Physio 2.0 Flashcards
What is the Cardiac cycle time?
0.8 seconds when the heart beats at 75 bpm
What I known as the contraction/emptying phase stage of the cardiac cycle?
Systole
What is known as the relaxation/filling phase of the cardiac cycle?
Diastole
Fill in th blanks.” Atrial systole is caused by ___________.”
Atrial depolarisation
What are the phases involved in Atrial Systole?
- Ventricles are relaxed
- AV valves ( tricuspid & mitral) are open because pressure in the atria is greater than ventricular pressure.
-Ventricles were filling prior to atrial systole, Atrial systole causes further increase in ventricular volume.
- Throughout atrial contraction , atrial pressure exceeds ventricular pressure so AV valves remain OPEN.
- Ends with ventricles maximally filled with blood ( EDV = 120ml)
What heart sound may be produced in Atrial systole?
S4 - may produce sound during atrial contraction as it causes the ventricular wall to vibrate if the ventricle is “stiff”
Fill in the blanks. “ Isovolumetric ventricular contraction is initated by ______.”
By the QRS complex - Ventricular depolarisation.
In which stage of the Cardiac cycle is the first heart sound produced ( S1) ?
Isovolumetric ventricular contraction.
True or False? In Isovolumetric ventricular contraction , there is NO change in ventricular volume as all valves are CLOSED.
TRUE!!
In which stage of the Cardiac cycle is the Second Heart sound produced (S2)?
Isovolumetric ventricular relaxation
What is the pressure in the Right atrium?
0-8 mmHg
What is the pressure in the left atrium?
2-10 mmHg
What is the pressure in the right ventricle?
25 / 6(2-8) mm Hg
What is the Pressure in the left ventricle ?
120 / 8(2-10)
What is the pressure in the aorta?
120/80
What is the pressure in the pulmonary artery?
25/10 mmHg
In the atrial pressure curve, what does the ‘a’ wave represent?
The atrial contraction as a primer pump
In the atrial pressure curve, what does the ‘c’ wave represent?
This represents when the ventricles begin to contract
In the atrial pressure curve, what does the ‘v’ wave represent?
It represents the end of ventricular contraction
Fill in the blanks.” When the aortic valve closes, blood rebounds against the valve causing a decrease then a rebound of aortic pressure. This causes the appearance of a ________.”
Dicrotic notch
What is the normal End diastolic volume?
120-130ml
What is the End Diastolic volume?
This is the Volume of blood in each ventricle at the end of diastole.
What is the normal End systolic volume?
50-60 ml
What is the stroke volume?
It is the volume of blood pumped out by each ventricle per beat . It is about 70-80 ml.
How is Stroke volume calculated?
EDV-ESV
What is Ejection Fraction?
It is the percentage of ventricular end diastolic volume which is ejected with each stroke.
What is the formula for Ejection Fraction?
EF= SV (EDV-ESV)/ EDV x 100
What is the norma ejection fraction?
60-65%
True or False? Diastole length (time) is shortened much more than systole length.
TRUE!!
Fill in the blanks.”The third heart sound can be heard during _________.”
Rapid filling of the ventricles( audible in children)
Fill in the blanks.”The fourth heart sound is heard during_________.”
Atrial systole ( normally not audible)
Where is the sound of the aortic semilunar valve heard?
Second intercostal space at the right sternal margin.
Where is the sound of the pulmonary semilunar valve heard?
Second intercostal space at the left sternal margin.
The sounds of which valve is heard is heard over the heart apex, in the 5th intercostal space, in one with the middle of the clavicle.
Mitral valve
Where is the tricuspid valve heard?
The sounds of the tricuspid valve is typically heard in the right sternal margin of the fifth 5th intercostal space . Variations include over sternum or over left sternal margin in 5th intercostal space.
If the third heart sound is heard , what pathological diseases could be suspected?
Congestive Heart Failure or Vascular disease
The fourth heart sound can be a sign of ?
Stiff , fibrotic ventricle
- Can also be a sign of Aortic stenosis, hypertrophic cardiomyopathy, hypertension.
What are the factors that determine systolic blood pressure?
- The characteristics of the stroke volume being ejected from the heart
- The ability of the aorta to stretch and accommodate the stroke volume.
What are the factors that determine the Diastolic pressure?
- The energy stored in the aorta as its elastic fibres are stretched during systole.
- The resistance to the runoff of blood from the peripheral blood vessels.
What is the formula to calculate blood pressure?
Blood pressure = Cardiac output x Peripheral resistance
What are the physiological factors that affect blood pressure?
Cardiac Output - (SV xHR)
Peripheral resistance
Blood volume
How is the Pulse Pressure Calculated?
Systolic BP- Diastolic BP
How is the mean arterial pressure calculated?
Diastolic BP + 1/3 Pulse pressure
What is Central venous pressure?
Central venous pressure is considered a direct measurement of the blood pressure in the right atrium and vena cava.
How else can the Mean arterial pressure be calculated?
MAP = (CO x SVR) + CVP (Central Venous Pressure)
Fill in the blanks. “ Atrial stretch receptors are activated by _________ and act to _________.”
They are activated by Increased venous return and act to reduce Blood Pressure.
What are the functions of Atrial Stretch receptors?
- They stimulate reflex tachycardia (increased HR)
- Inhibit ADH release
- Promote secretion of Atrial Natriuretic peptide.
What are the factors that determine Mean arterial pressure?
- Blood Volume
- Effectiveness of the heart as a pump.
- Resistance of the system to blood flow.
- Relative distribution of blood between arterial and venous blood vessels.
What are three important sources of resistance?
Blood viscosity
Total blood vessel length
Blood vessel diameter