Topic 1: Heart Flashcards
Key Summary: Why do many animals need a heart?
2 points
- To GENERATE PRESSURE to PUMP BLOOD around the body for MASS {TRANSPORT/FLOW}
- To OVERCOME THE LIMITATIONS OF DIFFUSION - as diffusion is not fast enough to ensure FAST ENOUGH DELIVERY of OXYGEN to all body cells, especially as many body cells are far from the gas exchange surface
Name all blood vessels in the heart
6 blood vessels
- Coronary arteries
- Coronary veins
- {Superior/inferior} vena cava
- Aorta
- Pulmonary artery
- Pulmonary vein
NOTE: superior comes from above the heart, inferior comes from below the heart
What is the purpose of the coronary arteries?
1 point
- deliver oxygenated blood from heart (chambers) to heart muscle cells (via capillaries)
What is the purpose of coronary veins?
1 point
- deliver deoxygenated blood from heart muscle cells to vena cava
What is the purpose of vena cava?
1 point
- carries deoxygenated blood from body cells to right atrium of the heart
What is the purpose of the aorta?
1 point
- carries oxygenated blood from left ventricle of heart to body cells
What is the purpose of the pulmonary artery?
1 point
- deoxygenated blood from right ventricle to lungs
What is the purpose of the pulmonary vein?
1 point
- oxygenated blood from lungs to left atrium
Key Summary: What is the function of the atrioventricular valves?
(3 points)
- OPEN DURING DIASTOLE (relaxation) to allow ventricles to fill up as atria are filling
- OPEN DURING ATRIAL SYSTOLE (contraction) to allow blood to pass from atria to ventricles
- CLOSE DURING VECTRICULAR SYSTOLE (contraction) to PREVENT BACKFLOW OF BLOOD from ventricles into the atria
Key Summary: What is the function of the semilunar valves?
2 points
- Open during ventricular systole (contraction) to allow blood to flow from ventricles into aorta and pulmonary artery
- Close during ventricle diastole (relaxation) to prevent backflow of blood from aorta and pulmonary artery into ventricles
Key Summary: Why is the left ventricle wall thicker than the right ventricle wall?
(4 points)
- Left ventricle wall has more muscle
- Thickness of muscular wall is related to blood pressure required
- Left ventricle pumps blood a FURTHER DISTANCE TO ALL PARTS OF THE BODY (except lungs) so it needs a thicker wall of muscle to GENERATE A HIGHER FORCE AND HIGHER PRESSURE to pump the blood against GREATER RESISTANCE.
- The RIGHT ventricle has a thinner wall, as it pumps blood a shorter distance to the LUNGS, WHICH ARE CLOSER TO THE HEART.
Key Summary: Explain why atria have thinner walls than ventricles.
(4 points)
- Right atrium wall has less muscle
- Thickness of muscular wall is related to blood pressure required – more muscle generates a greater force of contraction which can pump blood a greater distance
- Atria only pump blood to ventricles which are a shorter distance from them
- Ventricles have to pump blood a greater distance to reach lungs (RV) or the rest of the body (LV)
Key Summary: Why are two sides of the heart separate?
3 points
- It keeps OXYGENATED AND DEOXYGENATED BLOOD SEPARATED which MAINTAINS STEEP GAS CONCENTRATION GRADIENTS for a fast rate of DIFFUSION in lungs which results in as much oxygen as possible being carried to body tissues by MASS FLOW to allow {high activity/high rate of metabolism}
- Blood can be pumped to the lungs and body at DIFFERENT PRESSURES - higher pressure to body to deliver oxygen more quickly and efficiently, lower pressure to lungs so that delicate lung capillaries do not burst
- Allows REPRESSURISATION – oxygenated blood returning from lungs gets an extra ‘boost’ to increase the pressure of blood to the body
The walls of the heart chambers are made of ________ ________.
cardiac muscle
Name all the parts on the left side of the heart
6 parts
- Aorta
- Pulmonary veins
- Left atrium
- Atrioventricular valve
- Left ventricle
- Semilunar valve (leads to aorta)
