B4-organising Animals And Plants Flashcards
What makes up the human circulatory system?
The blood, blood vessels, and heart make up the human circulatory system which transports substances to and from the body cells.
What is plasma and what does it carry?
Your blood is a unique tissue, based on a liquid called plasma
Plasma carries red blood cells, white blood cells and platelets
. Waste carbon dioxide produced by the cells is carried to the lungs
Urea formed in your liver from the breakdown of excess proteins is carried to your kidneys where it is removed from your blood to form urine
The small soluble products of digestion pass into the plasma from your small intestine and are transported to the individual cells.
What are red blood cells and what are their adaptations?
Red blood cells pick up oxygen from the air in your lungs and carry it to the cells where it is needed
They are biconcave discs. Being concave on both sides gives them an increased surface area to volume ratio for diffusion
They are packed with a red pigment called haemoglobin that bones to oxygen
They have no nucleus making more space for haemoglobin
What are white blood cells?
They have a nucleus and form part of the body’s defence system against harmful microorganisms. Some white blood cells (lymphocytes) form antibodies against microorganisms. Some form antitoxins agains poisons made by microorganisms. Yet others (phagocytes ) engulf and digest invading bacteria and viruses.
What are platelets?
Platelets are small fragments of cells. They have no nucleus. They are very important for helping the blood clot at the site of a wound
Blood clotting is a series of enzyme-controlled reactions that result in converting fibrinogen to fibrin
What are the three main types of blood vessels?
Arteries, veins and capillaries
What do the arteries do?
They carry blood away from your heart to the organs of your body. Usually bright red oxygenated blood. Arteries stretch as blood is forced through them and go back into shape afterward . Arteries have thick walls containing muscle and elastic fibres. As the blood in the arteries is under pressure it is very dangerous if the artery is cut because the blood will spurt out rapidly every time the heart beats.
What do the veins do?
Veins carry blood away from the organs towards your heart. Blood usually low in oxygen therefore purple red colour. Veins do not have a pulse they have much thinner walls than arteries and often have valves to prevent back flow of blood. The valves open as the blood flows through them towards the heart, but if the blood starts to flow backward the valves close and prevent a back flow of blood. The blood is squeezed back towards the heart by the action of the skeletal muscles
What do the blood capillaries do?
Capillaries form a huge network of tiny bells linking the arteries and the veins. Capillaries are narrow with very thin walls. This enables substances such as oxygen and glucose to diffuse easily out of your blood into your cells. The substances produced by your cells such as carbon dioxide pass easily into the blood through the walls of the capillaries.
What circulatory system do human beings have?
Double circulatory system
Blood enters the top chambres of your gear what are they called
Atria
The blood coming from the right atrium from the vena cava is deoxygenated blood from your body
The blood coming into the left atrium on the pulmonary vein is oxygenated blood from your lungs
The atria contract together and force blood down into the ventricles. Valves close to stop the blood flowing backwards out of the heart
The ventricles contract and force blood out of the heart
The right ventricle forces deoxygenated blood to the lungs in the pulmonary artery
The left ventricle pumps oxygenated blood around the body in a big artery called the aorta.
What is coronary heart disease caused by?
A buildup of fatty materials on the lining of the vessels. If the blood flow through the coronary arteries is reduced, the supply of oxygen in the heart muscle is also reduced.
Ways to solve coronary heart disease
Stents can be used to keep narrowed or blocked arteries open
Statins reduce cholesterol levels in the blood, reducing the risk of coronary heart disease
What can damaged heart valves be replaced using?
Biological valves or mechanical valves
Mechanical valves are very good and last a very long time but you need to take medicine for the rest of your life to prevent clotting around it
Biological valves are good but do not last as long
10-15 years
The resting heart rate is controlled by a group of cells in the right atrium that form a natural pacemaker. What are artificial pacemakers used for
They are electrical devices used to correct irregularities in the heart rhythm. They send strong electrical signals to your heart that stimulate it to beat properly.
