What are the key antigens for human blood groups and the structural differences between arteries and veins?

Welcome back Mc — missed you this week. 6. The antigens that determine human blood groups are: Antigen A* Antigen B* Rh antigen (D antigen)* 7. Structural differences between arteries and veins: Arteries have thicker, more muscular, and elastic walls to withstand high pressure from the heart. Veins have thinner, less muscular, and less elastic walls*. Arteries have a narrower lumen relative to their overall diameter, while veins have a wider lumen*. Arteries generally do not have valves (except at the heart's exit), whereas veins contain valves* to prevent the backflow of blood. Arteries maintain a more circular shape when cut, while veins tend to collapse*. The tunica media (middle layer) is much thicker in arteries* than in veins. 8. Reasons for carrying out the following procedures when making temporary slides: a) Making thin sections:* To allow light to pass through the specimen, enabling clear observation of internal structures under a microscope. b) Adding water to the sections:* To prevent the specimen from drying out and to provide a medium for viewing, maintaining its natural state. c) Placing coverslip over the plant section:* To flatten the specimen, protect the objective lens from contact with the specimen, and hold the water/stain in place. 9. a) Distinguish between diffusion and osmosis: Diffusion is the net movement of particles (solutes or gases) from an area of higher concentration to an area of lower concentration*. It can occur in any medium (gas, liquid, solid) and does not necessarily require a semi-permeable membrane. Osmosis is the net movement of water molecules across a selectively permeable membrane from an area of higher water potential (lower solute concentration) to an area of lower water potential (higher solute concentration)*. b) The red blood cell "At end" is crenated (shrunken and spiky). This occurs when the red blood cell is placed in a hypertonic solution. Water moves out of the cell by osmosis into the surrounding solution, causing the cell to shrink. Send me the next one 📸