Which of the following is NOT an example of ultrafiltration?: (A) Filtration at systemic capillaries, (B) Formation of CSF, (C) Filtration at the glomerulus, (D) Secretion of bile by hepatocytes
Answer is D. Ultrafiltration is filtration under pressure. Filtration at the systemic and glomerular capillaries are examples of ultrafiltration. Formation of CSF is paly ultrafiltration and paly by secretion of ependymal cells. Secretion of bile is an active process.