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92 Cards in this Set
- Front
- Back
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What hormones are increased during anxiety?
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* CRH
* ACTH, prolactin * Vasopressin * Cortisol, adrenalin |
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What are the calorigenic actions of thyroid hormone?
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* ↑Heat production
* ↑glucose absorption & gluconeogenesis * ↑clearance of lipoproteins & lipolysis * ↑amino acid uptake & protein synthesis (except at very high levels of T4/T3) * Vitamin deficiency if T4/T3 too high |
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What are the sympathomimetic effects of thyroid hormone?
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* Potentiate effect of catecholamines
* ↑β adrenergic receptors (cause of peripheral vasodilation and ↑ pulse pressure) |
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How are catecholamines produced?
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Tyrosine --> DOPA by tyrosine hydroxylase
DOPA --> DA, NA, Adr |
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What are the main signs & symptoms of hyperthyroidism?
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* ↓Weight, ↑appetite
* ↑Heat production * Diarrhoea * Tiredness * Anxiety, irritiability, ↑HR, tremor * Proximal myopathy * Hyperreflexia * Lighter menstruation * Lid retraction & lid lag |
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What signs may be found in Graves disease?
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* Exophthalmos
* Pretibial myxoedema * Onycholysis * Diffuse goitre with bruit (sometimes) |
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What are specific features of hypothyroidism (apart from opposites of hyperthyroid signs)?
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* Dry hair & skin, hair loss
* Puffy face & hands * Hypercaretonaemia * Pleural & pericardial effusions * Delayed reflexes |
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What is the autoimmune mechanism in:
* Graves disease? * Hashimoto's? * Primary myxoedema? |
* Graves: stimulating auto-ab to TSH receptors
* Hashimoto's: activated T cells against thyroid tissue (thyroid peroxidase, thyroglobulin) * Primary myxoedema: blocking auto ab to TSH receptors |
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Which 4 hormones oppose the action of insulin?
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* Growth hormone
* Glucagon * Cortisol * Adrenaline (Administered to achieve hypoglycaemia as part of a growth hormone stimulation test) |
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What are the main causes of hypothermia apart from exposure to cold?
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2° to acute illness with severe metabolic acidosis
- congestive cardiac failure - uraemia - drug OD - respiratory failure - hypothyroidism |
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What are the main causes of hyperthermia apart from heat exposure?
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* CNS lesions
* Idiosyncratic reactions to medications (esp. anaesthetics) |
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Which drugs can be used to block synthesis of thyroxine in thyrotoxicosis? (2)
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* Carbimazole
* Propyl-thiouracil (PTU) (Inhibit oxidation of idoine and binding to tyrosine) |
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How would subacute thyroiditis manifest on a Technetium scan and blood tests?
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* Low uptake on Tc scan
* ↑WCC * ↑CRP |
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What is the mean age of menarche in Australia?
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12.3 years
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What are the endpoints of puberty? (4)
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* Epiphyseal fusion
* Near adult bone mass * Full 2° sexual development * Menstruation with ovulation / mature spermatogenesis |
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What are the endocrine controls of puberty?
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* FSH & LH (↑frequency & size of pusles)
* Oestrogen / Testosterone * GH & IGF1 * Adrenal androgens (--> acne, seborrhoea, body odor) |
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What are the features of McCune-Albright syndrome?
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* Pseudo-precocious puberty (abnormal stimulation of FSH receptors)
* Cafe au Lait skin pigmentation * Bone lesions (polyostotic fibrous dysplasia) |
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How much growth typically occurs in puberty?
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M: 28-35 cm
F: 25 cm |
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What are the 3 parts of the anterior pituitary?
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* Pars distalis (majority of anterior pit.)
* Pars tuberalis (sheath extending up & wrapping around stalk) * Pars intermedia (b/w anterior & posterior pit.) |
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What are the types of cells in the anterior pituitary? (5)
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Eosinophils:
* Lactotropes --> prolactin * Somatotropes --> GH Basophils: * Gonadotropes --> FSH, LH * Thyrotropes --> TSH * Adrenocorticotropes --> ACTH |
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Which nuclei of the hypothalamus synthesize vasopressin & oxytocin?
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* Supraoptic nuclei
* Paraventricular nuclei |
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What is the effect of somatostatin on pituitary hormones?
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Inhibits secretion of GH and TSH
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What is the pathway for secretion of melatonin?
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* Triggered by suprachiasmatic nucleus in absence of light
--> spinal cord sympathetics --> superior cervical ganglia --> pineal gland --> release of melatonin |
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What is the circadian rhythm of cortisol?
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* Peak in early morning
* ↓before sleep onset |
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What is the function of leptin?
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* Primarily produced in adipocytes
* Signals size of fat stores * Causes ↓food intake, ↑energy expenditure |
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What controls secretion of vasopressin?
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* ↑osmotic pressure of ECF
* Volume & baroreceptors (if loss of 10-15% of BV) * Nicotine is a strong inhibitor |
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What is the embryonic origin of the adrenal gland?
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* Cortex derived from mesoderm
* Medulla dervied from neural crest |
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What are the 3 parts of the adrenal cortex and what hormone does each part secrete?
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* Zona glomerulosa (outer)--> aldosterone
* Zona fasciculata (middle, 80% of volume) --> cortisol * Zona reticulata --> androgens |
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What are the actions of cortisol? (6)
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* ↑Glucose in blood ( ↓ uptake, ↑ gluconeogensis) but also ↑ hepatic glycogen
* ↑Protein catabolism * ↑Lipolysis * ↑Vascular responsiveness to catecholamines, angiotensin, etc. * ↓Lymphocytes & eosinophils * Anti-inflammatory (stabilize lysosomal membranes, ↓capillary permeability, inhibit fibroblasts) |
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What are the main clinical signs of Cushing's syndrome? (11)
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* Obesity (central)
* Type 2 diabetes * Skin: thin, acne, acanthosis nigricans, bruising++, abdominal striae * ↑ vellus hair * Proximal muscle weakness * CV: hypertension, oedema, atheroma * ↓ inflammatory response * ↓ growth in children * HypoK * Central hypogonadism * Irritability, insomnia, depression |
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What are signs of corticosteroid deficiency?
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* Hypoglycaemia
* Weight loss * Weakness * Anorexia,nausea, vomiting * Abdominal pain * ↓BP, ↓Na+, ↑K+ |
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What type of fibres are atrophied in steroid myopathy?
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Type IIB fibres (fast twitch)
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Congenital adrenal hyperplasia is most commonly due to deficiencies in which 2 enzymes?
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* 21-hydroxylase
* 11-β-hydroxylase (--> ↓synthesis of glucocorticoids & mineralocorticoids) |
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What are the main effects of insulin? (4)
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* ↑glucose uptake & glycogen synthesis
* ↑fat uptake & triglyceride synthesis * ↑amino acid uptake & protein synthesis * ↓ketogenesis by liver |
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What stimulates the secretion of insulin and glucagon?
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Insulin: ↑glucose, ↑amino acids, food intake
Glucagon: ↓glucose, ↓fatty acids, ↑amino acids |
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What is the immune mechanism of Type 1 diabetes?
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T-cell mediated destruction of β cells
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What are common presenting symptoms of both type 1 and type 2 diabetes?
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* Thirst & polyuria
* Blurred vision * Infection (neutrophil dysfunction) * Poor wound healing (↓collagen) * Tiredness |
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What are the features of diabetic retinopathy?
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NON-PROLIFERATIVE:
* Microaneurysms * Macular oedema * Hard & soft exudates PROLIFERATIVE: * Neovascularization --> retinal detachment, neovascular glaucoma |
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What are the features of diabetic nephropathy?
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* Glomerulosclerosis + tubular damage
* Microalbuminuria / proteinuria * Hypertension |
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How does insulin prevent oxidation of fatty acids?
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* Insulin --> ↑malonyl CoA
* Malonyl CoA inhibits attachment of Fatty Acyl CoA to Carnitine * Carnitine is needed to carry the FA into the matrix for oxidation |
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How does ↓insulin cause diabetic ketoacidosis?
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* ↓insulin --> ↑free fatty acids and ↑fatty acid oxidation --> ↑↑acetyl CoA
* Oxaloacetate used up --> acetyl CoA cannot enter the citric acid cycle * Acetyl CoA --> ketone bodies instead |
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What are the biochemical features of ketoacidosis? (4)
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* ↓pH
* ↓HCO3 * Kussmaul breathing * K+ high early, but intracellular depletion |
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What can cause diabetic ketoacidosis? (2)
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* Insulin therapy stopped
* ↑counter-regulatory hormones (glucagon, stress hormones) from infection, surgery, etc. |
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What is the pathway by which ↑glucose causes insulin secretion from beta cells?
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* Glucose taken up by GLUT-2 receptors
* Glucose metabolism --> K+ channels close * Change in membrane potential --> insulin release |
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Besides glucose, what other factors stimulate insulin secretion?
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* Other hormone levels (e.g., glucagon)
* ↑ PARA, ↓ SYMP * Sight/smell of food |
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At what BGL do counter-regulatory responses kick in?
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3.8 mmol / L
(glucagon, adrenaline, GH, cortisol) |
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What are symptoms of hypoglycaemia?
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From ↑Adr:
* Tremor * ↑HR, palpitations * Sweating * Weakness Neuro symptoms (later): * Headache * Altered mental status * Seizures * Other neurological deficits |
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What is the plasma half-life of insulin?
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4 minutes
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What causes the "honeymoon period" after first starting insulin treatment?
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* High blood sugar --> pancreatic toxicity
* Insulin treatment --> ↓ blood sugars --> pancreas temporarily recovers --> ↓ insulin dose |
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What HLA subtype is associated with type 1 diabetes?
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HLA-DR3
HLA-DR4 (also RA) |
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What are carried in the core of the different lipoproteins?
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* Chylomicrons & VLDLs: triglycerides
* LDLs & HDLs: cholesterol esters |
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How does diabetes promote atherosclerosis?
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Hyperglycaemia modifies ApoB100
--> ↑uptake of LDLs by foam cells & smooth muscle cells |
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Which receptor expressed on HDLs allows them to dock with cells containing cholesterol?
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Apo A1
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What cellular processes are initiated when insulin binds to insulin receptors?
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(↓cAMP)
* GLUT-4 transporters move to cell membrane * ↑glycogen synthase * ↑triglyceride synthesis |
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What are the mechanism of action and major side effects of sulphonylureas?
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* MOA: close K+ channels --> ↑insulin release
* SE: hypoglycaemia, skin rashes, ↑appetite & weight gain |
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What are the mechanism of action & main side effects of biguanides (e.g., Metformin)?
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* MOA: ↑glucose uptake, ↓appetite, ↓intestinal glucose absorption, ↓gluconeogenesis
* SE: Lactic acidosis (contraindicated in renal failure) |
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What are the mechanism of action & main side effects of α-glucosidase inhibitors (e.g., Acarbose)?
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* MOA: Prevent breakdown of complex carbohydrates in gut
* SE: Malabsorption |
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What are the mechanism of action & main side effects of glitazones?
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* MOA: act on PPARγ receptors in fat cells --> ↓insulin resistance
* SE: fractures, diabetic maculopathy, fluid retention (contraindicated in heart failure) |
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What are the features of glomerular lesions in diabetic nephropathy? (3)
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* Thickening of capillary basement membrane (but ↑permeability)
* Diffuse menangial sclerosis * Nodular glomerulosclerosis (Kimmelstiel-Wilson nodules) |
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What are pharmaceutical options for the treatment of obesity? (3)
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* Noradrenergic agents (amphetamine derivatives)
* Sibutramine (Reductil): 5-HT & NA reuptake inhibitor * Orlistat (Xenical): inhibits GI lipases |
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Where is the defect in insulin resistance?
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Post-receptor signalling
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How does weight gain lead to insulin resistance?
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* ↑TAG synthesis & storage in adipocytes
--> ↑adipose macrophages --> release TNF-α --> ↓local TAG synthesis, ↑TAG breakdown --> insulin resistance in fat cells --> ↑serum FFAs & VLDLs --> muscle cells take up fatty acids instead of glucose --> insulin resistance in muscle cells |
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What is the role of PPARγ?
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PPARγ = transcriptional modulator of insulin signalling components
(inhibited by TNF-α) |
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In normal semen what are standard values for:
* Volume? * Density? * Motility %? * Normal morphology %? |
* Volume: 2 - 6 mL
* Density: 20 - 200 million / mL * Motility > 50% * Normal morphology > 30% |
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What is the role of FSH & LH during the follicular/proliferative phase of the menstrual cycle?
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FSH:
* Follicular development * Granulosa cell stimulation (convert androgens to oestrogen) LH: * Theca cell stimulation (produce androgens) |
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What is the role of LH during the luteal/secretory phase of the menstrual cycle?
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* LH surge --> ovulation & meiosis I
* LH triggers formation of corpus luteum (which produces P) * ↓ LH --> ↓ P, ↓ E, & degeneration of corpus luteum |
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When is the window of opportunity for implantation?
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Day 20-24 (6-10 days after ovulation)
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What is the role of oestrogen in pregnancy?
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* Acts on uterus to secrete LIF to make endometrium receptive to attachment
* Acts on blastocyst to cause zona dissolution & hatching (Produced by embryo by day 40) |
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What are the roles of corticotropin releasing hormone (CRH) and placental lactogen in pregnancy?
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* CRH: prevents embryo rejection
* Placental lactogen: secreted by syncytiotrophoblasts after 6-7 weeks, important for foetal growth |
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What are the clinical features of polycystic ovarian syndrome? (4)
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* Hirsutism
* Acne * Infertility * Amenorrhoea / oligomenorrhoea / dysfunctional bleeding |
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What are proven indications for androgen treatment? (5)
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* Anaemia (alternative to EPO)
* Osteoporosis * Cachexia * Anti-oestrogen (e.g., breast cancer, endometriosis) * Hepatic angioedema (NOT male infertility, sexual dysfunction, depression) |
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What are risks with testosterone abuse? (4)
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* Cardiovascular & prostate disease
* Infertility, sexual dysfunction * Hepatotoxicity * Mood & behaviour disturbance |
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What are the embryological origins of the external genitalia?
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* Genital tubercle --> penis / clitoris
* Urethral folds --> penile urethra / labia minora * Genital folds --> scrotum / labia majora |
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What are the 3 phases of menstruation and the important hormone in each?
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* Proliferative phase (day 6-14): oestrogen
* Secretory phase (day 15-26): progesterone from corpus luteum * Menstrual phase (day 1-5): ↓Progesterone |
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What two cell types do trophoblasts differentiate into at implantation, and what is the function of each?
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* Cytotrophoblasts: inner layer, mitotically active
* Syncytiotrophoblasts: not mitotically active, invade epithelium & stroma, produce hCG |
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What are the 3 layers of decidual cells?
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* Decidua basalis: adjacent to embryo, part of placenta
* Decidua capsularis: overlies embryo * Decidua parietalis: remaining endometrium (Capsularis & parietalis fuse to obliterate uterine cavity) |
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Which of the "top 10" STDs do not cause discharge?
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* HPV
* HSV * Syphilis (treponema pallidum) * Donovanosis |
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What is the effect of oestrogen and progesterone on cervical mucus?
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* Oestrogen --> less viscous, more glycogen, favouring migration of sprem (1st half menstrual cycle)
* Progesterone --> more viscous, hostile to sperm (2nd half menstrual cycle) |
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What is the normal pH of the vagina and how is it maintained?
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* 4.0 - 4.5
* Maintained by metabolism of gylcogen by lactobacilli --> lactic acid (loss of bacteria --> ↑pH --> ↑susceptibility to yeast infections) |
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What are the clinical features of chlamydia? (7)
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* Cervicitis in females
* Urethritis in males & females * Low abdominal pain (PID) * Epididymitis * Conjunctivitis * Arthritis (Reiter's) * Rashes (similar for gonorrhoea) |
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What are routine STI screening tests for a male patient?
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NG & CT:
* Swab of urethral discharge, or urine sample * Rectal & throat swabs if indicated by sexual behavior + serology for syphilis, HepB, HIV |
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What are routine STI screening tests for a female patient?
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* Vaginal pH, "whiff", and vaginal swab for candidiasis, bacterial vaginitis, and trichomonas vaginalis
* Endocervical swab for NG & CT * Rectal & throat swabs, pap smears as indicated * Serology for syphilis, HepB, HIV |
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Which common STIs have "low priority" for contact tracing?
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* Genital herpes
* Genital warts (medium priority for HIV for gay men) |
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How is PID diagnosed?
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* Lower abdominal pain
* Signs of a lower genital tract infection * Cervical motion tenderness * One or more of: ↑ESR, ↑temp, palpable adnexal mass |
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What are risk factors for uterine cancer? (6)
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* Late menopause
* Nulliparity * Prolonged unexposed oestrogen exposure * Obesity * POS * Hypertension & diabetes (OCP, EtOH, progestogens protective) |
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What are the 3 types of uterine leiomyomas?
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* Intramural
* Submucosal (--> menorrhagia) * Subserosal (pedunculate) |
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What is the effect of oestrogen and progesterone on the vagina?
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* Oestrogen --> accumulation of glycogen
* Progesterone --> desquamation, release & fermentation of glycogen to lactic acid |
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How thick should the endometrium be at Day 14 of the menstrual cycle?
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6-10 mm
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What is the normal range of blood loss during menstruation?
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10-80 mL
(average 30 mL) |
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What is the effect of oestrogen and progesterone on the glands of the endometrium?
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* Oestrogen --> proliferation, ↑E & P receptors
* Progesterone --> ↓E & P receptors, ↓cellular replication, ↑cellular differentiation (--> secretory phase) |
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What is the effect on the endometrium of:
* early introduction of progesterone in the menstrual cycle? * prolonged progesterone therapy? |
* Early progesterone (eg OCP) stops proliferation early
* Prolonged progesterone exhausts P receptors --> endometrial apoptosis, patchy necrosis, irregular bleeding |
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What are the 2 clear risks of HRT?
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* Breast cancer (1.3x RR)
* Venous thromboembolism & arterial thrombosis (greatest risk in first year, but protective effects accrue long term) |
