Lectures- Cardio physiology Flashcards
is defined as an abnormal reversal of blood flow from the left ventricle (LV) to the left atrium (LA)
Mitral regurgitation
*caused by any disruption of the mitral valve apparatus
MV prolapse Rheumatic fever Infective endocaritis Cardiomyopathy Ischemic heart disease
..can all lead to
Mitral regurg
is the diastolic flow of blood from the aorta into the left ventricle (LV)
Aortic regurgitation
is due to incompetence of the aortic valve or any disturbance of the valvular apparatus (eg, leaflets, annulus of the aorta) resulting in the diastolic flow of blood into the left ventricular chamber
Regurgitation
The valve between the two chambers on the left side of your heart. It opens up enough so that blood can flow from the upper chamber of your heart (left atria) to the lower chamber (left ventricle). It then closes, keeping blood from flowing backwards.
Mitral valve
Heart Rate X Stroke Volume
Cardiac output
Resting cardiac output (CO)?
about 5 L/min
What is max cardiac output (CO)
20-25 L/min
220-age
is what?
Predicted max HR
+/- 10-12 bpm
- Decreased parasympathetic tone
- Increased sympathetic tone
- Bainbridge reflex (atrial reflex)
physiological variables affecting HR
is an increase in HR due to an increase in central venous pressure that is detected by the barorecptors in the atria and venoatrial junctions.
Bainbridge reflex
- Increased sympathetic tone
- Increased pre-load (venous return) leads to an increase in contractility
- Decreased arterial resistance (afterload)
Physiological variables affecting stroke volume
resistance against which the heart is working
After load
High after load, means the heart is working..
hard to get blood out!
ie..hypertension
Arterial vasodilation does what to after load?
Decreases! This makes workload on heart go down
i.e. ACE inhibitors
- skeletal muscle pump
- respiratory and abdominal pump
- venoconstriction (sympathetic tone)
All increase venous return!
amount of ventricular stretch based on the volume of blood in the chamber.
Pre load (LVED pressure)
Greater the ______ _______, the greater both Bainbridge reflex and Frank Starling mechanism
Venous return (VR)
states that when the myocardium is stretched, it contracts with greater force. Good example is blowing up a ballon.
Frank Starling Mechanism
greater volume in the chamber, greater stretch of the myocardium, leads to greater contractility, which leads to a greater SV
Frank Starling Mechanism
_______ is heart control that originates outside the heart for example adrenalin from the adrenal glands above the kidneys
Extrinsic
Frank Starling Mechanism to increase contractility and Bainbridge Reflex to increase HR are examples of…
Intrinsic heart control
Sympathetic stimulation moves the Frank Starling curve to the…
Left
Represents the % of blood that is being ejected
from the ventricle per beat
Ejection fraction
What do you need to measure ones ejection fraction?
End diastolic volume (EDV)
End systolic volume (ESV)
Nuclear imaging, MRI, Echo, CT, cardiac catheterization
Ways to assess ejection fraction
(EDV-ESV/EDV) x100
Ejection fraction %
Ejection fraction of 55-70%
Normal
Ejection fraction of 40-55%
Below normal
Ejection fraction of under 40%
May confirm diagnosis of heart failure
Ejection fraction under 35%
Pt may be at risk of life threatening irregular heartbeats
Vasodilation of the venous system will…
decrease preload
ie nitro
When oxygen supply and demand do not match up..
Angina
Sympathetic tone increases what when trying to compensate in heart failure
Contractility
which in turn causes an increase in stroke volume
You are in diastole____ of the time under resting conditions
2/3
*this will decrease when exercising
systole 1/3
elasticity
rigidity
resistance
all influence…
arterial pulse pressure
_____ flow is parabolic, highest velocity in center (least resistance), lowest adjacent to vessel walls
laminar
_____ flow is disoriented, no longer parabolic, energy wasted, thus more pressure required to drive blood flow.
turbulent
detectable w a stethoscope
Vasodilation due to…
Parasympathetic
Vasoconstriction due to..
Sympathetic
- Viscosity of the blood (thickness, blood doping)
- Length of the blood vessel
- Diameter of the blood vessel
(fourth power)
Variables that effect blood flow
If the radius of a blood vessel is doubled, how much is the blood flow increased by?
16x!
64% of your blood is stored where?
In systemic veins!
? = distensibility x volume
compliance
veins have a high…
compliance
What is the velocity of blood flow like in capillaries?
SLOW!!! to allow time for exchange to take place
distance/time
velocity
volume/time
flow
Where is velocity greatest? least?
Greatest= aorta Least= capillaries
**total cross section of capillaries is HUGE, which is why the velocity is slow here
