Cardiorespiratory System Flashcards
Why is the heart muscle described as myogenic
The heart is described as myogenic because it can generate it’s own electrical impulses
Describe the hearts cardiac conduction system
The heart generates it’s own electrical impulse from an electrical signal from the SAN
The impulse spreads across the heart and is called a wave of exication. This causes the atria systole and the atrium to contract
The impulse passes through the AVN where it is delayed for 0.1s to allow for atria and ventricle to fully contract
The impulse passes through the bundle of his which then divides into 2 branches then again into the purkinje fibres
This allows the impulse to spread throughout the ventricles causing them to contract. This is known as ventricular systole
What is the definition of diastole ?
Term used to describe the relaxation phase of the cardiac cycle. The heart ventricles are relaxed and fill with blood
What is the definition of systole ?
Term used to describe the contraction phase of the cardiac cycle - the ventricles contract and pump blood into the arteries
What is the definition of stroke volume ?
The volume of blood that leaves the heart during each contraction
What is the definition of health ?
A state of complete physical, mental and social well-being and not merely the absence of disease and injury
What is the definition of fitness ?
The ability to meet and cope with the demands of the environment
What is the definition of physical activity ?
Being active and taking part in exercise - can directly benefit your physical health and well-being
What is the definition of heart rate ?
The number of times the heart beats per minute
What is the definition of anticipatory rise ?
Slight increase in heart rate usually before activity starts due to the expectation of exercise
What is the definition of cardiac output ?
The amount of blood the heart pumps out. Measured in litres per minute
Q = SV x HR
State how exercise and being fit improves your physical health
Cardiovascular and respiratory improvement
Cardiac muscles surrounding the heart pump a greater volume of blood
Lungs become stronger
Decrease in resting heart rate
State the pathway of blood throughout the heart
Vena cava (superior and inferior)
Right atrium
Tricuspid valve
Right ventricle
Semilunar valve
Pulmonary artery
Lungs
Pulmonary vein
Left atrium
Bicuspid valve
Left ventricle
Aortic semilunar valve
Aorta
Body
What does the sympathetic nervous system do ?
Increases HR by releasing adrenaline
Adrenaline increases the strength of ventricular contraction which then increases stroke volume
Noradrenaline aids the spread of electrical impulse throughout the heart increasing HR
Increased metabolic activity causes increased concentration of CO2 and lactic acid, decreasing pH of blood
These changes are picked up by the chemoreceptors and inform the sympathetic centre to increase HR to flush out waste products
This results in an increased cardiac output
What does the parasympathetic nervous system do ?
Releases acetylcholine which slows the spread of impulses throughout the heart
This causes a lower HR
