Discuss the important factors in exchange of gases and substrates between capillaries and tissue cells.
Good answers were based around Fick’s Law, Starling forces and the Gibb’s
Donnan effect.
It was expected that candidates would give Fick’s equation and describe the
components :
Fick’s Law J = -DA dc/dx
Candidates were also expected to describe Starlings equation and the equation for
Osmotic Pressure. Starling Equation:
Fluid movement = k[(Pc-Pi) – s(πp – πi)]
Osmotic pressure : sRT(Ci-Co).
Gibb’s Donnan effect and, other mechanisms of transport (filtration and pinocytosis)
was also expected for a good answer.
Syllabus: A combination C1c2.d, C21 2.e, C2b2.c, C2b2.e
References: Pharmacology and Physiology in Anesthetic Practice, Stoelting pgs
294-300, 322- 325
This would have been a rather difficult question for the unprepared. Reading it carefully, one notices that "important factors" are asked for, not the mechanisms of molecular traffic. Judging by the college answer, those were required too, but clearly occupied some lower tier of importance.
Those "important factors" would probably include
Even though water was not mentioned anywhere in the question, it's clearly a "substrate", so we will include it (or, rather, it's obvious that the examiners intended it that way).
Thus:
Wilson, David B. "Cellular transport mechanisms." Annual review of biochemistry 47.1 (1978): 933-965.
Yang, Nicole J., and Marlon J. Hinner. "Getting across the cell membrane: an overview for small molecules, peptides, and proteins." Site-Specific Protein Labeling. Humana Press, New York, NY, 2015. 29-53.
Stein, Wilfred. Transport and diffusion across cell membranes. Elsevier, 2012.
Cussler, E. L., Rutherford Aris, and Abhoyjit Bhown. "On the limits of facilitated diffusion." Journal of membrane science43.2-3 (1989): 149-164.
Wu, Ling-Gang, et al. "Exocytosis and endocytosis: modes, functions, and coupling mechanisms." Annual review of physiology 76 (2014): 301-331.