171. Intro to Endo Flashcards
What are the 3 classes of hormones?
How are they synthesized?
Give examples of each
- Polypeptides: produced as HMW precursors cleaved to active form, water soluble (bind membrane receptors), largest # hormones in this class (ex: insulin)
- Steroids: derived from cholesterol + differ only in ring structure/side chain, lipid soluble (bind cytoplasmic receptors), (ex: GCs - cortisol, MCs - aldosterone, androgens - testosterone, estrogens - estradiol, progesterone, vitamin D)
- Amines: derived from tyrosine, bind membrane receptors (ex: thyroxine - lipid soluble, epinephrine - water soluble)
Anterior Pituitary
- how does it connect to hypothalamus?
- what hormones does it produce?
- sx of oversecretion and hypopituitary syndromes
Connects via H-P portal vessels
hormones: TSH, ACTH, FSH/LH, PRL, GH
Oversecretion Syndrome
PRL - prolactinoma (galactorrhea, amenorrhea, infertility, less libido, erectile dysfx)
GH - acromegaly (gigantism, facial changes, large hands/feet)
ACTH - cushing’s disease (centripetal obesity, purple striae, thin skin, bruising, DM, HTN)
TSH - hyperthyroidism (weight loss, weakness, tremor, sleepless)
FSH/LH - no syndrome, just mass effect
Hypopituitary Syndrome
PRL - cannot lactate after delivering baby
GH - growth failure, fatigue, muscle loss, fat gain, bone loss, heart risk
ACTH - fatigue, dizziness, weight loss
TSH - hypothyroidism: fatigue, weight gain, constipation, dry skin, sleepiness
LH/FSH - hypogonadism: amenorrhea, infertility, loss of libido, erectile dysfx
Neurohypophysis
- communication to hypothalamus?
- how is it regulated
- hormones secreted
- syndrome of hormone secretion
magnocellular neurons originate from supraoptic and paraventricular nuclei - project through stalk and diaphragm sella
regulated by neurons from osmoreceptors, baroreceptors, emetic center
Secretes: Oxytocin, AVP (ADH)
Diabetes Insipidus: decreased AVP, kidneys cannot concentrate urine = polyuria, polydipsia
High AVP secretion: increased kidney water retention = hyponatremia and water intoxication
Adrenal Glands
- parts of gland
- hormones and their function
- 3 primary adrenal diseases
Adrenal Cortex
- secretes lipid-based steroid hormones (CS)
MC: aldosterone: secreted due to low BP/blood volume (terminal RAAS hormone), prompts distal/collecting tubule to reabsorb more Na, water follows, increase BV
GC: cortisol: keeps BG high enough to support brain activity, catabolic (breaks down protein), redirects circulating lymphocytes to peripheral tissues where pathogens are, in large doses = suppress immune/inflammatory response
Androgens: androstenedione, DHEA-S
Adrenal Medulla - secretes EPI and NE
- Adrenal Insufficiency: Addison’s Disease (atrophy, hypocortisolism)
- Adrenal Excess: Cushing’s Syndrome (adenoma or ca)
- Congenital Hyperplasia: mutations in enzymes for cortisol synthesis (loss of cortisol, loss/excess MC/androgens)
Thyroid Gland
- location
- hormones produced
- composition
- function of each hormone
- two groups of thyroid diseases
- what is goiter?
Location: ant neck, inf to larynx; 2 lat lobes and isthmus
Hormones: Thyroid Hormone, Calcitonin
Spherical follicles: follicle cells (produce thyroglobulin - precursor of thyroid hormone), colloid lumen contains thyroglobulin, parafollicular C cells produce calcitonin
T3/T4: increase BMR, affects protein synthesis, bone growth, neuronal maturation, cell differentiation
Calcitonin: secreted when serum Ca too HIGH - lowers serum Ca by slowing oclast activity and increasing kidney Ca excretion; acts during childhood (minor in adults), produced in excess by MTC
Hyperthyroidism: HIGH T3/T4, LOW TSH - high BMR due to thyroid stimulating IgG
Hypothyroidism: LOW T3/T4, HIGH TSH - low BMR due to autoimmune
Goiters: enlarged thyroid, either diffuse or nodular, can be cancerous
Parathyroid Glands
- location
- hormone
- structure
- two broad disease classes
- effects of hormone
4 glands imbedded/behind thyroid gland
Chief Cells: produce PTH (+ Oxyphil cells: unknown fx)
PTH: stimulated by low serum Ca
effect of PTH: stim oclasts to resorb Ca from bone, decrease Ca excretion by kidney, activate vitamin D from kidney
Vit D: activated by PTH to 1,25 diOH vit D: increases gut Ca absorption, increases Ca bone resorption, decreases PTH secretion (negative feedback)
Hyperparathyroidism: excess PTH from adenoma/hyperplasia = hyperCa
Hypoparathyroidism: hypoCa due to removal of parathyroid, congenital, autoimmune cause
Pancreatic Islet Cells of Langerhans
- 3 cell types, their hormones, their fx
- 1 key disease, subtypes, pathogenesis for each
- other disease instance opposite of disease
Alpha cells: glucagon, increase BG, in periphery of islet
Beta cells: insulin, decrease BG, central of islet
Delta cells: SS, inhibit glucagon and insulin
Diabetes Mellitus
T1: Immune dysregulation + enviro triggers = beta cell injury = auto-antibodies = loss of ins response = glu intolerance = loss of C-peptide [B-cell destruction w/ lack of insulin]
T2: insulin receptors become resistant = impaired ins secretion w/ genes/lifestyle interaction b-cells cannot compensate [insulin resistance w/ insulin deficiency]
Hypoglycemia: due to high ins + nutrient intake during DM tx, or rare pancreas tumor (insulinoma), or reactive hypoglycemia due to timing problems of ins release and food absorption early in T2DM
