
Drag and drop the labels to their appropriate structures in the diagram.
Drag and drop the items below into the correct sequence from left to right.
As the adrenal gland releases glucocorticoids, which of the following effects may
be observed? Select all the answers that apply.
-Increased blood glucose levels
-Lipid breakdown in the liver will increase
-Decrease in immune system function
-Increased blood levels of amino acids
Increased blood glucose levelsLipid breakdown in the liver will increaseDecreased
blood pressure and volumeDecrease in immune system functionIncreased blood levels
of amino acids
Corticotropin-releasing hormone: Stimulates the anterior pituitary to release ACTH
Adrenocorticotropic hormone: Targets the adrenal gland to release glucocorticoids
and mineralocorticoids
Aldosterone: Increased sodium and water absorption
Cortisol: Increased metabolic effects from the liver
Epinephrine: Increased dilation of bronchioles and heart rate
Drag and drop the items below to the appropriate bin, depending if the item is
associated with the short-term or long-term stress response.
The target cells for the hormone ACTH are located in the _______.
adrenal cortex
Tropic hormones include which of the following?
both ACTH and CRH
Which of the following is NOT characterized by high levels of cortisol in the blood?
Addison's disease
Iatrogenic Cushing's syndrome is _______.
-a result of treatment with glucocorticoid hormones
-physician induced
-often referred to as "steroid diabetes"
-All of the above are correct.
All of the above are correct.
Mrs. L and her six-year-old son Wally are at the pediatrician's office for Wally's yearly
checkup and immunizations. Wally is a healthy-looking boy, slightly large for his age,
with normal heart rate, blood pressure, and temperature. Height and weight are the
same as at his previous visit last year. He is a little hoarse and has a drippy nose, and
you notice some blackish-blue discoloration of his nails and gums. His mother says he
is "doing fine on his meds, as long as he gets all the salt and water he wants," and you
see in the chart that Wally has a diagnosis of congenital adrenal hyperplasia and is
taking daily cortisol. The doctor does a regular examination, but also orders blood work
to test Wally's glucose, sodium, and potassium levels.
How is the adrenal gland related to glucose levels?
If the adrenal does not produce cortisol, the child will not be able to increase blood
glucose during illness or stress.
The doctor also ordered measurement of Wally's Na+Na+ and K+K+ levels. How is the
adrenal gland related to these?
Choose the most appropriate answer.
If the adrenal does not produce aldosterone, Na+Na+ cannot be reabsorbed from the
urine, and K+K+ cannot be secreted into it. K+K+ will build up in the blood, and Na+Na+
will be lost in the urine.
The adrenal glands produce several hormones. Based on what Wally's mother has told
you, which hormone(s) are not being produced normally in Wally's case?
Choose all the correct answers.
-Cortisol
-Aldosterone
As a child grows, his medication doses may need to be increased. The doctor has
ordered glucose, sodium, and potassium measurements on Wally's blood. If Wally's
medications are inadequate, what will happen to his blood glucose, sodium, and
potassium levels, and why?
Choose all the lab values that would indicate inadequate treatment of Wally's
problem.
-Elevated K+
-Decreased Na+
-Decreased glucose
You are discussing Wally's case with the other nurses when one of them says it does
not make any sense. "It's called adrenal hypertrophy," she says. "That means the
adrenal is bigger than normal! So why are they giving him cortisol? His adrenal should
be making more cortisol if it's bigger than normal."How is the adrenal cortex controlled?
Drag the components of the system controlling the adrenal cortex into position.
One of the other nurses has questioned why Wally's producing less cortisol than normal
although his adrenal cortex is enlarged.
Wally's primary problem is that he cannot synthesize cortisol. Drag the changes
this will cause in the system controlling the adrenal cortex into position. You may
use the same term in more than one place on the diagram and it might be easier
to start at the bottom, with the adrenal cortex and what it cannot do.
When you go back to the office, the doctor is looking Wally's chart over again. "I'm a
little worried about his height. Did you notice anything else out of the ordinary?" What
are cortisol's other functions in the body? Do they suggest anything about Wally that
you should bring to the doctor's attention?
Choose the best answer.
Cortisol helps adapt the body to stresses like illness, so Wally might not be able to cope
with an infection.
On the follow-up exam, the doctor checks Wally for axillary hair growth and signs of
puberty. How is the adrenal related to male sexual development? Why might a boy who
cannot make his own cortisol go into puberty early?
Wally cannot synthesize cortisol. Let's review the changes that will cause in his
hypothalamo-pituitary axis again −− and this time, let's add the hormones his
adrenal cortex CAN make!
Mrs. T has been brought into the ER with severe dehydration. Her daughter reports that
Mrs. T lives alone and has recently caught the norovirus, with vomiting and diarrhea for
the past two days. Mrs. T seems restless and frightened; has a high fever, rapid
respirations and heart rate, and pale skin; and is sweating. Her blood pressure is low.
There are several reasons for this woman's dehydration. Can you identify all of
them?
-Weakness
-Sweating
-Rapid breathing
-Vomiting and diarrhea
-Fever
A lot of factors affect water balance. Water can be lost by many routes - through urine,
feces, vomitus, sweating, and even through water evaporating from the lungs. A client
with a GI virus and a fever, sweating, and rapid breathing is going to lose a lot of
water.But water balance also depends on the client's ability to replace it. So weakness
is also contributing to Mrs. T's problem. She will be less able to get up and fetch a glass
of water.
The loss of fluids over the last two days must have decreased Mrs. T's blood volume,
but right now her blood pressure is only a little low. Let's review how her body
compensated to keep blood pressure near normal levels.
Drag the labels onto the figure to create a flow chart of how the barorefleceptor reflex
would respond to decreased mean arterial pressure.
You have identified that Mrs. T is using the sympathetic nervous system to keep her
blood pressure stable. What does this mean for her?
Choose the most accurate statement about Mrs. T's situation.
If this goes on, she might not send enough blood to her kidneys or GI tract.
A patient can keep blood pressure near or even above normal by using the sympathetic
nervous system. But the sympathetic system can cause its own problems - decreased
blood flow to the kidneys, GI tract, and skin, and an increased workload on the
heart.This is why just taking blood pressure alone might not be a good way to assess a
patient's status. In spite of her normal blood pressure, Mrs. T has a real problem - and
you would rather intervene while she is still able to maintain her blood pressure, not
once things have gotten worse.
Mrs. T is given intravenous isotonic fluids. The first thing she says is that she would like
a glass of water. Because she is still nauseated, you give her ice chips to suck on.After
a short while on the fluids, Mrs. T looks much better. She asks for help going to the
bathroom, but because she is still shaky you get her a bedpan instead. She produces a
lot of very pale urine and says "That IV's going right through me." Then she asks again
for a glass of water. Her blood pressure is still on the low end of normal, and her heart
rate is still elevated.The doctor is worried, and says Mrs. T's blood pressure should
have responded better to the fluids. He orders vasopressin and another IV. Mrs. T's
blood pressure starts to respond and in the next hour rises to the normal range. But
since she is still weak, the doctor decides to admit her overnight.Why is vasopressin an
appropriate treatment for low blood pressure?
It will constrict arterioles; it will also cause her body to reabsorb water from urine,
increasing blood volume.
Mrs. T's blood pressure starts dropping again around midnight and is not relieved by
giving more fluids; around 8:00 a.m. she gets up alone to use the bathroom, falls, and
hits her head.Because of her increased heart rate and respiratory rate and her
continued low blood pressure, she is moved to the ICU, put on more vasopressin, and
her blood pressure comes back up. The nurse notes that she has been urinating well
and keeps asking for water.When Mrs. T's daughter comes in, at first she is upset at
finding her mother in the ICU. When the nurse mentions water, though, she laughs.
"Mom's the opposite of a camel," she says. "You never see her without a drink in her
hand."When the doctor hears this, he decides to measure Mrs. T's serum
ADH/vasopressin as soon as she can be taken off the vasopressin, and checks her
history for any neurological problems or brain surgery. What might the doctor be
thinking about?
Mrs. T might be producing too little ADH/vasopressin, causing her dehydration.
Now that you understand why ADH/vasopressin levels might be a concern, but why is
the doctor looking at her brain? How is the brain related to ADH/vasopressin?
Drag the terms onto this figure of the brain structures involved in
ADH/vasopressin secretion. The same term may be used in more than one place.
The CT scan did not detect any abnormality, but after the vasopressin wore off, a blood
test showed that Mrs. T was not producing any ADH/vasopressin of her own. The doctor
has diagnosed her with idiopathic diabetes insipidus. The prescribed medication is oral
desmopressin, and Mrs. T's blood pressure stabilizes after it is given. She is moved out
of the ICU onto another floor of the hospital until they are sure of the correct dosage of
this drug.The nurse taking care of Mrs. T needs to teach her how to manage her
condition, since Mrs. T will be administering her desmopressin by herself at home. What
do you think the nurse needs to emphasize?
Choose the best answer.
-Overdosing on this medication may cause edema (swelling).
-Mrs. T needs to keep herself well hydrated and stay alert for any signs of low blood
pressure.
-The dosage may need to be adjusted by a physician in case of vomiting or diarrhea.
Where is the thyroid gland located?
adjacent to the trachea in the neck
Which of the following is NOT secreted by the thyroid?
-thyroxine
-thyroid-stimulating hormone
-calcitonin
-triiodothyronine
thyroid-stimulating hormone
What is the significance of the slight swelling (called a goiter) in Krista's neck?
It is a sign that her thyroid gland is overactive.
Under normal conditions, increased levels of thyroid hormone in the blood will cause
_______.
a decrease in TSH levels
Suppose Krista's hyperthyroidism was a result of a tumor that causes the anterior
pituitary gland to become overactive. Which of the following would Krista's lab reports
likely show?
high thyroid hormone, high TSH
Krista's treatment will likely involve destroying or surgically removing her thyroid gland.
What effect will this have on her level of TSH?
TSH will increase.
Name the two hormones commonly referred to as "thyroid hormone" and describe their
general actions.
Calcitonin- Low blood calcium T3 & T4 (Thyroid hormone)- Increased metabolism,
minimal blood pressure, body fat, temp
Why would an overactive thyroid cause Krista's weight loss, sweating, and elevated
heart rate?
This will be due to the thyroid gland producing too much thyroxine (T3 & T4). Her
metabolism will be accelerated which will lead to the weight loss; her higher body temp
causes the sweats, and her raised blood pressure increases the heart rate.
Krista wonders if TSH is a "thyroid hormone," and Dr. Weisman explains that it is not.
State the action of thyroid-stimulating hormone (TSH) and name the gland that secretes
it.
TSH is a precursor hormone that stimulates the thyroid and is secreted by the anterior
pituitary gland.
How is the secretion of TSH regulated under normal conditions?
This secretion will be regulated by the negative feedback of the thyroid gland.
In Graves' disease, the immune system makes antibodies that stimulate TSH receptors
on the thyroid gland. What effect does this have on Krista's thyroid?
The antibodies mimic TSH, which stimulates the thyroid gland to secrete thyroid
hormone, even in the absence of TSH.
Submit
Why is Krista's TSH level low instead of high?
The level of TSH is determined by negative feedback from levels of circulating thyroid
hormone. Low levels of thyroid hormone are a signal to the pituitary gland to secrete
more TSH in order to increase thyroid hormone. Krista's level of thyroid hormone is
high, which inhibits the secretion of TSH in an attempt to reduce thyroid hormone
secretion. However, the antibodies stimulate the release of excess thyroid hormone
regardless of how much TSH is present.
If Krista had been diagnosed with hypothyroidism, what would happen to her levels of
TSH and thyroid hormone?
In hypothyroidism, the thyroid gland fails to produce sufficient amounts of thyroid
hormone. The low levels of thyroid hormone produce an increase in TSH secretion,
which should then stimulate the thyroid gland. However, the thyroid gland fails to
respond to the TSH, so TSH levels remain elevated while thyroid hormone levels are
low.
A common treatment for Graves' disease involves ingesting a dose of radioactive
iodine, which slowly destroys the thyroid gland. Why are other tissues unaffected?
The thyroid gland readily takes up iodine in order to produce its hormones. Other glands
and tissues do not take up iodine and are therefore unaffected by the radioactivity.
Peptide hormones include which of the following?
follicle-stimulating hormone and calcitonin
Which of the following is INCORRECTLY matched with one of its functions?
• FSH - stimulates ovarian follicle growth
• estrogen - provides protection against osteoporosis
• calcitonin - inhibits osteoblast activity
• All of the above are matched correctly.
calcitonin - inhibits osteoblast activity
Which of the following is INCORRECTLY matched with its primary secreting organ?
• calcitonin - thyroid gland
• FSH - ovaries
• estrogen - ovaries
• All of the above are matched correctly.
FSH - ovaries
Inhibiting osteoclast activity would prevent _______.
osteopenia and osteoporosis
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