1.1 Cardiovascular System Flashcards
Structure of the heart
Deoxygenated blood enters the heart through through the pulmonary artery. It passes through the right atrium into the fright ventricle where the vena cava carries the blood out of the heart to the lungs to pick up oxygen. The now oxygenated blood the returns to the heart through the pulmonary vein, through the left atrium and left ventricle where it is sent to the rest of the body.
What are the 3 main blood vessels and their role in the body?
Vein- transports ———- blood into the heart
Artery- transports ——— blood away from the heart
Capillary
Myogenic
The capacity of the heart to generate its own impulses
Sinoatrial 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
The 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
A part of the autonomic nervous system that decreases heart rate
Parasympathetic system
A part of the autonomic nervous system that decreases heart rate
Medulla Oblongata
The most important part of the brain as it regulates processes that keep us alive such as breathing and heart rate
Chemoreceptors
But structures in the carotid artery and aortic arch that detect changes in blood acidity caused by an increase or decrease in the contraction of carbon dioxide
Baroreceptors
Special sensors in tissues in the aortic arch, carotid sinus and heart and pulmonary vessels that respond to changes in blood pressure to either increase or decrease heart rate
Proprioreceptors
Sensory nerve endings in the muscles, tendons and joints that detect changes in muscle movement
Adrenaline
Stress hormone released by sympathetic nerves and cardiac nerve during exercise which causes increase in heart rate
Stroke volume
Volume of bloody pumped out by the heart ventricles in each contraction (ml)
Diastole phase
When the heart relaxes to fill with blood
Ejection fraction
Percentage of blood pumped out by the left ventricle per beat
Cardiac output
The volume of blood pumped out by the heart ventricles per minute
Cardiac hypertrophy
Thickening of the muscular wall of the heart so it becomes bigger and stronger; also can mean a larger ventricular cavity
Bradycardia
A decrease in resting heart rate to below 60 bpm
The cardiac conduction system
Heart generates its own electrical nerve impulses, myogenic. This impulse starts in sinoatrial node. Then passed onto the atrioventricular node. Acts as a distributor and passes action potential to the bundle of His which with the Purkinje fibres spread the impulse through the ventricles
Diastole
Relaxation phase of the cardiac cycle
The relationship between SV, CO and HR
Stroke volume * heart rate= cardiac output
Explain how the chemoreceptors cause an increase in breathing rate
Detected by chemoreceptors in the carotid arteries/aortic arch. Sends impulses to respiratory control centre in medulla. Sends impulses to respiratory muscle via the phrenic nerve/sympathetic system. Increase in rate of contraction of diaphragm and external intercostal muscles therefore breathing rate increases
