Cardiovascular System Keywords Flashcards
Myogenic
The capacity of the heart to generate its own impulses
Sinoatrial node (SAN or SA node)
A small mass of cardiac muscle found in the wall of the right atrium that generates the heartbeat.
More commonly called the pacemaker
Atrioventricular node (AVN or AV 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
Sympathetic system
Part of the autonomous nervous system that speeds up heart rate
Parasympathetic system
Part of the autonomic nervous system that decreases heart
Medulla oblongata
Most important part of the brain as it regulates processes that keep us alive such as breathing and heart rate
Chemoreceptors
Tiny structures in the carotid arteries and aortic arch that detect changes in blood acidity caused by an increase or decrease in the concentration of carbon dioxide
Baroreceptors
Special sensors in tissues in the aortic arch, carotid sinus, heart and pulmonary vessels that respond to changes in blood pressure to either increase or decrease heart rate
Proprioceptors
Sensory nerve endings in the muscles, tendons and joints that detect changes in muscle movement
Adrenaline
A stress hormone that is released by the sympathetic nerves and cardiac nerve during exercise which causes an increase in heart rate
Stroke volume
The volume of blood pumped out by the heart ventricles in each contraction
Ejection fraction
The percentage of blood pumped out by the left ventricle per beat
Diastole phase
When the heart relaxes to fill with blood
Cardiac output
The volume of blood pumped out by the heart ventricles per minute
Cardiac hypertrophy
The thickening of the muscular wall of the heart so it becomes bugger and stronger; also can mean a larger ventricular cavity
Bradycardia
A decrease in resting heart rate to below 60 beats per minute
Atherosclerosis
Occurs when arteries harden and narrow as they become clogged up by fatty deposits
Atheroma
A fatty deposit found in the inner lining of an artery
Angina
Chest pain that occurs when the blood supply through the coronary arteries to the muscles of the heart is restricted
Stroke
Occurs when blood supply to brain is cut off
Steady state
Where the athlete is able to meet oxygen demand with the oxygen supply
Blood pressure
The force exerted by the blood against the blood vessel wall
Systolic pressure
The pressure in the arteries when the ventricles are contracting
Diastolic pressure
The pressure in the arteries when the ventricles are relaxing
Venous return
The return of blood to the right side of the heart via the vena cava
Plasma
The fluid part of the blood (mainly water) that surrounds blood cells and transports them
Haemoglobin
An iron-containing pigment found in red blood cells, which combines with oxygen to form oxyhaemoglobin
Myoglobin
Often called ‘muscle haemoglobin’
An iron containing muscle pigment in slow-twitch muscle fibres which has a higher affinity for oxygen than haemoglobin.
It stores the oxygen in the muscle fibres which can be used quickly when exercise begins
Mitochondria
‘Powerhouse of cell’
Where respiration and energy production occur
Bohr shift
When an increase in blood CO2 and a decrease in pH results in a reduction of the affinity of haemoglobin for oxygen
pH
A measure of acidity
The range goes from 1-14
Anything less than 7 indicates acidity
Vascular shunt mechanism
Redistribution of cardiac output
Vasodilation
Widening of blood vessels to increase the flow of blood into capillaries
Vasoconstriction
The narrowing of the blood vessels to reduce blood flow into capillaries
Arterio-venous difference
A-VO2 diff
The difference between the oxygen content of the arterial blood arriving at the muscles and the venous blood leaving the muscles
