Part 5 Cardiac Output (Module 14)
tachycardia
A prolonged, resting heart rate above 100 BPM is called ___ .
100
A prolonged, resting heart rate above ___ BPM is called tachycardia.
bradycardia
A prolonged, resting heart rate below 60 BPM is known as ___ .
60
A prolonged, resting heart rate below ___ BPM is known as bradycardia.
right
An increase in blood volume in the ___ atrium stretches the cells and triggers the SA node, as well as a sympathetic reflex called the atrial reflex.
atrial
An increase in blood volume in the right atrium stretches the cells and triggers the SA node, as well as a sympathetic reflex called the ___ reflex.
SA
An increase in blood volume in the right atrium stretches the cells and triggers the ___ node, as well as a sympathetic reflex called the atrial reflex.
maximal
An individual's high-end CO is called ___ CO.
negative
Any substance that decreases heart rate is a ___ chronotropic.
chronotropic
Any substance that decreases heart rate is a negative ___ .
positive
Any substance that increases heart rate is a ___ chronotropic.
chronotropic
Any substance that increases heart rate is a positive ___ .
inotropic
Anything that decreases the contractility of cardiac muscle is negative ___ .
inotropic
Anything that increases the contractility of cardiac muscle is positive ___ .
70
Average stroke volume is ___ mL per beat.
The Frank-Starling law states that an increase in ventricular volume stretches cardiac cells, which increases contraction force, which increases stroke volume.
Describe the Frank-Starling law.
An increase of Ca+ into cardiac muscle cells increases contractility. 777 [verify] perhaps because the increase in positive ions causes greater depolarization in more cardiac cells, and the more cardiac muscle cells contract, the greater the contractility of the heart muscle.
How do calcium levels affect heart contractility?
Hormones such as epinephrine increase contractility.
How does epinephrine affect heart contractility?
Hypertension causes an increase in afterload, which can stress the heart and cause damage over time.
How does hypertension affect the heart?
The greater the afterload, the harder the heart must work with every beat to overcome the pressure difference.
How does increased afterload affect the heart?
The atrial reflex increases heart rate.
How does the atrial reflex affect heart rate?
The parasympathetic system reduces heart rate by opening K+ channels in pacemaker cells, causing hyperpolarization.
How does the parasympathetic system reduce heart rate?
Thyroid hormone increases heart rate and sensitizes cardiac cells for norepinephrine and epinephrine.
How does thyroid hormone affect the heart?
Cardiac Output is abbreviated CO.
How is Cardiac Output abbreviated?
Cardiac output is determined by multiplying heart rate by stroke volume.
How is cardiac output calculated?
Heart rate is measured in beats per minute (BPM).
How is heart rate measured?
Stroke volume is the difference between end-diastolic and end-systolic ventricular volume.
How is stroke volume measured?
contractility
In addition to an increase in heart rate, norepinephrine also increases the ___ of cardiac muscle.
5
Most people can increase their CO 4- ___ times during activity or strenuous work.
4
Most people can increase their CO ___ -5 times during activity or strenuous work.
Stroke volume is governed by 3 factors: preload, contractility, and afterload.
Name 3 factors that affect stroke volume.
SA
Norepinephrine causes the ___ node to send impulses more frequently.
chronotropic
Norepinephrine is both positive ___ and positive inotropic.
inotropic
Norepinephrine is both positive chronotropic and positive ___ .
blockers
Substances that block Ca+ channels are called calcium channel ___ (aka Ca+ antagonists).
antagonists
Substances that block Ca+ channels are called calcium channel blockers (aka Ca+ ___ ).
Bainbridge
The atrial reflex is also known as the ___ reflex.
4.5
The average resting CO is 5.25L/min for men and ___ L/min for women.
5.25
The average resting CO is ___ L/min for men and 4.5L/min for women.
60
The heart will adapt to chronic demand by slowly increasing in size; endurance athletes can have a heart that is ___ % larger than average.
Cardiac output is the volume of blood pumped by each ventricle in one minute.
What is Cardiac Output?
Afterload is the pressure the ventricles have to overcome to force semilunar valves to open.
What is afterload?
The difference between maximal CO and resting CO is known as cardiac reserve.
What is cardiac reserve?
Preload is the degree of stretch cardiac muscle cells have before contraction.
What is preload?
Stroke volume is the amount of blood ejected from each ventricle with each beat.
What is stroke volume?
At rest, the heart is slowed down by parasympathetic signals from the vagus nerve known as the vagal tone.
What is vagal tone?
d
d
