0.2 Cardio-vascular Flashcards
What are the two phases of the cardiac cycle
Systole and diastole
Describe the diastole phase of the cardiac cycle
- atria fills with bloods
- pressure rises
- atrioventricular valves open
- blood passes into ventricles
Describe the Systole phase of the cardiac cycle
- both atria contract
- remaining blood goes to ventricles
- ventricular systole
- they contract at the same time
- blood pressure increases
- AV valve forced shut
- BP into aorta and pulmonary artery
Describe the conduction system
1) Impulse starts at SA node
2) 👋 of contraction goes through atria
3) impulses passed to AV node
4) goes theoght bundle of his
5) split into left and right ventricle
6) purkinje fibres
7) causing ventricular systole
What is stroke volume
Volume of blood ejected from the ventricles in one contraction
What is heart rate
Number of contractions in one min
What is cardiac output
Volume of blood ejected from the ventricles in one min
What is the equation to work out cardiac output
CO= HR x SV
What is heart rate regulated by
The cardiac control centre found in the medulia oblongata of the brain
What is the sympathetic nervous system
The nerves increase heat rate
What is parasympathetic nervous system
The nerves decrease heart rate
What are the three receptors associated within neurole Control
Propro-receptors
Chemoreceptors
Baroceptors
Describe what happens in neurole control
The CCC responds to the receptors by stimulating the SA node by the sympathetic NS, accelerates nerve to increase HR
Parasympathetic- vagus nerve to decrease HR
Describe what happens in hormonal control (3points)
1) Adrenaline is released in the blood
2) anticipatory rise
3) stimulates SA node to increase HR and SV
What happens in intrinsic control
1) increase temp, increase nerve impulse
2) increase HR
3) increase venous return
4) increase myocatdial stretch
5) increase in EDV
6) increase SV
What is venous return
Amount of blood that returns to the heart
What are the 5 machanisms for Venous return
1) pocket valve
2) skeletal muscle pump
3) respiratory pump
4) smooth muscles
5) gravity
What is the vascular shunt mechanism
The process of re-distributing blood supply
Short term effects on cardio vascular
Cardio- increase in HR,SV,EDV,CO
Vascular - increase blood flow, pressure and increase venous return
Long term effects on cardio vascular ?
Cardio- hypertrophy, increase in max SV,CO. More blood to working muscles. Removal of lactic acid. Decrease in resting HR.
Vascular- Greater tolerance to lactic acid, enhanced vascular shunt mechanism, Elasticity of arterial walls
Factors effecting cardio vascular diseases
Smoking, stress, poor diet, lack of exercise
What is atherosclerosis?
- Build up of fatty deposit
- narrows the lumen( possible clots)
- overtime increase in BP then this becomes chronic ( hypertension)
What is the average blood pressure
120/80
What is CHD/ heart attack?
A lack of blood flow and oxygen supply, limits heart functions to respire and angina or HA may occur
HA- when the supply of blood to heart heart is suddenly blocked .
What is a stroke?
A blockage in either the cerebral artery (ischaemic) or a blood vessel bursting on the surface of the brain (haemorrhagic)
What should you do do reduce risk of CVD
30mins + 3-5x a week - low/medium intensity
Why should you exercise to reduce CDV?
1) reduces cholesterol
2) decrease hardening arteries
3) decrease in blood velocity
4) decrease body fat
5) decrease RHR,BP
