Lecture 25 - Hypertension I Flashcards
What does hypertension relate to?
Hypertension relates to high BP, specifically arterial blood presure.
What is pulse pressure?
Difference between systolic and diastolic pressure
How can we find MAP from SAP and DAP?
MAP= DAP +1/3(SAP-DAP)
What is SAP and DAP in normal arterial pressure?
SAP<120 and DAP<80
What is SAP and DAP in elevated arterial pressure?
SAP=120-129 and DAP<80
What is the SAP or DAP in Stage I Hypertension?
SAP=130-139 or DAP=80-89
Dont need both to have hypertension
What is the SAP or DAP in Stage II Hypertension?
SAP>140 or DAP>90
Dont need both to have hypertension
What happens to the physical factors of MAP during hypertension?
Arterial blood volume increase
Arterial compliance decrease
What regulates arterial blood volume long-term?
Kidney
What is arteriosclerosis?
Disease of media which alters stiffness
Media thickening in large or resistance arteries
Increasing stiffness of the arteries
What is atherosclerosis?
Disease of the intima which alters conduit
Changes of the intima
Blockage of the arteries
What does increases in blood volume measure?
Vessel compliance. Increase of volumes is a measure of compliance, as vessel compliance decreases, so does the increase/change in volume.
Why does vessel compliance decrease with age?
Structure remodelling of the arterial wall
What are the changes in the vessel wall due to age?
Less elastin, more collagen, different type and more crosslinking
Collagen 1000x stiffer than elastin
Why does peripheral vascular resistance increase with age?
Because there is a decrease in arterial compliance
What does the increased peripheral vascular resistance do to BP?
Increase SAP and DAP
What increases more, SAP or DAP, when there is an increase in peripheral vascular resistance and why?
An increase in peripheral vascular resistance will elevate systolic pressure more than diastolic pressure
At higher pressures (systole) the arteries are stiffer (less compliant) than at diastole (vessels are less stiff, more compliant).
Why does arteriosclerosis cause hypertension?
Because arteriosclerosis alters media stiffness, which makes the vessel less compliant, thus increasing BP
In systole, what is the flow wave generated by?
The heart
In diastole, what maintains capillary flow?
In diastole, recoil of aorta maintains capillary flow
What is flow wave?
Flow wave – blood flow caused by ejection of the heart which runs through the vasculature
What does the distensibility of the act aorta as?
Storage of stroke volume in conduit vessels
What is the flow of blood throughout the body?
Pulsatile flow into the aorta, but continuous/constant flow through the capillaries
What is essential for dampening the pulsatile flow wave of the heart?
Compliance of the aorta