Topic 1 Heart and circulatory system Flashcards
State the different types of circulatory system an organism can have
None (rely on diffusion),
Open circulatory,
Closed circulatory,
Closed Double circulatory.
Explain the reasons why there are different types of circulatory system
Differing metabolic rates between species means different circulatory requirements (animals with a lower metabolic rate require a less efficient circulatory system)
Explain the advantages of an organism having a double circulatory system
Differential pressure
Blood pumped at high pressure to body
- blood can reach extremities of the body
Blood pumped at low pressure to the lungs
- wont damage the lungs
- allows more time for gas exchange via diffusion
Describe the difference between mass flow and diffusion
Mass flow is the movement of a liquid down a pressure gradient, whereas diffusion is movement of a substance down the concentration gradient
Why do certain organisms need a mass flow system
Because they need to bring substances quickly from one exchange site to another to maintain a high metabolic rate
What is the arterial pulse
Waves of blood travelling at high pressure in the arteries
Describe the structure of a capillary
Narrow lumen
One layer thick walls
Porous.
High surface area to volume ratio.
Explain how the structure of a capillary enables them to carry out their functions
High surface area to volume ratio maintains high rate of diffusion for gas exchange with surrounding tissues.
Porous walls allow for constant movement of liquids from the bloodstreams into tissues and vice versa.
Narrow lumen keeps blood pressure low to allow for more time for gas exchange
Describe the structure of an artery
Narrow lumen,
Thick elastic fibres
Thick collagen layer
Smooth endothelium layer inside.
Explain how the structure of an artery enables them to carry out their functions
Narrow lumen maintains high blood pressure,
Thick elastic fibres expand with pressure, and contract to keep the artery’s shape,
Thick collagen layer provides strength to the artery and prevents it from bursting, allowing it to maintain a higher pressure,
Smooth endothelium layer provides less resistance for blood to travel faster.
Describe the structure of a vein
Wide lumen,
Thin collagen layer,
Thin layer of smooth muscle,
Smooth endothelium layer,
Valves.
Explain how the structure of a vein enables them to carry out their functions
Wide lumen allows more blood to flow under lower pressure,
Thin collagen layer allows vein to have pressure applied from outside sources,
Smooth endothelium layer provides less resistance for blood,
Valves prevent the backflow of blood inside of the vein
Explain what is meant by the dipole nature of water molecules
The Hydrogen atoms have a partial positive charge, whereas the oxygens have a partial negative charge. This is due to Electronegativity.
Explain why water is a good solvent
Water can create hydrogen bonds through intermolecular forces, which means water can attract polar solutes and form hydrogen bonds with them, which causes them to dissolve into the water
Explain how the properties of water are essential for organisms
Water can create hydrogen bonds, which gives it properties such as being a good solvent (allows dissolved substances to be transported), being adhesive (sticking to cell walls and other substances with extra hydrogen atoms sticking out), having a high specific heat capacity (allows water to maintain a consistent temperature as extreme levels of energy are required to change its temperature)
Which two cells form the basis of a blood clot
Platelets and Damaged tissue cells
What do soluble and insoluble mean
A soluble substance is one that dissolves, especially in water, whereas an insoluble substance does not dissolve
What are the two cofactors of Thromboplastin
Prothrombin and fibrinogen
What is the name of the initial mass of platelets at the site of endothelial damage
Platelet plug
Which fibre comes into contact with platelets to form a clotting cascade
Fibrin
What are the risk factors for development of atherosclerosis
High cholesterol diet, lack of exercise, hereditary heart problems.
How does atherosclerosis develop
Tear in endothelium due to hypertension / toxins
Inflammatory response where white blood cells gather at site of tear
Cholesterol gathers with white blood cells forming atheroma
Calcium ions gather at atheroma forming a fibrous mesh creating a plaque
Artery lumen narrows.
How does atherosclerosis impact blood flow and respiring tissues
It narrows the lumen of the artery, which reduces blood flow through that artery, meaning respiring tissues which rely on that artery wont receive enough oxygen and may eventually die
Describe the events in a blood clotting cascade
Platelets find a wound in the vessel and form a platelet plug. Prothrombin finds this platelet plug in the blood stream, and will produce thrombin. Thrombin will trigger fibrinogen in the bloodstream to produce fibrin, which connects to the platelets and forms a clot
Explain how blood clotting can impact blood flow and respiring tissues
A blood clot narrows the lumen of the vessel it forms in, which means the blood flow is slower through that vessel. This means that tissues that rely on that vessel will not receive enough oxygen and may eventually die if blood supply is not regained
Describe the events that take place in one cardiac cycle
The heart completely relaxes (diastole) and blood enters the atria. Then the atria contract downwards (atrial systole) which opens the atrioventricular valves and blood flows into the ventricles. Then the ventricles contract upwards (ventricular systole) which opens the semilunar valves and blood flows into the pulmonary artery and aorta.
What causes the atrioventricular valves to close
Ventricular systole
What causes the semilunar valves to open
Ventricular systole
What causes the semilunar valves to close
Diastole
What causes the atrioventricular valves to open
Atrial systole
Define causation and correlation
Correlation: A change in one variable happening alongside a change in another variable
Causation: A change in one variable directly causing a change in another variable
How do you identify a correlational relationship
Using correlation coefficients such as spearman rho
How to identify a causation relationship
by using a controlled study with no external effects that could change the outcome of the experiment
Define risk and risk factor in a lab context
Risk: the chance for injury, harm or loss to come about.
Risk factor: something that increases the risk e.g . working with a bunsen burner
Explain why peoples perception of risk and actual risk differ
People often consider a more normal, everyday task to have less risk as it is something they are used to, whereas they treat new things as though they have more risk associated with them
