Topic 1 - Lifestyle, Health and Risk Flashcards
Give features of a mass transport system.
- Vessels
- Transport medium
- Maintains speed
Why do some organisms require a mass transport system?
Larger animals have a smaller surface area to volume ratio and a higher metabolic rate. Diffusion alone is insufficient to supply all cells with the substances they need.
What makes water a dipolar molecule?
O is more electronegative than H, so attracts the electron density in the covalent bond more strongly. Forms O delta- (slight negative charge) and H delta+ (slight positive charge).
How is water used in transport?
Due to its polar nature it acts as a solvent, allowing transport of biological molecules.
How does public perception of risk differ from actual risk?
- People overestimate risk if something is not under their control, is unfamiliar, or has particularly sever consequences.
- People underestimate risk if something only has an effect in the long-term.
Give some ethical issues surrounding the use of invertebrates in research.
Some consider it wrong to harm any living creature. However others argue that invertebrates are not complex enough to suffer stress or pain.
Draw a diagram of the human hear, including names of chambers, vessels and valves.
Right side:
- Pulmonary artery
- Vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
Middle:
- Semilunar valve
Left side:
- Aorta
- Pulmonary vein
- Left atrium
- Bicuspid valve
- Left ventricle
Relate the structure of the heart’s chambers to their function.
- Atria: thin-walled and elastic, so they can stretch when filled with blood.
- Ventricles: thick muscular walls pump blood under high pressure. The left ventricle is thicker than the right because it has to pump blood all the way around the body.
Describe the function of the heart’s major blood vessels.
- Vena cava = brings deoxygenated blood from the body to the heart.
- Pulmonary artery = takes blood from the heart to the lungs.
- Pulmonary vein = brings oxygenated blood from the lungs to the heart.
- Aorta = takes blood from the heart around the body.
Relate the structure of arteries to their function.
Thick, muscular walls to handle high pressure without tearing. Elastic tissue allows recoil. Narrow lumen to maintain pressure.
Relate the structure of the veins to their function.
Thin walls due to lower pressure. Require valves to ensure blood doesn’t flow backwards. Have less muscular and elastic tissue as they don’t have to control blood flow.
Relate the structure of capillaries to their function.
- Walls only one cell thick; short diffusion pathway.
- Very narrow, so can permeate tissues and red blood cells can lie flat against the wall, effectively delivering oxygen to tissues.
- Numerous and highly branched, providing a large surface area.
Describe what happens during cardiac diastole.
The heart is relaxed. Blood enters the atria, increasing the pressure and pushing open the atrioventricular valves. This allows blood to flow into the ventricles. Pressure in the heart is lower than in the arteries, so semilunar valves remain closed.
Describe what happens during atrial systole.
The atria contract, pushing any remaining blood into the ventricles.
Describe what happens during ventricular systole.
The ventricles contract. The pressure increases, closing the atrioventricular valves to prevent backflow, and opening the semilunar valves. Blood flows into the arteries.
What causes atherosclerosis?
Endothelium becomes damaged which leads to an inflammatory response and possible blood clotting. Substances in the blood build up and harden into a plaque that narrows the artery and raises blood pressure.
Why does blood need to clot?
- Prevents blood loss.
- Prevents entry of harmful bacteria.
- Provides a framework for repair.
Explain the process of blood clotting.
- Platelets release thromboplastin in response to damage.
- Causes prothrombin to change to its active form, thrombin.
- Turns soluble fibrinogen into insoluble fibrin, forming a mesh that traps blood cells.