1.1 Cardiovascular System Flashcards
Health
A state of complete physical, mental and social well-being and not merely the absence of disease and infirmity/injury.
Fitness
The ability to meet the demands of the environment
Physical activity
Being active and taking part in exercise - can directly benefit your physical health and wellbeing.
Heart rate (HR)
The number of times the heart beats per minute
Anticipatory rise
Slight increase in heart rate usually before activity starts due to the expectation of exercise
Stroke Volume (SV)
The volume of blood that leaves the heart during each contraction
Cardiac output (Q)
The amount of blood the heart pumps out per minute . Measured in litres per minute (L/min)
Q = SV xHR
Systole
Term used to describe the contraction phase of the cardiac cycle - the ventricles contract and pump blood to the arteries
(RV to the pulmonary artery and lungs, LV to the aorta and the body)
Diastole
Term used to describe the relaxation phase of the cardiac cycle.
The heart ventricles are relaxed and fill with blood
What is the Cardiac cycle ?
The mechanic event of ONE heart beat
Explain the diastole phase
The relaxation phase of the cardiac cycle
1. The heart at this point is relaxing and filling up with blood.
2. The atria fill with blood and pressure builds within these chambers.
3. As the pressure increases, the valves begin to slowly open and let small amounts of blood through.
Explain the systole phase
( the contraction part of the cardiac cycle)
Pressure has built up in the atria during diastole phase.
ATRIAL SYSTOLE PHASE
1. Valves are now forced open, both atrial contract and remaining blood is forced into ventricles.
VENTRICULAR SYSTOLE PHASE
1. Blood is now in ventricles, ventricles now contract increasing the pressure within these chambers.
2. Aortic valve and Pulmonary valve are forced open, allowing blood to be pushed through into the Aorta or Pulmonary Artery.
The heart muscle is myogenic. What does this mean?
The ability of the heart to generate its own electrical impulses – the heart muscle starts the beat itself with the electrical signal from the SAN – spreads across the heart like a Mexican wave and is called a wave of excitation.
Explain the Conduction System of the heart
Impulse starts in the SINOATRIAL NODE (SA NODE)
Then the pulse travels down into the ATROVENTRICULAR NODE (AV NODE) and onto the BUNDLE OF HIS.
These impulses here stimulate the atria (0.1 second delay)
From here, the pulse travels down the left and right branches and down into the PURKINJE FIBRES.
Here the ventricles are squeezed.
Short term effects of exercise
- Increased HR due to rising adrenaline levels
- Increase in Stroke Volume due to stronger ventricular contractions
- Increase Cardiac Output
Long term effects of Exercise
- Decrease in RHR
- Thicker left ventricle wall
- Increase in resting stroke volume - more typical in endurance athletes
- hypertrophy of the heart
- increase number of capillaries in muscles = more efficient oxygen delivery to muscles
- improvement in cardiac output during exercise
- increase in blood volume = increase in red blood cells to carry more oxygen
Name the four chambers of the heart
Right atrium and right ventricle Left atrium and left ventricle
Which chambers are larger? Explain why ?
The ventricles are larger because they have to pump the blood further
Which side of the heart is larger ? Explain why ?
Left as it has to push blood around the whole body compared to the right that only pushes blood to the lungs
Name the main blood vessels that enter and leave the heart
Vena Cavae – from body to right atrium, pulmonary artery from RV to lungs, pulmonary vein from lungs to left atrium, aorta from left ventricle to body and back to the vena cavae
What are the names of the valves in the heart and where are they located ?
Tricuspid – between RA and RV
Bicuspid valve between LA and LV
Semi lunar valves – in the pulmonary artery (stops backflow into the RV) and the aorta (stops back flow into the LV)
What is the main function of the valves ?
Prevents back flow of blood
Starting at the venae cavae (inferior and superior vena cava), place the following structures in the correct order that a red blood cell would pass on its journey through the heart
Venae cavae – RA – Tricuspid valve – RV – semilunar valve – pulmonary artery – lungs – pulmonary vein – LA – bicuspid valve – LV – semilunar valve - aorta - body
What is the order that the impulse through the heart travels in
SAN - atrial systole – AVN – bundle of His – bundle branches – purkinje fibres –
ventricular systole
What happens to HR during a football match ?
The heart rate fluctuates as intensities during the match change ie. Standing, jogging or sprinting.
Sinoatrial node (SAN)
A small mass of cardiac muscle found in the wall of the right atrium that generates the
heartbeat. It is more commonly called the pacemaker.
Atrioventricular node (AVN)
This node relays the impulse between the upper and lower sections of the heart.
Systole
When the heart contracts
Bundle of His
A collection of heart muscle cells that transmit electrical impulses from the AVN via the bundle branches to the ventricles.
Purkinje fibres
Muscle fibres that conduct impulses in the walls of the ventricles.