PHAR6 - Hypertension Flashcards
Define hypertension.
High blood pressure.
When referring to blood pressure, which blood vessels are being considered?
Arteries.
Define blood pressure.
The pressure at which the blood within arteries pushes against the arterial walls.
What formula is commonly used to calculate blood pressure?
Blood pressure equals the force exerted by the blood, divided by the area of the arterial wall.
How does the area of the arterial wall vary within humans?
Larger elastic arteries have larger arterial wall areas comparative to smaller, less elastic arterioles.
Which artery is used for the measurement of blood pressure in clinical settings ?
Brachial artery.
What are the two distinct general stages of the cardiac cycle?
Relaxation and contraction.
Discuss the change in arterial blood pressure during a single cardiac cycle.
During cardiac systole, blood pressure rises to a maximum (systolic blood pressure). During cardiac diastole, blood pressure gradually decreases until a minimum is reached (diastolic blood pressure).
What is the approximate length of one cardiac cycle?
0.8 seconds.
What change in blood pressure is associated with the opening of the heart valve?
Rapid increase in blood pressure, giving rise to the systolic blood pressure (maximum).
What change in blood pressure is associated with closing of the valve?
Gradual decrease in blood pressure until lowest blood pressure is reached - diastolic blood pressure.
Define systolic blood pressure.
The maximum force exerted by the blood against the arterial wall, following full heart contraction.
Discuss the pathway by which blood goes from the heart to the brachial artery.
Blood is ejected from the left ventricle through the aorta, as the heart contracts forcefully. The aorta branches into the brachial artery.
Define systole.
Stage of the cardiac cycle when the ventricles are contracting and ejecting blood into the pulmonary arteries or aorta.
Define diastolic blood pressure.
Minimum force exerted by the blood against the wall of the artery.
When does diastolic blood pressure occur ?
When the ventricles of the heart are fully relaxed.
What is diastolic blood pressure?
The lowest possible blood pressure.
What is the main factor contributing to why diastolic blood pressure (within arteries) does not reduce to zero?
Elastic recoil of the arteries.
Why does ventricular blood pressure decrease to zero?
Ventricles do not contain elastic vessel walls therefore blood pressure will go down to zero.
Describe how the elastic recoil characteristic of the artery ensures that the blood pressure does not decrease to zero.
When blood is pumped into the arteries, the elastic arterial walls expand. When the heart relaxes (and no more blood is being pumped into the arteries) the arteries recoil to the original size and shape.
Define elastic recoil.
The ability of the arteries to change shape and size due to the presence of elastic fibres within the arterial walls.
What unit is used to measure blood pressure?
mmHg.
Why is the elastic recoil characteristic of the arteries vital?
Ensures that blood continues to flow around the circulatory system and never reaches a minimum state with no blood flow.
What is the name of the machine used to measure blood pressure and what does it consist of?
Sphygmomanometer- inflatable arm cuff, pump and pressure gauge. Stethoscope is usually used.
What is the purpose of the stethoscope when measuring blood pressure ?
Measure/observe the regions at which blood flow is disturbed.
Describe the general process of measuring blood pressure.
Pump is used to inflate the inflatable arm cuff to a sufficient pressure. The pressure causes a disruption to regular blood flow within the brachial artery. Pressure is slowly released menacing that the artery slowly widens (due to the elastic recoil ability) allowing blood to flow through the artery once more.
When measuring blood pressure, what does systolic pressure concern?
Maximum pressure that the heart is able to exert - point at which blood starts flowing through the brachial artery once the disruption (increased pressure) is removed.
When measuring blood pressure, what does diastolic pressure concern?
Concerns the point at which blood pressure within the brachial artery is at its lowest due to the being no tubule the flow.
What is the name of the sounds that are heard when measuring blood pressure?
Korotkoff sounds.
Why are Korotkoff sounds heard?
Rhythmic noises are made within the brachial artery due to turbulent blood flow within the partially compressed brachial artery.
When do Korotkoff sounds stop being heard when measuring blood pressure?
When the brachial artery is completely relaxed and there is no more turbulent flow within the artery. As the elastic recoil ability of the arteries causes the pressure to be slowly released.
What measurement is taken when Korotkoff sounds are no longer heard?
Diastolic blood pressure
What are the five factors influencing blood pressure?
Cardiac output. Total peripheral resistance. Volume of circulating blood. Blood viscosity. Elasticity of vessel walls.
What is the formula to calculate cardiac output?
Cardiac output is equal to stroke volume multiplied by heart rate.
Define cardiac output.
Volume of blood pumped through the circulatory system (out of the heart) in one minute.
Define stroke volume.
The volume of blood pumped out of the heat per beat.
Define heart rate.
The number of contractions that the heart undergoes within one minute.
Discuss the link between cardiac output and blood pressure.
Increased cardiac output means more blood is present within systemic circulation, resulting in a higher blood pressure.
What is the other name used for total peripheral resistance?
Systemic vascular resistance.
Define total peripheral resistance.
The total resistance that a blood vessel has to the flow of blood within it. Considered the total of all peripheral blood vessels.
Discuss the link between total peripheral resistance and blood pressure.
The greater the total peripheral resistance, the greater the blood pressure.
Discuss the link between volume of circulation blood and blood pressure
The higher the volume of circulating blood, the greater the the blood pressure.
What is circulating blood volume?
Volume of blood flowing within the blood vessels.
Discuss what blood viscosity is.
Blood viscosity refers to the thickness of the blood. Also can include stickiness.
Discuss the link between blood viscosity and blood pressure.
The greater the viscosity of the blood, the greater the blood pressure.
What two fibres are present within vessel walls to give them elasticity ?
Collagen. Elastic fibres.
Why do different blood vessels have differing elastic abilities?
Contain different amounts of collagen and elastic fibres within their walls.
Why is elasticity a useful characteristic for blood vessels - specifically arteries ?
Ensures that vessels are able to expand and recoil during periods of increased force within the vessel.
What are the two factors that influence blood pressure, that are controlled primarily by the autonomic nervous system?
Cardiac output. Total peripheral resistance.
What are the two factors that pharmacological intervention can alter to reduce blood pressure? How should they be altered?
Cardiac output - can be decreased by lowering heart rate.
Total peripheral resistance - can be decreased by inducing vasodilation to increase blood vessel diameter.
Which factors that influence blood pressure may not undergo pharmacological intervention to reduce blood pressure? Why?
Circulating blood volume, blood viscosity and vessel wall elasticity. Unable to be rapidly changed therefore would have none/little effect with pharmacological intervention.
What are the three main factors of a person that affect blood pressure? What additional variable could be considered?
Age, weight, height.
Gender plays a role within some of these categories.
Discuss the basic link between height and blood pressure, providing explanation.
Generally, the greater the height, the greater the blood pressure. Greater height means larger surface area for blood to perfuse to meaning higher blood pressure is required.
Give a scenario which serves as evidence for the link between blood pressure and height.
Children have lower blood pressures than adults.
Children - 100/60 mmHg
Adults - 120/80 mmHg
Give one piece of evidence that contradicts the relationship: increasing height, increases blood pressure.
Older adults - as height increases, a lower blood pressure is observed.
Discuss the link between weight and blood pressure, giving an explanation.
The greater the weight, the higher the blood pressure. Larger weight suggests larger surface area meaning greater surface area that the blood needs to perfuse to, so a higher blood pressure is required.
What medical condition concerning weight behaves as a high blood pressure risk factor? Explain.
Obesity. Various pathophysiological processes are affected, in addition to the larger surface area for blood to perfuse to, resulting in an increased risk of high blood pressure.
Discuss the link between age and blood pressure, giving an explanation.
Increasing age is associated with increasing blood pressure. Due to loss of elasticity within arterial walls.
Name one potential condition that can develop with age, that increases the risk of high blood pressure.
Atherosclerosis. Refers to build up of fatty acids and substances on arterial walls. Constricts the lumen meaning blood pressure increases.
What is the standard blood pressure?
120/80 mmHg.
What are the six categories of blood pressure ?
Hypotensive, Normal, elevated, hypertensive stage 1, hypertensive stage 2, hypertensive crisis.
What blood pressure is considered as hypertensive ?
Above 130/80 mmHg.
What is the threshold for blood pressure to be considered hypertensive crisis?
Above 180/120mmHg
What is the threshold for blood pressure to be considered elevated ?
Above 120/80.
Why is hypertension referred to as the silent killer?
No symptoms are shown.
What factors affect the treatment of hypertension?
Condition severity. Age. Risk of CVD. Target organ damage. Underlying medical conditions.
If symptoms are not apparent for hypertension, how can it be monitored?
Monitor blood pressure regularly.
What are the two types of hypertension ?
Primary and secondary.
Can also be considered as stage I, stage II and crisis when considering levels of hypertension.
What is primary hypertension?
Hypertension that is not caused by any underlying medical condition.
What is secondary hypertension?
Hypertension caused by a known underlying medical condition.
Give examples of underlying medical conditions that can contribute to secondary hypertension.
Chronic kidney disease. Diabetes.
.
Which organs/systems, when adversely affected, provide higher risk of hypertension development ?
Kidneys, heart, arteries and endocrine system.