EXAM REVIEW
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ENDOCRINE SYSTEM
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INTRODUCTION
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The human body has two types of glands:
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Exocrine glands contain cells that produce secretions transported through ducts
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Endocrine glands (ductless glands) secrete hormones directly into the bloodstream or to
neighboring cells
Some organs possess endocrine qualities:
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Hypothalamus
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Thalamus
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Kidneys
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Gastric and intestinal mucosa
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Heart
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Placenta
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The organs listed have primary functions, but also produce and secrete hormones, giving them
endocrine qualities. It is notable that these organs are not under the control of the pituitary gland.
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Endocrine system works with the nervous system to coordinate the functions of all body systems
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Nervous system uses impulses to communicate information quickly, whereas endocrine system
uses hormones to communicate information over long distances with widespread effects
THE ENDOCRINE SYSTEM
ANATOMICAL STRUCTURES
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Adrenals
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Gonads
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Hormones
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Pancreatic islets
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Parathyroids
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Pineal
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Pituitary
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Thyroid
PHYSIOLOGICAL PROPERTIES
OF THE
ENDOCRINE SYSTEM
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Produce and secrete hormones
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Regulate body activities
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Regulate activities of smooth muscle, cardiac muscle and some glands
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Help body adapt during times of stress
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Regulate chemical composition and volume of body and cell fluids
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Contribute to the reproductive process
HORMONES
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Internal secretions that function as chemical messengers
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Act as catalysts in biochemical reactions and regulate physiological activity of cells
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Hormones only affect target cells that have receptor sites for that hormone
EXAMPLE OF HORMONES IN ACTION
HORMONAL CONTROL
SYSTEMS
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Hormonal secretions are regulated by three systems:
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Negative feedback system
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Hormonal control system
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Neural control system
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Some hormones stimulate or inhibit the release of other hormones
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Hormonal Control System Example:
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Hypothalamus secrets hormones, activating the anterior portion of the pituitary
gland
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Some hypothalamic hormones cause an increase in secretions
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Other hypothalamic hormones cause a decrease in secretions
NEGATIVE FEEDBACK SYSTEM
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Primary means of hormonal regulation
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When the amount of a hormone (or desired product) is too high, the gland is triggered to
secrete less hormone
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When the amount of a hormone (or product) is too low, the gland is triggered to secrete
more hormone
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An analogy to the negative feedback system for hormones is a house’s heating system.
When the temperature meets or exceeds the set point, the furnace shuts off. When the
house is too cool, the furnace turns back on. In fact, thermostat and homeostasis have a
common Greek root meaning “to stand.”
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An example of this is the regulation of blood calcium levels.
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Positive feedback systems, which aren’t specifically covered in this chapter because they
are not common, accelerate a process. For example, when labor contractions begin,
oxytocin is released to increase their pace and intensity.
NEURAL CONTROL SYSTEM
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Hormonal secretion due to direct nerve stimulation
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Example: adrenal gland release of epinephrine and norepinephrine as a stress
response
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Neural control system has the fastest response time
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This system is functioning when nerve impulses from the hypothalamus trigger
release of hormones stored in the posterior pituitary gland.
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Injections of these hormones can also trigger glandular release of the same
hormones; for instance, epinephrine is often added to anesthetic injections to speed
the effect of the pain reducing medication.
INDIVIDUAL ENDOCRINE GLANDS
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The endocrine glands:
S Pituitary gland
S Pineal gland
S Thyroid gland
S Parathyroid glands
S Adrenal glands
S Pancreatic islets
S Female ovaries and male testes
S The female ovaries and male testes are
referred to collectively as the gonads.
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Other organs also possess endocrine qualities
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Pituitary’s posterior lobe and adrenal medulla are not
technically endocrine glands—specialized
neurosecretory cells secrete hormones.
PITUITARY GLAND
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Attached to hypothalamus and sits in the sella turcica of the sphenoid bone
PITUITARY GLAND
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About the size of a small grape
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Pituitary hormones regulate many other glands; pituitary itself is regulated by the
hypothalamus
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Anterior lobe—adenohypophysis
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Produces 7 of the 9 pituitary hormones
Posterior lobe—neurohypophysis
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Stores and releases hormones produced by the hypothalamus
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The pituitary gland was once known as “the master gland”, but the hypothalamus, which
controls the secretions of the pituitary, is the true master gland.
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To remember the hormones of the anterior pituitary, one can use the mnemonic “Flat
miles per gallon.” (Follicle-stimulating hormone, luteinizing hormone, adrenocorticotropic
hormone, thyroid-stimulating hormone, melanocyte-stimulating hormone, prolactin, and
human growth hormone).
PITUITARY GLAND LOBES
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The posterior pituitary is not technically an endocrine gland because it does not produce the
hormones it secretes. The hypothalamus produces ADH and oxytocin, which is stored and
secreted by the posterior lobe.
ANTERIOR PITUITARY HORMONES
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Adrenocorticotropic hormone (ACTH)—regulates adrenal cortex, especially cortisol
secretions
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Growth hormone (GH)—stimulates muscle and bone growth
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Thyroid-stimulating hormone (TSH)—stimulates thyroid to produce its hormones such as
triiodothyronine (T3) and thyroxine (T4)
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Follicle-stimulating hormone (FSH)—stimulates estrogen and egg production in ovaries;
stimulates sperm production in testes
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Luteinizing hormone (LH)—stimulates ovulation and production of estrogen and
progesterone by ovaries, and testosterone production by testes
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Both of these hormones are used in Assisted Reproductive Technologies, or ART. FSH
is injected to cause more than a single follicle to develop and LH is used to cause
ovulation.
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Prolactin (PRL)—stimulates milk production in the mammary glands
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Melanocyte-stimulating hormone (MSH)—increases skin pigmentation by stimulating
distribution of melanin granules
POSTERIOR PITUITARY
HORMONES
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Antidiuretic hormone (ADH)—stimulates kidneys to retain water to prevent
dehydration
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Alcohol consumption inhibits secretion of ADH, increasing urine production.
“Hangovers” are caused, in part, by the resulting dehydration.
Oxytocin—stimulates uterine contractions; involved in milk expression from
mammary glands
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When a new mother nurses her baby during the first few days after delivery, she
can often feel uterine contractions. These contractions are caused by the
release of oxytocin during nursing, and they help the uterus to return to its prepregnant size.
PINEAL GLAND
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Pinecone-shaped structure in the brain
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Pineal gland hormone:
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melatonin—involved in control of circadian rhythms (sleeping and eating) and in
growth and development of sexual organs
THYROID GLAND
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The thyroid is situated anterior to the trachea at the level of the C5 and T1 vertebrae. It
consists of two lobes connected by a section of tissue called the isthmus.
THYROID GLAND
HORMONES
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Triiodothyronine (T3) and thyroxine (T4), which increase metabolic rate
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Cannot be made without iodine
Calcitonin (CT) increases calcium storage in bones and lowers blood calcium levels
PARATHYROID GLANDS
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Four tiny glands on the posterolateral surface of the thyroid lobes
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Parathyroid gland hormone
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Parathyroid hormone (PTH)—Raises blood calcium levels by breaking down
bone tissue, and by increasing reabsorption into the blood
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Parathyroid hormone stimulates osteoclast activity. This moves calcium from
the bone to the blood.
ADRENAL GLANDS
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The adrenal glands are situated superior to
the kidneys. Another term for them is
suprarenals. This positioning is the source of
both names for these glands: ad + renal
means adjacent to the kidneys, and supra +
renal means above the kidneys.
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The two parts of the adrenal gland arise from
two different embryonic tissues. The adrenal
cortex arises from endoderm, whereas the
adrenal medulla arises from ectoderm.
Cortex means “outer covering” and
medulla means “middle.” Note that the
“medullary cavity” in a bone was the
middle section.
ADRENAL GLANDS
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Located superior to each kidney
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Highly vascular
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Divided into two regions:
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Adrenal cortex—outer region, comprises most of the gland; produces steroid
hormones
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Adrenal medulla—inner region, produces neurohormones in response to
sympathetic nervous system and prolongs its effects
ADRENAL CORTEX
HORMONES
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Aldosterone—stimulates water and sodium retention by kidneys; maintains mineral
balance
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Cortisol—affects metabolism; produces anti-inflammatory response
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Adrenal androgens and estrogens—support sexual functions
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Epinephrine (adrenaline)—increases blood pressure by stimulating vasoconstriction
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Norepinephrine (noradrenaline)—increases heart rate, blood pressure, and blood
glucose levels; dilates bronchii
PANCREATIC ISLETS
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Pancreatic gland located inferior to the stomach and has both endocrine and
exocrine functions
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Hormones secreted by specialized cells called pancreatic islets or islets of
Langerhans
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Consists of alpha and beta cells
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Pancreatic hormones are involved in carbohydrate metabolism
PANCREATIC HORMONES
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Insulin
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Secreted by beta cells
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Decreases blood glucose levels by stimulating body cells to take up glucose in
blood
Glucagon
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Secreted by alpha cells
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Increases blood glucose levels by stimulating breakdown of glycogen from liver
and skeletal muscles
GONADS
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Female—ovaries
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Located in pelvic cavity
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LH and FSH from anterior pituitary work with ovarian hormones to regulate
reproductive cycle
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Contains the corpus luteum
Male—testes
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Located in scrotum
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Androgens, primarily testosterone, produced by interstitial cells of Leydig
OVARIAN HORMONES
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Estrogen—secreted by follicle cells; responsible for female secondary sex characteristics
and regulating menstrual cycle
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Progesterone—secreted by corpus luteum; prepares endometrium for pregnancy
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Relaxin—softens connective tissue of pregnant women to facilitate fetal delivery
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A number of hormones thought of as “male” or “female” are produced at some level
in both sexes (though in vastly different quantities). For example, men produce low levels
of estrogen, and women produce low levels of testosterone.
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Pregnant women sometimes feel clumsier than normal (e.g., dropping things more often
than usual) from the effects of relaxin on their joints.
TESTICULAR HORMONES
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Androgens—maintain male sex characteristics
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Testosterone—principal testicular androgen; promotes secondary male sex
characteristics, libido (sex drive), and sperm production
PLACENTA
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Temporary reproductive organ with endocrine tissues
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Produces and secretes human chorionic gonadotropin (hCG)
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hGC stimulates secretion of estrogen and progesterone and decreases
lymphocyte activation
Also produces estrogens
THYMUS GLAND
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Bilobed gland posterior to sternum
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Considered to be primarily a lymphatic organ
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Thymic Hormones
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Thymosin and thymopoietin
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Both assist in growth and development of the immune system and the
growth and maturation of T cells
GASTRIC AND INTESTINAL
MUCOSA
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The mucus lining of the stomach and intestines secrete hormones to regulate and
coordinate the digestive process
Gastric Hormones:
S Gastrin: Stimulate bile, pancreatic enzymes, and gastric juices
Intestinal Hormones:
S Cholecystokinin: Stimulate gallbladder and pancreas
S Secretin: Stimulates pancreas
EXAMPLES OF
ENDOCRINE
SYSTEM
PATHOLOGIES
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PATHOLOGICAL CONDITIONS OF THE
ENDOCRINE SYSTEM
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Diabetes insipidus—caused by posterior pituitary gland dysfunction resulting in deficient
production of antidiuretic hormone (ADH)
S Not related to pancreas or insulin
S Increases urine production and thirst
S The term for increased urination is polyuria. The increase in urine production
triggers increased thirst.
S The term for increased thirst is polydipsia.
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Diabetes mellitus—group of disorders leading to elevated blood glucose levels
(hyperglycemia)
S Type I diabetes—autoimmune disease, immune system attacks the beta cells and the
body doesn’t produce insulin; they require injected insulin
S Type II diabetes—90% of cases; body still produces insulin, but the body’s cell are not
utilizing it properly (can be managed with diet, exercise, and sometimes pills)
S Complications include peripheral vascular disease and neuropathy in hands and feet
S The concern is blood sugar levels and injection sites, as well as the rate the insulin is
being utilized; massage has similar effects as exercise
S If client has insulin pump, avoid insertion site; if they take injections, avoid most recent
injection site
PATHOLOGICAL CONDITIONS OF THE
ENDOCRINE SYSTEM
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Hyperthyroidism—hyperactivity of the thyroid gland
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Marked by overproduction of T4
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Characterized by enlarged thyroid, nervousness and tremor, heat intolerance,
increased appetite with weight loss, rapid forceful pulse, or increased respiration
rate
Hypoglycemia—excess loss of blood glucose levels
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Can be due to an overdose of prescribed insulin, excessive pancreatic insulin
production, extreme dietary deficiencies, stress overload, and big thinking (high
activity of the brain)
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Signs include weakness, light-headedness, hunger, visual disturbances, anxiety,
or sudden changes in personality
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If left untreated, can result in delirium, coma, or death
SUMMARY
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Endocrine system—the endocrine glands and the hormones they secrete
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Ductless glands empty directly into the bloodstream
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Functions—regulate growth, development, metabolism, fluid balance; maintain
homeostasis; contribute to reproduction
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Hormones—chemical messengers that act as catalytic agents
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Levels are regulated by negative feedback, other hormones, and the nervous
system
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Related diseases include diabetes, hypoglycemia, and obesity
INSTRUCTOR
DEMO
As review if time allows
Neck / Face Massage Sequence
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LAB
In partners: Practice Neck / Face Massage
Sequence
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BREAK
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LAB
In partners: Full client intake with neck and back
massage (1 hour 15 minutes) – One partner
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DISCUSSION ABOUT
INTAKE LAB
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LUNCH
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LAB
In partners: Full client intake with neck and back
massage (1 hour 15 minutes) – Other partner
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DISCUSSION ABOUT
INTAKE LAB
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CLIENT MASSAGES
Follow up with discussion
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