Physiology Flashcards
Organification
Occurs in the follicular lumen
Iodine + Thyroglobulin
Cleavage products of Proinsulin
C-peptide and Insulin
Anabolic effects on insulin
↑glucose in skeletal and adipose, ↑glycogen syn and storage, ↑TG synthesis, ↑Na retention (kidney), ↑protein syn, ↑K &amino acid uptake
Insulin-dependent glucose transporter
GLUT4 for skeletal tissue and adipose tissue
GLUT1
RBC, Brain, cornea
GLUT2
bidirectional: beta islet cells, liver, kidney, small intestine
GLUT5
fructose; spermatocytes and GI tract
beta-2 agonist
↑ insulin
Glucose enters Beta-cells
↑ ATP, closes K-channels, depolarizes membrane, open VGC-Ca gates, insulin is exocytosed
Secreted in response to hypoglycemia
Glucagon
Catabolic effects of Glucagon
increase glycogenolysis, gluconeogenesis, lipolysis and ketone production
Function of CRH
↑ACTH, MSH, beta-endorphin
Dopamine
tonically inhibits prolactin
Tonic GnRH
suppresses HPA axis
Pulsatile GnRH
puberty and fertility
Somatostatin analogs
tx acromegaly by decreasing GH
TRH
↑TSH and Prolactin
Milk Production
Prolactin
inhibits ovulation in females and spermatogenesis in males by inhibiting GnRH synthesis and release
Prolactin
Increases Dopamine Synthesis
Prolactin
Bromocriptine
Dopamine agonist, inhibits prolactin, used to tx prolactinoma
Stimulates linear growth and muscle mass trhrough IGF-1/somatomedin secretion
Growth Hormone (somatotropin)
increases insulin resistance
Growth Hormone (somatotropin)
Secretion ↑ during exercise and sleep
Growth Hormone
Secretion inhibited by glucose and somatostatin
Growth Hormone, and glucagon
Acromegaly
↑GH in adults
Gigantism
↑GH in children
Supraoptic Nuclei
In hypothalamus, makes ADH
V2-receptors
ADH receptors in kidneys
V1-receptors
ADH receptors in blood vessels
ADH fx
decrease serum osmolarity via increasing aquaporin transcription in principal cells
ADH levels in Central Diabetes insipidus
decrease ADH
ADH levels in Nephrogenic Diabetes insipidus
increased ADH
ADH levels in polydipsia
increased ADH
Tx for Central Diabetes Insipidus
Desmopressin
Inhibits Cholesterol desmolase
Ketoconazole
Activates Cholesterol Desmolase
ACTH
Enzyme making pregnenolone to 17-hydroxypregnenolone
17alpha-hydroxylase
Enzyme making Progesterone to 17-hydroxyprogesterone
17alpha-hydroxylase
Enzyme making progesterone into 11-deoxycorticosterone
21-hydroxylase
enzyme that makes dihydrotestosterone
5alpha-reductase
Increased mineralocorticoids, decreased cortisol and sex hormones, Hypertension, Hypokalemia, decreased DHT
17alpha-hydroxylase deficiency
pseudo-hermaphroditism (ambiguous genitalia, undescended testes)
XY, 17alpha-hydroylase deficiency
Lack Secondary sexual development
XX, 17alpha-hydroylase deficiency
Salt Wasting in Infants
21-hydroxylase deficiency
Precocious puberty in childhood
21-hydroxylase deficiency
Hypotension, Hyperkalemia, increased renin, virilization in women
21-hydroxylase deficiency
Decreases aldosterone, increased 11-deoxycorticosterone, HTN, low renin
11beta-hydroxylase deficiency
Upregulates alpha-1 receptors on arterioles increasing sensitivity to NE and epinephrine
Cortisol
Increases gluconeogenesis, lipolysis, and proteolysis
Cortisol
decreases fibroblasts causing striae
Cortisol
Chronic stress induces prolonged secretion
Cortisol
Come from chief cells from parathyroid
PTH
Stimulates 1alpha-hydroxylase
PTH
Increases production of macrophage colony-stimulating factor and RANK-L to increase osteoclast stimulation and increase calcium
PTH
Decreases reabsorption of Phosphate in prox convoluted tubule and increase calcium absorption in distal convoluted tubule
PTH
PTH-related peptide
functions like PTH and is commonly increased in malignancies, (paraneoplastic syndrome)
low serum calcium
causes PTH secretion
low serum Mg
cause PTH secretion
Causes of decreased Magnesium
diarrhea, aminoglycosides, diuretics, and alcohol abuse
Plasma Calcium
45% ionized
40% bound to albumin (increases with increased pH)
15% bound to anions
Cramps, pain, paresthesia, carpopedal spasm
Hypocalcemia (can be due to increased pH so more Ca is albumin bound)
Fx of Vit D (cholecalciferol)
increase absorption on phosphate and calcium
Secreted from Parafollicular cells (C cells) of thyroid
Calcitonin
Decreases Serum Calcium
Calcitonin
Endocrine Hormones using cAMP
FSH, LH, ACTH, TSH, CRH, hCG, ADH (V2), MSH, PTH, calcitonin, CHRH, glucagon
FLATChAMP
Endocrine Hormones using cGMP
ANP, NO (EDRF) - think vasodilators
Endocrine Hormones using IP3
GnRH, Oxytocin, ADH (V1), TRH, Histamine, AngII, Gastrin
GOAT HAG
Endocrine hormones using Steroid receptor
Vitamin D, Estrogen, Testosterone, T3/T4, Cortisol, Aldosterone, Progesterone
Endocrine Hormones using Intrinsic Tyrosine Kinase
Insulin, IGF-1, FGF, PDGF, EGF
MAP Kinase
(think growth factors)
Endocrine Hormones using receptor-associated tyrosine kinase
Prolactin, Immunomodulators (IL2, 6, 8, IFN) and GH
JAK/STAT pathway
Increase in sex-hormone binding globulin in men
Lowers free testosterone causing gynecomastia
Decrease in sex-hormone binding globulin in women
raises free testosterone causing hirsutism
Functions of T3
Brain maturation, Bone growth, beta-adrenergic effects, increase BMR (4Bs)
glycogenolysis, gluconeogenesis, lipolysis
Wolff-Chairkoff Effect
Excess iodine temporarily inhibits thyroid peroxidase thus decreasing iodine organification
5’-deiodinase
T4 into T3 in peripheral tissue
Peroxidase
used in oxidation, organification of iodide as well as coupling MIT and DIT
Propylthiouracil
inhibits both peroxidase and 5’deiodinase
Methimazole
inhibits peroxidase only
Do 25
JUMPING JACKS