Download endocrine system

ENDOCRINE SYSTEM
© 2009 Delmar, Cengage Learning
Endocrine System
• Consists of a group of ductless (without tubes) glands
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Pituitary
Thyroid
Parathyroid
Adrenal
Pancreas
Ovaries
Testes
Thymus
Pineal body
Placenta
• Secrete substances called hormones
• Hormones that are secreted directly into bloodstream
© 2009 Delmar, Cengage Learning
Hormones
• Chemical substances produced and secreted
by the endocrine glands, and they are
frequently called “chemical messengers”.
• Perform many functions:
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Stimulate endocrine glands to produce secretions
Stimulate other endocrine glands
Regulate metabolism
Maintain fluid and chemical balance
Control various sex processes
© 2009 Delmar, Cengage Learning
Pituitary Gland
• “Master gland” of the body because it produces many hormones that
affect other glands
• Located at the base of the brain
• Divided into 2 lobes:
– Anterior and posterior lobes
– Each lobe secretes certain hormones
© 2009 Delmar, Cengage Learning
Pituitary Gland –
Diseases and Abnormal Conditions
• Acromegaly
– Results from an over secretion of somatotropin (growth hormone) in an
adult (after normal bone growth has stopped)
– Usually caused by a benign tumor of the pituitary called an ademoma.
– Slow progression of signs over many years
– Signs & Symptoms:
• Bone of the hands, feet, and face enlarge
• Skin and tongue thicken
• Slurred speech develops
– Treatment includes:
• Medications that decrease growth hormone secretion
• Surgical removal and/or radiation of the tumor
• The disease eventually causes cardiovascular and respiratory diseases that
shorten life expectancy
© 2009 Delmar, Cengage Learning
Pituitary Gland –
Diseases and Abnormal Conditions
• Gigantism
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Rare disorder
Results from oversecretion of somatotropin before puberty
Usually caused by a benign tumor of the pituitary gland
Signs and Symptoms:
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Excessive growth of long bones
Extreme tallness
Decreased sexual development
Retarded mental development (at times)
– Treatment:
• Medications to reduce growth hormone release and hormone levels
• Surgical removal and/or radiation of the tumor
© 2009 Delmar, Cengage Learning
Pituitary Gland –
Diseases and Abnormal Conditions
• Diabetes Insipidus
– Caused by a decreased secretion of vasopressin, or antidiuretic hormone (ADH)
– Risk factors include:
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Pituitary surgery
Trauma
Encephalopathy
Autoimmune disorders
– Low ADH levels prevents water from being reabsorbed in the kidneys
– Signs and Symptoms:
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Polyuria (excessive urination)
Polydipsia (excessive thirst)
Dehydration
Weakness
Constipation
Dry skin
– Treatment:
• Administration of ADH
© 2009 Delmar, Cengage Learning
Pituitary Gland –
Diseases and Abnormal Conditions
• Dwarfism
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Results from an undersecretion of somatotropin.
A random genetic mutation is the cause of most dwarfism
Can also be caused by a tumor, infection, or injury
Signs and Symptoms:
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Adult height of less than 4ft 10inches
Small body size
Short extremities
Lack of sexual development
Mental development is usually normal
– Treatment:
• If diagnosed early, it can be treated with somatotropic injections for 5 or
more years until long bone growth is complete
© 2009 Delmar, Cengage Learning
Thyroid Gland
• Regulates the body’s
metabolism and controls the
level of calcium in the blood
• Located in front of the upper
trachea
• Has 2 lobes, one on either
side of the larynx, connected
by the isthmus
• Requires iodine from food
intake to produce hormones
© 2009 Delmar, Cengage Learning
Thyroid Gland –
Diseases and Abnormal Conditions
• Goiter
– An enlargement of the thyroid gland
– Causes can include a hyperactive thyroid, an iodine deficiency,
oversecretion of thyroid-stimulating hormones, or a tumor
– Signs and Symptoms:
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Thyroid enlargement
Dysphagia (difficulty swallowing)
Dyspnea (difficulty breathing)
Cough
Choking sensation
– Treatment
• Directed at eliminating the cause (giving iodine if there is a deficiency)
• Surgery for large or rapidly growing goiters
© 2009 Delmar, Cengage Learning
Thyroid Gland –
Diseases and Abnormal Conditions
• Hyperthyroidism
– Over activity of the thyroid gland – causes an increased production of thyroid
hormones and increased basal metabolic rate
– Signs and Symptoms:
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Extreme nervousness
Tremors
Irritability
Rapid pulse
Goiter formation
Diarrhea
Diaphoresis (excessive perspiration)
Heat intolerance
Polydipsia (excessive thirst)
Hypertension
– Excessive appetite with extreme weight loss is a classic symptom
– Treatment:
• Antithyroid medications
• Can remove the thyroid, but must be given hormones for the duration of life
© 2009 Delmar, Cengage Learning
Thyroid Gland –
Diseases and Abnormal Conditions
• Graves’ Disease
– Severe form of hyperthyroidism more common in women
– Signs and Symptoms:
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Strained and tense facial expression
Exophthalmia (protruding eyeballs)
Goiter
Nervous irritability
Emotional instability
Tachycardia
Tremendous appetite accompanied by weight loss
Diarrhea
– Treatment:
• Medications
• Thyroidectomy
© 2009 Delmar, Cengage Learning
Thyroid Gland –
Diseases and Abnormal Conditions
• Hypothyroidism
– Underactivity of the thyroid gland and a deficiency of thyroid
hormones
– Two main forms:
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Cretinism: develops in infancy or early childhood, and results in a lack of
mental and physical growth, leading to mental retardation and abnormal,
dwarfed stature.
Myxedema: occurs later in childhood or adulthood. Symptoms include:
course, dry skin, slow mental function, fatigue, weakness, intolerance of
cold, weight gain, edema, puffy eyes, and slow pulse
Treatment:
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Oral thyroid hormones to restore normal metabolsim
© 2009 Delmar, Cengage Learning
Parathyroid Glands
• 4 small glands located behind and attached to the
thyroid gland
• Parathormone (the hormone):
– Regulates the calcium in the blood
– Stimulates bone cells to break down bone tissue and release
calcium and phosphates into the blood
– Causes kidneys to conserve and reabsorb calcium
– Activates intestinal cells to absorb calcium from digested food
• Calcium in the blood is important for blood
clotting, the tone of the heart muscle, and muscle
contraction
© 2009 Delmar, Cengage Learning
Parathyroid Glands –
Diseases and Abnormal Conditions
• Hyperparathyroidism
– Over activity of the parathyroid gland resulting in an
overproduction of parathormone, this causes hypercalcemia
– Hypercalcemia – increased calcium in the blood which leads to
renal calculi (kidney stones)
– Signs and Symptoms:
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Kidney stones
Lethargy
Gastrointestinal disturbances
Calcium deposits on the walls of blood vessels and organs
Bones become weak, deformed, and likely to fracture
– Causes: adenoma
– Treatment: surgery (90% cure rate) and diuretics
© 2009 Delmar, Cengage Learning
Parathyroid Glands –
Diseases and Abnormal Conditions
• Hypoparathyroidism
– Under activity of the parathyroid gland
– Causes low level of calcium and a high level of phosphorus in
the blood
– Causes include the surgical removal of or injury to the
parathyroid and/or thyroid glands
– Signs and Symptoms:
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Tetany (sustained muscle contraction)
Hyperirritability of the nervous system
Convulsive twitching
Patchy hair loss
Death can occur if the larynx and respiratory muscles are involved
– Treatment: vitamin D and parathormone
© 2009 Delmar, Cengage Learning
Adrenal Glands
• Frequently called the
suprarenal glands because one
is located above each kidney
• Each gland has 2 parts:
– Cortex: secretes many steroid
hormones
– Medulla: secretes epinephrine and
norepinephrine (cause the fight or
flight response)
© 2009 Delmar, Cengage Learning
Adrenal Glands –
Diseases and Abnormal Conditions
• Addison’s Disease
– Caused by a decreased secretion of aldosterone on the
part of the adrenal cortex
– This interferes with the reabsorption of sodium and
water and causes an increased level of potassium in the
blood
– Signs and Symptoms:
• Dehydration, diarrhea, fatigue, hypotension, anorexia,
weight loss, muscle weakness, edema, excessive
pigmentation leading to a “bronzing” of the skin,
hypoglycemia, mental lethargy, and in severe cases, coma
or death
– Treatment:
• Corticosteroid hormones, controlled intake of sodium, and
fluid regulation to combat dehydration.
© 2009 Delmar, Cengage Learning
Adrenal Glands –
Diseases and Abnormal Conditions
• Cushing’s Syndrome
– Caused from an over secretion of glucocorticoids due to a tumor, excessive
production of ACTH, or overuse of corticosteroids
– Signs and Symptoms:
• Hyperglycemia, hypertension, muscle weakness, fatigue, hirsutism (excessive
growth and/or abnormal distribution of hair), poor wound healing, bruise easily,
“moon face”, fatty hump between the shoulders, and obesity
– Treatment:
• Surgical removal of the tumor (if that is the cause), then hormone therapy
• Gradually reduce corticosteroid usage if that is the cause
© 2009 Delmar, Cengage Learning
Pancreas
• A fish-shaped organ located
behind the stomach
• Both an exocrine (secrete
hormones via a duct) and
endocrine (secrete hormones into
the bloodstream) gland
• Produces insulin which is needed
for the cells to absorb sugar from
the blood and produces glucagon
which increases the glucose level
in the blood
© 2009 Delmar, Cengage Learning
Pancreas –
Diseases and Abnormal Conditions
• Diabetes Mellitus
– A chronic disease caused by decreased secretion of insulin
– 2 types of diabetes
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Type 1 (Insulin Dependent or Juvenile)
– Occurs early in life, is more severe, and requires insulin
2.
Type 2 (Non-insulin Dependent or Adult-Onset)
– Occurs in obese adults and is usually controlled by diet
– Signs and Symptoms:
• Hyperglycemia, polyuria, polydipsia, polyphagia, glycosuria, weight loss,
fatigue, slow healing, and vision changes
– Treatment:
• Regulated diet, regulated exercise, and hypoglycemic drugs or insulin
injections
© 2009 Delmar, Cengage Learning
Fasting blood glucose:1
Less than or equal to 100 milligrams per
deciliter (mg/dL) (5.6 millimoles per liter, or
mmol/L).
2 hours after eating (postprandial):2
Less than 140 mg/dL (7.8 mmol/L) for people
age 50 and younger; less than 150 mg/dL (8.3
mmol/L) for people ages 50–60; less than 160
mg/dL (8.9 mmol/L) for people age 60 and
older.
Random (casual):3
Levels vary depending on when and how
much you ate at your last meal. In general:
80–120 mg/dL (4.4–6.6 mmol/L) before meals
or when waking up; 100–140 mg/dL (5.5–7.7
mmol/L) at bedtime.
© 2009 Delmar, Cengage Learning
Other Endocrine Glands
• Ovaries:
– female sex glands
– located in the pelvis
– secrete hormones that regulate menstruation
and secondary sexual characteristics
• Testes:
– male sex glands,
– located in the scrotal sac
– produce hormones that regulate secondary
sexual characteristics
© 2009 Delmar, Cengage Learning
Other Endocrine Glands
• Thymus
– A mass of tissues located in the upper part of chest and under the
sternum
– Active in early life and activates cells in the immune system
– Atrophies (wastes away) during puberty
– Produces thymosin
© 2009 Delmar, Cengage Learning
Other Endocrine Glands
• Pineal Body
– Small structure located in the brain
– Exact function unknown
• Placenta
– Temporary endocrine gland
produced during pregnancy
– Acts as a link between the mother
and baby, provides nutrition for the
developing baby, and promotes
lactation
– Expelled after the birth of the child
© 2009 Delmar, Cengage Learning