Cardiovascular System Flashcards
Artery
Carries blood away from the heart.
Oxygenated blood taken to organs and working muscles.
Arteriole
Controls blood distribution by changing diameter.
During exercise muscles require increased blood flow.
Capillary
Connect the arteries and veins by uniting the arterioles and venules.
One cell thick to allow gas exchange to occur easily.
Surround the muscles.
Venule
Small vessels that connect the capillaries to the vein.
Take blood from the capillaries and transport this deoxygenated blood under low pressure to the veins.
Vein
Thinner walls that arteries and a relatively larger diameter.
Veins and valves within their structure prevent back flow of blood.
Facilitate venous return.
Blood flows slowly under low pressure.
Contracting muscles push thin walls of veins, squeezes blood back towards the heart.
Venous return
the flow of blood back to the heart.
Red blood cell (Erythrocytes)
Main function is to carry oxygen.
All red blood cells contain a protein called haemoglobin - gives blood it’s red colour.
Red blood cells are round, flattened discs with an indented shape so it can flow easily in plasma.
White blood cells (Leucocytes)
The component of blood that protects the body from infection.
Identifies, destroys and removes pathogen e.g. bacteria, viruses.
Originate in the bone marrow and stored in the blood.
Plasma
Straw-coloured liquid where blood cells are located.
Approximately 90% is made up of water and electrolytes (sodium,potassium and protein).
Plasma carries carbon dioxide, which is then dissolved as carbonic acid.
Platelets (Thrombocytes)
Disc-shape cell fragments.
Produced in bone marrow.
Main function is clotting the blood to prevent blood loss.
Delivery of oxygen and nutrients
Delivers oxygen and nutrients to the tissue of the body through the blood stream.
During exercise the body needs more oxygen so the cardiovascular system has to work harder.
When the cardiovascular system can no longer meet the demands, fatigue will kick in, performance will decrease.
Removal of waste products -Carbon dioxide and Lactate
Removes carbon dioxide and lactate acid from the body.
If waste products aren’t removed it causes fatigue.
Fighting infection
White blood cells fight infection.
This component of blood is constantly produced in the bone marrow.
They are stored in, and transported around the body by the blood to consume and ingest pathogens and destroy them. They produce antibodies which also destroy pathogens and produce antitoxins which will neutralise the toxins that may be released by pathogens.
Thermoregulation (vasodilation)
During exercise , vasodilation of blood vessels occur in parts of the active muscles.
This is caused by the relaxation of involuntary muscle fibres in the walls of the blood vessels and causes an increase in the diameter of the blood vessel.
This decreases the resistance to the flow of blood to the areas supplied by the vessels.
This results in a decrease of body temperature as heat within the blood can be carried to the skin surface.
Thermoregulation (vasoconstriction)
Blood vessels can also be temporarily shut down or limit blood flow to tissues.
This is caused by contraction of the smooth muscle in the blood vessel walls which result in a decrease in diameter of blood vessel.
This will result in an increase in body temperature, as heat loss is reduced as blood is moved away from the surface.
Blood clotting
Blood clotting is a complex process where white blood cells form solid clots.
A damaged blood vessel wall is covered by a fibrin clot to help repair the damaged vessel.
Platelets form a plug at the site of the damage.
Plasma components known as coagulation factors respond to form fibrin strands which strengthens the platelet plug.
This happens because the blood supply is constant around the body.
The Sinoatrial node (SAN)
Located in the walls of the right atrium near the vena cava.
Commonly referred to as the hearts pacemaker.
Produces electrical impulses.
Sends impulse to the muscles of the atria to cause them both to contract.
This contraction forces the blood within the atria down into the ventricles.
The Atrioventricular node (AVN)
Located in the centre of the heart between the atria and ventricles.
Acts as a buffer to slow the signal down from the SA node.
Slowing the signal down allows the atria to contract before the ventricles.
This means the ventricles are relaxed (or open) and ready to receive blood from the atria at the top of the heart.
The bundle of His
Located in the septum.
Specialist heart muscle cells that are responsible for transporting the electrical impulse from the AV node.
Conducts the electrical impulse down the central part of the heart in two branches.
Purkinje fibres
Located at the end of the of the bundle of his and branch up through the muscular walls of ventricles.
Conducts the electrical impulse back up the ventricle walls.
Enables the ventricles to complete their contraction.
Causes the blood within the ventricles to be pushed up and out the valves - towards either the lungs or the body.
Anticipatory rise
It’s an anticipatory response.
HR will increase just before exercise in order to prepare for the increase in demand.
Nerves and chemicals in the blood can rapidly alter the bodies heart rate.
A 100m sprinter will experience a greater anticipatory heart rate response due to the high demands the sport will require.
Increased heart rate
Heart rate increases, body can have more oxygen and nutrients transported to the working muscles to keep the body working at a high intensity.
Nerves detect cardiovascular activity and the nerves increase the heart rate to make it pump faster.
During exercise, the cardiovascular system redistributes the blood so that more of it goes to the working muscles and less of it goes to other body organs such as the digestive system.
Cardiac output
Cardiac Output(Q) = Heart Rate(HR) x Stroke Volume(SV)
This is the amount of blood pumped out to the left side of the heart in one minute.
Cardiac output increases during exercise, because of an increase in heart rate.
Your maximum cardiac output decreases with age because your maximum heart rate will decrease.
Systolic pressure
The pressure exerted on your artery walls when your heart contracts and forces blood out of the heart into the body.
During exercise systolic blood pressure will increase because your heart is working harder to oxygenated blood to the working muscles.
