Body Systems L11 Notes Flashcards
What are the functions of the cardiovascular system?
Maintain adaptable supply of blood -> tissues.
» Supply nutrients & signalling molecules
»Remove waste products
Establish pressure differentials across tissues -> capillary exchange.
What are the two factors which determine blood flow?
Blood flow determined:
- Resistance -> R
- Pressure difference -> P
What is the equation representing blood flow?
F = ▲P / ▲R
What is vascular resistance determined by?
Determined by: ->> L = length of vessel ->> r = radius of vessel ->> ꞃ = fluid viscosity >>(protein conc.)
What determines the fluid viscosity of blood?
-» ꞃ = fluid viscosity
|»_space;(protein conc.)
What is the equation for calculation of vascular resistance?
R = (8Lꞃ) / (πr4)
What is the equation for calculation of blood flow using pressure & viscosity?
F = ▲P((πr4) / (8Lꞃ))
What are the two equations for calculation of blood flow & what values do both equations require?
F = ▲P / ▲R
Pressure difference & resistance difference
F = ▲P((πr4) / (8Lꞃ))
Pressure difference, radius, length & fluid viscosity.
What does the Poiseuille-Hagen Eqn state?
Poiseuille-Hagen Eqn:
Flow -> proportional -> r4
Small changes in arteriole diameter
»_space;Drastically alter tissue blood flow
Rate of flow -> blood through vessels
-» Proportional -> Vessel diameter
What causes cardiovascular pressure gradient formation?
Contraction -> Heart muscles -> Generates CVS pressure gradient.
State the intra-cardiac pressures of each component of heart during systole & diastole.
Left Ventricle: Contraction (systole) -> 100-140mmHg Relaxation (diastole) -> 3-12mmHg Left Atrium: Contraction (systole) -> 6-12mmHg Right Ventricle: Contraction (systole) -> 15-30mmHg Relaxation (diastole) -> 3-8mmHg Right Atrial: Contraction (systole) -> 2-6mmHg
State the intra-cardiac pressures of the left ventricle of heart during systole & diastole.
Left Ventricle:
Contraction (systole) -> 100-140mmHg
Relaxation (diastole) -> 3-12mmHg
State the intra-cardiac pressures of the right ventricle of heart during systole & diastole.
Right Ventricle:
Contraction (systole) -> 15-30mmHg
Relaxation (diastole) -> 3-8mmHg
State the intra-cardiac pressures of the left atrium of heart during systole.
Left Atrium:
Contraction (systole) -> 6-12mmHg
State the intra-cardiac pressures of the right atrium of heart during systole.
Right Atrial:
Contraction (systole) -> 2-6mmHg
State the intra-cardiac pressures of the right ventricle of heart during systole
Contraction (systole) -> 15-30mmHg
State the intra-cardiac pressures of the left ventricle of heart during systole
Contraction (systole) -> 100-140mmHg
State the intra-cardiac pressures of the right ventricle of heart during diastole.
Relaxation (diastole) -> 3-8mmHg
State the intra-cardiac pressures of the left ventricle of heart during diastole.
Relaxation (diastole) -> 3-12mmHg
What is classed as a high blood pressure gradient in systole & diastole?
High:
Systolic: >140mmHg
Diastolic: >90mmHg
What is classed as a high blood pressure gradient in systole?
Systolic: >140mmHg
What is classed as a high blood pressure gradient in diastole?
Diastolic: >90mmHg
What is classed as a pre-high blood pressure gradient in systole & diastole?
Pre-high:
Systolic: 120-140mmHg
Diastolic: 80-90mmHg
What is classed as a pre-high blood pressure gradient in systole?
Systolic: 120-140mmHg
What is classed as a pre-high blood pressure gradient in diastole?
Diastolic: 80-90mmHg
What is classed as an ideal blood pressure gradient in systole & diastole?
Ideal:
Systolic: 90-120mmHg
Diastolic: 60-80mmHg
What is classed as an ideal blood pressure gradient in systole?
Systolic: 90-120mmHg
What is classed as an ideal blood pressure gradient in diastole?
Diastolic: 60-80mmHg
What is classed as an ideal blood pressure gradient in systole & diastole?
Low:
Systolic: <90mmHg
Diastolic: <60mmHg
What is classed as an ideal blood pressure gradient in systole?
Systolic: <90mmHg
What is classed as an ideal blood pressure gradient diastole?
Diastolic: <60mmHg
What is pulse pressure?
Pulse pressure:
|»_space; Difference between Systolic & Diastolic Pressure
What is the equation for pulse pressure?
> > Pulse pressure = (Systolic pressure) – (Diastolic pressure)
- >> Systolic -> Higher - >> Diastolic -> Lower
What is the equation for calculation of mean arterial pressure?
Mean arterial pressure:
|»_space; Mean Arterial pressure = Diastolic pressure + 1/3 Pulse pressure
State Darcy’s Law
Darcy’s Law:
The flow of a fluid through -> porous medium.
What does the cardiac cycle determine?
• Cardiac cycle determines force of blood upon ejection -> heart.
Describe the electrical events of the cardiac cycle
- Electrical events:
Initaited by pacemaker -> Sinoatrial node.
Sinotarial node -> Atria
Atria -> Atrioventricular node
»Cell-to-cell conduction
Atrioventricular node -> Bundles of His
»Delays cycle -> 0.1s
>Enabling atrial contraction
Bundles of His -> Ventricular myocardium
»Rapid signal -> enables simultaneous contraction -> ventricular cells
How is the cardiac cycle initiated?
Initaited by pacemaker -> Sinoatrial node.
Describe the pathway of electrical conduction in cardiac cycle
- Electrical events:
Initaited by pacemaker -> Sinoatrial node.
Sinotarial node -> Atria
Atria -> Atrioventricular node
Atrioventricular node -> Bundles of His
Bundles of His -> Ventricular myocardium
ventricular cells
How are electrical currents conducted from the atria to the atrioventricular node?
> > Cell-to-cell conduction
What happens on conduction of electrical signals from AV node to Bundles of his and why does this occur?
> > Delays cycle -> 0.1s
>Enabling atrial contraction
Why is there a rapid signal from bundles of his to ventricular myocardium in cardiac cycle?
> > Rapid signal -> enables simultaneous contraction -> ventricular cells
Describe the mechanical events of the cardiac cycle
Atrial systole
Atrial contraction -> forces blood -> relaxed ventricles
Atrial diastole
Ventricular systole I
Ventricular contraction -> AV valves close
»Insufficient pressure -> Open semilunar valves
Ventricular systole II
Incr. ventricular pressure forces semilunar valves -> open
»Blood ejected
Ventricular Diastole -> Early
Ventricular relaxation -> decr. pressure -> backflow of blood against cusp of valves
»Closes semilunar valves
»Blood flow -> relaxed atria.
Ventricular Diastole -> Late
Relaxation of all chambers
»Passive filling of ventricles
Outline the stages in the mechanical events of the cardiac cycle
Atrial systole Atrial diastole Ventricular systole I Ventricular systole II Ventricular Diastole -> Early Ventricular Diastole -> Late
What happens during atrial systole of cardiac cycle?
Atrial contraction -> forces blood -> relaxed ventricles
What happens during ventricular systole I of cardiac cycle?
Ventricular contraction -> AV valves close
|»_space;Insufficient pressure -> Open semilunar valves
What happens during ventricular systole II of cardiac cycle?
Incr. ventricular pressure forces semilunar valves -> open
|»_space;Blood ejected
What happens during early Ventricular Diastole of cardiac cycle?
Ventricular relaxation -> decr. pressure -> backflow of blood against cusp of valves
»Closes semilunar valves
»Blood flow -> relaxed atria.
What happens during late Ventricular Diastole of cardiac cycle?
Relaxation of all chambers
|»_space;Passive filling of ventricles
What is the role of the ECG?
ECG detects electrical responses -> heart
» Profile -> accumulative representation -> action potentials across heart.
» Reflects stages of cardiac cycle:
i.) Atrial contraction / relaxation
ii.) Ventricular contraction / relaxation
iii.) Conduction velocities -> electrical signals
What is the P-wave?
> > Atrial depolarization & contraction
What is the QRS complex?
»Spread -> electrical signal
>Causes ventricular myocyte depolarisation
& contraction
-»Arterial relaxation event masked -> larger ventricular event.
What is the T-wave?
> > Ventricle repolarisation & relaxation
What is the QT interval?
> > Time from initiation -> ventricular contraction -> end -> ventricular relaxation.