HTN Flashcards
Optimal blood circulation requires ______ (of blood) that fills the blood vessels, and _______ to move the blood into all parts of the body
Optimal blood circulation requires volume (of blood) that fills the blood vessels, and pressure to move the blood into all parts of the body
what is the inner wall of the arteries called and some risk factors associated with it?
the endothelium
o Endothelium injury is a factor in developing atherosclerosis or arteriosclerosis
Atherosclerosis
is the deposition of fatty plaques in the endothelium
Arteriosclerosis
is the hardening of the artery walls
possible causes of arteriosclerosis (2)
- increased blood sugar (DM)
2. smoking
what is cardiac output (CO)? w/ normal CO
the amount of blood that flows from the heart’s left ventricle per minute
- about 5 L of blood per minute
Blood pressure (arterial blood pressure) measures what?
measures the force against the walls of the arteries as the heart pumps blood
- higher in the arteries than in the veins
describe Total Peripheral Vascular Resistance (PVR)
amount of obstruction to blood flow caused by vessel diameter, vessel length, and blood viscosity
list the 2 equations for obtaining CO
- BP / PVR (hard to compute)
2. SV x HR
what do baroreceptors do? where are they located?
- regulate BP - it is a neural mechanism
- located along the walls of arteries particularly carotid artery and carotid arch
describe systolic BP
max pressure that the heart exerts while beating - during contraction
describe diastolic BP
pressure in the arteries in between beats - during relaxation
describe the pathway of cardiovascular regulation in the brain (2)
- pons and medulla
2. transmit sympathetic and parasympathetic signals to the heart and blood vessels
describe stroke volume
the volume of blood ejected per ventricular contraction
- same thing as EF
describe ejection fraction w/ example
how much blood the left ventricle pumps per contraction (%)
- at any given time there is 100ml of blood in the left ventricle
- ex: if patient has 70% EF then only 70% of blood is being ejected from the LV = 70ml
describe orthostatic hypotension
significant drop of BP when changing position = decrease in cerebral perfusion = dizziness
if HR is 68 and EF is 65%, what is the CO in L/min?
68 x 65 ml = 4,420 ml = 4.42 L/min
what is RAAS?
Renin - Aldosterone - Aldosterone Syndrome
what is the function of RAAS?
Raises BP in response to decreased blood circulation
- the kidney is very sensitive to the drop in blood pressure
describe the pathway of RAAS to increase BP
- kidney detects drop in BP
- nephrons release Renin = stimulates the liver to secrete angiotensinogen
- angiotensinogen reaches the lungs = is transformed into Angiotensin I
- then ACE transforms Angiotensin I to Angiotensin II
- Angiotensin II stimulates adrenal gland to release Aldosterone
- Aldosterone works at nephrons to increase sodium and water reabsorption into the bloodstream (increases potassium excretion in the urine)
what is important to note about Angiotensin II?
Angiotensin II is a strong arterial vasoconstrictor
what is the anti-diuretic hormone (ADH) also called?
vasopressin
what is the function of ADH?
secreted by posterior pituitary gland to increase water reabsorption
what chemicals affect the arteries?
- lipids
- glucose
- free radicals
- nicotine
- homocysteine
describe natriuresis
sodium being excreted in the urine
describe how lipids affect the arteries
Fats that circulate in the bloodstream; mainly composed of cholesterol
- Cholesterol: comes from diet and also synthesized by the liver
- Triglycerides: lipid molecules acquired through diet and stored as fat tissue - usually elevated in a high-carb diet
- LDL; HDL
- LDL: bad cholesterol, fatty plaques deposited along the walls of the arteries = inflammatory reaction which macrophages try to engulf but they get stuck
- HDL: brings LDL back to the liver = lower blood LDL level
describe how glucose affect the arteries
- Chronic elevation of blood glucose can injure the endothelial walls of the arteries
- uncontrolled diabetes
= high risk for atherosclerosis and myocardial infarction
describe how free radicals affect the arteries
Have high affinity to cell membranes
= can damage the endothelial lining of the arteries
describe how nicotine affect the arteries
can cause vasoconstriction
describe how homocysteine affect the arteries
- Amino acid involved in metabolism Vitamin B complex but a deficiency in Vitamin B
- decreased breakdown of homocysteine
= high level of homocysteine can damage the endothelial walls of the arteries; also linked to increased thrombosis formation
- homocysteine is high in meats
describe HTN
The elevation of blood pressure to values that are correlated with cardiovascular damage
AHA/AAC description of HTN
HTN exists when 2 or more diastolic blood pressure measurement on at least 2 or more clinical visits is 80 mmHg or higher; or when systolic blood pressure measurement is consistently 130 mmHg or higher
what is the cause of primary HTN
exact cause is unknown
what is the cause of secondary HTN
effect or complication of other systemic disorders; or side effects of some drugs/toxins
what are some risk factors for HTN (9)
- Family history
- advancing age
- race
- obesity
- tobacco use
- high salt and saturated fat intake
- excessive alcohol intake
- sedentary lifestyle
- chronic stress
describe the pathologic changes of HTN (5)
- changes in arterial bed/ endothelial lining = increased peripheral resistance
- increased tone in the SNS = increased peripheral resistance
- increased blood volume
- arterial wall thickening = increased peripheral vascular resistance
- abnormal release of renin, produces Angiotensin II = increased blood volume and increased constriction of arterioles
= could lead to prolonged HTN
describe the pathway of prolonged HTN
- increases resistance to ventricular ejection and workload of heart increases
- left ventricle hypertrophies
= further increases workload of the heart
complications of prolonged HTN (7)
- Stroke
- MI
- heart failure
- arrhythmias
- retinopathy
- encephalopathy
- renal failure
treatment of HTN
- diet
- moderate exercise
- medications
- α - adrenergic blocker like Doxazosin; terazosin (lowers BP)
- β - adrenergic blocker like Atenolol, metoprolol, propranolol, carvedilol (lowers BP & HR)
- Diuretics (lowers BP)
- ARB/Ace-inhibitors/Ace-receptor blockers (lowers BP)
s/s of HTN
it is asymptomatic except an elevated BP
- in severe untreated cases
= headaches or neck pain
= organ specific s/s
