Download Chapter 13 Endocrine System

CHAPTER 13
Endocrine System
Endocrine System Overview
• Endocrine system
– Consists of ductless glands
• Secrete hormones directly into bloodstream
– Affect the function of specific body organs
• Regulates many intricate body functions
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Pituitary Gland
• Referred to as “master gland”
– Secretes hormones that control functions of
other glands
– Known as hypophysis
– Has two distinct lobes with specific functions
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Pituitary Gland
• Anterior Pituitary Gland = Adenohypophysis
– Secretes Growth Hormone (GH)
• Also called Somatotropic Hormone (STH)
• Regulates growth of bone, muscle, and other body
tissues
– Secretes Adrenocorticotropic Hormone (ACTH)
• Stimulates normal growth and development of
adrenal cortex and secretion of corticosteroids
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Pituitary Gland
• Anterior Pituitary Gland
– Secretes Thyroid-Stimulating Hormone (TSH)
• Promotes and maintains normal growth and
development of the thyroid gland
• Stimulates secretions of the thyroid hormones
– Secretes Lactogenic Hormone (LTH)
• Also called Prolactin
• Promotes development of breasts during
pregnancy
• Stimulates secretion of milk from breasts after
delivery of baby
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Pituitary Gland
• Anterior Pituitary Gland
– Secretes Follicle-Stimulating Hormone (FSH)
• Stimulates secretion of estrogen and production of
eggs in the female ovaries
• Stimulates production of sperm in the male testes
– Secretes Luteinizing Hormone (LH)
• Stimulates female ovulation and the secretion of
testosterone in the male
– Melanocyte-Stimulating Hormone (MSH)
• Controls intensity of pigmentation in pigmented
cells of the skin
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Pituitary Gland
• Posterior Pituitary Gland = Neurohypophysis
– Secretes Antidiuretic Hormone (ADH)
• Decreases excretion of large amounts of urine
• Increases reabsorption of water by the renal tubules
– Secretes Oxytocin (OT)
• Stimulates contraction of the uterus during childbirth
• Stimulates release of milk from the breasts of lactating
women in response to the suckling reflex of the infant
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Pineal Gland
• Tiny, pinecone-shaped gland
– Located behind dorsal aspect of midbrain
region
– Plays a part in supporting body’s biological
clock
• Regulation of patterns of eating, sleeping, and
reproduction
– Secretes melatonin
• Induces sleep
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Thyroid Gland
• Located in front of the neck just below
the larynx, on either side of the trachea
– Consists of a right and left lobe
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Thyroid Gland
• Secretes Triiodothyronine (T3)
– Helps regulate growth and development of
body
– Helps control metabolism and temperature
– Secretes Thyroxine (T4)
• Helps maintain normal body metabolism
– Secretes Calcitonin
• Helps regulate the level of calcium in the blood
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Parathyroid Glands
• Four tiny rounded bodies located on dorsal
aspect of thyroid gland
– Secrete Parathyroid Hormone (PTH)
• Also known as parathormone
• Regulates level of calcium in blood
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Thymus
• Single gland located in mediastinum near
the middle of the chest, just beneath
sternum
– Large in fetus and infants, shrinks with age
– Secretes thymosin and thymopoietin
• Stimulates production of T cells that are involved in
the immune response
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Adrenal Glands
• Two small glands, one positioned atop
each kidney
• Also known as suprarenal glands
– Consists of an adrenal cortex and an adrenal
medulla
• Each has independent functions
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Adrenal Glands
• Adrenal cortex secretes corticosteroids
– Mineralocorticoids
• Regulate how mineral salts (electrolytes) are
processed in the body
– Glucocorticoids
• Influence metabolism of carbohydrates, fats, and
proteins in the body
• Necessary for maintaining normal blood pressure
• Have an anti-inflammatory effect on the body
• Increase glucose available during “fight-or-flight”
responses by the body
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Adrenal Glands
• Adrenal cortex secretes
– Gonadocorticoids
• Sex hormones secreted in small amounts
• Contribute to secondary sex characteristics in
males and females
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Adrenal Glands
• Adrenal medulla secretes catecholamines
– Epinephrine = adrenaline
• Sympathiomimetic agent
• Increases heart rate and force of heart muscle
contraction
• Dilates bronchioles in the lungs
• Decreases peristalsis in the intestines
• Raises blood glucose levels by causing the liver to
convert glycogen into glucose
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Adrenal Glands
• Adrenal medulla secretes
– Norepinephrine = noradrenaline
• Known as a sympathomimetic agent
• Produces a vasoconstrictor effect on the blood
vessels, thereby raising blood pressure
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Pancreas
• Elongated gland located in upper left
quadrant of the abdomen
– Behind the stomach
• Extends horizontally across the body
– Beginning at first part of small intestines and
ending at edge of spleen
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Pancreas
• Islets of Langerhans secrete:
– Glucagon
• Increases blood glucose levels by stimulating liver
to convert glycogen into glucose when blood sugar
is extremely low
– Insulin
• Makes it possible for glucose to pass from blood
through cell membranes to be used for energy
• Promotes conversion of excess glucose into
glycogen for storage in the liver for later use
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Ovaries
• Female sex glands = female gonads
– Pair of almond shaped glands
• Located in upper pelvic cavity, on either side of
lateral wall of uterus
• Near fimbriated ends of the fallopian tubes
– Responsible for producing mature ova and
releasing them at monthly intervals during
ovulation
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Ovaries
• Hormones secreted by the ovaries
– Estrogen
• Promotes maturation of ovum in the ovary
• Stimulates vascularization of uterine lining each
month to prepare for implantation of a fertilized egg
• Contributes to secondary sex characteristic
changes in female with onset of puberty
– Progesterone
• Primarily responsible for changes within the uterus
in anticipation of a fertilized ovum
• Responsible for development of maternal placenta
after implantation of a fertilized ovum
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Testes
• Testes = male gonads = testicles
– Two small ovoid glands located in scrotum
– Primary organs of male reproductive system
– Responsible for production of sperm and
secretion of androgens (male steroid
hormones)
– Secrete testosterone
• Responsible for secondary sex characteristic
changes that occur in male with onset of puberty
• Responsible for maturation of sperm
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PATHOLOGICAL CONDITIONS
Pituitary Gland
Acromegaly
• Pronounced
– (ak-roh-MEG-ah-lee)
• Defined
– Chronic metabolic condition characterized by
the gradual, noticeable enlargement and
elongation of the bones of the face, jaw, and
extremities, due to hypersecretion of the
human growth hormone after puberty
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Diabetes Insipidus
• Pronounced
– (dye-ah-BEE-teez in-SIP-ih-dus)
• Defined
– Deficiency in secretion of antidiuretic hormone
(ADH) by posterior pituitary gland
• Characterized by large amounts of urine and
sodium being excreted from the body
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Dwarfism
• Pronounced
– (DWARF-ism)
• Defined
– Generalized growth retardation of body due to
deficiency of human growth hormone
– Also known as congenital hypopituitarism or
hypopituitarism
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Gigantism
• Pronounced
– (JYE-gan-tizm)
• Defined
– Proportional overgrowth of body’s tissue due
to hypersecretion of human growth hormone
before puberty
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Hypopituitarism
• Pronounced
– (high-poh-pih-TOO-ih-tah-rizm)
• Defined
– Complex syndrome resulting from absence or
deficiency of pituitary hormone(s)
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PATHOLOGICAL CONDITIONS
Thyroid Gland
Cancer, Thyroid Gland
• Pronounced
– (CAN-sir, THIGH-royd gland)
• Defined
– Malignant tumor of the thyroid gland
– Leads to dysfunction of gland and inadequate
or excessive secretion of thyroid hormone
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Goiter, Simple; Nontoxic
• Pronounced
– (GOY-ter simple; nontoxic)
• Defined
– Hyperplasia of thyroid gland
• Results from a deficient amount of iodine in diet,
required for synthesis of T3 and T4, thyroid
hormones produced by the thyroid gland
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Graves’ Disease
(Hyperthyroidism)
• Pronounced
– (high-per-THIGH-royd-izm)
• Defined
– Hypertrophy of thyroid gland resulting in
excessive secretion of thyroid hormone
• Causes extremely high body metabolism, thus
creating multisystem changes
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Graves’ Disease
Hyperthyroidism
• Three distinguishing characteristics
– Hyperthyroidism
– Thyroid gland enlargement (goiter)
– Exophthalmia
• Unnatural protruding of the eyes
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Hypothyroidism
• Pronounced
– (high-poh-THIGH-royd-izm)
• Defined
– Condition in which there is a shortage of
thyroid hormone causing an extremely low
body metabolism due to a reduced usage of
oxygen
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Hypothyroidism
• Most severe form known as myxedema
– Water retention all over body in connective
tissues
– Person has puffy appearance and thick
tongue
– Reduced metabolic rate
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Thyroiditis
(Hashimoto’s)
• Pronounced
– (thigh-royd-EYE-tis)
– (HASH-ee-moh-TOZ)
• Defined
– Chronic inflammation of the thyroid gland,
leading to enlargement of the thyroid gland
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Thyrotoxicosis
(Thyroid Storm)
• Pronounced
– (thigh-roh-toks-ih-KOH-sis)
• Defined
– Acute, sometimes fatal, incident of overactivity
of the thyroid gland resulting in excessive
secretion of thyroid hormone
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PATHOLOGICAL CONDITIONS
Parathyroid Gland
Hyperparathyroidism
(Hypercalcemia)
• Pronounced
– (high-per-pair-ah-THIGH-royd-izm)
– (high-per-kal-SEE-mee-ah)
• Defined
– Overactivity of any one of the parathyroid
glands
– Leads to high levels of calcium in blood and
low levels of calcium in bones
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Hypoparathyroidism
• Pronounced
– (high-poh-pair-ah-THIGH-royd-izm)
• Defined
– Decreased production of parathyroid hormone
resulting in hypocalcemia
– Characterized by nerve and muscle weakness
with muscle spasms or tetany
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PATHOLOGICAL CONDITIONS
Adrenal Glands
Addison’s Disease
• Pronounced
– (AD-ih-sons dih-ZEEZ)
• Defined
– Life-threatening disease process due to failure
of the adrenal cortex to secrete adequate
mineralocorticoids and glucocorticoids
• Resulting from an autoimmune process, a
neoplasm, an infection, or a hemorrhage in the
gland
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Conn’s Disease
(Primary Aldosteronism)
• Pronounced
– (PRYE-mary al-doss-STAIR-ohn-izm)
• Defined
– Condition characterized by excretion of
excessive amounts of aldosterone
• Leads to an increased volume of blood and
hypertension
• Causes body to retain extra sodium and excrete
extra potassium
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Cushing’s Syndrome
• Pronounced
– (CUSH-ings SIN-drom)
• Defined
– Cluster of symptoms in the adrenal gland as a
result of an excessive amount of cortisol or
ACTH circulating in blood
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Cushing’s Syndrome
• Cushing’s Syndrome
– Symptoms
•
•
•
•
•
•
•
•
•
•
Central obesity
Round “moon” face
Edema
Hypertension
Supraclavicular fat pads (buffalo hump)
Muscular weakness and wasting
Skin infection
Poor wound healing
Low potassium level
Emotional changes
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Pheochromocytoma
• Pronounced
– (fee-oh-kroh-moh-sigh-TOH-mah)
• Defined
– Vascular tumor of adrenal medulla
– Produces extra epinephrine and
norepinephrine
– Leads to persistent or intermittent
hypertension and heart palpitations
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Virilism
• Pronounced
– (VEER-il-izm)
• Defined
– Development of male secondary sex
characteristics in the female due to the
excessive secretion of adrenocortical
androgens from the adrenal cortex
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Virilism
• Virilism
– Symptoms
•
•
•
•
•
•
•
•
Excessive hair on the body and face (hirsutism)
Absence of menstruation
Deepening of the voice
Acne
Oily skin
Muscular hypertrophy
Atrophy of the breasts and uterus
Ovarian changes
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PATHOLOGICAL CONDITIONS
Pancreas
Diabetes Mellitus
• Pronounced
– (dye-ah-BEE-teez MELL-ih-tus)
• Defined
– Disorder of pancreas in which beta cells of
islets of Langerhans of the pancreas fail to
produce an adequate amount of insulin
• Results in body’s inability to appropriately
metabolize carbohydrates, fats, and proteins
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Diabetes Mellitus
• Classifications
– Type I Diabetes
– Formerly known as Insulin-Dependent
Diabetes Mellitus (IDDM)
•
•
•
•
Usually occurs before age of 30
Sudden onset
Controlled with insulin injections
Individuals are prone to developing ketosis
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Diabetes Mellitus
• Classifications
– Type II Diabetes
– Formerly known as Non-Insulin-Dependent
Diabetes Mellitus (NIDDM)
• Usually appears in adults after age of 40
• Majority of these individuals are obese
• Usually controlled through diet and exercise
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Diabetic Retinopathy
• Pronunciation
– (dye-ah-BET-ik ret-in-OP-ah-thee)
• Defined
– Disorder of blood vessels of retina in which
capillaries of the retina undergo localized
areas of bulging (microaneurysms),
hemorrhages, leakage, and scarring
• Consequence of 8-10 year duration of diabetes
mellitus
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Gestational Diabetes
• Pronounced
– (jess-TAY-shun-al dye-ah-BEE-teez)
• Defined
– Disorder in which women who are not diabetic
before pregnancy develop diabetes during the
pregnancy
• Inability to metabolize carbohydrates
• Results in hyperglycemia
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Pancreatic Cancer
• Pronounced
– (pan-kree-AT-ik CAN-sir)
• Defined
– Life-threatening primary malignant neoplasm
typically found in head of pancreas
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Pancreatitis
• Pronounced
– (pan-kree-ah-TYE-tis)
• Defined
– Acute or chronic destructive inflammatory
condition of the pancreas
• Creates symptoms that vary from mild self-limiting
pancreatic edema to massive necrotizing
hemorrhagic pancreatitis
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Diagnostic Techniques,
Treatments, and Procedures
Endocrine System
Diagnostic Techniques,
Treatments, and Procedures
• Thyroid function tests
– Tests that measure blood levels of hormones
T3, T4, and TSH
• Thyroid-Stimulating Hormone (TSH) Blood
Test
– Measures concentration of TSH in blood
• Used to differentiate primary hypothyroidism from
secondary hypothyroidism
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Diagnostic Techniques,
Treatments, and Procedures
• Fasting Blood Sugar (FBS)
– Blood glucose sample taken usually early in
the morning after the person has been without
food or drink since midnight
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Diagnostic Techniques,
Treatments, and Procedures
• Glucose Tolerance Test (GTT)
– Test that evaluates person’s ability to tolerate
a concentrated oral glucose load by
measuring glucose levels:
• Prior to glucose administration
• 30 minutes after glucose administration
• 1, 2, and 3 hours after glucose administration
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Diagnostic Techniques,
Treatments, and Procedures
• Radioactive Iodine Uptake (RAIU) Test
– Thyroid function test
– Evaluates function of thyroid gland
– Administers radioactive iodine
– Places gamma ray detector over thyroid
gland
– Determines percentage of radioactive iodine
absorbed by gland over specific time periods
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Diagnostic Techniques,
Treatments, and Procedures
• Serum Glucose Tests
– Tests that measure amount of glucose in
blood at time sample was drawn
• Thyroid Echogram (Ultrasound)
– Examination to distinguish solid thyroid
nodules from cystic nodules
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Diagnostic Techniques,
Treatments, and Procedures
• Thyroid scan
– Examination to determine position, size,
shape, and physiological function of thyroid
gland through use of radionuclear scanning
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