Flashcards in Hypertension Deck (49):
Describe systolic arterial blood pressure.
The pressure of the arteries during systole (contraction of the heart)
Describe diastolic arterial blood pressure.
The pressure of the arteries during diastole (rest/filling of the heart)
Describe the Mean Arterial Pressure (MAP)
Represents the average pressure throughout the cardiac cycle
MAP = 2/3 diastole + 1/3 systole
(66% of the time the heart is in rest and 33% of the time the heart is in contraction
High blood pressure
Explain the difference between essential and secondary hypertension
Essential - cause is unknown (90% of cases)
Secondary - comorbid diseases or drug causing elevated BP (10% of cases)
What is the mathematical formula for blood pressure?
BP = total peripheral resistance (TPR) X cardiac output (CO)
What is the formula for cardiac output?
heart rate X stroke volume
What is TPR?
The amount of resistance in the periphery or the blood vessels.
When TPR increases this is called?
What happens when TPR increases? (vasoconstriction)
Define: cardiac output
(Remember cardiac output = heart rate X stroke volume)
How much the heart is pumping
Define: heart rate
How fast the heart is pumping
Define: stroke volume
How much blood the heart is pumping
There are 5 Mechanisms of BP Regulation: List them.
1. Renal (RAAS)
2. Electrolytes (Na, K, Ca)
Describe the Renal Mechanism (RAAS)
1. Juxtaglomerular cells (which are baroreceptors) sense a decrease in blood pressure.
2. Renin is secreted which converts angiotensinogen that is circulating in the blood into angiotensin I.
3. Angiotensin I is then converted into Angiotensin II by a converting enzyme.
4. Angiotensin II then affects all areas including adrenal cortex, kidneys, intestines, CNS, peripheral nervous system, vascular smooth muscle and the heart.
Explain how adrenal cortex is affected by angiotensin II.
There is an increase in aldosterone synthesis which increases sodium/water reabsorption which increases the blood volume and increases the TPR and increases BP.
Explain how the kidneys and intestines are affected by angiotensin II.
There is an increase in sodium/water reabsorption which increases the blood volume and increases the TPR and increases BP.
Explain how CNS is affected by angiotensin II.
Causes a release of Vasopressin (an antidiuretic hormone) which causes water (urine) to stay in the body and increase blood volume which increases the TPR and increases BP
Explain how the PNS is affected by angiotensin II.
It causes sympathetic discharge (fight or flight system) which increases the TPR and increases BP.
Explain how vascular smooth muscle is affected by angiotensin II.
Causes vasoconstriction which increases the TPR and increases BP.
Explain how the heart is affected by angiotensin II.
Causes increased contractility (the heart pumps harder) which increases CO and increases BP.
What does RAAS stand for?
Renin Angiotensin Aldosterone System
Explain the Electrolyte Mechanism.
Wherever sodium goes, water follows. Patients with higher sodium levels, have increased water retention which increases blood volume which increases TPR which increases BP.
Lower Ca and Lower K levels can increases TPR which would also cause increased BP.
The Neuronal Mechanism has 3 parts to it: Explain extrinsic reflexes.
Outside circulatory system through hypothalamus (ex. pain or cold temp: You want to increase BP to warm someone up or get rid of pain)
The Neuronal Mechanism has 3 parts to it: Explain intrinsic reflexes.
Within the circulatory system (baroreceptor/chemoreceptors)
What is a baroreceptor?
Senses a change in pressure
What is a chemoreceptor?
Senses a change in chemical balance.
The Neuronal Mechanism has 3 parts to it: Explain higher center reflexes.
Mood and emotions can also have an affect on BP
ex. If you are nervous you can have a higher heart rate which will increase your blood pressure
Explain the Vascular Mechanism.
Endothelium secretes factors that promote vasodilation or vasoconstriction.
Explain vasoconstriction and list the drugs that can cause this.
Vasoconstriction is when blood vessels get smaller in diameter. This can be caused by drugs such as: angiotensin II, vasopressin, endothelia.
Explain vasodilation and list the drugs that can cause this.
Vasodilation is when blood vessels get bigger in diameter. This can be caused by drugs such as: Prostacyclin, nitric oxide, bradykinin.
Vasoconstriction increases and vasodilation decreases _________ _______.
An increase in vascular resistance promotes _____.
The Hormonal Mechanism has 2 parts to it: Explain Natriuretic hormones
Natriuretic hormones inhibits Na/K ATPase which blocks active Na out of vascular smooth muscle cells. The end result is increased vascular tone (vasoconstriction)
The Hormonal Mechanism has 2 parts to it: Explain Hyperinsulinemia
It means you have too much insulin and it increases renal Sodium retention. This acts a growth hormone leading vascular smooth muscle cells to grow (hypertrophy). It increases Ca in vascular smooth muscles leading to constrictions which increases BP
It also increases sympathetic nerve activity.
What is a normal BP?
List some risk factors for hypertension?
-Age: >55 for men, >65 for women
-Family history of hypertension
-Lifestyle: alcohol, diet, exercise, smoking, etc.
Describe the symptoms of hypertension.
-Usually none (silent killer)
-Sometimes headaches, blurred vision can happen from really high blood pressure
Untreated hypertension can have consequences in 5 areas: Discuss the brain
You could have a stroke occur from either a vessel bursting or a clot occurring.
Untreated hypertension can have consequences in 5 areas: Discuss the kidneys
You could get a renal disease
Untreated hypertension can have consequences in 5 areas: Discuss the eyes
-You have very small blood vessels in the eye so if you have hypertension then the capillaries can rupture and you can go blind
Untreated hypertension can have consequences in 5 areas: Discuss the heart
Left ventricular dysfunction or heart failure. You could also get coronary artery disease (stable angina or ACS)
Untreated hypertension can have consequences in 5 areas: Discuss the vessels
You could get peripheral artery disease
What types of lifestyle modifications could be made to reduce BP
-dietary sodium restriction
-increase physical activity
-decrease alcohol intake
How can blood pressure be defined?
As the pressure against the artery wall
What is white coat hypertension?
When a patient is nervous to see a doctor so their BP is elevated more than normal and the reading for BP therefore is not accurate.
What types of medications can be used to lower BP
-A drug that blocks angiotensin II being formed
-A diuretic (promotes water loss)
-A drug that stops renin production
-A drug that stops blood vessels from constricting. (Drugs that can stop vasospasm ?)
-Nitric Oxides - cause vasodilation
-Beta blockers - decrease oxygen demand by lowering heart rate
How do beta blockers work?
They decrease the heart rate which decreases oxygen demand which decreases oxygen supply. This works to lower blood pressure.