Therapeutics I Exam I (HTN) Flashcards
Antihypertensives (431 cards)
What is the pacemaker of the heart?
Sinoatrial node (SA)
What is the blood pressure equation?
BP= Cardiac Output (CO) x Systemic Vascular Resistance (SVR)
What sensor in the body is the short-term regulator of blood pressure?
Baroreceptors
What system in the body is the long-term regulator of blood pressure?
Kidneys with RAAS
What is cardiac output?
This is the amount of blood pumped by each ventricle in one minute. Typical output is 5-6L/min for a normal person.
What is systemic vascular resistance?
The resistance the heart has to pump against in the vasculature to get the blood out of the heart.
What is the equation to calculate the cardiac output?
Cardiac output= Stroke volume x heart rate
What is stroke volume?
This is the amount of blood pumped out of the heart in one heart beat. Typically the heart leaved 30-45% of the blood in the heart while the rest is pumped through the body.
What are the 3 things that make up stroke volume?
Preload, afterload, and contractility
What is preload?
Preload is the amount of stretch that the cardiac myocytes feel at the end of ventricular filling.
What is afterload?
Afterload is the resistance the left ventricle must overcome to eject blood through the aorta.
What is contractility?
Contractility is the force of contraction of the heart muscle.
Based on the blood pressure and cardiac output equation, it would make sense that as HR increases so does BP. However, does this actually occur?
It can occur but mainly if the heart rate increases, the vasculature will dilate to bring back blood pressure homeostasis via the reflex arc.
What is the equation for stroke volume?
Stroke volume = end diastolic volume - end systolic volume
What is inotropy?
Inotropy is the change in force of contraction of the heart. If inotropy is +, then the force of contraction has increased and vice versa.
What is chronotropy?
Chronotropy is the change in the heart rate. If chronotropy is +, then the heart rate has increased and vice versa.
If inotropy is negative, then the force of contraction of the heart has ____________.
Decreased
If inotropy is positive, then the force of contraction of the heart has ____________.
Increased
If chronotropy is negative, then the heart rate has ____________.
Decreased
If chronotropy is positive, then the heart rate has ____________.
Increased
Baroreceptors are _____________ that relay information about blood pressure to the ___________ ___________.
Mechanoreceptors
Adrenal Medulla
If baroreceptors detect a falling blood pressure, what are the steps that occur to bring the blood pressure back to normal?
- Baroreceptors sense low BP
- Baroreceptors signal adrenal medulla to secrete catecholamines
- This release triggers increases sympathetic activity via alpha and beta receptors
- Via beta-1, the heart rate and stroke volume increase which increase cardiac output to increase BP
- Via alpha-1, smooth muscle vasoconstriction which increases systemic vasculature resistance which increases BP
Intrarenal baroreceptors activate _______ when they sense low BP or blood perfusion.
RAAS
Kidneys are primarily responsible for long-term BP control by controlling _______ _________.
Blood volume