Endocrine system Flashcards
Where is the pituitary gland?
It sits in the sella turcica in the center of the sphenoid bone
What is the adenohypophysis?
Anterior pituitary gland.
It comes from the facial area called rathke’s pouch
What is neurohypophysis?
The posterior pituitary gland.
It comes from the neuroectoderm of the forebrain.
Remember
Posterior pituitary will have neurological tubes called secretory axons.
This tube would take ADH and oxytocin to the posterior pituitary for storage
Remember
Anterior pituitary has venous system called portal venous system
What are the hormones in the anterior pituitary?
Prolactin Adrenocorticotropic hormone (ACTH) Growth hormone leutinizing hormone (LH) Follicle-stimulating hormone Thyroid-stimulating hormone
Hypopituitarism
Lesions in hypothalamus or adenohypophysis
Sheehan’s syndrome, empty sella
Sheehan’s syndrome
Postpartum pituitary gland necrosis
Disorder where cells in the pituitary gland of a new mother start to die
Because of excess blood loss during childrbirth
Diabetes Insipidus
no ADH from posterior pituitary
Cannot concentrate urine
Thirst wakes from sleep due to electrolyte disturbances
Hyperpituitarism
Adenoma secreting one hormone
Prolactinoma
Most common hyperpituitarism
Unneeded lactation
Somatotropic adenomas
Excess GH
Acromegaly in adults or giantism in children
Corticotroph tumors
Secrete ACTH
Reason for Cushing’s disease (overproduction of cortisol)
What are the molecules that make thyroid hormone?
Tyrosine and iodine
What enzyme converts T4 to T3?
Type I deiodinase appears to be responsible for most of the T3 in the bloodstream. The type I enzyme catalyzes the conversion of T4 to T3 within the thyroid gland.
What is thyroglobulin?
Protein made by the follicular cells of the thyroid gland
are thyroid hormones anabolic or catabolic?
Anabolic
After de-iodination of thyroid hormones, what happens to them?
Urine or recycles towards the thyroid gland
Hypothyroid
Myxedema - Myxedema is another term for severely advanced hypothyroidism. This is a condition that occurs when your body doesn’t produce enough thyroid hormone.
causes of hypothyroid:
- Hashimotos (most common)
- Iodine def
Symptoms
Fatigue, lethargy, constipation, cold intolerance, slowed mentation, cardiomyopathy, dry skin, periorbital edema.
Hashimoto’s Thyroiditis
Autoimmune
Most euthyroid then hypothyroid
Transient hyperthyroid is possible
Hyperthyroid/thyrotoxicosis
Grace's disease Women > men Unintended weight loss, tachycardia, heat intolerance lid retraction, lid lag, proptosis Goiter, increased T3 and T4, low TSH
Grave’s disease
Graves’ disease is an immune system disorder that results in the overproduction of thyroid hormones (hyperthyroidism).
De Quervain’s Subacute Granulomatous Thyroiditis
Self-limted painful inflammation of thyroid
Reidel’s Thyroiditis
R to Rock Rock hard, woody thyroid,, mimics carcinoma older women Fibrotic proliferation may cause hypothyroidism
Goiters
A goiter is used to describe any enlarged thyroid gland.
Simple = def of iodine or too many goitrogens (calcium and fluorine in water, brassicas, polluted water)
Multinodular goiter = very large, often mistaken for cancer
The patient can have goiter due to grave’s disease, low iodine, swelling’s goiter that are benign
Adenomas of Thyroid
90-99% of nodules are benign adenomas
May cause pressure symptoms
post-menopausal women
Malignant Tumors of Thyroid
Most papillary carcinoma
Estrogen receptors, well differentiated
Low mortality, solitary nodules more likely to be cancer
Men < 40 more likely cancer
Calcitonin
Produced in the parafollicular cells of the thyroid
Lower blood Ca+ preserves Bone calcium
Acts on BONE and KIDNEY
What are the germinal layers of the adrenal gland?
Cortex and the medulla
How many layers is the cortex divided into?
3 layers:
- Zona Glomerulosa - mineralcorticoids (Aldosterone)
- Zona Fasciculata - glucocorticoids (cortisol)
- Zona Reticularis- glucocorticoids (sex hormones)
What is made in the cortex of the adrenal gland?
Mineralcorticoids (aldosterone)
Glucocorticoids ( Cortisol and sex steroids)
What is made in the medulla?
Epinephrine and norepinephrine
What stimulates the medulla?
Sympathetic nervous system
Aldosterone
Sodium and potassium manipulator
Cortisol
Cortisol can help control blood sugar levels, regulate metabolism, help reduce inflammation, and assist with memory formulation. It has a controlling effect on salt and water balance and helps control blood pressure
Hyperparathyroidism
Primary:
- Adenoma of parathyroid gland
- Elevated calcium
Secondary hyperparathyroidism:
- Hyperplasia due to hypocalcemia or hyperphosphatemia, renal failure, vitamin D def
Serum calcium often low
Hypoparathyroidism
Low serum calcium and high serum phosphate
Chvostek’s sign, Trousseau’s sign
Spontaneous spasm
Pheochromocytoma
Tumor in the medulla
Secretes catecholamines (too much epinephrine and norepinephrine)
Hypertension, arrhythmias
Hyperglycemia and hypermetabolism
Neuroblastoma
Childhood tumor of adrenal medulla
Most occur sporadically
Large abdominal mass
Course variable, some fatal
Addison’s
in Addison’s diseases, you need to ADD cortisol
Hypoadrenalism
most often due to autoimmune adrenalitis
Sometimes TB or idiopathic atrophy, medulla unaffected
Weakness, fatigue, weight loss, diarrhea, vomiting
Hyperpigmentation from increased ACTH, low NA, CL, cortisol
hypoglycemia
hyponatremia
Cushing’s
Hyperadrenalism
Iatrogenic, pituitary adenoma, ectopic ACTH production by neoplasm, thyroid carcinoma, adrenal cortex tumor
Conn’s syndrome
Solitary aldosterone secreting adenoma in the adrenal cortex
causes hyperaldosteronism
What are the cofactors for converting epinephrine to epinephrine in the medulla?
Vitamin B12, folate, and SAMe
What is the parent steroid?
Pregnenolone
What makes pregnenolone?
cholesterol
How does aldosterone work?
Acts in the distal tubule to reabsorb Na +
Pumps K and H out into urine
How is aldosterone stimulated?
ACTH
HYPERKALEMIA
ANGIOTENSIN - 2
Alpha cells secrete what/?
Secrete glucagon
Beta cells secrete what?
secrete insulin
Delta cells
secrete somatostatin
PP cells
Secrete pancreatic polypeptide
