hormone definition: mainly peptides, shorter or longer, secreted in the bloodstream, travel long distances where they are received by other cells

endocrine system is a system of glands

elevated or depressed hormone levels: (what can cause it)

• failure or respond (response?) to inappropriate signal of feedback systems

• dysfunction of an endocrine gland

• secretory cells are unable to produce, obtain, or convert hormone precursors

• the endocrine gland synthesizes or releases excessive amounts of hormone

• increased hormone degradation or inactivation

• ectopic hormone release

target cell failure:

• receptor associated disorders

  • decrease in number of receptors

  • impaired receptor function

  • presence of antibodies against specific receptors

  • antibodies that mimic hormone action

  • unusual expression of receptor function

    • how hormones work at the target cell (my notes, he said to know it)

      • the hormone binds to a receptor (either on plasma membrane or in cell depending on water/lipid solubility)

      • once the hormone binds to the receptor a signal cascade is triggered

        • for surface receptors, this often involves activating a g protein which is linked to the receptor and when inactive bound to gdp

        • once activated, the g protein released gdp and binds to gtp

        • the now activated g protein (attached to gtp) interacts with adenylate cyclase

        • adenylate cyclase converts atp into cyclic amp (cAMP) which is a second messenger

      • cAMP then goes and triggers a set of events that actually causes the cells response to the hormone

    • any issue in this process can cause disease

      • ex. receptor dysfunction, second messenger dysfunction, signaling pathway dysfunction

hormone delivery: (flow chart)

• is appropriate amount of biologically active hormone being delivered to target cell?

  • yes → is another substance mimicking action of hormone?

    • yes → pathogenic mechanism

    • no → is hormone receptor binding abnormal?

      • yes → pathogenic mechanism

      • no → is initiation of intracellular events (ex. generation of second messenger) lacking?

        • yes → pathogenic mechanism

        • no → is cell response to events lacking?

          • yes → pathogenic mechanism

          • no → target cell is responding appropriately to hormone

  • ? (unknown?) → is appropriate need recognized?

    • no → pathogenic mechanism

    • yes → is secretory cell synthesizing biologically active hormone?

      • no → pathogenic mechanism

      • yes → is delivery system functioning?

        • no → pathogenic mechanism

        • yes → is hormone metabolism appropriate? (is it being removed properly after release)

          • no → pathogenic mechanism

          • yes → is hormone being ectopically produced? (is it being produced somewhere where it shouldnt be)

            • no → target cell is receiving appropriate amount of hormone

            • yes → pathogenic mechanism

alterations of the hypothalamic-pituitary system:

• (decreased hypothalamic function causes ___ which leads to anterior pituitary hormone effect __)

• GnRH ↓ —> FSH ↓ && LH ↓

• TRH ↓ —> TSH ↓

• CRH ↓ —> ACTH ↓

• PIF ↓ —> prolactin ↑

• GHRH ↓ —> GH ↓

diseases of the posterior pituitary

• syndrome of inappropriate antidiuretic hormone secretion (SIADH)

  • hypersecretion of adh without the presence of physiological stimuli

  • for diagnosis, normal adrenal and thyroid function must exist

  • clinical manifestations are related to enhanced renal water retention, hyponatremia, and hypoosmolarity

• diabetes insipidus

  • insufficiency of adh

  • polyuria and polydipsia (frequent drinking/excessive thirst)

  • partial or total inability to concentrate urine

  • neurogenic

    • insufficient amounts of adh

  • nephrogenic

    • inadequate response to adh

diseases of the anterior pituitary

• disorders of anterior pituitary may involve hypo or hyper function of the gland

  • hypopituitarism (deficiency or failure hormonal function)

    • one of the cause is pituitary infarction (death of tissue). pituitary infarction can be seen in

      • sheehan syndrome (ischemic pituitary necrosis)- pituitary gland is highly vascular so it is vulnerable to ischemia and infarction

      • hemorrhage

      • shock

    • others: head trauma, infections, and tumors

• clinical manifestation depend on the affected area and affected hormones

  • hypopituitarism

    • panhypopituitarism- when all hormones are absent

    • acth deficiency leads to cortisol deficiency

    • tsh deficiency leads to thyroid hormone deficiency

    • fsh and lh deficiency leads to failure or loss of secondary sexual characteristics

    • gh deficiency leads to deficiency in growth

    • diagnosis: radioimmunoassay (measure hormone level), mri or ct (to measure size/look for abnormal areas)

    • treatment: hormone therapy

• hyperpituitarism

  • commonly due to a benign, slow growing, pituitary adenoma

    • expansion of pituitary adenoma may cause both neurogenic (due to infiltration of cranial nerves) and secretory defect

  • manifestations

    • headache and fatigue

    • visual changes (if the tumor infiltrates the optic chiasm)

    • hyposecretion of neighboring anterior pituitary hormones

• hypersecretion of growth hormone (gh)

  • acromegaly

    • hypersecretion of gh in adulthood (after growth plates close)

  • gigantism

    • hypersecretion of gh in children and adolescents (before growth plates close)

  • manifestation

    • interstitial edema

    • increased in size and function of sebaceous and sweat gland (causes increased body odor)

    • coarse (thick) skin

    • enlargement of facial bones

    • arthritis and backaches due to cartilaginous growth

• hypersecretion of prolactin

  • caused by prolactinomas

    • in females, increased levels of prolactin cause amenorrhea (menstrual disturbances), galactorrhea (nonpuerperal milk production [milk production not caused by childbirth/breastfeeding]), hirsutism (excess hair growth), and osteopenia (reduced bone mass but not enough for osteoporosis)

    • in males, increased levels of prolactin cause hypogonadism (gonads dont produce enough sex hormones), erectile dysfunction, impaired libido, oligospermia (low sperm count), and diminished or decreased ejaculate volume

alterations of thyroid function

• hyperthyroidism

  • thyrotoxicosis- primarily caused by excess thyroid hormones secreted by thyroid gland, but also could be caused by tsh secreting pituitary adenoma

    • manifestation: increased metabolic rate, cardiac output

  • graves disease- autoimmune disease

  • hyperthyroidism resulting from nodular thyroid disease

    • goiter

• hypothyroidism can be primary or secondary

  • caused by

    • defective hormone synthesis due to autoimmune thyroiditis, iodine deficiency, or antithyroid drugs

    • loss of thyroid tissue

  • primary hypothyroidism

    • subacute thyroiditis- inflammation of thyroid by a viral infection

    • autoimmune thyroiditis- results granular destruction of thyroid tissue

    • postpartum thyroiditis

    • manifestation: decrease energy metabolism, low basal metabolic rate, cold intolerance, tiredness

    • diagnosis and treatment: clinical symptoms, decrease t4 (a hormone), hormone therapy

  • thyroid carcinoma

alterations of parathyroid function

• hyperparathyroidism

  • primary hyperparathyroidism

    • excess secretion of pth from one or more parathyroid glands

  • secondary hyperparathyroidism

    • increase in pth secondary to a chronic disease

  • manifestations: excessive osteoclastic activity, pathologic fractures, curvature of spine

• hypoparathyroidism

  • abnormally low pth levels

  • usually caused by parathyroid damage in thyroid surgery

  • manifestation: muscle spasm, hyporreflexia, laryngeal spasm

type 1 diabetes mellitus

• demonstrates pancreatic atrophy and specific loss of beta cells

• macrophages, t and b lymphocytes, and natural killer cells are present

• two types

  • immune- environmental genetic factors result cell mediated destruction of beta cells

  • nonimmune- occurs secondary to other diseases

• manifestations

  • type 1 diabetes affects metabolism of fat, protein, and carbohydrates

  • hyperglycemia, polydipsia, polyuris, polyphagia, weightloss, and fatigue

  • diagnosis- clinical symptoms

dysfunction of the pancreas

• type 2 diabetes mellitus

  • maturity onset diabetes of youth (mody)

  • gestational diabetes mellitus (gdm)

  • common form of diabetes mellitus type 2

    • insulin resistance

acute complications of diabetes mellitus

• hypoglycemia

• diabetic ketoacidosis

• hyperosmolar hyperglycemic nonketotic syndrome (hhnks)

• somogyi effect

• dawn phenomenon

diabetic ketoacidosis:

chronic complications of diabetes mellitus

• hyperglycemia and nonenzymatic glycoslytion

• hyperglycemia and the polyol pathway

  • protein kinase c

• microvascular disease

  • retinopathy

  • diabetic nephropathy

    

• macrovascular disease

  • coronary artery disease

  • stroke

  • peripheral arterial disease

• diabetic neuropathies

• infection

alterations of adrenal function

• disorders of the adrenal cortex

  • cushing disease

    • excessive anterior pituitary secretion of acth

  • cushing syndrome

    • excessive level of cortisol, regardless of cause

      • manifestation: hyperpigmentation, muscle wasting and protein wasting, weight gain due to:

        • accumulation of adipose tissue in the trunk, facial, and cervical areas

        • sodium and water retention

  • hypoaldosteronism

    • primary hyperaldosteronism (conn disease)

    • secondary hyperaldosteronism

    • manifestions: hypertension, hypokalemia, electrolyte and fluid imbalances

    

  • adrenocortical hypofunction

    • primary adrenal insufficiency (addison disease)

      • idiopathic addison disease

    • secondary hypocortisolism

    • manifestation: weakness, fatigue, anorexia, weight loss, nausea, diarrhea, hypotension

  • hypersecretion of adrenal androgens and estrogens

    • feminization: development of female sexual characteristics (in males)

    • virilization: development of male sexual characteristics (in females)

• disorders of the adrenal medulla

  • adrenal medulla hyperfunction

    • caused by tumors derived from the chromaffin cells of the adrenal medulla

      • pheochromocytoma’s

    • secrete catecholamines on a continuous or episodic basis