Endocrine Flashcards
The decreased secretion of PTH or decreased hormonal response to PTH in the tissues due to removal (surgery) or destruction (autoimmune) of parathyroid gland
Hypoparathyroidism
- loss of receptors on target tissue
- production of antibodies that block ability of hormone to bind receptor
Alterations in Target Tissue Responsiveness
Peptide and Catecholamines
- Synthesis:
- Release:
- Transport:
- Receptor:
- Mechanism:
- synthesized in advance and stored in vesicles
- released by exocytosis with calcium signal
- transported without a carrier to target tissue
- receptor found on target cell surface
- uses second messenger systems
How is Hashimoto’s diagnosed and how is it treated
- Hashimoto’s diagnosis involves detection of these autoantibodies, along with low serum levels of TH.
- Elevated TSH levels will also be detected in primary hypothyroidism as the body tries to stimulate the thyroid gland to produce more TH
- Treatment involves replacement of TH.
Reduction of one or more hormones secreted from the adrenal cortex
Adrenal insufficiency
______ has both exocrine and endocrine functions
Pancreas
Steroid and Thyroid Hormones
- Synthesis:
- Release:
- Transport:
- Receptor:
- Mechanism:
- synthesized on demand and cannot be stored
- released by diffusion once made
- transport requires a protein carrier to target tissue
- receptor found inside the cell (cytoplasm or nucleus)
- alters gene transcription
What does the adrenal medulla produce?
-
Catecholamines (neurohormones)
- Epinephrine
- Norepinephrine
Released in response to sympathetic stimulation
*Short term stress*
A major metabolic hormone
Thyroid hormone
Deficits of growth hormone in children leads to _____ that may be congenital or acquired
Dwarfism
- Congenital-symptoms appear early and include
- short stature, obesity, immature appearance/voice, delay in skeletal maturation, hyperlipidemia with normal intelligence.
- Acquired—abnormalities of the hypothalamus and pituitary lead to obesity, skeletal maturation delayed, increased cardiovascular mortality other syndromes
gland that influences all major body systems
thyroid
Excess PTH is associated with _____
Renal Calculi
An autoimmune disease involving the production of antibodies against the TSH receptor
Grave’s Disease
- antibodies overstimulate the thyroid gland to produce TH independently of TSH
- This leads to excess TH and goiter
Growth hormone excess is commonly caused by _____ that may occur in acute illness, chronic renal failure, or cirrhosis
secretory pituitary adenoma
_____ is released from the parathyroid gland, whihc are tiny masses of glandular tissue on the posterior surface of the thyroid gland
PTH (parathyroid hormone)
an autoimmune destruction of the thyroid gland and production of autoantibodies against thyroglobulin, throidal peroxidase and the TSH receptor that blocks receptor function
Hashimoto’s Thyroiditis (Disease)
Untreated hypothyroidism that may be life threatening
Myxedema Coma
Causes of Goiter in hypo and hyperthyroidism
- Hypothyroidism- the gland enlarges in an attempt to produce more thyroid
- insufficient iodine intake is the most common cause of increased thyroid-stimulating hormone, leading to goiter
- diffuse enlargement of the thyroid is most commonly caused by prolonged stimulation by TSH
- Hyperthyroidism- the thyroid enlarges due to overstimulation
- enlargemetn may be stimulated by autoantibodies (as in Graves’ disease)
- nodular goiters may be caused by malignancy, dietary iron deficiency, and Graves’
- Dysphagia and dyspnea may result from extremely large goiters
the active form of thyroid hormone
Triiodothyronine (T3)
- Most T3 is formed by converting T4 into T3 in the tissues
Adult Symptoms include weakness, fatigue, cold intolerance, constipation, dry skin, bradycardia, delayed deep tendon reflexes, anemia, hyponatremia, depression
Hypothyroidism
List some of the s/s of Addison’s Disease and treatments
- Signs and Symptoms
- Hyperpigmentation (increased ACTH stimulates melanocytes)
- Hypoglycemia, Hypotension
- Decreased mineralcorticoid activity
- Fluid/electrolyte abnormalities
- Changes in WBC ratios
- Weakness, fatigue, anemia, anorexia, vomiting, diarrhea, muscle/joint pains
- Treatments
- Replace missing hormones
- Hydrocortisone, has the ability to counter the loss of mineralcorticoids and glucocorticoids
Whole body effects of ___ lead to increases in
- cardiac output; ventilation; food intake; mobilization of glycogen, protein and fat stores; C02 and heat production
Thyroid hormone
Tertiary endocrine disorders
due to dysfunction of the hypothalamus
Involves autoimmune production of an antibody against the TSH receptor that continually stimulates TSH action on the thyroid
Grave’s Disease
Name the three steroid hormones that the adrenal cortex produces
-
Mineralcorticoids (outer layer)
- regulates minerals (sodium and potassium)
-
Glucocorticoids (middle layer)
- Cortisol- promotes metabolism and response to long-term stress by regulating glucose levels
-
Sex hormones (inner layer)
- Androgens
- Some estrogens
_____ disorders commonly involve either an excess or a deficiency of hormone levels, usually due to hyperfunction or hypofunction
Endocrine
_____ and _____ are decreased in secondary hypothyroidism
TSH and TH
- Also known as thyroitoxicosis
- accelerates all metabolic processes
- characterized by an increases synthesis and secretion of T3/T4 giving rise to an increased metabolic rate
Hyperthyroidism
_____ is elevated in primary hypothyroidism
TSH
- congenital defect resulting in loss of gland or key enzyme
- destruction of the gland due to:
- ischemia, infection, inflammation, autoimmunity, or neoplastic growth
- aging or atrophy of a gland may result in decrease function
Hypofunction
Pancreatic islets are hormone-producing tissue that release both _____ and _____
Insulin and glucagon
- beta islet cells release insulin in response to high blood glucose levels
- alpha islet cells release glucagon in response to low blood glucose levels
Most common cause in adults of hypothyroidism
Hashimoto’s Disease
Disease caused by adrenal atrophy secondary to autoimmune adrenalitis
- results in 90% loss of adrenal cortices
- often stable until an illness/stress
- decrease in adrenal secretion of cortisol
- increase in ACTH release
Addison’s Disease
hypersecretion of GH in children before closure of epiphyseal plates results in symmetric linear growth
Gigantism
Name the clinical consequences of diabetes mellitus
- Microvascular disease
- thickening of arterioles and capillaries leads to decreased perfusion
- ischemia can damage vulnerable tissues, such as those in the eye
- Atherosclerosis
- fibrous plaque formation can lead to CAD and stroke
- Most common with T2DM
- Neuropathies
- changes in the schwann cells, which produce myelin that aid in neural conduction
- Infection
- a loss of sensation, decreased perfusion, increased glucose foster microbial growth
- impaired white blood cell function
Cortisol is produced by the ______ in response to ____-term stress
Cortisol – Adrenal Cortex– long term stress
- acts to alter metabolism to maintain elevated glucose levels
- acts to suppress inflmamatory and immune responses
- glucocorticoid
The major form of thyroid hormone that is secreted by the thyroid follicles
Thyroxine (T4)
Hormone levels are regulated by ______
negative feedback inhibition
- excessive endogenous hormone production
- excessive administration of exogenous hormones
- autoimmune stimulation of the gland
Hyperfunction
Enhanced activity of the parathyroid glands that results in the hypersecretion of PTH that results in elevated serum calcium levels and excessive secretion of potassium by the kidneys
Hyperparathyroidism
- Primary—caused by adenoma (~85%), hyperplasia (~15%), or rare carcinoma of the parathyroid glands.
- Secondary—chronic renal failure, decreased synthesis of vitamin D, or renal phosphate retention promote hyperplasia of the parathyroid gland and increased synthesis and release of PTH.
- Persons are often asymptomatic, but may may present with fatigue, hypertension, constipation, renal stones, bone pain.
A reduction in the amount of thyroid hormone produced
Hypothyroidism
- cretinism in children (TH deficiency in an embryo or neonate)
- myxedema in adults
Lipid-soluble hormones include ____ and _____
Steroid and thyroid hormones
An enlargement of the thyroid gland
goiter
- can be caused by hyperthyroid or hypothyroid
Neurohormones (E/NE) are produced by the _______ in response to ____-term stress
Neurohormones– Adrenal Medulla- Short-term stress
Signs/Symptoms of Cushing’s Syndrome
- largely result from excess cortisol
- altered fat metabolism and redistribution (“moon” face or “buffalo hump”)
- muscle wasting (weakness)
- accelerated bone metabolism (fx, renal calculi)
- altered glucose metabolism (diabetes)
- increased risk of infection (anti-inflammatory)
- increase androgens
- hirsutism, acne, irrular menstruation
- Treatment:
- surgery, irradiation, medicines
Thyroid gland produces _____ and _____
thyroid hormone and calcitonin
Hypothyroidism is almost always _______
- Primary or secondary
- is almost always primary (95% are a disorder of gland itself)
- may be secondary (caused by complications in pituitary or hypthalamic functions)
- may be congenital or acquired
- A metabolic disorder characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency
- Decreased responsiveness to insulin due to decreased receptor number or sensitivity
- Genetic component but obesity is most important factor
Type 2 DM (NIDDM, Adult-onset)
- accounts for 90-95% of DM
- Underlying causes are considered genetic and environmental, with increased risk among individuals with a positive family history
____ are released from endocrine glands, travel through the blood, and interact with a target organ
Hormones
The most common cause of hyperthyroidism
Graves’ Disease
Hypersecretion of GH in adults results in
- thickening of tissues on hands, feet, nose and mandible
- arthritis
- hypertension, CAD, CHF
Acromegaly
What are some of the treatments for Graves’ Disease
- Surgery
- Radioactive iodine to ablate part of the thyroid
- Thiouracil to block TH synthesis
- lithium to block TSH secretion
- iodine to block the additional production of TH
Primary endocrine disorders
originate in the gland responsible for producing/releasing the hormone
Secondary endocrine disorders
- caused by decreased hormone production or release from the pituitary
- target gland is essentially normal but its function is abnormal by defective levels of stimulating hormones
Prolonged untreated hyperthyroidism may decompensate and become _______ which may be triggered by illness or surgery
Thyrotoxic Crisis
A life-threatening situation that occurs as a result of insufficient glucocorticoids and may be precipitated by severe infection, trauma, surgery and dehydration
Presents with confusion, headache, N/V, muscular weakness, hypotension, dehydration and vascular collapse
Clinical manifestations: hypoglycemia, hyperkalemia, hyponatremia
Tx: fluid and glucocorticoid replacement, followed by mineralcorticoid replacement
Adrenal Crisis
Often occurs because of excess production of ACTH from a pituitary tumor
Cushing’s Disease
Occurs when there is a lack of ACTH from the anterior pituitary, may occur with exogenous glucocorticoid therapy or with a pituitary or hypothalamic tumor
Secondary insufficiency
- Signs and symptoms may be similar to primary but aldosterone secretion is normal and hyperpigmentation is usually absent
- presence of cushingoid fetures accompanys adrenal insufficiency due to exogenous glucocorticoids
What are some of the consequences of Grave’s Disease
- hypermetabolism
- weight loss, muscle weakness, increased ventilation to meet oxygen demand, increased heat production
- increased sympathetic nerve activity
- incrased expression of beta-adrenergic receptors, increased sympathetic activation
Reduces plasma calcium levels by causing calcium to be deposited into the bone
Calcitonin
_____ released when glucose levels are high (absorptive phase), and acts to take glucose into cells, thereby lowering blood glucose levels.
_____ released when plasma glucose levels decrease (post-absorptive), thereby raising plasma glucose levels by stimulating glucogenolysis, lipolysis, and gluconeogenesis.
Insulin
Glucagon
Insulin acts to take glucose into cells, lowering blood glucose levels
Glucagon raises plasma glucose levels and acts the opposite of insulin
_____ is released from the thyroid gland and stimulates uptake of calcium when blood levels are high
Calcitonin
refers to the physiologic manifestations of excess glucocorticoids or hypercorticalism from any cause
Cushing’s Syndrome
- Causes include
- excess production of ACTH from a tumor in pituitary (Cushing disease)
- adrenal tumor
- ectopic ACTH-releasing tumar (small cell lung carcinoma)
- glucocorticoid treatment (iatrogenic Cushing syndrome)
_____ can have profound and diverse effects
- mental function, cardiac function, energy utilization
- Symptoms are insidious and nonspecific
Thyroid dysfunction
Decreased calcium levels cause _____ and _____
May be life threatening and can cause _____
Decreased calcium levels causes increased neuromuscular and symptoms of tetany
May be life-threatening with vocal cord palsy, stridor, and seizures
Why does primary adrenal insufficiency occur and what are the two major causes of it?
- When there is damage to the adrenal cortex
- Is mainly caused by autoimmune disease and tuberculosis
Complete or near absence of insulin due to the desctruction of the beta cells (autoimmune, viral, genetic)
Type 1 Diabetes Mellitus
(IDDM, juvenile)
- associated with high plasma glucose levels, metabolic disorders, and ketoacidosis
- Often presents with DKA
- treatment with exogenous insulin
- Regulates metabolism and is important for growth and development
- Permissive for growth promoting actions of growth hormone
- Essential the development of the nervous system
- increases protein synthesis in many types of cells
- regulates the rate at which oxidative phosphorylation takes place
- controls oxygen consumption and the production of heat and this determines the basal metabolic rate.
Thyroid Hormone
_____ also called somatotropin, is a general metabolic hormone that promotes growth of skeletal muscle and stimulates extension of the long bones before puberty, by acting on the epiphyseal plate
Growth hormone Metabolic effects include:
- stimulation of protein anabolism and fat catabolism, while sparing glucose to helps maintain glucose homeostasis.
Water soluble hormones include ____ and _____
peptides and catecholamines
