control of BP Flashcards
what is normal range for BP and what is high
normal = 90/60 - 120/80 mmHg and high is anything over 140/90 mmHg (its mainly systolic pressure responsible for death in hypertension
causes of hypertension
primary hypertension = unknown cause secondary hypertension is usually due to disease; renovascular chronic renal failure hyperaldosreronism bushings syndrome
which organs does hypertension affect
eyes, brain, heart, kidneys and arteries
How can hypertension cause heart failure
It creates a larger after load which then means the ventricles have to work harder to pump blood out leading to left ventricular hypertrophy. This eventually leads to heart failure
Which clinical defects can hypertension cause
Heart failure, coronary disease, stroke, cerebral haemorrhage, chronic kidney failure, retinopathy, peripheral vascular disease, aortic aneurysm, left ventricular hypertrophy and myocardial infarction
How can hypertension cause retinopathy
High BP causes damage to retinas blood vessels limiting retinas function and putting pressure on the optic nerve causing vision problems
How can hypertension cause nephrosclerosis and renal failure
Walls of blood vessels thicken and fat becomes deposited in the degenerated walls. Causes blood supply to kidney to be blocked= tissue necrosis and renal is ease/failure
How can hypertension cause an aneurysm
Over time weakened artery can cause a section to enlarge= aneurysm. V dangerous if ruptures. Is. Bubble in blood vessels
How can hypertension cause cerebral a scalar disease/ stroke
Atherosclerosis blocks blood supply to brain = stroke
How can hypertension cause myocardial infarction
More o2 needed and fatty streak in aorta lead to loss of elasticity and reduced function of Herat
Physiological effects of hypertension
Greater after load on Herat and arterial damage. Greater after load leads to left ventricular hypertrophy and increased myocardial oxygen demand. Arterial damage leads to weakened vessels and atherosclerosis.
Short term regulation of blood pressure and why this mechanism is not long term
Use of baroreceptors. - baroreceptor reflex. Affects para/sympathetic input into heart and alters cardiac output and adjusts sympathetic output to peripheral resistance to alter TPR. This is a rapid response BUT does not control sustained high BP because threshold for baroreceptor just resets and higher BP.
Equation for mean arterial BP and equation needed to find cardiac output
Mean arterial pressure= CO x TPR
To find CO for this; CO = SV (circulating volume) x HR
What are the long term ways of regulating BP
Neurohumoral response composes of 4 pathways. Mainly uses mechanism to control Na+ balance because water flows in or out o plasma following it
What are the 4 pathways involved in the neurohumoral response to high BP
- Renin-angiotensin-aldosterone system
- Sympathetic nervous system
- Antidiuretic hormone (ADH)
- Atrial natriuretic peptide (ANP)