Mrs Rex 1.1 - CV System Flashcards
Systole
Describes the contraction phase of the cardiac cycle. The ventricles contract and pump blood to the arteries.
Diastole
Relaxation phase of cardiac cycle. The heart ventricles are relaxed and fill with blood.
5 stages of cardiac conduction system
1) SA node fires
2) impulse spreads through atrial myocardium
3) AV node fires
4) Excitation spreads down bundle of his
5) purkinje fibres distribute impulse through ventricular myocardium
What valve prevents back flow of blood from pulmonary valve to RA?
The semilunar valve
What 2 arteries are semilunar valves in?
Pulmonary artery, aorta
The heart is myogenic, what does that mean?
It has the ability to generate it’s own electrical impulses.
Cardiac muscle hypertrophy
Heart muscle becomes bigger after exercise and therefore cardiac output increases
Sympathetic system
Part of the autonomic nervous system which speeds up heart rate.
Parasympathetic system
A part of the autonomic nervous system that decreases heart rate.
Medulla oblongata
Most important part of the brain as it regulates processes that keep us alive such as breathing and HR.
Chemoreceptors
Detect an increase in CO2 and increase heart rate.
Baroreceptors
Detect an increase in blood pressure and decrease heart rate.
Proprioceptors
Detect an increase in muscle movement and increase heart rate.
Anticipatory rise
When you know you’re about to do exercise, your heart rate increases slightly.
Adrenaline
A stress hormone released by the sympathetic and cardiac nerves during exercise which increases heart rate.
Diastole phase
When the heart relaxes to fill with blood.
Ejection fraction
The percentage of blood pumped out by the left ventricle per beat.
Plasma
The fluid part of the blood, mainly made of water.
Haemoglobin
Iron containing pigment in red blood cells which combines with oxygen to form oxyhemoglobin.
Myoglobin
Iron containing muscle pigment in slow twitch muscle fibres which has a higher affinity for oxygen than haemoglobin. It stores the oxygen in muscle fibres which can quickly be used when exercise begins.
Mitochondria
The powerhouse of the cell where all chemical reactions and energy production takes place.
Pathway of the blood in the heart
Vena cava > right atrium > tricuspid valve > right ventricle > pulmonary semi lunar valve > pulmonary artery > lungs > pulmonary veins > left atrium > bicuspid valve > left ventricle > aortic semi lunar valve > aorta > rest of body
Myogenic
The capacity of the heart to generate its own impulses
SAN
Small mass of cardiac muscle found in wall of the right atrium that generates the heart beat. More commonly called the pacemaker.
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 ventricles.
Cardiac output
Volume of blood pumped out by the heart per minute
SV x HR =
Cardiac output (Q)
Cardiac hypertrophy
The thickening of the muscular wall of the heart so it becomes bigger and stronger; also can mean a larger ventricular cavity.
Bradycardia
When someone’s rhr is below 60bpm
Steady state
When the athlete is able to meet the oxygen demand with the oxygen supply.
Cardiovascular drift
the phenomenon where some cardiovascular responses begin a time dependent change, or “drift” after around 10 minutes of exercise in a warm or neutral environment without an increase in workload.
Systolic pressure
The pressure in the arteries when the ventricles are contracting.
Diastolic pressure
The pressure in the arteries when the ventricles are relaxing.
The skeletal muscle pump (venous return)
When muscles contract and relax they change shape. This means they press against nearby veins and create a pumping effect, squeezing blood towards the heart.
The respiratory pump (venous return)
When muscles contract and relax during breathing, pressure changes in the thoracic and abdominal cavities. These changes in pressure compress nearby blood vessels, pumping blood back to the heart.
Pocket valves (venous return)
Ensure that the blood only travels in one direction in the veins. They close to prevent the back flow of blood.
Myoglobin
Often called ‘muscle haemoglobin’, it is a muscle pigment in slow-twitch muscle fibres which stores oxygen so that it can be used quickly at the start of exercise.
Vasodilation
The widening of the blood vessels to increase the flow of blood into the capillaries.
Vasoconstriction
The narrowing of the blood vessels to reduce the flow into the capillaries.
Vascular shunting
Redistribution of cardiac output.
