The Heart Flashcards
What is the heart made of ?
Cardiac muscle ( specialised tissue that can contract continuously without tiring ). Has to be supplied with oxygen and glucose.
Order of blood flow through the heart
Vena Cava
Right Atrium
Right Ventricle
Pulmonary Artery
-Lungs-
Pulmonary Vein
Left Atrium
Left Ventricle
Aorta
Why is the left side of the heart thicker than the right side ?
To pump blood around the whole body, rather than just to the lungs
Why are there valves in the heart ?
To prevent backflow, ensuring that oxygenated blood and deoxygenated blood go in the right directions.
Why is a double circulatory system useful ?
It separates oxygenated and deoxygenated blood into different circuits. It allows for low and slow pressure in lungs but high and fast pressure around the body.
What are the names of the 2 circuits in the circulatory system ?
Pulmonary circuit
Systemic circuit
What is open circulation ?
Blood comes into direct contact with tissues
What is closed circulation ?
Blood circulates within enclosed vessels
Where are pacemaker cells located ?
Right atrium. They generate electrical signals which cause the heart to contract.
What is plasma ?
Makes up 55% of blood.
The fluid part of blood.
Transports dissolved substances eg hormones, antibodies, co2, nutrients
Distributes heat
What are platelets ?
Cell fragments which are essential for blood clotting. They produce enzymes.
What are red blood cells ?
They carry oxygen via haemoglobin. They have a bi-concave shape and are small and flexible. They have no nucleus.
What are white blood cells ?
2 types - Lymphocytes, which produce antibodies, and phagocytes, which ingest and destroy invading microorganisms.
They are large and have large nuclei
How is oxygen carried in blood ?
Binds to red pigment, haemoglobin, in our red blood cells.
This is weak and reversible binding to form oxyhemoglobin.
How is carbon dioxide carried in our blood.
Dissolves in plasma to form carbonic acid.
Also binds to haemoglobin.
What is the function of arteries ?
They carry blood away from the heart to organs.
When blood passes through them, arteries stretch and can return to the same shape.
They have thick walls containing muscle and elastic fibres.
Small lumen
What is the function of a vein ?
They carry blood away from organs back to the heart.
They have thinner walls than arteries, and valves to prevent backflow as they are in low pressure.
They have a large lumen.
What is the function of capillaries ?
They form huge networks of tiny vessels linking arteries to veins.
They are narrow with single cell walls to enable substances to diffuse easily out of blood and into cells ( and vice versa ).
What is coronary heart disease ?
Where fatty deposits containing cholesterol build up along the blood vessel going to the heart, which can stop blood flow to the heart, potentially causing a heart attack
How is cholesterol carried in the blood ?
Low density lipoprotein and high density lipoprotein
How are saturated fats bad for you ?
They raise LDL in you blood, which increases risk of heart disease and strokes
Why is HDL good for you ?
It removes cholesterol from where there is too much of it, to the liver, where its disposed of.
Risks for coronary heart disease
Diet high in saturated fats
Smoking
Alcohol
Stress
Lack of exercise
Obesity
Symptoms of coronary heart disease
Fatigue
Weakness
Breathing problems
High heart rate
Decreased cardiac output
Pale
Heart palpitations
Heart attack
Chest pain
What is a stent ?
A metal grid that is placed into an artery to allow the blood to flow.
A catheter with a balloon is inserted into the blood vessel. When it has found the narrow section of the artery, the balloon is inflated, the stent expands and keeps the artery open.
Blood and oxygen can then flow freely around the body.
Pros of stents
Lowers the risk of a heart attack
Works for a long period of time
Recovery time is short
Cons of a stent
Risks of a blood clot
Complications during surgery
Risk of infection
What are statins ?
Drug ( taken daily ) that lower the level of LDL and increase the level of HDL.
They also reduce fatty deposits and prevent new ones forming.
Pros of statins
Reduce fatty deposits and prevent new ones forming
Increase HDL and lower LDL
Non invasive
Cons of statins
Cause headaches, nausea and liver failure
Doesn’t work instantly
Need regular monitoring
What is an artificial heart ?
A mechanical device that replaces the function of the heart.
It is temporary whilst a donor heart is being found, or to allow the heart to rest.
Cons of an artificial heart
Surgery risks bleeding out and infection
Risk of clotting, leads to strokes
Must take blood thinners
Pros of artificial heart
Not easily rejected
What is a heart transplant ?
If the heart is severely damaged, it may be necessary to have a heart transplant to save their life.
Cons of heart transplants
Must take immunosuppressants
Could be rejected
Essential to find a donor match, may be difficult
Tachycardia
Heartbeat is too quick
Bradycardia
Heartbeat is too slow
What is a pacemaker ?
A small box that sits on your chest with wires going into your heart that send electrical currents, which make your heart beat
