The circulatory/cardiovascular system Flashcards
How do you calculate the size of a cell?
Divide the number of cells that cross the diameter of the field of view into the diameter of the field of view to figure out the length of one cell. If the diameter of the field is 5mm and you estimate that 50 cells laid end to end will cross the diameter, then 5mm/50 cells is 0.1mm/cell.
What is haemolymph?
A mix of clear blood and tissue fluid
How does an open circulatory system work?
One or more hearts push haemolymph through open ended vessels into the body cavities to bathe the organs. Then the fluid is drawn back into the heart through opening called ‘ostia’.
What is the pathway of blood?
arteries, arterioles, capillaries (from heart), venules, veins, (back to heart) heart
What is lymph?
tissue fluid, white blood cells and digested lipids.
Artery function:
Carries blood away from the heart. Arteries have thick muscular walls and high pressure blood flow.
Vein function:
Carries blood back to the heart. Lower blood flow pressure than arteries. Veins have valves which keep the blood flowing up against gravity.
Capillaries:
The site of where oxygen and nutrients diffuses out of the blood and into cells, and where CO2 and waste diffuses back into the blood from the cells to be excreted.
Capillaries join arteries and veins together.
Plasma:
Pale yellow, makes up 55% of blood.
Carries everything in the blood stream: blood cells, water, antibodies, nutrients from digestion, oxygen, carbon dioxide, urea, ions and hormones
Red blood cells:
Biconcave in shape for pliability and elasticity (to maximise surface area), makes up 45% of blood
Contains haemoglobin which contains oxygen
White blood cells:
Makes up less than 0.1% of blood.
Kills bacteria and viruses, part of immune system
Platelets:
Small crescent shaped cell fragments that makes up less than 0.001% of blood. Clots blood and seals wounds. Can form a scab.
What are the four chambers of the heart?
Right atrium, right ventricle, left atrium, left ventricle
What is the pathway of blood in the heart?
Right atrium receives O2 poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the O2 poor blood to the lungs, where it is oxygenated. The now O2 rich blood then enters the left atrium where it is then pumped to the left ventricle. From the left ventricle, the blood is pumped to the body.
What do the superior and inferior vena cava do?
Pumps deoxygenated blood from the body into the right atrium.
