endocrine

• endocrine glands secrete hormones into the blood stream
• hormones are messengers in a communication network
• endocrine hormones exert their action on body tissues remote from their site of origin
• principle endocrine glands: hypothalamus, pituitary, thyroid, parathyroid, and adrenal
• endocrine system disorders

  • hyposecretion
  • hypersecretion
• endocrine system disorders

  • hyposecretion ( autoimmune destruction, non-secreting tumors, ischemia/infarction, surgical removal, receptor defects)
• endocrine system disorders

  • hypersecretion (idiopathic, secreting tumors)
• relationship between hypothalamus and pituitary = hypothalamic pituitary axis (HPA)
• releasing and release-inhibiting hormones

  • regulation of secretion of pituitary hormones
  • pituitary hormones then control secretion of hormones in target organ
  • negative feedback mechanism in hormone function
  • hypothalamic hormones
  • anterior pituitary hormones
• releasing and release-inhibiting hormones

  • hypothalamic hormones
  • growth hormone releasing hormone
  • growth hormone inhibiting hormone (somatostatin); inhibits GH and TSH
  • thyrotropin releasing hormone; TSH and prolactin
  • corticotropin releasing hormone; AcTH
  • gonadotropin releasing hormone; LH and FSH
  • prolactin inhibiting factor (dopamine)
• releasing and release-inhibiting hormones

  • anterior pituitary hormones
  • thyroid-stimulating hormone
  • adrenocorticotropic hormone (proteins for adrenal cortex)
  • follicle stimulating hormone (M/F function)
  • luteinizing hormone (M/F function)
  • prolactin ( breast milk after child is born)
  • growth hormone (regulate metabolic function related to growth)
• anterior pituitary disorders

  • hypopituitarism
  • hyperpituitarism
• anterior pituitary disorders

  • hypopituitarism
  • deficiency of pituitary hormone
  • pituitary tumor
  • pituitary infarction (decreased oxygen)
• anterior pituitary disorders

  • hypopituitarism
  • single pituitary hormone deficiencies
  • prolactin deficiency (no milk production)
  • example: Sheehan syndrome (pituitary infarction during delivery)
  • gonadotropin deficiency (releases LH and FSH)
  • male: testicular atrophy
  • female: atrophy of uterus and breast, amenorrhea
  • thyrotropin deficiency
  • hypothyroidism
  • adrenocorticotropic hormone deficiency (AcTH lost so cortisol loss)
  • loss of adrenal response
• anterior pituitary disorder

  • hypopituitarism
  • single pituitary hormone deficiencies
  • growth hormone deficiency
  • example: dwarfism (genetic or sister tumor)
  • short stature, delayed puberty, poorly developed muscles, dry skin, thin hair, NORMAL IQ
• anterior pituitary disorders

  • hyperpituitarism
  • decreased negative feedback signal
  • hypofunction of target gland
  • pituitary response -> increase production of stimulating hormone
  • hyperprolactinemia
  • increased prolactin levels = milk production in non-lacting females or males (stop menstruating or sperm)
  • excess secretion of ACTH
  • cortisol increased
  • excess secretion of growth hormone
  • example: giantism (before puberty) and acromegaly (after puberty)
  • liner growth, increased bulk
  • cardiomegaly (hypertension and cardiac failure)
• posterior pituitary disorders

  • syndrome of inappropriate ADH secretion (SIADH)
  • causes: increased secretion of ADH due to pituitary tumor or tumor in another part of body that secretes ADH
  • pathophysiology: increase in ADH
  • clinical mani: fluid overload, hyponatremia (affect CNS: seizure, coma, confusion), hemodilution
• posterior pituitary disorders

  • diabetes insipidus
  • causes: genetics, lesions (tumors, thrombosis, infections, immunologic disorders), medications, kidney disorders
  • pathophysiology: lack of ADH
  • clinical manifestations: polyuria, polydipsia, increased serum osmolality
• posterior pituitary disorders

  • pituitary tumors
  • adenomas
  • space occupying properties
  • destruction or suppression of surrounding tissue
  • CNS or visual symptoms
  • secreting properties
  • clinical mani: related to whichever hormone is involved
  • malignant tumor: rare, usually anterior lobe
• Thyroid disorders: parathyroid glands are on posterior of thyroid gland
• thyroid disorders

  • thyroid gland hormones: Thyroxine (T4, precursor to T3), Tri-iodothyronine (T3), thyroid hormone which increases basal metabolic rate, calcitonin
• thyroid disorders

  • hyperthyroidism (thyrotoxicosis)
  • increased release of circulating thyroid hormones
  • clinical mani:
  • goiter
  • skin (flushed and warm)
  • hair/nails (fine/soft hair)
  • exophthalmos (bulging eyes)
  • cardiovascular alterations (tachycardia, hypertension)
  • nervous system alterations
  • weight loss
• thyroid disorders

  • hyperthyroidism (thyrotoxicosis)
  • example: Grave's Disease (autoimmune process)
  • immunoglobulins bind to TSH receptors
  • inappropriate stimulation of thyroid gland
• thyroid disorders

  • hyperthyroidism (thyrotoxicosis)
  • example: thyrotoxic crisis (thyroid storm)
  • sudden increase in thyroid hormone
  • marked increase in all symptoms
  • uncontrolled fever; can be fatal
• thyroid disorders

  • hypothyroidism (congenital or acquired)
  • lack of thyroid hormone
  • insufficient stimulation of metabolism and heat production
  • clinical mani:
  • dry skin
  • myxedema (edema in face, eye and cheeks)
  • fatigue
  • weight gain
  • intolerance to cold
  • brittle hair
  • decreased muscle movement and reflexes
  • elevated TSH (adaptive response); both hypo- and hyper- thyroidism
• thyroid disorders

  • hypothyroidism
  • example: Hoshimoto thyroiditis
  • autoimmune disorder
  • clinical mani: all overs and GOITER (just like hyperthyroidism)
• thyroid disorders

  • hypothyroidism
  • example: myxedema coma (can be fatal)
  • caused by illness
  • extreme hypothyroidism
  • clinical mani: unresponsive, hypothermic -> coma (vital sign suppress
• thyroid disorders

  • thyroid cancer
  • usually progresses slowly
  • thyroid nodule
• Parathyroid disorders

  • Parathyroid hormone (PTH) -regulates serum calcium levels -> controls rate of bone metabolism
  • hyperparathyroidism
  • hypoparathyroidism
• Parathyroid disorders

  • hyperparathyroidism
  • hyper-secretion of PTH (usually related to benign tumor) -> elevated serum calcium levels (hypercalcemia), increased excretion (decreased) of phosphorus -> possible precipitation of calcium in kidneys
• Parathyroid disorders

  • hypoparathyroidism
  • PTH deficiency or failure to act at the tissue level
  • inadvertent damage to gland during thyroid surgery
  • suppression of PTH from chemical mediators (burn, sepsis)
  • decreased calcium levels -> life threatening if tetany develops
  • clinical mani: numbness, tingling, and stiffness in muscles
• Adrenal disorders

  • adrenal cortex (outer layer)
• Adrenal disorders

  • adrenal cortex
  • Mineralocorticoids (aldosterone): stimulated be renin-angiotensin system
  • sodium depletion or potassium excess trigger aldosterone production
  • target tissue: distal renal tubules intestines, sweat, salivary glands
  • increases sodium reabsorption by distal tubules and increases potassium excretion by kidneys
• Adrenal disorders

  • adrenal cortex
  • glucocorticoids (cortisol): direct effect on glucose
  • stimulated by ACTH (adrenocorticotropic hormone)
  • target tissue: body cells
  • important in stimulation of carbohydrate, protein, fat, and glucose metabolism by enhancing glucose production by the liver
  • cellular repair and membrane integrity (blocks inflammatory response and keeps cells healthy)
• Adrenal disorders

  • adrenal cortex
  • adrenal androgens (gonadocorticoids)
  • male sex hormones: testosterone precursor
• Adrenal disorders

  • adrenal cortex
  • hyperfunction
  • Cushing syndrome
  • cause: adrenal or pituitary neoplasm and exogenous glucocorticoid administration
• Adrenal disorders

  • adrenal cortex
  • hyperfunction Cushing syndrome)
  • pathophysiology
  • elevated plasma ACTH or excess cortisol production (increase ACTH, cortisol, glucose)
  • excessive catabolism of protein and fat
• Adrenal disorders

  • adrenal cortex
  • hyperfunction (Cushing Syndrome)
  • clinical mani:
  • weight gain (moon face or buffalo hump)
  • adipose tissue redistribution
  • metabolic abnormalities (glucose)
  • capillary and collagen fragility (striae)
  • masculinization in females
• Adrenal disorders

  • adrenal cortex
  • hyperfunction (hyperaldosteronism)
  • cause:
  • aldosterone producing tumor
  • increased production of renin in kidneys
• Adrenal disorders

  • adrenal cortex
  • hyperfunction (hyperaldosteronism)
  • pathophysiology
  • excess secretion of aldosterone
  • reabsorption of sodium and water
  • excretion of potassium
  • suppressed renin secretion and activity
  • electrolyte imbalances