Hyperaldosteronism Flashcards
What are natriuretic peptides?
ANP and BNP
Peptide hormones that work to increase sodium excretion, in order to lower blood pressure
What 3 things stimulate release of natriuretic peptides?
- Distension of the atria
- Sympathetic stimulation of beta-3. adrenoreceptors
Angiotensin II
What are the 3 effects of natriuretic peptides?
- Inhibit renin release
- Cause vasodilation by signalling through cGMP
- Increase GFR
What is the equation for blood pressure?
Cardiac output X Total Peripheral resistance
What is Aldosterone?
Mineralocorticoid (type of steroid) hormone
Increases sodium reabsorption to increase blood pressure
Where is aldosterone released from?
Adrenal cortex
What are the effects of aldosterone?
Upregulates Na+/K+ pumps in the kidney to increase sodium reabsorption
Can lead to too much sodium reabsorption, causing high blood pressure
Can lead to too much sodium excretion (hypokalaemia)
Where are Na+/K+ pumps located in the kidney?
Basolateral side of principal cells in the PCT
Also in the late DCT and collecting duct
Where is ADH release from?
Posterior pituitary
What are the 3 effects of ADH?
- Binds to v1 receptors in vascular smooth muscle, causing vasoconstriction through Gq
- Binds to v2 receptors (Gs) causing insertion of aquaporin-2 channels into the collecting duct
- Stimulates the Na+/K+/Cl- cotransporter in the ascending loop of Henle
What two systems control blood pressure?
Short term: Baroreceptor reflex
Long term: RAAS
What is the baroreceptor reflex?
Baroreceptors in the aortic body and carotid arch detect BP
Send signals to the cardiovascular centre in the medulla
Sympathetic innervation acts on B1 and B2 receptors to increase heart rate
Parasympathetic innervation acts on M2 receptors to decrease heart rate
Which hormones are released from the anterior pituitary vs posterior pituitary?
Posterior pituitary: ADH and Oxytocin
Anterior pituitary: Everything else
How is the anterior/posterior pituitary connected to the hypothalamus?
Posterior: By neurons
Anterior: By blood vessels
What are corticol hormones?
Type of steroid hormone released by the adrenal cortex
What are the 3 types of corticol hormones? And given one example of each
Mineralocorticoid: Aldosterone, Progesterone
Glucocorticoid: Cortisol
Androgens: Testosterone, Estradiol
What is the Hypothalamic-Pituitary-Adrenal Axis?
Hypothalamus releases corticotropin releasing hormone (CRH)
Anterior pituitary release adrenocorticotropic hormone (ACTH)
Adrenal cortex releases cortisol
What is a tertiary endocrine disorder?
An imbalance of hormones as a result of a problem to do with the hypothalamus
What is a secondary endocrine disorder?
An imbalance of hormones as a result of under/overstimulation of the pituitary (or the kidney, in the case of RAAS)
What is a tertiary endocrine disorder?
An imbalance of hormones as a result of under/overstimulation of the gland (or the adrenal gland, in the case of RAAS)
What is secondary hyperaldosteronism?
Increased levels of aldosterone due to excessive renin release from the kidney
What are 4 possible causes of secondary hyperaldosteronism?
Consistently low BP
Consistent low NaCl in renal filtrate
Kidney tumour
Kidney damage due to diabetes