long term control of blood pressure Flashcards
long term blood pressure control is related to the kidneys, list the functions of the kidney:
- Excretion of waste products
- Maintenance of ion balance
- Regulation of :
pH
osmolarity
plasma volume (to regulate MAP)
state the 3 distinct hormone systems that regulate the permeability of the collecting duct:
(Negative feedback systems)
[1] Renin-angiotensin-aldosterone system → increases MAP
[2] Antidiuretic factor (ADH, vasopressin) → increases MAP
[3] Atrial natriuretic peptide (factor) & brain natriuretic peptide (factor) → decreases MAP
what does control over the permeability of the collecting duct to water determine?
determines if water follows that osmotic gradient or not
more permeable, more water reabsorption, little urine, and conserve plasma volume.
collecting duct less permeable, less water reabsorption, lots of urine (diuresis), and a reduction in plasma volume
role of renin:
converts inactive angiotensinogen to angiotensin I
angiotensin l is then converted by angiotensin converting enxyme (ACE) to angiotensin ll
role of myocardial cells
in the atria produce and release atrial natriuretic peptide (ANP)
in the ventricles produce and release brain natriuretic peptide (BNP)
what does increased distension of the atria and ventricles trigger?
atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)
what 3 things trigger ADH release?
– A decrease in blood volume
(as sensed by cardiopulmonary baroreceptors and relayed via medullary cardiovascular centres)
– An increase in osmolarity of interstitial fluid
(as sensed by osmoreceptors in the hypothalamus)
– Circulating angiotensin II
(triggered by the renin-angiotensin-aldosterone system)
list 4 factors that factors that influence mean arterial pressure include:
[1] Blood volume
[2] Cardiac output
[3] Resistance to blood flow
[4] Distribution of blood
what is an increase in osmolarity a sign of?
lower fluid volume
Only 5-10% of hypertension cases are classed as secondary, i.e. due to a known cause e.g.
– The rest is classed as primary (or essential) hypertension, meaning of unknown cause
give 5 negative feedback mechanisms that give a rational basis for drug treatments, e.g.
[1] Ca2+ channel antagonists
[2] b-adrenoceptor antagonists
[3] – Thiazide diuretics
[4] – Angiotensin-converting enzyme - ACE inhibitors
[5] – Angiotensin II antagonists
role of Ca2+ channel blockers antagonists:
block the L-type voltage calcium channels on the myocardium, vascular and smooth muscle cells,
preventing calcium from entering the cells which lowers blood pressure
role of b-adrenoceptor antagonists:
block the sympathetic nervous system effects of increasing heart rate and blood pressure
role thiazide diuretics
they act on the distal tubule, inhibiting NaCl reabsorption and therefore increasing its excretion accompanied by water.
role of angiotensin-converting enzyme - ACE inhibitors:
inhibit the conversion of Angiotensin I to Angiotensin II.
causes a decrease in peripheral resistance, with a reduction in blood pressure and a reduction in the end-diastolic left ventricle pressure.
role of angiotensin ll antagonists:
block Angiotensin II thus the vasoconstricting properties of Angiotensin II are blocked causing relative systemic vasodilatation
define natriuresis:
the process of sodium excretion in the urine through the action of the kidneys.
