Valves and the heart.
Atrio-ventricular valves are found between the atria and ventricles.
Semi-lunar valves are found at the base of the pulmonary artery and aorta.
The muscular wall of the atria is thinner than the walls of the ventricles.
The wall of the left ventricle is thicker than the wall of the right ventricle.
Deoxigenated blood returns from the body in two main veins. The anterior and posterior vena-cava.
Once oxygenated in the lungs, the blood returns to the heart in the pulmonary vein.
To ensure one way flow of blood there are valves within the heart.
Blood flow through arteries; the walls stretch then recoil pushing blood along.
narrow lumen helps maintain blood at high pressure
thick wall containing lots of elastic fibres so it can stretch.
Blood flow through veins; lining layer of epithilial called endotheliu
blood is under low pressure
carries blood back to heart
wide lumen.Capillary structure; lie close to near all cells in the body
connect the arterioles and venuoles
creates a big SA for efficent exchange
slows blood down die to narrow diametre walls only one cell thick.
Joining and Splitting sugar units.
Joining sugar units.
condensation reaction, h2o formed and glycosidic bond made between the two sugar units.
Splitting sugar units.
H2o is added, hydrolysis is the name of the reaction.
A single sugar unit is called a Monosaccharide.
Two sugar units is called a Disaccharide.
Many sugar units is called Polysaccharide.
Controlling blood pressure
Relax blood vessels, prevent the body from creating a hormone called angiotestin II.
Reduces the amount of water reabsorbtion by the kidneys, this reduces blood pressure.
Calcium channel Blockers.
Effects the way calcium passes into certain muscle cells, this causes the muscles to relax. effects- reduced blood pressure.
Increase urine excretion
they inhibit salt reabsorbtion from nephron inside the kidney,
decrease blood volume.