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Diabetes, Metabolism, and Hormones
Biochem, Pathology, Phsyiology, and Beyond...anything your med school ever wanted you to know about the above topics and didn't want to anyways...
79
Medical
Professional
09/11/2010

Additional Medical Flashcards

 


 

Cards

Term
What is the relationship between bile acids and lipid digestion?
Definition

Bile acids are the major transporters of fat products in the intestine.  They

 

  • form mixed micelles with the fat products 
    • phospholipids, lysolecithin, FFAs, cholesterol, 2-MG, Vit A/D/E/K
  • in order to solubilize them
  • in order to transport them to intestinal cells for absorption

 

Term
What is the role of CCK in digestion?
Definition

CCK is stimulated by 

  • Release of chyme and FFAs into duodenal lumen (fat digestion)
  • Release of AAs into duodenal lumen (protein digestion)

CCK once secreted by the intestine goes to 2 locations

 

  • Intestinal lumen
  • Blood→pancreas, gallbladder

 

In the PANCREAS, CCK stimulates release of fat-digesting hormones, protein-digesting hormones and bicarb:

  • Trypsinogen
  • Procolipase
  • Lipase
  • Esterase
  • Pro-PLA2
  • Chymotrypsinogen (protein-digesting)
  • Proelastase (protein-digesting)
  • Procarboxypeptidase (protein-digesting)
  • HCO3- (neutralizes acid so enzymes can work)

 

In the INTESTINE, CCK stimulates secretion of 

 

  • Enteropeptidase
    • Trypsinogen→Trypsin (causes activation of pancreatic zymogens in intestine)

 

 

Term
Vitamin A--Name the 3 types of retinol-binding proteins, and include their locations and the Vitamin A metabolites they bind.
Definition

  1. RBP = retinol (blood transport)
  2. CRBP = retinol (cytoplasm)
  3. CRABP = retinoic acid (produced in epithelial cells)

Term
Name 4 Vitamin A metabolites and their functions.
Definition
  1. Retinal = vision
  2. Retinol = gonads
  3. Retinol palmitate = storage form in liver
  4. Retinoic acid = embryonic development, epithelial cell growth/differentiation

 

Term
Light perception in the eye is based on ____ neurotransmitter release.  Name the neurotransmitter and G protein type.
Definition

Decreased

Glutamate

Gt

Term
The ultimate function of rhodopsin is to (open/close) Na+/Ca++ channels to (hyperpolarize/depolarize) the cell membrane to (increase/decrease) glutamate release--this release is interpreted as light perception.
Definition

Close

Hyperpolarize

Decrease

Term
Name the 2 enzymes/proteins involved in inactivating metarhodopsin 2.   
Definition

Rhodopsin kinase (for cessation)

Arrestin (for complete inactivation ~ prevents dephoshoprylation)

Term
Name the pigment occurring in the rod cells of the retina that accept photons of light to mediate vision.  Name the active form.
Definition

Rhodopsin

Metarhodopsin II

Term
Name 3 major effects of Vitamin A deficiency.
Definition

Embryo (neural crest = craniofacial, cardiac, CNS/PNS)

Eye (night vision, keratinization of lens)

Infection (keratinization of skin/GI/GU/lungs→ cracking→ infection)

Term
What is the difference between endocrine and exocrine glands?
Definition

Endocrine = ductless glands

Exocrine = glands that secrete into ducts

Term
Name 2 mechanisms by which hormones exert their effects in cells.
Definition

1) Intracellular = go into cell and exert effects on genes

2) Extracellular = exert effects via 2nd messenger systems

Term
Name 2 ways the hypothalamus influences the pituitary gland.
Definition

1) Neural = hypothalamohypophyseal tract

2) Humoral = hypophyseal portal system.  Neuronal axons terminate in the median eminence, a site lacking the BBB, so hormones leak into here, which carries hormones via the portal plexus system to the anterior pituitary.

Term
Name the 2 parts of the pituitary gland, their constituent parts, and their unique embryologic origins.
Definition

  • Adenohypophysis (oral ectoderm invagination = Rathke's pouch)
    • Pars distalis (big pouch)
    • Pars intermedia (intermediate)
    • Pars tuberalis (stalk)
  • Neurohypophysis (neuroectoderm)
    • Pars nervosa
    • Pars infundibulum
NOTE:  The 2 major components mentioned in most areas are the pars nervosa and pars distalis.

Term
Name the cell types in the Neurohypophysis (2), Adenohypophysis (5), Pineal gland (2)
Definition

Neurohypophysis

  • Neurons (axons)
  • Pituicytes (neuroglia)
Adenohypophysis
  • Somatotrophs (GH, STH, somatotropin)
  • Mammotrophs (Prolactin)
  • Gonadotrophs (LH, FSH)
  • Thyrotrophs (TSH)
  • Corticotrophs (ACTH)
Pineal Gland
  • Pinealocytes
  • Interstitial cells (astrocyte-like)

 

Term
Name the hormones released by the neurohypophysis, adenohypophysis and their target tissues.
Definition

Neurohypophysis =

  • ADH = kidney
  • OT = uterus, breast

Adenohypophysis = 

  • GH, Somatotropin, STH = bone growth
  • Prolactin = mammary glands
  • LH = ovaries, testicular IC cells
  • FSH = follicles, spermatogenesis
  • TSH = thyroid
  • ACTH = adrenal cortex

Term
Does the anterior pituitary have its own blood supply?
Definition
No, all of the blood it gets first passes through the hypothalamus.  This can result in ischemic damage with sudden losses of pressure = postpartum pituitary necrosis
Term
Anything special about the pars intermedia?
Definition
Yup.  It's rudimentary in adults, but it also seems to secrete MSH (melanocyte-stimulating hormone).
Term
Name the hormones secreted by the pineal gland.
Definition

Melatonin

Serotonin

Term
What does the visual system have to do with the pineal gland?  Describe both the anatomic and visual effects.
Definition

Anatomic = the pineal gland's neural input is from the superior cervical ganglion (visual system).  

Physiologic = visual input INHIBITS melatonin release.  Thus, greater amounts of melatonin are released at night.  

Term
Visual input (inhibits/stimulates) melatonin release.
Definition
Inhibits.
Term
Describe the neurologic pathway by which vision affects melatonin release in the pineal gland.
Definition
Retina→Suprachiasmatic nucleus→SNS neurons (SC)→Superior cervical ganglion→Pineal gland
Term
Name the hormones secreted by the thyroid and parathyroid gland.
Definition

Thyroid

  • T3, T4
  • Calcitonin

Parathyroid

  • PTH

Term
Describe thyroid histo.
Definition
A bag of thyroid follicles full of colloid, which is actually thyroglobulin.  The follicles are lined by round cells.  Pretty little bracelets  :P
Term
What do the thyroid colloid follicles contain?
Definition
They contain thyroglobulin, the stored form of thyroid hormone.  Thyroid follicles are pretty unique in that the thyroglobulin in the colloid is the stored, inactive form.  Upon TSH binding to the thyroid, this colloid is endocytosed into follicular cells around the follicles.  The thyroglobulin is then activated.  
Term
What bone cell types are affected by the thyroid gland and parathyroid glands?
Definition

Thyroid = Osteoclast (inhibition), via Calcitonin

Parathyroid = Osteoclast (stimulation), via PTH

Term
Name the classic triad of Grave's disease.
Definition

 

  • Goiter
  • Exophthalmos
  • Dermatopathy
    • Pre-tibial myxedema = scaly skin on shins

 

Term
Which is the most potent form of thyroid hormone, T3 or T4?
Definition
T3.  Its effects are faster and more powerful.
Term
Explain the function of rT3.
Definition
rT3 is the inactive form of thyroid hormone, so in a fasting state (when you you don't want to increase metabolism), it serves as an outlet for storing excess hormone until it's needed.  
Term
What is the effect of excess blood iodide on the amount of iodide intake into the cell?  What is the name of this effect?
Definition

Wolff-Chaikoff effect--Iodide trapping is inhibited when blood iodide is high.  

 

Reason: protects against short-term fluctuations in in thyroid function due to dietary iodine intake.


Term
What is organification of iodine?
Definition
Organification describes the binding of iodide to organic compounds and synthesis into thyroxine, after it has entered the follicular lumen, via the follicular cell.  
Term
Name 2 enzymes in the thyroid hormone production pathway that could be affected by inherited enyzme defects, causing hypothyroidism.
Definition

  1. Peroxidase
  2. Thyroid-specific deiodinase

Term
If there is a circadian rhythm of TRH and TSH release, why don't T3/T4 levels also reflect these rhythms?
Definition

Thyroid hormones are the most sluggish of the hormones; plus the circadian rhythms only affect the hypothalamo-pituitary axis--so, T3/T4 levels tend to dampen the diurnal rhythm obvious in TSH levels.

 

 

Term
Name the 3 thyroid transport proteins and their relative affinities/capacities.
Definition

 

  1. TBG = 70%; hi-affinity, low-capacity
  2. Albumin = 20%; low-affinity, high-capacity
  3. TBPA/Transthyretin = 10%; intermediate

 

Term
How does the body deal with an increase in the amount of thyroid-binding proteins, and why is this significant?
Definition

It's significant because only the unbound form of thyroid hormone is available for affecting cells.

 

The body deals with an increase in the amount of thyroid binding proteins (eg, in pregnancy!!!) by:

  1. Decreasing excretion rate 
  2. Increasing production rate

Term
The primary determinant of the overall metabolic rate of the body is ____
Definition
Thyroid hormone!  :)
Term
Explain the effect of thyroid hormone on protein metabolism in the body.
Definition

NET protein use→muscle wasting, wt. loss, weakness

  • Med concentrations = increased synthesis
  • Hi concentrations = increased breakdown

Term
Explain the effects of thyroid hormone on lipid metabolism in the body.
Definition

NET lipolysis

  • (TG, CE synthesis also increased)

Term
Explain the effect of thyroid hormone on carbohydrate metabolism in the body.
Definition

CATABOLIC = glycogenolysis, gluconeogenesis, glucose oxidation.

 

On GLUCOSE:

 

  • Increased GI absorption
  • Increased peripheral uptake (by insulin)
On GLYCOGEN:
  • Increased glycogenesis (small amounts)
  • Increased glycogenolysis (large amounts)

 

Term
Name the effects of thyroid hormone on 3 organs.
Definition

 

  1. Heart = increased BP/HR, etc.
    • Upregulates Beta-1 receptors (not amount of catecholamines!!)
  2. CNS = development
    • Path = cretinism = severe irreversible mental retardation
  3. Skeleton = maturation

 

Term
Name 1 full-body effect of thyroid hormones
Definition

 

  1. Calorigenic effect = energy metabolism, heat production 
    • via increased Na/K ATPase

 

Term
What does a starvation state do to levels of thyroid hormone?
Definition
DECREASES it!!!  Decrease BMR in low-energy states!
Term
Name some enzymes/proteins intracellular thyroid hormone causes coding for.
Definition

Oxidative enzymes (G3PDH)
Mitochondrial UCP

Na/K ATPase

Growth hormone

Beta-1 receptors

Term
List the main components of bone.  
Definition

Mineral

Collagen

Cells

Term
List the main bone manifestations of osteoporosis, osteomalacia, rickets, and von Recklinghausen's syndrome (in terms of their effects on bone).
Definition

Osteoporosis = decreased overall bone mass (collagen, mineral, cells)

Osteomalacia/Rickets = decreased bone mineral

von Recklinghausen's = hyperparathyroidism-induced decreased bone mineral with increased cysts (decalcification, cystic brown tumor lesions with fibrosis)

 

Term
List the main causes of osteoporosis, osteomalacia, rickets, and von Recklinghausen's.
Definition

Osteoporosis = decreased estrogen→increased OCs, decreased OBs

 

Osteomalacia = decreased Vitamin D (adults)→hypocalcemia→increased PTH→increased OCs

 

Rickets = decreased Vitamin D (children)→hypocalcemia→increased PTH→increased OCs

 

von Recklinghausen's = increased PTH→increased OCs

Term
What is the main similarity and difference between osteomalacia and rickets?
Definition

Similiarity = both caused by Vitamin D deficiency

 

Difference = 

  • Osteomalacia = ↓ Vitamin D in mature bone (adults)
  • Rickets = ↓ Vitamin D in growing bone (kids)

Term
List the main causes of osteomalacia.
Definition

Osteomalacia = vitamin D absorption/metabolism problems, so:

  • chronic renal failure
  • Malabsorption 

Term
List the main causes of rickets.
Definition

 

  • Decreased intake = due to decreased nutrition/sunlight (nutritional rickets)
  • Decreased production = 1-OHase defect (Type 1 HVDRR)
  • Decreased cell uptake = Vitamin D receptor defect (Type 2 HVDRR)
    • DNA-binding domain
    • Hormone binding domain

 

Term
Can patients with Hereditary Hypocalcemic Vitamin D-Resistant Rickets (HVDRR) be treated with physiologic replacement of 1,25 (OH)2D3?
Definition

Type 1 HVDRR = Yes

Type 2 HVDRR = 

 

  • DNA-binding domain = NO
  • Hormone-binding domain = Yes

 

Term
Distinguish the lab difference between HVDRR Types 1 and 2. 
Definition

HVDRR 1 = high 25(OH)D3, low 1,25(OH)2D3

HVDRR 2 = high 1,25(OH)2D3 

Term
What is the difference between senile and post-menopausal osteoporosis?
Definition

  • Senile = old people.  Due to aging (decreased OBs).
  • Post-menopausal = women.  Due to decreased estrogen (increased OC activity, decreased OB activity)

Term
Describe histology of osteoporosis.
Definition
Decreased thickness of cortical and trabecular bone.  
Term
Name the anatomic sites that are most prone to damage in osteoporosis.  
Definition

  1. Hip
  2. Radius
  3. Vertebrae

Term
Diagram the roles of estrogen, cytokines, and signaling pathways (RANKL/OPG) in osteoporosis. 
Definition
See "Bone Remodeling," Dr St John's "Normal Cartilage and Bone" Lecture from MSS block.  (or my own picture of it...)
Term
Describe the pathology of osteomalacia.  
Definition

Normal =  (note normal thickness of osteoid)

http://content.edgar-online.com/edgar_conv_img/2005/12/21/0000950134-05-023569_A15650A1565002.GIF

 

Osteomalacia = widened osteoid seams

 http://www.scielo.br/img/revistas/abem/v54n2/02f2.jpg

 


Term
Name the causes of hypercalcemia.
Definition

C = Carcinoma

H = HHM

I = Intoxication of Vitamin D, immobilization

M = Milk-alkali syndrome, 

P = Paget's disease

S = Sarcoidosis

Term
Name the causes of hypocalcemia.
Definition

  • PTH = 
    • Low supply = hypoparathyroidism
    • End-organ resistance = pseudohypoparathyroidism
  • Vitamin D
    • Low supply = rickets, Type 1 HVDRR
    • End-organ resistance = Type 2 HVDRR

Term
Name the 3 types of hyperparathyroidism by cause.
Definition

  • Primary = increased tissue
    • Adenoma, Hyperplasia, Carcinoma
  • Secondary = ↓ Ca→↑ PTH
    • Renal disease, Malabsorption
  • Tertiary = long-standing ↓ Ca→↑ PTH→ autologous PTH secretion
    • Chronic renal disease

Term
Describe the genetics of primary hyperparathyroidism.
Definition
  • 95% of primary hyperparathyroidism is sporadic
  • 5% of primary hyperparathyroidism is familial = MEN-1, MEN-2, FHH
    • MEN-1 = most.  loss of MEN-1 gene from chromosome 11q13
    • MEN-2 = activating mutation of RET proto-oncogene (TYK receptor) on chromosome 10q.
  • Adenomas
    • PRAD1 gene defect coding for cyclin D1 (tumor suppressor)

 

Term
Describe FHH (causes, S/S).
Definition

Cause = resistance to Calcium receptor (CaR)

S/S = hypercalcemia, hypOcalciuria!

  • Hypocalciuria because calcium reabsorption in the kidneys is not feedback-inhibited.

Term
Describe HHM (cause, effect)
Definition

  • Cause = PTHrP binds to PTH receptors on bone and acts just like PTH, but is NOT feedback-inhibited.  
  • Effect = hypercalcemia

Term
Name the 3 histopathologic lesions causing primary hyperparathyroidism and their characteristics.
Definition

 

  • Adenoma = solitary (usually).  Thin wispy capsule.  No fat.  Lower glands especially!!!
    • MUST bx all glands to distinguish between adenoma vs. hyperplasia.
  • Hyperplasia = all glands (usually).  chief cell hyperplasia. 
  • Carcinoma = vascular invasion + capsule invasion!

 

Term
What is the most common cause of hypoparathyroidism?  
Definition
Surgical ablation (radical neck dissxn, thyroid surgeries)
Term
Describe pseudohypoparathyroidism and associated labs.  Does PTH injection change labs?
Definition

 

  • PTH G protein mutation→end-organ resistance
  • Labs = hypocalcemia, hyperphosphatemia.
  • (PTH injection→no change in these labs or in urinary cAMP) 

 

Term
Predict Calcium and PTH levels for: Primary hyperparathyroidism, Malignancy & hypercalcemia, Hypoparathyroidism, Chronic renal failure
Definition

  • Primary hyperparathyroidism
    • High PTH
    • High Ca
  • Malignancy & hypercalcemia
    • Low PTH
    • High Ca
  • Hypoparathyroidism
    • Low PTH
    • Low Ca
  • Chronic renal failure
    • High PTH
    • Normal Ca

Term
Describe the S&S of primary hyperparathyroidism.
Definition

Stones & bones...

  • Bone disease = mild decalcification - osteoporosis
  • Renal stones
  • GI abnormalities = ulcers, pancreatitis, gallstones
  • Metastatic calcifications = leads to CRF if in kidney 
    • In gastric mucosa, kidney, lungs, systemic arteries, pulm veins
  • von Recklinghausen disease of bone = late-stage hyperparathyroidism.  General bone decalcification + osteitis fibrosa cystica + multiple fx + renal stones
    • Osteitis fibrosa cystica = fibrosis + cysts (X-ray) + brown tumors (hemorrhage) + lots multi-nucleated OCs

Term
Describe the pathology of secondary hyperparathyroidism.
Definition
Secondary = Hyperplasia!
Term
Name the uses of B6 (pyridoxine)
Definition

 

  • Catecholamine synthesis (L-dopa→Dopamine)
  • Transaminase reactions

 

Term
Explain the effects of Epi/NE on carbohydrate metabolism (include adrenergic receptors).
Definition

  • alpha-1 receptor = increased liver glycogenolysis
  • beta-2 = more comprehensive:
    • increased liver/muscle glycogenolysis
    • increased gluconeogenesis
    • decreased glycogenesis

Term
Explain the effects of NE/Epi on fat metabolism.
Definition

  • alpha-2 receptor = decreased lipolysis
  • beta-2 receptor = increased lipolysis

Term
Explain the effect of NE/Epi on hormone secretion.  
Definition

  • Alpha-2 receptor = decreased insulin, glucagon
  • Beta-2 receptor = increased insulin, glucagon

Term
What is the biggest difference between beta-2 receptors and the other adrenergic receptors?
Definition

 

  • Beta-2 receptors are activated by Epi only.
  • Beta-2 receptors are NOT innervated by sympathetic nerves.
  • Beta-2 receptors are located on bronchial smooth muscle and skeletal muscle.  
  • Thus, Epi can cause vasodilation in certain tissues while NE/Epi cause vasoconstriction in other vessels.

 

Term
Where are Beta-3 receptors and what do they do?  What stimulates them?
Definition
Beta-3 receptors are on adipose cells.  Stimulation causes lipolysis.  Only NE can stimulate adipose cells.
Term
Is the affinity of Epi for beta-2 the same as it is for alpha-2, and does this have any implications for BP regulation?
Definition

Epi has higher affinity for beta-2 receptors>alpha-2 receptors.

 

At low doses, Epi decreases blood pressure.  

At high doses, Epi increases blood pressure.

Term
Name 2 diagnostic tests for pheochromocytoma.
Definition

Urinary catecholamines, metanephrine.

Plasma metanephrine.

Term
Name the alpha/beta agonists/blockers.
Definition

Alpha-1 agonist = phenylephrine

Alpha-1 antagonist = phenoxybenzamine (pheochromocytoma Tx)

Beta-1 agonist = dobutamine

Beta-2 agonist = albuterol

Beta antagonists = olol's 

Term
Name the locations of GLUT-2 (organ, side of cell).
Definition

Facilitated diffusion in:

 

  1. Small intestine (blood side)
  2. Pancreas (blood side)
  3. Liver (blood side)

Term
Name the transporters that transport glucose in the intestinal cell (include type of transporter, molecule transported, and side of cell).
Definition

Lumen side:

  1. SGLT-2 (sodium-glucose transporter) = active transport/Na+ cotransporter
  2. GLUT-5 
Blood side;
  1. GLUT-2 (facilitated diffusion)

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