Lesson 61/62 - Heart structure and cardiac cycle Flashcards
(19 cards)
What are the coronary arteries for?
They supply the heart muscle with blood, enabling its muscles to respire.
What are parts of the heart?
Aorta
Pulmonary artery
Semilunar valve x2
Right atrium
Left atrium
Tricuspid and bicuspid valves (atrioventricular valves)
Left ventricle
Right ventricle
Ventricular septum
Vena cava
Pulmonary vein
What do the blue and red colours represent in a heart diagram?
Red: Oxygenated blood (Left)
Blood that contains oxygen
Blue: Deoxygenated blood (Right)
Blood that does not contain oxygen
What are the 4 stages of blood movement round the body?
- Deoxygenated blood is pumped from the heart to the lungs
- The blood receives oxygen and is pumped back to the heart
- The oxygenated blood is then pumped to the rest of the body
- The oxygen leaves the blood to be used for respiration in the body and the blood goes back to the heart
What happens during 1 heartbeat (1 cardiac cycle)?
- A heartbeat lasts around 0.8 seconds
- During a heartbeat the atria will receive blood from the veins
- The atria will contract and push blood into the ventricles
- The ventricles will contract pushing blood into the arteries
- The atria and ventricles will relax allowing the heart to fill with blood
What are the different types of valves?
- Pocket valves – in veins
- Atrioventricular valves- between atria and ventricles
- Semilunar valves - in aorta and pulmonary artery (only arteries that have valves!)
How are valves controlled by pressure?
- High pressure behind the valve forces it to open
- High pressure in front of the valve closes it
What are the 3 stages of the cardiac style?
- Atrial Systole
- Ventricular Systole
- Diastole
What happens in atrial systole?
- Atria muscles contract, and pressure increases
- Semi-lunar valves in vena cava and pulmonary vein close
- The atrioventricular valves open, allowing blood into the ventricles
What happens in ventricular systole?
- The ventricle muscles contract
- The pressure inside the ventricles increases
- The atrioventricular valves close
- The semi-lunar valves in the aorta and the pulmonary arteries open
What happens in diastole?
- Pressure in the ventricles decreases
- The semi-lunar valves in the aorta and pulmonary arteries close
- All the heart muscles relax
- Blood flows into the atria from the vena cava and pulmonary vein
- Blood pressure remains low inside the atria and ventricles
Which blood vessel that takes oxygenated blood to the body?
Aorta
What is the name of the blood vessel that takes deoxygenated blood to the lungs?
Pulmonary artery
Why is the muscle on the left side of the heart thicker than the right?
Needs to provide more force as is sending blood all the way round the body (not just to lungs)
What is the job of the semilunar valves?
What is the job of the tricuspid and bicuspid valves?
Stop blood flowing back into the heart after leaving via arteries
Stops blood flowing back into atria from ventricles during contraction of ventricles. Blood instead leaves heart via arteries
Why is the left side of the heart separated from the right?
Efficient supply of oxygenated blood to tissues (separates oxygenated from deoxygenated blood)
Why do atria have thinner walls than ventricles?
Receive blood at low pressure. Pump to ventricles only.
What is the formula for cardiac output?
cardiac output = stroke volume x heart rate
Cardiac output: vol. of blood pumped by the heart per minute
Heart rate: Number of beats per minute
Stroke volume: Volume of blood pumped during each heartbeat
What are the cords in the heart for?
They attach the atrioventricular valves to the ventricles to stop them being forced up into the atria when the ventricles contract.
