Unit 1: Section 5 - Circulatory System Flashcards
The right side of the heart pumps what blood to were?
Deoxygenated to the lungs
The left side of the heart pumps what blood to were?
Oxygenated to the body
Where does deoxygenated blood enter the heart?
Vena cava
Where does deoxygenated blood leave the heart?
Pulmonary artery
Where dos oxygenated blood enter the heart?
Pulmonary vein
Where does oxygenated blood leave the heart?
Aorta
Are the atriums or ventricle at the bottom of the heart?
Ventricles
What valves control what blood enter the ventricles?
Atrioventricular valves
What valves control what blood leaves the ventricles?
Semi-lunar valves
On the drawing what side will the right atrium be on?
The left hand side
Where are cords attached in the heart and what is their purpose?
They attach the atrioventricular valve to the ventricles to stop them being forced up into the atria when the ventricles contract
Why does the left ventricle have a thicker more muscular wall?
Because it needs to contract powerfully to pump blood all the way around the body
Why do the ventricles have thicker walls than the atria?
Because they need to pump blood out of the heart where as the atria just need to pump it a small distance
Why are there valves in the heart?
To stop blood from flowing backwards
What happens when there is higher pressure behind a valve and when there is higher pressure in front of the valve?
Forced open
Forced shut
What does the cardiac muscle is myogenic mean?
It can contract and relax without receiving signals from nerves
What is the pace maker of the heart called
Sino atrial node (SAN)
How does the SAN make the left and right atria contract at the same time?
It sends out regular electrical waves to both atrial walls, which causes them to both contract
Why are the electrical impulses passed from the SAN to the AVN?
There is non conducting tissue preventing the electrical waves reaching the ventricles, so to get these to contract the waves have to be passed to the AVN.
What does AVN stand for?
atrioventricular node
How does the AVN make the ventricles contract?
It passes the electrical waves down the bundle of His, which passes it onto the finer muscle fibres called the Purkyne fibres. The purkyne fibres carry the electricl impulse tot the left and right ventricular walls and causes them to contract
Why is there a delay before the AVN reacts?
To make sure the ventricle contract after the atria are emptied
What is cardiac output?
The volume of blood pumped by the heart per minute
What is the formula for cardiac output?
Cardiac output = stroke volume x heart rate
What is heart rate?
The number of heart beats per minute
What is stroke volume?
The volume of blood pumped during each heartbeat
What three stages can the cardiac cycle be simplified into?
- ) ventricles relax, atria contract
- ) ventricles contract, atria relax
- ) ventricles relax, atria relax
Why is blood forced into the ventricles when the atria contract?
It decreases the volume of the chamber, increasing the pressure pushing the blood through the valves into the ventricles
What happens when the ventricles contract?
It decreases the volume of the chamber, increasing the pressure, forcing the atrioventricular valves shut, forcing the semi lunar valves opening, forcing the blood out of the arties?
Is it vein or arties that take blood to the heart?
Veins - to the heart
Arteries - away
What happens when both the ventricles and atria relax?
Higher pressure in the pulmonary artery and the aorta force the semi lunar valve shut. Higher pressure in the vena cava and pulmonary vein means the atriums begin to fill with blood again, meaning the cycle can start again
A cardiac contraction is also called a?
systole
A cardiac relaxation is also called a?
diastole
What I cardiovascular disease?
Diseases that are associated with the heart and blood vessels
Name three common cardiovascular diseases?
aneurysm, thrombosis, myocardial infarction
How is an atheroma formed?
If damage occurs to the endothelium in an artery (could be due to high blood pressure), white blood cells, dead cells, connective tissue and lipids begin to clump together under the lining. Over time more stuff gets deposited and it builds up and hardens to form an atheroma.
How can an atheroma lead to an aneurysm?
The atheroma damages and weakens the arties, and the narrower lumen increasing blood pressure. When high pressure blood travels through the weakened artery it may push the inner layers of the artery through the outer elastic layers forming an aneurysm.
Thrombosis is he formation of a ?
Blood clot
How can an atheroma lead to thrombosis?
If the atheroma bursts through the endothelium it leaves a rough surface, this causes platelets and fibrin to accumulate forming a blood clot.
What causes a myocardial infarction?
If a coronary artery becomes blocked (by a blood clot)part of the heart will be cut off from its blood supply and will receive no oxygen. This causes the myocardial infarction
What does myocardial infarction mean?
Heart attack
What are coronary arteries ?
Arties that supply the heart with blood
What are three symptoms of a heart attack?
Pain in chest and upper body, shortness of breath and sweating
What is coronary heart disease?
When the coronary arties have lots of atheroma’s in them, restricting blood flow and causing blood clots
Why does a high blood pressure cause an increases risk in atheroma formation?
An increase in blood pressure means there is more risk of damage to the endothelium so it is more likely an atheroma will form
Name three things that can increase blood pressure?
Being over weight, not exercising and excessive alcohol consumption
Why does high blood cholesterol level increases the risk of an atheroma formation?
Cholesterol is one of the main parts of the fatty deposits in the atheroma so more fatty deposits more atheroma’s
Why does salt increase the risk of atheroma formation?
It increases blood pressure
What found in cigarettes increases the risk of myocardial infarction?
Carbon monoxide and nicotine
Why does carbon monoxide increase the risk of myocardial infarction?
Combines with the haemoglobin and reduces the amount of oxygen transported in the blood, so reduces the amount of oxygen available to the heart which could lead to a heart attack
What else does smoking do to the blood which leads to an increase risk of myocardial infarction and why?
Decreases the amount of antioxidants in the blood (important from protecting cells from damage) meaning the endothelium is more easily damaged increasing the chance of atheroma formation and so myocardial infarction
What risk factor of coronary heart disease cant you control?
Genetics which might make you more likely to get the disease
