Cardiovascular system Flashcards
What is meant by myogenic?
This means your heart can function independently without external stimulation.
What is systole?
When an area of your heart is contracting.
What is diastole?
When an area of your heart is relaxing.
What does the cardiac muscle do?
It constantly contracts to make your heart beat, to pump blood around your body.
In order to do this it needs to be constantly supplied with oxygen from the blood vessels.
What are the chambers of the heart?
• Atria
• Ventricles
What do the atria do? include wall thickness.
They have thin walls and receive blood coming from the rest of the body to the heart.
They contract simultaneously.
What do the ventricles do? include wall thickness.
They have thick walls and forcefully pump blood to the lungs and the rest of the body.
They contract a short time after the atria.
What are the 3 main blood vessels?
• Arteries
• Veins
• Capillaries
What are the key features of the arteries?
• Thick and muscular walls to withstand the flow of blood at a high pressure as it leaves the heart.
• Small lumen
What are the key features of the veins?
• Thin walls
• Large lumen
• Contain valves to prevent back flow
What are the key features of the capillaries?
• One cell thick
• Small lumen so blood can pass through one cell at a time
• Walls have a semi-permeable membrane to allow the transport of gases and nutrients into and out of the blood. This also helps to provide energy for contraction.
What do the arteries do?
They carry oxygenated blood away from the heart. Unless it is the pulmonary artery, as this carry’s deoxygenated blood from the heart to the lungs.
What do the veins do?
They carry deoxygenated blood towards the heart. Unless it is the pulmonary vein, as this carry’s oxygenated blood from the lungs to the heart.
What do the capillaries do?
They allow the diffusion of gases (O2) and nutrients from the blood.
What is the heart protected by?
• Sternum
• Ribs
• Enclosed in the pericardium
How do you identify the sides of the heart on a diagram?
The left side of the heart has thicker muscle.
What does the right side of the heart do?
The right side of the heart receives deoxygenated blood from the vena cava and pumps it to the lungs via the pulmonary artery.
What does the left side of the heart do?
The left side of the heart receive oxygenated blood from the pulmonary veins and pumps it to the whole body via the aorta.
What pathway does deoxygenated blood take through the body?
Inferior vena cava
|
Right atrium
|
Tricuspid valve
|
Right ventricle
|
Pulmonary valve
|
Pulmonary artery
|
Lungs
What pathway does oxygenated blood take through the body?
Lungs
|
Pulmonary vein
|
Left atrium
|
Bicuspid valve
|
Left ventricle
|
Aortic valve
|
Aorta
What is the cardiac cycle?
• Atrial diastole - The atria fill with blood from the vena cava and pulmonary veins.
• The SA (sinoatrial node) of the right atrium lets out an impulse, that spreads through the atria walls causing them to contract in unison.
• The blood is then forced into the ventricles.
• The impulse is received by the AV (atrioventricular node) and the signal is then delayed by 0.1 second. This is to ensure the atria are empty before the ventricles contract.
• The signal is then conducted through the Bundle of His, to the purkinje fibres.
• The purkinje tissue then conducts the signal through the ventricle walls, causing them to contract from the apex up.
• The pressure increase in each ventricle forces the semi lunar valves to open.
• The heart chambers then relax to prepare for the next cycle.
What is cardiac output?
The volume of blood pumped by the left side of the heart per minute.
This can be used to calculate heart efficiency.
How do you calculate cardiac output and what is it measured in?
It is measured in ml/min (ml per min).
Cardiac
output = BPM x Stroke Volume
What is stroke volume and what is it measured in?
The volume of blood pumped per beat.
It is measured in ml.
What is the average stroke volume?
50-100 ml of blood per beat.
What is the average BPM?
60-100
What 2 things are an indicator of fitness?
• A lower resting heart rate.
• A higher at rest stroke volume as it indicates a more efficient heart.
What 3 things indicate a person is healthy?
• Having a high stroke volume as it indicates a more efficient heart beat.
• A lower resting BPM.
• A slower pulse increase.
• A faster pulse decrease.
Does cardiac output give a full picture of someone’s cardiac health?
No
What is an ECG?
An ‘electrocardiogram’.
Attaching electrical sensors (electrodes) to someone’s skin to monitor the electrical activity of the heart.
What is tachycardia?
When the heart is beating too fast.
What is bradycardia?
When the heart is beating to slow.
What is a sinus arrhythmia?
An irregular heart beat. This is characterised by different lengths of time between contractions.
What is ventricular fibrillation?
This is when the ventricles contract in a rapid and or uncoordinated manner.
What is atrial fibrillation?
This is when the atria contract in a rapid and or uncoordinated manner.
How would an unhealthy heart be identified on an ECG?
The shape and or frequency between sections or contractions would be inconsistent or differ from normal.
What happens if the two atria don’t contract in unison?
The blood pumping will be inefficient, causing the blood to pool and form clots.
This is atrial fibrillation.
What do the PQRST waves stand for?
• P wave - Atrial systole.
• Q wave - Initial downwards deflection.
• R wave - Initial upward deflection.
• S wave - The fall.
• T wave - General diastole.
On an ECG.
What is the QRS complex?
This indicates ventricular systole on an ECG
What does a normal heart rhythm look like on an ECG?
R
/\
/ \ T
P / \ /\
/\ / \ / \
____/ \___ / \ ____/ \_________
\/ \/
Q S
QRS complex skinnier on an ECG.
What are the functions of the cardiovascular system?
Transport:
• nutrients like glucose and amino acids to the tissues.
• oxygen from the lungs to the tissues.
• hormones around the body.
What is blood made of?
• Plasma
• Platelets
• Red blood cells
• White blood cells
What is plasma?
A fluid containing proteins, known as plasma proteins, hormones and all the small molecules like carbon dioxide, glucose and amino acids and ions transported in the blood.
What are platelets?
Small disc shaped cell fragments without nuclei that are also called thrombocytes.
They’re present in large numbers in the blood and play a role in blood clotting.
What are red blood cells?
Also known as erythrocytes, are differentiated cells without a nucleus or the majority of their organelles.
They’re filled with haemoglobin, the protein that transports oxygen from the lungs to the tissues.
What are white blood cells?
Also known as leucocytes, are celles that are mostly involved in protection against infection, like the immune response.
The cardiovascular system facilitates circulation of blood to transport what?
• nutrients (glucose, amino acids, lipids, vitamins etc.), which are required for cell growth and repair.
• oxygen, required for cellular respiration.
• carbon dioxide, transported to the lungs to be eliminated from the body.
• hormones to target cells.
• blood cells: erythrocytes for the transport of oxygen and leucocytes as part of the immune system.
How is the human circulatory system a double circulatory system?
The blood passes through the heart twice for every circuit of the body.
The first loop is from the heart to the lungs and then back to the heart.
The second loop is form the heart through all the other organs and back to the heart.
