Heart ( 2 ) Flashcards
What direction does oxygenated blood pass through?
Oxygenated blood passes through the left side of the hear
What vessels is the heart supplied by?
Coronary Arteries, these are used to provide oxygen to the heart
Where are the coronary arteries present?
They branch off the aorta shortly after it leaves the heart
What can cause a myocardial infarction?
- Blockage of coronary arteries which supply blood to the arteries
- An area of the heart muscle will be deprived of blood and therefore oxygen also, muscles cells in this region are unable to respire and so they die
How are the ventricles adapted?
- Ventricles have thicker walls than the atria, because they have to push blood out of the heart whereas atria need to push blood a short distance tot he ventricles
- Left ventricle is thicker more muscular than the right ventricle because it needs to contract more powerfully to pump blood all the way round the body, the right side only needs to get blood to the lungs
How does smoking affect risk of cardiovascular disease?
- Carbon monoxide combines irreversibly with haemoglobin in the red blood cells to form carboxyhaemoglobin.
- Reduces the oxygen carrying capacity of the blood
- To supply the equivalent quantity of oxygen to the tissues, the heart works harder
- This raises blood pressures increases the risk of coronary heart disease and strokes
- Reduction of oxygen carrying capacity of bloods means it is insufficient to supply the heart muscle during exercise, and can lead to a heart attack
How does nicotine affect the body?
Stimulates the production of hormone adrenaline, which increases heart ate and raises blood pressure
• Greater risk of suffering coronary heart disease of a stroke
• Nicotine makes platelets in the blood sticky, leading to a higher risk of thrombosis, which can lead to a heart attack
How does high blood pressure increase the risk of heart disease?
- Higher pressure in the arteries means the heart must work harder to pump blood into them, which makes them more prone to failure
- Higher blood pressure within the arteries means that they are more likely to develop an aneurysm and burst causing a haemorrhage
- To resist higher pressure, the walls of the arteries tend to become thickened and harden, restricting the flow of blood
What area HDLs?
- Remove cholesterol from tissues and transport it to the liver for excretion
- Help protect arteries against heart disease
- LDLs transport cholesterol from the liver to the tissues including the artery walls, which they infiltrate leading to atheroma, which can cause heart disease
How can diet affect risk of heart disease?
- High levels of salt raise blood pressure
* High levels of saturated fat increase LDL levels and blood cholesterol concentration
How does atheroma affect arteries?
- Atheroma plaques damage and weaken arteries.
- They narrow arteries, increasing blood pressure
- Atheroma plaque can rupture the endothelium, of an artery
- Damages the artery wall and leaves a rough surface
How can an atheroma cause aneurysms?
• When blood travels through a weakened artery at high pressure, it may push the inner layers of the artery through the outer elastic layer to form a swelling > aneurysm.
How can an atheroma cause thrombosis?
- Damage to the artery wall leaves a rough surface
- Platelets and fibrin accumulate at the site of damage and form a blood clot
- Blood clot can cause a complete blockage of the artery, or it can become dislodged and block a blood vessel elsewhere in the body
- Debris from rupture can cause another blood clot to form further down the artery
How are arteries adapted?
- Arteries divide into smaller vessels called arterioles
- These form a network throughout the body, blood is directed to different areas of demand in the body by muscles inside the arterioles
- Which can contract to restrict the blood flow or relax to allow full blood flow
How are veins adapted?
- Veins take blood back to the heart under low pressure
- They have a wider lumen than equivalent arteries with very little elastic or muscle tissue
- Veins contain valves to stop the blood flowing backwards
- Blood flow through the veins is helped by contraction of the body muscles surrounding the them
- All veins carry deoxygenated blood except for pulmonary veins
