Anatomy and Physiology

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Anatomy and Physiology

• Chapter 11 Endocrine System

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Introduction to the Endocrine System

• Works with the nervous system to maintain
  homeostasis
• Includes a network of specialized cells and
  glands that secrete hormones which travel in the
  blood stream and affect the functioning of target
  cells.

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Hormones

• Function to
• Help regulate metabolic processes
• Help regulate rates of chemical reactions
• Aid in transport of substances across membranes
• Regulate water and electrolyte balances
• Play a vital role in reproduction, development,
  and growth.

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Other Secretions

• Paracrine secretions local hormones. Affect only
  neighboring cells. Break down rapidly
• Autocrine secretions affect only the secreting
  cell itself. (also called a local hormone)
• Exocrine glands secrete outside the body through
  tubes or ducts that lead to the surface of the
  skin. Ex. sweat glands

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Larger Endocrine Glands (10 of them)

• Pituitary gland
• Thyroid gland
• Parathyroid gland
• Adrenal gland
• Pancreas

• Thymus
• Hypothalamus
• Pineal gland
• Ovary
• Testis

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Locations of major endocrine glands
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Comparison to the Nervous System
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Hormone Action

• Steroids and Steroid-like substances
• Non-steroid Hormones
• Prostaglandins

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Steroids and Steroid-like substances

• Synthesized from cholesterol
• Contain complex rings of carbon and hydrogen
• Insoluble in water lipid-soluble ? easily
  diffuse into cells
• Combines with specific receptor protein after
  entering cell.
• Joins with target cells DNA and activates
  specific gene.
• Gene directs production of specific proteins
  which may be enzymes, transport proteins, or
  hormone receptors which exert the characteristic
  effects of that particular steroid hormone.

Animation of Aldosterone
Step through slides
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Steroid hormones. 1.) A steroid hormone crosses a
cell membrane and 2.) combines with a protein
receptor, usually in the nucleus.3.) The
hormone-receptor complex activates synthesis of
specific messenger RNA (mRNA) molecules. 4.) The
mRNA molecules leave the nucleus and enter the
cytoplasm 5.) where they guide synthesis of the
encoded proteins.
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Nonsteroid Hormones

• Amines, peptides, proteins, glycoproteins
• Synthesized from amino acids
• Combine with receptors in target cell membranes
  to deliver its message.
• Cellular responses include
• May alter function of enzymes or membrane
  transport mechanisms or activate a secondary
  messenger which can alter membrane
  permeabilities,
• Activate enzymes
• Promote synthesis of proteins
• Stimulate/inhibit specific metabolic pathways
• Move the cell
• Initiate secretion of hormones or other
  substances.

Step through Slides
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One mechanism of non-steroid hormones. 1.) Body
fluids carry nonsteroid hormone molecules to
target cell. Where 2.) they combine with receptor
molecules on the cell membrane. 3.) This
activates molecules of adenylate cyclase, which
4.) catalyze conversion of ATP into cyclic
adenosine monophosphate (cAMP) 5.) The cAMP
promotes a series of reactions leading to the
cellular changes associated with the hormones
action.
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• Hormones can stimulate changes in target cells
  even if present in extremely low concentrations.
  Very potent

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Prostaglandins

• Lipids synthesized from a fatty acid in cell
  membranes.
• Produced by liver, kidneys, heart, lungs, thymus
  gland, pancreas, brain, and reproductive organs.
• Usually act more locally than hormones, affecting
  only the organ where produced.
• Potent. Present in small quantities. Not stored.
  Synthesized just before released. Rapidly
  activated.

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• Produce diverse effects
• Relax smooth muscles in airways of lungs and in
  blood vessels
• Contract smooth muscles in uterus and intestines
• Stimulate hormone secretion from adrenal cortex.
• Inhibit secretion of hydrochloric acid in stomach
• Influence movement of sodium ions and water in
  kidneys
• Regulate blood pressure
• Effect male and female reproductive physiology

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Control of Hormonal Secretions

• Precisely regulated.
• Continually excreted in urine and broken down by
  the liver.

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• Controlled in three ways all of which employ
  negative feedback
• In response to releasing hormones secreted by the
  hypothalamus
• In response to nerve impulses
• In response to levels of a substance in the
  bloodstream

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Control of the endocrine system occurs in 3 ways
A.) the hypothalamus and anterior pituitary, B.)
the nervous system directly, and C.) glands that
respond directly to changes in the internal
environment. Negative feedback inhibition is
indicated by (-)
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• Negative Feedback
• A gland is sensitive to the concentration of a
  substance it regulates.
• When concentration reaches a certain high point,
  it inhibits the gland
• Inhibited gland releases less hormone, controlled
  substance level also decreases.
• Maintains relatively stable hormone
  concentrations.

Animation of Positive and Negative Feedback
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As a result of negative feedback, hormone
concentrations remain relatively stable, although
they may fluctuate slightly above and below
average concentrations.
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Pituitary Gland (hypophysis)

• Located at the base of the brain attached to the
  hypothalamus
• 1cm in diameter and consists of 2 lobes
• Most pituitary activities are controlled by the
  hypothalamus.

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The pituitary gland is attached to the
hypothalamus and lies in the stella turcica of
the sphenoid bone.
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The two parts of the pituitary gland secrete
hormones by different mechanisms. Hypothalamic
releasing hormones stimulate cells of the
anterior lobe to secrete hormones. Nerve impulses
originating in the hypothalamus cause nerve
endings in the posterior lobe of the pituitary
gland to release hormones.
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Anterior Pituitary Hormones (anterior lobe)

• Growth Hormone (GH) stimulates cells to increase
  in size and divide more frequently. Enhances
  movement of amino acids across membranes.
• Disorders include
• Acromegaly
• hypopituitary dwarfism
• gigantism

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Dwarfism

• Insufficient secretion of growth hormone (GH)
  during childhood that limits growth
• Body parts usually correctly proportioned, normal
  mental development
• Usually accompanied by deficient secretion of
  other anterior pituitary hormones additional
  symptoms
• Treatment with hormone therapy

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Deficiency of growth hormone early in life leads
to pronounced inhibition of longitudinal growth,
resulting in dwarfism. The interrelationship
between the pituitary and the thyroid is
demonstrated by the concomitant hypothyroidism
secondary to deficiency of thyrotropic hormone.
Therefore, growth is not only stunted but the
development of secondary ossification centers is
noticeably delayed, and the epiphysial and
apophysial growth plates remain open late in
adult life, although they do ultimately close in
old age. The cranial sutures remain widely open
into adult age. The sella turcica may show
widening, if the tumor was intersellar, or an
aperture may remain on the floor of the
endocranial bones. The skeleton is gracile in
dimensions, the cortices are thin, and the
spongiosa porotic and sparse. Although growth
plates may remain, the metaphysial surface is
usually closed by a thin layer of bone, an
indication of arrested growth.
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Gigantism

• Oversecretion of GH during childhood
• Height may exceed 8 ft
• Rare. Results of a pituitary gland tumor.
• May have over-secretion of other pituitary
  hormones.
• Often have several metabolic disturbances.

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Acromegaly

• Overproduction of growth hormone in adulthood
• Symptoms include enlarged heart, bones, thyroid,
  facial features, hands, feet, and head.
• Early symptoms include headache, joint pain,
  fatigue, and depression.

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• Prolactin (PRL) stimulates and sustains a womans
  milk production following birth of an infant
• Thyroid-stimulating Hormone (TSH) controls
  thyroid gland secretions

Thyrotropin-releasing hormone (TRH) from the
hypothalamus stimulates the anterior pituitary
gland to release thyroid-stimulating hormone
(TSH), which stimulates the thyroid gland to
release hormones. These thyroid hormones reduce
the secretion of TSH and TRH.
Step through Slides
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• Adrenocorticotropic Hormone(ACTH) controls
  secretion of certain hormones from adrenal cortex

Adrenal gland stimulating hormone (Cushing's
Disease)           (ACTH)         widened face
with acne and flushing         fatty deposits
over back of neck         stretch marks, easy
bruising, hair growth         diabetes
mellitus         muscle loss and fatigue        
depression and psychosis
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Cushing's disease medical treatment for tumors
which cause the over secretion of corticosteroids
by the adrenal glands is unsatisfactory because
of their side effects and response rates. Two
classes of medication are used those which
interfere with the production of steroids in the
adrenal glands and those which act within the
brain. Removal of the adrenal glands is an option
when pituitary surgery and medical measures fail
to control Cushing's disease. This may lead to
rapid growth of the pituitary tumor and massive
blood levels of ACTH. ACTH stimulates melanin
production in the skin, darkening the skin
color. This is termed Nelson's syndrome
Nelson's syndrome with excessive pigmentation of
the skin due to ACTH stimulation of the
melanocytes in the skin
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• Follicle-stimulating Hormone (FSH) a
  gonadotrophin (exerts action on the gonads or
  reproductive organs) responsible for the
  development of egg-containing follicles in
  ovaries and stimulates follicular cells to
  secrete estrogen.
• Luteinizing Hormone (LH) a gonadotrophin that
  promotes secretion of sex hormones and plays a
  role in releasing an egg cell in females.

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Posterior Pituitary Hormones (posterior lobe)

• Antidiuretic Hormone (ADH) causes kidneys to
  conserve water. In high concentration it
  increases blood pressure.
• An injury or tumor damaging any parts of the ADH-
  regulating mechanism causing too little ADH
  produces diabetes insipidus. Individual produces
  25-30 liters of very dilute urine/day and solute
  concentrations in body fluids rise.
• Oxytocin (OT) contracts muscles in the uterine
  walls, contracts muscles associated with
  milk-secreting glands.
• Commercial preparations of oxytocin are sometimes
  used to stimulate uterine contractions, inducing
  labor. Also used following childbirth to contract
  uterine muscles to normal size and minimize risk
  of hemorrhage.

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Thyroid Gland

• Located in the neck and consists of two lobes
• Consists of many follicles that are fluid-filled
  and store hormones
• Thyroxine (T4) and Tri-iodothyronine (T3)
  increase the metabolic rate of cells, enhance
  protein synthesis, and stimulate lipid
  utilization.

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Thyroid gland. A.) Consists of 2 lobes connected
anteriorly by an isthmus. B.) Follicular cells
secrete thyroid hormones.
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• Thyroid hormones
• Major factors in determining basal metabolic rate
  (BMR)
• Required for normal growth and development and
  essential to nervous system maturation.
• Up to 80 of the iodine in the body is in the
  thyroid gland. 25x higher concentration than
  bloodstream.
• Iodine salts absorbed from food in the intestine

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• Calcitonin lowers blood calcium and phosphate ion
  concentration by inhibiting release of calcium
  and phosphate ions from bones and increasing
  excretion of these ions by kidneys.
• Thyroid disorders
• Hyperthyroidism overactivity. Elevated metabolic
  rate, restlessness, overeating. Protruding eyes
  due to tissue swelling. Goiter enlarged thyroid
  gland
• Hypothyroidism underactivity.

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Simple Goiter This condition is characterized by
an enlargement of the entire gland, or of one of
its two lobes, caused by a deficiency of iodine
in the diet. The disease is especially apt to
appear in adolescence. Simple goiter occurs in
inland areas of all continents. It was common in
what was at one time referred to as the goiter
belt of the U.S., which includes the Great Lakes
region and inland mountain areas. The
administration of iodine, or of the
iodine-containing hormone thyroxine, effectively
prevents the disease. Prevention requires taking
small doses of iodine for long periods. Ingestion
of iodine during pregnancy prevents development
of the disease in the infant as well as in the
mother. Public health measures, including the
addition of iodine to water supplies and to table
salt, have helped to reduce the incidence of
simple goiter in certain areas. Iodine is most
effective when administered to children who have
the disease. Thyroidectomy, or surgical removal
of the gland, may be necessary in cases in which
the gland has become greatly enlarged. Toxic
Goiter This disease, also called exophthalmic
goiter, hyperthyroidism, thyrotoxicosis, or
Graves' disease, for the Irish physician Robert
James Graves, is caused by an excess of thyroxine
secretion. The cause of the excessive secretion
is obscure. In some cases it may result from
excessive stimulation by the pituitary gland. The
symptoms of toxic goiter may include a rapid
heartbeat, tremor, increased sweating, increased
appetite, weight loss, weakness, and fatigue.
Some patients have eye problems, such as staring
or protrusion. Thiouracil and iodine are
sometimes used in the treatment of toxic goiter,
as is irradiation of the gland by radioactive
iodine.
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Parathyroid Glands

• On the posterior surface of the thyroid gland
• Usually 4 parathyroid glands a superior and
  inferior on each of the thyroids lateral lobes.
• Structure thin capsule of connective tissue
  covers each small, yellowish-brown parathyroid
  gland. Inside consists of many tightly packed
  secretory cells closely associated with capillary
  networks.

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The parathyroid glands are embedded in the
posterior surface of the thyroid gland.
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Parathyroid Hormone (PTH)

• Increases blood calcium concentration and
  decreases blood phosphate ion concentration
• Affects bones, kidneys, and intestine
• Bones inhibits osteoblast (build bone) and
  stimulates osteocytes and osteoclasts to resorb
  bone and release calcium and phosphate ions into
  the blood.
• Kidneys conserve blood calcium and excrete more
  phosphate ions in urine
• Intestine stimulates calcium absorption from
  food in the intestine, increasing blood calcium
  concentration.

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Parathyroid hormone (PTH) stimulates bone to
release calcium (Ca2) and the kidneys to
conserve calcium. It indirectly stimulates the
intestine to absorb calcium. The resulting
increase in blood calcium concentration inhibits
secretions of PTH
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Hyperparathyroidism

• Can be caused by a tumor
• Increases PTH secretion
• Bones are resorbed and soften, deform more
  easily. Fracture spontaneously
• Excess calcium and phosphate released into body
  fluids may be deposited in abnormal places.
  (kidney stones)

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Hypoparathyroidism

• Can be caused by injury or surgical removal
• Decreased PTH
• Reduced osteoclast activity. Bones are strong,
  but blood calcium concentration decreases.
• Abnormally excitable nervous system. Trigger
  spontaneous impulses. Tetanic contractions may
  cause respiratory failure and death.

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Adrenal Glands

• Sits atop each kidney and is embedded in the mass
  of adipose tissue that encloses the kidney
• Structure
• Adrenal medulla central portion. Irregularly
  shaped cells organized in groups around blood
  vessels. Connected with the sympathetic division
  of the autonomic nervous system. Modified
  post-ganglionic neurons
• Adrenal cortex outer portion. Epithelial cells
  in layers. Well supplied with blood vessels.

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Adrenal glands. A.) An adrenal gland consists of
an outer cortex and an inner medulla. B.) The
cortex consists of the three layers or zones of
cells.
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Hormones of the Adrenal Medulla

• Epinephrine (adrenalin) and Norepinephrine
• Effects resemble those of the sympathetic neurons
  stimulating their effectors but last up to 10x
  longer because the hormones are broken down more
  slowly than neurotransmitters.
• Increased heart rate, increased force of cardiac
  muscle contraction, increased breathing rate,
  elevated blood pressure, increased blood glucose,
  decreases digestive activity.

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• Stimulated by nerve fibers originating in the
  hypothalamus in response to stress. fight or
  flight responses
• Tumors in the adrenal medulla increase hormonal
  secretion. Treatment involves surgical removal of
  tumor.

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Hormones of the Adrenal Cortex

• Produces more than 30 different steroids
• Some are vital cannot survive without. Death
  within 1 week unless extensive electrolyte
  therapy is provided.
• Aldosterone a mineralocorticoid that causes the
  kidneys to conserve sodium ions and water and to
  excrete potassium ions.

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• Cortisol a glucocorticoid that affects
  carbohydrate, protein, and fat metabolism.
• Helps keep blood glucose concentration within
  normal range between meals.
• Controlled by negative feedback. Set point of
  feedback mechanism changes in response to
  conditions such as stress, injury, disease

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Negative feedback regulates cortisol secretion,
similar to the regulation of thyroid hormone
secretion.
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Addison Disease

• Caused by hyposecretion of adrenal cortical
  hormones
• Characterized by decreased blood sodium, increase
  blood potassium, low blood glucose concentration
  (hypoglycemia)
• Dehydration, low blood pressure and increased
  skin pigmentation.
• Lethal within days without treatment due to
  severe disturbances in electrolyte balance

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Cushing Syndrome

• Associated with an adrenal tumor and
  hypersecretion of hormones.
• Alters carbohydrate and protein metabolism and
  electrolyte balance.
• Blood glucose concentration remains high
  depleting tissue protein.
• Too much sodium is retained increasing tissue
  fluids (puffy skin).
• Increased adrenal sex hormone may cause
  masculinizing effects in a female.

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• Adrenal Sex Hormones (adrenal androgens)
• Mostly male, some converted to female hormones
  (estrogens) in the skin, liver, and adipose
  tissue.
• Supplement supply of sex hormones from the gonads
• Stimulate early development of reproductive
  organs.

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Pancreas

• Consists of two major types of secretory tissues
  that involve two functions
• Exocrine gland secrete digestive juice
• Endocrine gland releases hormones

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• Structure elongated somewhat flattened organ
  posterior to the stomach and behind the parietal
  peritoneum
• Duct joins the pancreas to the duodenum (first
  section of the small intestine). Juices help
  digest carbohydrates, fats, nucleic acids, and
  proteins.
• Endocrine portion involves groups of cells called
  Islets of Langerhans that are closely associated
  with blood vessels and secrete glucogon and
  insulin

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The hormone-secreting cells of the pancreas are
grouped in clusters, or islets, that are closely
associated with blood vessels. Other pencreatic
cells secrete digestive enzymes into ducts.
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Light micrograph of an islet of Langerhans within
the pancreas.
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• Glucogon
• Stimulates the liver to break down glycogen and
  amino acids into glucose, raising blood sugar
  concentrations (more effective than epinephrine)
• Negative feedback regulation prevents
  hypoglycemia between meals or during exercise

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Effective blood glucose regulation is
fundamentally important for health. Even mild
disruptions of glucose homeostasis can have
adverse consequences. After a carbohydrate meal,
blood sugar increases for several hours, then
returns to base line in response to homoeostatic
mechanisms. The rise in blood glucose is due to
the intestinal absorption of glucose, released
from starch and sugars by amylase and
disaccharidases. Fructose and galactose are more
slowly metabolized to glucose by the liver.
Insulin secreted by beta cells of the endocrine
pancreas is released in response to elevated
blood sugar. Insulin, a major anabolic hormone,
stimulates skeletal muscle and adipose tissue to
take up glucose from the circulation.
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The liver, brain and red blood cells do not
require insulin for glucose uptake. The central
nervous system requires glucose as its primary
fuel. Though the brain accounts for only about
10 of body weight, it uses more than 30 of
blood glucose. To maintain fasting blood glucose
levels in the face of this steady drain of
glucose, a variety of hormones are required,
chiefly, glucagon from alpha cells of the
endocrine pancreas and glucocorticoids from the
adrenal glands. Glucagon acts rapidly on the
liver to break down stored glycogen to glucose,
while glucocorticoids more slowly stimulate
protein breakdown for example, in skeletal
muscle to release free amino acids. Many amino
acids can be converted to glucose by the liver
(gluconeogenesis). Fat breakdown to free fatty
acids is also stimulated by glucagon in order to
provide an alternative fuel for most of the body,
exclusive of the CNS. Other glands involved the
thyroid gland helps determine the metabolic rate,
while the pituitary orchestrates most endocrine
activity including the thyroid. The kidneys
reabsorb most of the glucose in the filtrate.
However, when blood glucose increases above a
threshold, the kidneys spill glucose into the
urine, a sign of abnormal glucose regulation.
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• Insulin has the opposite effect of glucogon
• Stimulates the liver to form glygocen from
  glucose and inhibits conversion of
  non-carbohydrates into glucose.
• Promotes facilitated diffusion of glucose across
  cell membranes that have insulin receptors
• Promotes transport of amino acids into cells,
  increases protein synthesis and stimulates
  adipose cells to synthesize and store fat.
• Negative feedback helps to prevent too high blood
  glucose concentrations.
• Nerve cells are particularly sensitive to changes
  in blood glucose concentrations

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Insulin and glucagon function together to help
maintain a relatively stable blood glucose
concentration. Negative feedback responding to
blood glucose concentration controls the levels
of both hormones.
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Diabetes mellitus

• Results from insulin deficiency
• Disturbs carbohydrate, protein, and fat
  metabolism
• Blood sugar levels rise (hyperglycemia)
• Kidneys excrete excess glucose in urine causing
  more water and electrolytes than usual to be
  excreted and the person becomes dehydrated.
• Glucose-starved cells increase their use of
  proteins as an energy source. Tissues waste away
• Ketone bodies accumulate in blood, lower pH,
  cause dehydration.
• May harm brain cells, disorientation, coma, death

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Type 1Insulin-dependent diabetes mellitus or
Juvenile-onset diabetes mellitus

• Appears before age 20
• Autoimmune disease immune system destroys beta
  cells of the pancreas.
• Treatment involves insulin injections or
  implantation of insulin pump
• Historically treatments used insulin extracted
  from pig pancreases, now human version obtained
  from bacteria modified with human insulin gene.
  People less allergic to new form.

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Type 2Noninsulin-dependent diabetes mellitus
or Maturity-onset diabetes mellitus

• 70-80 of people with diabetes.
• Develops gradually after age 40
• Milder symptoms. Most are overweight
• Beta cells of pancreas function but body cells
  lose sensitivity to insulin
• Treatment involves controlling diet, exercising,
  maintaining desirable body weight, and medication
• Monitor blood glucose levels
• Complications involving coronary artery disease
  and retinal and nerve damage.

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Pineal Gland

• Small structure located deep between the cerebral
  hemispheres where it attaches to the upper
  portion of the thalamus
• Secretes melatonin in response to light
  conditions outside the body
• Nerve impulses from the retinas of the eyes send
  information to the pineal gland
• Acts on certain brain regions that function as a
  biological clock and helps regulate circadian
  rhythms
• Patterns of repeated activity associated with the
  environmental cycles of day and night. (p299)

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Thymus Gland

• Lies in the mediastinum, posterior to the sternum
  and between the lungs.
• Large in children, but shrinks with age
• Thymosins affect production and differentiation
  of certain white blood cells (lymphocytes) and
  plays a role in immunity

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             In the thymus gland lymphocytes
become specialized. The thymus plays an important
role in lymphocyte specialization and immunity.
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Reproductive Glands

• Ovaries produce estrogens and progesterone
• Placenta produces estrogens, progesterone, and
  gonadotropin

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• Testes produces testosterone
• (more in Ch 19-20)

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Digestive Glands

• Associated with the linings of the stomach and
  small intestines
• (more in Chapter 15)

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Other Hormone-Producing Organs

• Heart atrial natriuretic peptid stimulates
  urinary sodium excretion
• Kidneys secrete red blood cell growth hormone
  called erythropoietin

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Stress and Health

• When the body senses danger, nerve impulses to
  the hypothalamus trigger physiological responses
  that preserve homeostasis
• Increased activity in the sympathetic division of
  the autonomic nervous system
• Increased secretion of adrenal and other hormones

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Types of Stress

• Physical factors
• Exposure to extreme heat or cold
• Decreased oxygen concentration
• Infections
• Injuries
• Prolonged heavy exercise
• Loud sounds

• Physiological factors
• Thoughts about real or imagined dangers
• Personal losses
• Unpleasant social interactions
• Anger
• Fear
• Grief
• Anxiety
• Depression
• Guilt

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General Stress Syndrome

• Physiological responses to stress are under
  hypothalamic control and work to maintain
  homeostasis
• The hypothalamus stimulates hormone action from
  the adrenal medulla, anterior pituitary, and the
  adrenal cortex.

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During stress, the hypothalamus helps prepare the
body for fight or flight by triggering
sympathetic impulses to various organs. It also
stimulates epinephrine release, intensifying the
sympathetic responses.
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Clinical Terms Related to the Endocrine System
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Adrenalectomy

• Surgical removal of the adrenal glands

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Adrenogenital Syndrome

• A group of symptoms associated with changes in
  sexual characteristics
• Results from increased secretion of adrenal
  androgens.

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Diabetes insipidus

• Condition due to insulin deficiency or the
  inability to respond to insulin.
• Disturbs carbohydrate, protein, and lipid
  metabolism.

Part of the job of the kidneys is to continually
filter water from the blood that passes through
them and reestablish the balance of the bodys
water by reabsorbing fluid from the
blood.  Efficient re-absorption requires an
adequate level of a hormone known as antidiuretic
hormone (ADH) which is produced by the posterior
lobe of the pituitary gland in the brain. If this
hormone is not produced in sufficient quantities
or if the kidney fails to respond to it, diabetes
insipidus can occur. Diabetes insipidus is a
rare form and is only definitely diagnosed after
extensive blood and urine tests.
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Exophthalmos

• Abnormal protrusion of the eyes.

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Goiter

• Bulge in the neck resulting from an enlarged
  thyroid gland.

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Hirsutism

• Excess hair growth, especially in women.

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Hypercalcemia

• Excess blood calcium

Causes of hypercalcemia and hypocalcemia
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Hyperglycemia

• Excess blood glucose

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Hypocalcemia

• Deficiency of blood calcium

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Hypoglycemia

• Deficiency of blood glucose

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Hypophysectomy

• Surgical removal of the pituitary gland

The pituitary gland is a small, oval-shaped
endocrine gland about the size of a pea located
in the center of the brain above the back of the
nose. Its major role is to produce hormones that
regulate growth and metabolism in the body.
Removing this important gland is a drastic step
that is usually taken in the case of cancers or
tumors that resist other forms of treatment,
especially craniopharyngioma tumors.
Hypophysectomy may also be performed to treat
Cushing's syndrome, a hormonal disorder caused by
prolonged exposure of the body's tissues to high
levels of the hormone cortisol, in most cases
associated with benign tumors called pituitary
adenomas. The goal of the surgery is to remove
the tumor and try to partially preserve the
gland.
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Parathyroidectomy

• Surgical removal of the parathyroid glands

The parathryoid gland is accessed through an
incision in the neck (A). Muscles and connecting
tissues, or fascia, are cut open (B). The thyroid
gland is exposed, and the superior (C) and
inferior parathyroid glands are removed (D). The
muscle layers are stitched (E), and the wound
closed
Parathyroidectomy is the removal of one or more
parathyroid glands. A person usually has four
parathyroid glands, although the exact number may
vary from three to seven. The glands are located
in the neck, in front of the Adam's apple, and
are closely linked to the thyroid gland. The
parathyroid glands regulate the balance of
calcium in the body. Parathyroidectomy is usually
performed to treat hyperparathyroidism (abnormal
over-functioning of the parathyroid glands).
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Pheochromocytoma

• Type of tumor in the adrenal medulla usually
  associated with high blood pressure.

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Polyphagia

• Excessive eating

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Thymectomy

• Surgical removal of the thymus gland

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Thyroidectomy

• Surgical removal of the thyroid gland

Thyroidectomy is a surgical procedure in which
all or part of the thyroid gland is removed. The
thyroid gland is located in the forward
(anterior) part of the neck just under the skin
and in front of the Adam's apple. The thyroid is
one of the body's endocrine glands, which means
that it secretes its products inside the body,
into the blood or lymph. The thyroid produces
several hormones that have two primary functions
they increase the synthesis of proteins in most
of the body's tissues, and they raise the level
of the body's oxygen consumption. All or part of
the thyroid gland may be removed to correct a
variety of abnormalities. If a person has a
goiter, which is an enlargement of the thyroid
gland that causes swelling in the front of the
neck, the swollen gland may cause difficulties
with swallowing or breathing. Hyperthyroidism
(overactivity of the thyroid gland) produces
hypermetabolism, a condition in which the body
uses abnormal amounts of oxygen, nutrients, and
other materials. A thyroidectomy may be performed
if the hypermetabolism cannot be adequately
controlled by medication, or if the condition
occurs in a child or pregnant woman. Both
cancerous and noncancerous tumors (frequently
called nodules) may develop in the thyroid gland.
These growths must be removed, in addition to
some or all of the gland itself.
To remove the thyroid gland, an incision is made
at the front of the neck (A). Muscles and
connecting tissue, or fascia, are divided (B).
The veins and arteries above and below the
thyroid are severed (C), and the gland is removed
in two parts (D). The tissues and muscles are
repaired before the skin incision is closed (E)
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Thyroiditis

• Inflammation of the thyroid gland.

he inflamed thyroid gland can release an excess
of thyroid hormones into the blood stream,
resulting in a temporary hyperthyroid state. Once
the thyroid gland is depleted of thyroid
hormones, the patient commonly goes through a
hypothyroid (low thyroid) phase. This phase can
last 3-6 months until the thyroid gland fully
recovers. Thyroiditis can be diagnosed by a
thyroid scan (a picture taken of the thyroid
gland after radioactive iodine is taken by
mouth).
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Virilism

• Masculinization of a female.