The Cardiovascular System Flashcards
Blood vessels of the heart
The vena cava brings deoxygenated blood back to the right atrium and the pulmonary vein delivers oxygenated blood to the left atrium.
The pulmonary artery leaves the right ventricle with the oxygenated blood to go to the lungs and the aorta leaves the left ventricle with oxygenated blood leading to the body.
Valves of the heart
Open to allow blood to pass through and then close to prevent backflow.
The tricuspid valve is located between the left atrium and right ventricle and the bicuspid valve between the left atrium and left ventricle is.
The semi lunar valves can be found between the right and left ventricles and the pulmonary artery and aorta.
Cardiac Conduction System
A group of specialised cells in the wall of the heart which sent electrical impulses to the cardiac muscle causing it to contract.
Myogenic impulse sent
sinoatrial node
atrioventricular node
Ventricular Systole begins
bundle of his
purkinje fibres
Contraction
sinoatrial node (SAN)
generates heartbeat
(pacemaker)
Atrioventricular node
Please impulse between the upper and lower sections of the heart
systole
heart contracts
bundle of his
transmit electrical impulses from the AVN via the bundle branches to the ventricles
pirkinje fibres
conduct impulses in the walls of the ventricles
sympathetic nervous system
stimulates the heart to beat faster
Impulses sent to the SAN and there is a decrease in parasympathetic nerve impulses so the heart rate increases
parasympathetic nervous system
Returns the heartbeat to resting level
What is the central nervous system made up of?
The brain and the spinal cord
What is the peripheral nervous system made up of?
Nerve cells that transmit information to and from the central nervous system (CNS)
Cardiac control centre
located in medulla oblongata in the brain.
co-ordinates CNS and PNS
stimulated by chemoreceptors, baroreceptors and proprioreceptors
Chemoreceptors
sense chemical changes (increase in CO2 during exercise). stimulates sympathetic nervous system to beat heart faster.
found in carotid arteries and aortic arch
Baroreceptors
Respond to the stretching of the arterial wall caused by changes in blood pressure.
send signals to the medulla oblongata
an increase in arterial pressure causes a decrease in HR
proprioceptors
located in muscles tendons and joints
provide information about movement and body position
send impulse to medulla
hormonal control mechanism
release of adrenaline stimulates SAN which increases speed and force of contraction and cardiac output
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 (70ml increases 40-60% during exercise)
Diastole phase
When the heart relaxes to fill with blood
ejection fraction
The percentage of blood pumped out by the left ventricle per beat (60% but can increase to 85%)
Cardiac output
The volume of blood pumped out by the heart per minute
heart rate
the number of times the heart beats per minute (72)
220 - age = maximum HR
Maximal exercise
anticipatory rise.
Sharp rise in HR due to anaerobic work.
Stress of anaerobic systems.