Week 3: The cardiovascular system Flashcards
What is the purpose of the CV system?
Controls blood transport around the body
Regulation of body temperature
Immune function
What does the blood transport in the CV system?
Transports O2 and nutrients to tissues
Removal of CO2 and waste from tissues
Transport of hormones
What are the components of the CV system?
Heart
Arteries and arterioles
Capillaries
Veins and venules
What are the two main components of the cardiac cycle?
Diastole
Systole
What occurs in the diastole phase of the cardiac cycle?
Cardiac muscle relaxes
Ventricles fill with blood
Aortic valves open
During the diastole phase of the cardiac cycle what has higher pressure the atria or the ventricular? What does this cause?
Atria therefore blood flows into the ventricle
What occurs during the systole phase of the cardiac cycle?
Cardiac muscle contracts
Pressure rises in ventricles
Blood ejected in pulmonary and systemic circulation
Semilunar valves open
What are the three recognisable electrical activity waves of the heart?
P wave (atrial depolarisation) QRS complex (Ventricular repolarisation) T wave (ventricular repolarisation)
What does it indicate if the electrical activity of someones heart is abnormal?
Indicates disease
What is the frequency of the heart known as?
Beats per minute
What are is the resting BPM values for untrained males and females?
70 BPM
What is the resting BPM in trained males?
50 BPM
What is the resting BPM in trained females?
55 BPM
What is tachycardia?
When someone heart rate exceeds the normal resting rate
What is the resting BPM of someone with bradycardia?
less than or equal to 60
What is stroke volume?
Amount of blood pumped per heart beat (ml)
What is the resting BPM of someone with tachycardia?
Greater than or equal to 100
How is stroke volume calculated?
End diastolic volume - End systolic volume (Before contraction - After contraction)
What is ejection fraction?
The proportion of blood pumped out of the left ventricle each beat
What is an untrained males stroke volume?
70ml
What is an untrained females stroke volume?
55ml
What is a trained males stroke volume?
100ml
What is a trained females stroke volume?
70ml
What is ejection fraction?
The proportion of blood pumped out of the left ventricle each beat as a percentage
What is blood pressure?
The force exerted by blood against the arterial walls during cardiac cycle (mmHg)
What is ejection fraction basically calculating?
How much of what was in the left ventricle got pumped
What is the average resting ejection fraction?
60%
What is cardiac output?
The total volume of blood flow from the heart per minute (L/min)
What pressure does systolic blood pressure measure?
Lowest pressure within the vascular system
What is the average cardiac output when resting?
5 L/min
What is rate-pressure product?
An estimate of myocardial workload and resulting O2 consumption
What does rate pressure product equal?
SBP x HR
How is vessel resistance calculated?
(Vessel length x Viscosity)/ Vessel radius foured
How is vessel flow calculated?
Pressure gradient / Resistance
What is the normal values for systolic blood pressure?
120 mmHg
What is the normal values for systolic blood pressure?
80 mmHg
What happens to the radius and resistance during vasodilation?
Radius increases
Resistance to flow decreases
What determines blood pressure?
Blood volume Stroke volume Peripheral resistance Heart rate Blood viscosity
What does the cardiac control centre consist of?
Cardioaccelerator centre (SNS) Cardioinhibitory centre (PNS)
What does the parasympathetic nervous system do to your HR?
Decreases it
What does the sympathetic nervous system do to your HR?
Increases
What does the sympathetic nervous system do to your HR?
Increases
What does the sympathetic nervous system do to your veins?
Increases ventricular contrarily
What does sympathetic nervous system activate?
Sympathetic cardiac accelerator nerves
What does the SNS and PNS regulate?
BP and blood flow
What does the SNS and PNS regulate?
BP and blood flow
How does EDV (end-diastolic volume) effect stroke volume?
Volume of blood in the ventricles at end of diastole
Ventricular preload
How does the average aortic blood pressure effect stroke volume?
Pressure the heart must pump against to eject blood
Ventricular afterload
How does the strength of the ventricular contraction effect stroke volume?
Ventricular contractility
What does a greater EDV result in?
More forceful contractions
What causes venoconstriction?
SNS (Sympathetic nervous system)
How does the skeletal muscle pump work?
Rhythmic skeletal muscle contractions force blood in the extremities towards heart
What does the skeletal muscle pump prevent?
Back flow with veins
What does the respiratory pump do?
Changes in thoracic pressure compress veins
What does the respiratory pump do?
Changes in thoracic pressure compress veins
What to the radius of the vessel, resistance and blood flow during vasodilation?
Radius increases
Resistance decreases
Blood flow increases
What happens to ventricular SNS activity increases?
Ventricular contraction
What is the cardiac cycle?
Mechanical and electrical events that occur during one beat
What is the cardiac cycle?
Mechanical and electrical events that occur during one beat
What does the P wave show us?
Atrial depolarisation
What does the QRS complex show us?
Ventricular depolarisation
What does the T wave show us?
Ventricular repolarisation
What does the T wave show us?
Ventricular repolarisation
What does the parasympathetic nervous system release?
Acetylcholine
What does the sympathetic nervous system activate?
Sympathetic cardiac accelerator nerves
What do baroreceptors do?
Measure blood pressure
How does the HR increase from resting to 100 BPM?
WIthdrawal of PNS
How does the heart increase past 100 BPM?
Activation of SNS
How do we alter EDV therefore altering stroke volume?
Venous return
Vasodilation
Ventricular contraction
What regulates stroke volume?
EDV
Average aortic blood pressure
Strength of the ventricular contraction
