Tutor profile: Dennis G.

Why do individuals (e.g. young/teens ) need to be vaccinated against COVID-19 even if they are usually asymptomatic and do not get the severe disease?

Because one of the ways to prevent the spread of a highly infectious disease like COVID-19 is to have "herd immunity", wherein both susceptible and non-susceptible populations are vaccinated so that communal protection will be achieved. This will prevent the disease from spreading and also protect those who are vulnerable and unvaccinated.

What is the underlying pathophysiology of sickle cell disease?

The fundamental pathophysiological mechanism of sickle cell disease is the polymerization of deoxy-Hemoglobin S. This is due to a point mutation that leads to the replacement of glutamic acid by a valine residue at position 6 in the β-globin polypeptide chain.

What is the anatomical relationship between the ureter with the uterine artery and what is its clinical significance?

The ureter normally crosses below the uterine artery. This is commonly referred to as "water under the bridge", wherein the ureter is the water signifying"urine". This is very important for urologic and gynecologic surgeries because iatrogenic injury may result in the ureters during uterine artery ligation if the ureters were not properly identified.