Step 1 Subjects > Endocrine > Flashcards

Endocrine Flashcards

(69 cards)

Study These Flashcards
1
Q

Congenital hypothyroidism

A

Decreased T4 levels

  • Endemic Cretinism= insufficient iodine in utero
  • Sporadic= defect in T4 formation in utero, developmental thyroid formation failure

Symptoms:
- Lethargy, poor feeding
- Jaundice, macroglossia
- Constipation, umbilical hernia, myxedema
- Muscle hypotonia, hoarse cry
- ASD, VSD
Pot bellied, Pale, Puffy-faced child with Protruding umbilicus, protuberant tongue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Somatomedin C

A

AKA IGF-1= insulin-like growth factor 1

  • GH Secreted by pituitary–> liver produces IGF-1
  • induces chondrocytes to proliferate along epiphyseal plate (long bone growth!)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Fetal adrenal gland

A

Outer zone= adult zone

  • No function until late in gestation: begins secreting cortisol
  • Controlled by ACTH and CRH from fetal pituitary and placenta
  • Cortisol–> fetal lung maturation and surfactant secretion

Inner zone= Active fetal zone

  • Produces androgens with placenta
  • Lacks 3-beta-hydroxysteroid to convert pregnolone–> progesterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Anterior pituitary

A

Secretes FSH, LH, ACTH, TSH, prolactin, GH, MSH

  • Derived from oral ectoderm (Rathke’s pouch–> craniopharyngioma) vs posterior pituitary= neuroectoderm
  • Alpha subunit= TSH, LH, FSH, hCG common subunit
  • Beta subunit= hormone-specific
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

GLUT-1 receptors

A

Insulin INDEPENDENT

- RBCs, Brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

GLUT-2 receptors

A

Bidirectional

  • Beta-islet cells
  • Liver, kidney, small intestine (insulin-independent uptake)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

GLUT-4 receptors

A

Insulin DEPENDENT

  • Adipose tissue
  • Skeletal muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Insulin release

A

Beta cells in pancreas: center of islet

  1. GLUT-2 transporter brings in glucose
  2. Glycolysis in Beta cell–> ATP/ADP ratio increase
  3. ATP binds and closes K+ channels
  4. Membrane depolarizes
  5. Ca+2 influx into beta cell
  6. Exocytosis of insulin granules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Glucagon release

A

Alpha-cells in pancreas: periphery of islet

Secreted in response to:

  • Hypoglycemia
  • Increased serum [amino acids]
  • Adrenergic stimulation (epi–> alpha2 receptors)
  • CCK
  • Ach

Inhibited by:

  • Insulin
  • Hyperglycemia
  • Somatostatin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

17-alpha-hydroxylase deficiency

A

Hypertension, hypokalemia

Males: decreased DHT–> pseudohermaphroditism (ambiguous genitalia, undescended testes

Females: internally and externally phenotypic female lacking secondary sex characteristics

**Enlarged adrenal glands d/t increased ACTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

21-hydroxylase deficiency

A

HYPOtension, hyperkalemia, increased renin activity, volume depletion

Females: masculinization; pseudohermaphroditism

**Enlarged adrenal glands d/t increased ACTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

11-beta-hydroxylase deficiency

A

HYPERtension:

  • increased 11-deoxycorticosterone= mineralocorticoid, secreted in excess (HTN)
  • Decreased aldosterone

Females: Masculinization

**Enlarged adrenal glands d/t increased ACTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Growth Hormone

A

Anterior pituitary

Stimulates linear growth:
- increases liver IGF-1/somatomedin C secretion–> - induces chondrocytes to proliferate along epiphyseal plate (long bone growth)

Increased secretion in exercise, sleep
- Inhibited by glucose, somatostatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Cortisol

A

Adrenal zona fasciculata, bound to corticosteroid-binding globulin (CBG)

  • Maintains BP (upregulates alpha1 receptors on arterioles–> increased sensitivity to NE, epi
  • Decreases bone formation
  • Anti-inflammatory/immune suppressive (blocks IL-2, etc)
  • Increased insulin resistance
  • Increased gluconeogenesis, lipolysis, proteolysis
  • Inhibits fibroblasts–> striae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

PTH

A

Secreted by chief cells in parathyroid

Regulated by:

  • depleted Ca+2–> increased PTH
  • Decreased Mg+2–> increased PTH
  • Absent Mg+2–> decreased PTH (needs Mg+2 for manufacuring in chief cells); can be caused by diarrhea, aminoglycosides, diuretics, alcohol abuse

MOA:

  • Stimulates cAMP–> increased osteoblastic RANK-L + M-CSF expression–> increased osteoclast activity
  • Decreases osteoprotegerin release (OPG= inhibitor at RANK-L)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

cAMP signaling hormones (Gs/Gi)

A 
Releasing hormones:
FSH
LH--> leydig (testosterone)/ Corpus luteum (progesterone)
SCT
TSH
CRH
hCG
ADH (V2 receptor)
MSH
PTH
Calcitonin
GHRH
Glucagon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

cGMP signaling hormones

A

Vasodilators:

ANP
NO (endothelial derived relaxing factor)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

IP3 signaling hormones (Gq)

A 
GnRH
GHRH
Oxytocin
ADH
TRH
Histamine (H1)
Angiotensin II
Gastrin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Steroid receptor

A 
Vitamin D
Estrogen
Testosterone
T3/T4
Cortisol
Aldosterone
Progesterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Intrinsic tyrosine kinase

A

Growth factors:

Insulin
IGF-1
FGF
PDGF
EGF
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Receptor-associated tyrosine kinase (JAK/STAT)

A

Prolactin
Immunomodulators (cytokines, IL-2,6,8, IFN)
GH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Sex hormone binding globulin (SHBG)

A

Binds sex hormones:

Men: increased SHBG–> decreased free T–> gynecomastia

Women: decreased SHBG–> increased free T–> hirsutism
- SHBG increased in pregnancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Thyroid hormone function

A
  1. bone growth (synergism with GH)
  2. CNS maturation
  3. increases B1 receptors in heart
  4. increases BMR (basal metabolic rate)
  5. increases glycogenolysis, gluconeogenesis, lipolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Thyroid hormone production

A
  1. Iodine (I-) uptaken from blood by follicular cell
  2. TPO (Thyroid Peroxidase) oxidizes I- –> I2
  3. Follicular cell secretes I2, thyroglobulin into lumen (colloid)–> MIT/DIT
  4. Peroxidase (TPO) in lumen couples MIT/DIT–> T3/T4
  5. T3/T4 re-imported into follicular cell–> proteolysis–> released into blood (bound to TBG= thyroid binding globulin)
    - TBG increased by estrogen, decreased by liver failure
    - T4= major product; converted by 5’-deiodinase in periphery to active T3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Wolff-Chaikoff effect
Excess iodine temporarily inhibits TPO (thyroid peroxidase) --> decreased iodine organification --> Decreased T3/T4 production
26
Propylthiouracil
PTU MOA: - blocks TPO formation of T3/T4 - Blocks 5'deiodinase conversion of T4--> T3 Tox: skin rash, agranulocytosis, aplastic anemia, hepatotoxicity
27
Methimazole
MMI MOA; blocks TPO formation of T3/T4 Tox: skin rash, agranulocytosis, aplastic anemia, teratogen?
28
Dexamethasone suppression test
Normal function: cortisol suppressed by low dexamethasone ACTH-pituitary tumor (Cushing's): suppressed by high dexamethasone - Also can take venous sample of petrosal sinus - 24 hour urine collection: free cortisol 3x upper limit of normal Ectopic ACTH-producing tumor (SCLC, bronchial carcinoids)/ Cortisol-producing tumor (adrenal adenoma): remains elevated with high dose dexamethasone
29
Conn's syndrome
Aldosterone-secreting adrenal adenoma - Hypertension, Hypokalemia (like 17-alpha-hydroxylase deficiency) - Metabolic alkalosis - low plasma renin Symptoms: - HTN - Weakness, paresthesias (hypoklemia) Bilateral or unilateral Treatment: - Surgery to remove tumor - Spironolactone (aldosterone antagonist)
30
Secondary hyperaldosteronism
Low perfusion in kidney (d/t renal artery stenosis, chronic renal failure, CHF, cirrhosis, nephrotic syndrome) --> increased renin production Treatment: - Spironolactone
31
Addison's disease
Chronic primary adrenal insufficiency - Adrenal atrophy/destruction of adrenals (autoimmune- increased risk with T1DM, TB, metastasis) Deficiency of aldosterone, cortisol - Hypotension (hyponatremic volume contraction) - Hyperkalemia - Acidosis - Skin hyperpigmentation (MSH: increased ACTH--> MSH increase from POMC) Treatment: Corticosteroids
32
Secondary adrenal insufficiency
Decreased pituitary ACTH - No skin hyperpigmentation - no hyperkalemia Tx: responds to ACTH
33
Pheochromocytoma
Tumor of adrenal medulla in ADULTS - Chromaffin cell (neural crest) Secretes epi, NE, DA--> episodic HTN Labs: - Increased urinary VMA (breakdown product of NE, epi) - Increased plasma catecholamines Associated with: - NF-1 - MEN 2A, 2B Treatment: - Alpha-antagonist (irreversible): pheoxybenzamine (avoid hypertensive crisis) - Beta blocker: slow HR - Surgical removal rule of 10s (10%): malignant, bilateral, extra-adrenal, calcify, kids
34
Neuroblastoma
MOST Common Tumor of adrenal medulla in children Presentation: - Opsoclonus-myoclonus syndrome= non-rhythmic conjugate eye movements + myoclonus - Retroperitoneal mass, anorexia, weight loss - Less likely to see HTN - elevated HVA in urine (catecholamines) Histo: - Solid sheets of small blue round cells - Can occur anywhere along sympathetic chain **Overexpression of N-myc--> rapid tumor progression (transcription factor)
35
Hashimoto's thyroiditis
anti-TPO, antithyroglobulin antibodies - HLA-DR5 - Increased risk of non-Hodgkin's lymphoma - Normal ESR - Chronic, progressive Histo: - Hurthle cells - Lymphocytic infiltrate with germinal centers - Enlarged, nontender thyroid
36
Subacute thyroiditis (de Quervain's)
Self-limited hypothyroidism after flu-like illness Histo: granulomatous inflammation - Neutrophils: lymphocytes, histiocytes, multi-nucleated giant cells (granuloma) - disrupted follicles around collioid Findings: - Increased ESR, jaw pain, early inflammation, tender thyroid - Thyrotoxic--> hypothyroid--> euthyroid Tx: NSAIDs for pain
37
Riedel's thyroiditis
Thyroid replaced by fibrous tissue (hypothyroid) Findings: - Fixed, hard (rock-like) painless goiter - May extend into surrounding tissue * * Manifestation of IgG4-related systemic disease (autoimmune pancreatitis)
38
Hypothyroid myopathy
Pale muscle fibers with: - decreased striation - deposition of mucinous material - atrophy of Type II mucle fibers Symptoms: - Weakness - Fatiguability - Muscle pain, cramping
39
Toxic multinodular goiter
Focal patches of hyperfunctioning follicular cells - Work independently of TSH (mutation in TSH receptor) - Increased release of T3, T4 Jod-Basedow phenomenon= thyrotoxicosis after repletion of iodine deficency
40
Grave's disease
Diffusely enlarged goiter secreting TSI (thyroid-stimulating immunoglobulins)--> autoimmune hyperthyroidism - Proptosis (opthalmopathy, EOM swelling) - Pretibial myxedema - Increase in connective tissue deposition Stress-induced (Childbirth)
41
Thyroid Storm
Thyrotoxicosis: - Stress-induced catecholamine surge--> death by arrhythmia - Serious complication of Grave's, hyperthyroid disorders Increased ALP d/t increased bone turnover Tx: - Glucocorticoids for exopthalmos - Beta-blockers for relief of sympathetic activation - Block iodine organification (Iodide salts, Propylthiouracil, Methimazole) - Radioactive iodine (ablate thyroid with I-131)
42
Primary hyperparathyroidism
Adenoma--> Hypercalcemia - Hypercaluria, hypophosphatemia - Increased PTH, alk phos, cAMP in urine - Weakness, constipation Osteitis fibrosa cystica= cystic bone spaces with brown fibrous tissue (bone pain)
43
Secondary hyperparathyroidism
Decreased gut Ca+2 absorption, increased phosphate - Chronic renal disease (hypovitaminosis D--> decreased Ca+2 absorption) Hypocalcemia, hyperphosphatemia in chronic renal failure (decreased phosphate in other causes) - Increased alk phos, PTH Renal osteodystrophy= bone lesions d/t secondary/tertiary hyperpara
44
Tertiary hyperparathyroidism
Refractory (autonomous) hyperparathyroidism d/t chronic renal disease VERY elevated PTH, elevated Ca+2
45
Albright's hereditary osteodystrophy
AD: kidney unresponsive to PTH - -> hypocalcemia, - shortened 4th/5th digits - short stature - Resistance to TSH, LH, FSH (all stimulate Gs alpha pathway)
46
Acromegaly
Pituitary adenoma--> excess GH - Large tongue, deep furrows - Deep voice - Large hands, feet, coarse faces - Impaired glucose tolerance Diagnosis: - Increased serum IGF-1 - fail to suppress serum GH after oral glucose tolerance test Tx: resect adenoma, somatostatin analog if not cured
47
Causes of diabetes insipidus
``` Central: lack ADH - Pituitary tumor - Trauma - Surgery - Langerhans cell Histiocytosis Treatment: intranasal Desmopressin ``` Nephrogenic= kidney doesn't respond to ADH - hereditary - secondary to hypercalcemia - Lithium - Demeclocyline (ADH antagonist) Treatment: HCTZ, indomethacin (NSAID), amiloride
48
SIADH
Causes: - Ectopic ADH (SCLC) - CNS/head trauma - Pulmonary disease - Drugs (cyclophosphamide) ``` Treatments: Fluid restriction IV saline Conivaptan Tolvaptan Demeclocycline ```
49
Maternal diabetes
Insulin must be given to control blood glucose (insulin does not cross placenta) Poor control - Hypoglycemia of newborn (beta islet cell hyperplasia due to excess glucose exposure in utero) - Caudal regression syndrome (sacral agenesis--> lower extremity paralysis, urinary incontinence) - Transposition of the great vessels
50
Glucagonoma
Pancreatic tumor (rare) Presentation: - Migratory erythema - Hyperglycemia (diabetes) - Stomatitis, chelosis - Abdominal pain
51
VIPoma
Pancreatic tumor Presentation: - Diarrhea - Metabolic acidosis - Hypokalemia
52
Somatostatinoma
Pancreatic delta cell tumor Presentation: - Abdominal pain - Gallstones - Constipation - Steatorrhea Labs: - Decreased insulin, glucagon, CCK, secretins - Decreased gastric motility
53
Carcinoid syndrome
Carcinoid tumor= neuroendocrine cells - Metastatic small bowel tumor secreting 5-HT (most common tumor of appendix) - Only seen if tumor metastasizes from bowel (5-HT digested in liver) Symptoms: - Recurrent diarrhea - Cutaneous flushing - Asthmatic wheezing - Right-sided valvular disease - Increased serotonin in urine - Niacin deficiency Treatment: Somatostatin analog (octreotide)
54
MEN 1
Werner's syndrome: Autosomal Dominant DIAMOND; 3Ps - Pituitary tumor - Parathyroid tumors - Pancreatic endocrine tumors (Zollinger-Ellison, insulinoma, VIPoma, glucagonoma) Presentation: kidney stones, stomach ulcers
55
MEN 2A
Sipple's syndrome: Autosomal Dominant SQUARE: 2 Ps - Parathyroid tumors: 3rd/4th pharyngeal pouch - Pheochromocytoma - Medullary thyroid carcinoma (calcitonin): 4th/5th pharyngeal pouch ** ret gene mutation (tyrosine kinase)
56
MEN 2B
Autosomal dominant TRIANGLE: 1 P - Oral/intestinal ganglioneuromatosis (marfanoid habitus) - Medullary thyroid carcinoma (calcitonin) - Pheochromocytoma ** ret gene mutation (tyrosine kinase)
57
Metformin
Biguanide MOA: unknown; - decreases gluconeogensis - increases glycolysis, peripheral glucos uptake Oral: 1st line in T2DM Tox: - GI upset - Lactic acidosis (contraindicated in renal failure)
58
Tolbutamide, chlorpropamide
Sulfonylureas (1st generation) MOA: close K+ channel in Beta cell membrane (like ATP)--> cell depolarizes--> Ca+2 influx--> insulin release Only for T2DM Tox: Disulfiram-like effects
59
Glyburide Glimepiride Glipizide
Sulfonylureas (2nd generation) MOA: close K+ channel in Beta cell membrane (like ATP)--> cell depolarizes--> Ca+2 influx--> insulin release Only for T2DM Tos: hypoglycemia
60
Pioglitazone, Rosglitazone
Glitazones/thiazolidinediones MOA: Binds PPAR-gamma nuclear transcription regulator--> increased insulin-responsive genes--> increased insulin sensitivity in peripheral tissue Mono or combo in T2DM Tox: - Weight gain, edema, hepatotoxic, heart failure
61
Acarbose, miglitol
Alpha-glucosidase inhibitors MOA: inhibit intestinal brush-border alpha-glucosidases--> delayed sugar hydrolysis, glucose absorption Mono or combo in T2DM Tox: GI disturbances
62
Pramlintide
Amylin analog MOA: decreases glucagon T1 and T2DM TOx: hypoglycemia, nausea, diarrhea
63
Exenatide, Liraglutide
GLP-1 analogs MOA: increased insulin, decreased glucagon release T2DM Tox: N/V, pancreatitis
64
Linagliptin Saxagliptin Sitagliptin
DPP-4 inhibitors MOA: increased insulin, decreased glucagon release T2DM Tox: urinary, respiratory infections
65
Somatostatin
Octreotide Use: acromegaly, carcinoid tumor gastrinoma, glucagonoma, esophageal varices
66
Demeclocyline
Tetracycline, ADH antagonist Use: SIADH Tox: - Nephrogenic DI - Photosensitivity - Abnormalities of bone, teeth
67
Basal insulin types
NPH (2 times/day) | Glargine, Detemir (1x/day)
68
Post-prandial insulin
Regular: peaks 2-4 hours after administration - use IV in DKA Lispro, aspart, glulisine: peak 45 minutes after administration - Use to prevent post-meal hyperglycemia
69
T2 Mature onset diabetes of the young (MODY)
Defect in Glucokinase enzyme (specific to liver, pancreatic beta-cells)- has high Km - Can also have defect in transcription factors for insulin
Step 1 Subjects
flashcards
Decks in class (26)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions