Class 9 Flashcards
Blood pressure represents the force exerted by blood against the __________________ during the _________________. It is a combination of ________________ pressure & __________________ pressure
• arterial walls
• cardiac cycle
• hydrostatic
• hemodynamic
What is hydrostatic pressure?
The pressure applied equally by water on the walls of its container
What is hemodynamic pressure?
Is exerted as a result of the flow of blood & changes according to the contours & branching of the walls.
Although, there is some amount of pressure in all parts of cardiovascular system except entry into the RA, arterial blood pressure is central to delivery of ________________ into body’s tissues. Its highest in the ________________________ & becomes increasingly less intense as vessels ______________ in size.
• perfusion
• aorta/large aa.
• decrease
The elastic stretch & recoil properties of large arteries give rise to ______________________, but this becomes completely attenuated into one ___________________________ as blood arrives at capillary bed level & moves through the veins.
• two pressure poles
• milder propellant flow
The “bellows” effect of large aa. is necessary to mitigate force & move ______________ through the __________________, but it must be removed by the time blood is delivering _______________ in a steady stream to the body’s cells.
• blood
• vascular circuit
• nutrients
The two pressure poles reflect the impact of _____________________________________.
the two phases of the cardiac cycle on the aorta and its immediate branches.
What is systolic pressure?
Highest reading achieved as an ejection of blood
What is stroke volume?
Moves into the vessel
What is diastolic pressure?
Lowest reading after the blood has left the vessel.
What is pulse pressure?
Difference between systolic & diastolic pressures is called pulse pressure. It represents force of LV contraction as it “pushes” blood into the aorta—in other words, how hard heart is working. Pulse pressure tends to increase when heart is working harder
What is mean arterial pressure?
Average pressure in large arteries. MAP = diastolic pressure + ⅓ of pulse pressure. Reading represents quality of perfusion. If average blood pressure is either too high or too low, blood flow through capillaries will not be optimal for nutrient delivery to cells. MAP is carefully monitored in intensive care patients.
By convention, blood pressure is taken at brachial artery, where normal BP is 120/80 (some argue normal is closer to 110/70 in women). Using 120/80 as reference point, systolic pressure is 120, diastolic is 80, pulse pressure is 40, & MAP is 93.3.
Determinants of Blood Pressure - what is Blood Volume?
The higher the volume of blood in the system, esp. in core circulation, the harder the heart & vessels have to work to pump it.
Determinants of Blood Pressure - what is Vessel Compliance?
» elastic characteristics of large vessels reduce/dampen systolic pressure as LV stroke volume enters them, & their elastic recoil helps maintain baseline pressure during diastole
» capacitance function of veins diverts blood volume from arterial tree to help manage pressure
» state of constriction or dilation of small arteries & arterioles influences how readily blood leaves core circulation to flow into tissue beds; easy flow reduces blood pressure, significant peripheral vasoconstriction increases blood pressure
Determinants of Blood Pressure - what is Cardiac Output (CO)?
Quantity of blood heart pumps into systemic circulation each minute; its a factor of heart rate & stroke volume; increased heart rate & larger SV both increase cardiac output; increase in CO can cause arterial pressure to rise.
What are Determinants of Systolic Pressure?
LV stroke volume, strength & velocity of blood ejection from LV, elasticity/compliance of the aorta
What is total peripheral resistance?
The sum of all factors the heart overcomes in order to push blood out & create flow through the body’s circulatory circuits.
BP = CO x TPR
Since cardiac output is a factor of heart rate & stroke volume, the equation can be expressed as?
BP = HR x SV x TPR
What are Determinants of TPR?
● Elasticity/stiffness of large vessels in arterial system
● Tone (constriction state) of small arteries & arterioles
● Condition of capillaries
● Ease of blood clearance in filtration systems (kidneys, lungs, liver)
● Diaphragm tension level
● Blood viscosity
What is Orthostatic/Postural Hypotension?
Is a drop in blood pressure following a change in position, usually moving from recumbent to standing. Caused by decreased venous return to heart due to pooling of blood in lower part of body and/or by inadequate circulatory reflexes.
When person moves from lying down (sometimes prolonged sitting) to upright position, blood distribution has shifted. There has been a _______________ in central blood volume & arterial pressure. As person gets up, & effects of gravity shift, baroreceptors reflexively cause ____________________ & ____________________ to elevate blood pressure, key concern being to ensure that brain’s blood supply remains adequate.
• decrease
• vasoconstriction & increase heart rate
How is BP affected with orthostatic hypotension?
With orthostatic hypotension, BP does not regulate fast enough. Person feels light-headed, dizzy, unfocused, & may faint (syncope). For a few seconds to a few minutes, they can’t safely stand upright (orthostatic intolerance). They may also experience visual changes, head & neck discomfort, palpitations, tremor, anxiety. Hypotension is usually transient in nature.
What are causes of orthostatic hypotension?
• Decreased blood volume (e.g., dehydration, diuretic use)
• Blood pressure regulation issues (hypo- or hypertensive)
• Drug-induced hypotension (e.g., antihypertensives, antidepressants)
• Heart issue (e.g., valve problem, atrial fibrillation)
• Altered vascular response (aging, bedrest, neurological conditions with ANS dysfunction)
• Can be aggravated by heat, humidity, heavy meal (postprandial hypotension), exercise
What is orthostatic intolerance?
For a few seconds to a few minutes, they can’t safely stand upright
What is syncope?
Person feels light-headed, dizzy, unfocused, and may faint
What is Hypertension?
Traditionally been defined as BP above 90 diastolic & 140
systolic, when taken on 2 or more separate occasions. These are the values at which it was understood that damage to blood vessels, heart & other vital organs begins to occur. Hypertension diagnosis is based on which is higher above-normal reading (systolic/diastolic).
In 2017 US Clinical Practice Guideline & in 2018 Hypertension Canada Guidelines were updated to modify threshold for what is considered hypertension.
• The Hypertension Canada Guidelines now state BP of 130-139 systolic & 80-89 diastolic indicates “normal-high” BP, & may suggest medical treatment should be started depending on factors (illness, age, etc.) For eg. for person with diabetes or kidney disease, threshold of ≥ 130/80 is now typically used for initiating treatment, with goal of maintaining BP below that level.
• For RMTs using cuff in their clinic, ≥ 140/90 is still applicable threshold for treatment adaptation for most patients.
T/F Does what is considered normal blood pressure increases with age?
- True
What is considered normal blood pressure increases with age. 120/80 is the usual normal for young healthy adult males & 110/70 for females. By the time someone reaches age 60, normal BP is 134/87. Note that this BP is much closer to tissue damage threshold.
T/F a person can only fall into1 hypertension category?
- False
The categories are not mutually exclusive – individuals can fall into more than 1.
What is Systemic Hypertension Category?
Chronically high BP, affecting whole arterial system
As opposed to isolated hypertension (eg. pulmonary hypertension, a heart-lung problem)
What is Primary (AKA Benign/Essential/Idiopathic Hypertension) Hypertension Category?
Hypertension linked to risk factors such as:
• family history
• chronic stress
• poor diet
• salt sensitivity
• alcohol consumption
• lack of exercise
• obesity
90% of the hypertensive population; can reduce life expectancy by 10-15 years. Is idiopathic. Two key cause theories:
• Hypersensitive sympathetic n.s.
• Hypersensitive renin- angiotensin response
What is Secondary Hypertension Category?
Hypertension secondary to a known cause such as:
• atherosclerosis
• diabetes
• kidney disease
• renal artery stenosis
• liver disease
• respiratory disease
• thyroid and other
endocrine disorders (incl. adrenal tumors),
• preeclampsia/eclampsia
• long-term oral contraceptive use
5-10% of hypertensive population
Diastolic tends to be higher than in primary hypertension
What is Malignant Hypertension Category?
Describes acute spike of BP – an emergency situation
Typically secondary to situations like kidney failure, liver cancer, unstable diabetes, etc.
What is Labile/Borderline Hypertension Category?
Intermittent BP elevation interspersed with normal readings
What is White Coat Hypertension Category?
Otherwise normal BP which rises when measured by medical professional – a nervous/phobic reaction
What is Isolated Systolic Hypertension Category?
High systolic but normal diastolic readings There is still increased risk of stroke, MI, kidney disease, dementia
Common in seniors (secondary to pathophysiological changes of aging in heart & blood vessels as well as modifiable risk factors)
