Download Common form is Graves disease May result in goiter (enlarged thyroid)

ENDOCRINE
SYSTEM
Hormones
• Self-regulating system
• Production
– Extremely small amounts
– Highly potent
• Affect:
– Growth
– Metabolism
– Behavior
• Two categories:
– Lipid (Steroid)
– Amino acid
Pituitary
• Also known as hypophysis
• Located beneath brain
• Divided into two lobes:
– Anterior
• Releases six hormones
– Posterior
• Releases two hormones
Thyroid and Parathyroids
• Thyroid gland
– Located on either side of larynx and
upper trachea
– Two lobes
– Secretes mixture of hormones
• Parathyroid glands
– Located at posterior surface of thyroid
– Affect calcium metabolism
Adrenal Glands
• Hormones produced involved in body’s
response to stress
• Located atop each kidney
• Divided into two regions
– Outer cortex produces:
• Steroid hormones
• Cortisol
• Aldosterone
• Sex hormones
– Inner medulla produces
• Epinphrine
• Norepinephrine
Pancreas
• Islet cells produce two hormones:
– Insulin
• Increases cellular use of glucose
• Decreases sugar levels in blood
– Glucagon
• Decreases cellular use of
glucose
• Increases sugar levels in blood
Other Endocrine Tissues
• Thymus
– Secretes thymosin
• Gonads
– Secrete sex hormones
• Prostaglandins
– Group of hormones produced by many
cells
– Variety of effects
• Uterine contractions
• Inflammatory response
• Vasomotor activities
Clinical Aspects of Endocrine
System
• Endocrine diseases result from:
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Hypersecretion
Hyposecretion
Secretion at wrong time
Failure of target tissue to respond
• Causes may originate:
– In gland itself
– With hypothalamus or pituitary failing
to release proper amount of hormone
stimulators
Pituitary
• Pituitary adenoma usually increases
secretion of growth hormone
– Excess in children causes gigantism
– Excess in adults causes acromegaly
• Treatment
– Surgery
– Drugs to reduce hormone level in blood
Pituitary (con’t)
• Panhypopituitarism
– Hypofunction of pituitary
– Caused by tumor or interruption of gland’s
blood supply
– Widespread effects
• Lack of ADH
– Results in diabetes insipidus
• Kidneys with diminished ability to conserve
water
• Symptoms include:
– Polyuria
– Polydipsia
Thyroid
• Deficiency of thyroid hormone causes:
– In infants
• Physical retardation
• Mental retardation
• Congenital hypothyroidism
– In adults
• Myxedema
• Hyperthyroidism
– Common form is Graves disease
– May result in goiter (enlarged thyroid)
• Not always results from thyroid malfunction
Parathyroids
• Overactivity causes high level of calcium in
blood
– Calcium obtained from bones
– Possible development of kidney stones
• Underactivity results in decreased calcium
– May cause:
• Tingling
• Numbness
• Tetany
Adrenals
• Addison disease = hypofunction of adrenal
cortex
– Caused by:
• Autoimmune destruction of gland
• ACTH deficiency
– Results in:
• Water loss
• Low blood pressure
• Electrolyte imbalance
• Weakness
• Nausea
• Increase of brown pigmentation
Adrenals (cont’d)
• Cushing syndrome = excess of adrenal
cortisol hormones
– Caused by:
• Therapeutic administration of steroid hormones
• Tumor
– Results in:
• Moon-shaped face
• Localized obesity
• Weakness
• Hirsutism
• Fluid retention
Pancreas and Diabetes
• Diabetes mellitus
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Most common endocrine disorder
Failure to use glucose effectively
Excess glucose causes hyperglycemia
Two types:
• Type 1 (juvenile-onset or insulin-dependent)
• Type 2 (adult-onset or non-insulin dependent)
Type 1 Diabetes
• Usually appears in children and
teenagers
• Caused by failure of pancreatic
islets to produce insulin
• For proper management:
– Monitor blood sugar levels
– Give insulin in divided doses
– Regulate diet
Type 2 Diabetes
• Initiated by cellular resistance to insulin
• May result in:
– Metabolic syndrome
– Hypoglycemia
– Insulin shock
• Diagnosed by measuring levels of glucose
in blood plasma
• Most cases linked to obesity
• Another form is gestational diabetes
mellitus