CV System - The heart and Cardiac Conduction System Flashcards
what is the definition of systole
the contraction phase of the cardiac cycle - the ventricles contract and pump blood to the arteries(Right Ventricle to the pulmonary artery and lungs, Left Ventricle to the aorta and the body)
what is the definition of diastole
Term used to describe the relaxation phase of the cardiac cycle. The heart ventricles are relaxed and fill with blood
what vein carries blood back to the heart
superior vena cava (delivers deoxygenated blood from any part above the heart)inferior vena cava (delivers deoxygenated blood from any part below the heart)
what chamber in the heart does the both vena cava’s empty into
right atrium
what artery takes blood to the rest of the body
aorta
what prevents the backflow of blood
valves
what are the three valves in the heart
tricuspid valvebicuspid valvesemilunar valves
what is the sheet of cardiac muscle between both ventricles called
inter-ventricular septum
why does the left side of the heart have more cardiac muscle than the right
the left side holds oxygenated blood, this blood needs to be pumped to the rest of the body. the larger muscle size allows the heart to generate enough force necessary to pump the blood to the whole body
what is the pathway of blood
- Venae Cavae (Superior and Inferior)2. Right Atrium3. Tricuspid Valve4. Right Ventricle5. Pulmonary semilunar valve6. Pulmonary artery7. LUNGS to drop off CO2 and pick up O28. Pulmonary Veins9. Left Atrium10. Bicuspid valve11. Left ventricle12. Aortic semilunar valve13. Aorta14. BODY
why is a trained person resting heart rate lower than untrained person
cardiac hypertrophy -> heart is bigger -> pumps more blood -> larger SV ->increased size of chambers -> bigger SV -> heart doesn’t have to beat as many times
what is the heart conduction system
the system that allows the heart to produce a heart beat
why is the heart myogenic
because it has the ability to make its own electrical impulse
what is the first stage of the heart conduction system
the sinoatrial node will send an electrical impulse throughout the atria
what happens in the second stage of the heart conduction system
the impulse spreads across the atria, this will cause the atria to contract
what happens in the fourth stage of the heart conduction system
the impulse then travels through the bundle of his which then divides into two branches and then again into purkinje fibres
what happens in the fifth and final stage of the heart conduction system
this allows the impulse to spread throughout the ventricles causing them to contract - also known as ventricular systole
What are the three main mechanisms that can control the impulses from the SAN
Sympathetic nervous systemParasympathetic nervous systemMedulla Oblongata
What is the sympathetic system
A part of the autonomic nervous system that speeds heart rate
What is the Parasympathetic System
A part of the autonomic nervous system that decreases heart rate
What is the medulla oblongata
The most important part of the brain as it regulates processes that keep us alive such as breathing and heart rate
What is the ANS
Autonomic nervous system
What does the ANS do
Determines the rate at which the SAN sends out impulses
How does the sympathetic nervous system increase HR
It releases adrenaline
What does adrenaline increase in the sympathetic nervous system
It increases the strength of ventricular contraction which then increases stroke volume
In the sympathetic nervous system what does noradrenaline do
Aids the spread of electrical impulse throughout the heart, increasing HR
In the sympathetic nervous system what does an increased metabolic rate cause
Increased CO2 and lactic acid, decrease in blood PH (more acidic)
How are the changes of an increased metabolic rate picked up
By the chemoreceptors and they inform the sympathetic system to increase HR to flush out the waste products. This results in an increased cardiac output
What is the parasympathetic nervous system
The nervous system that slows the speed of the heart down which decreases HR
What does the parasympathetic nervous system do to lower the heart rate
Releases Acetylocholine which slows the spread of impulses throughout the heart, this results in a lower heart rate
