physiological systems 1

Part B – Questions based on calculations in lectures
Q1.  The table below shows the current recorded from patch clamp experiments on potassium channels in cultured rabbit lacrimal gland cells at different stimulating membrane potentials.

Current (pA)

Membrane potentials (mV)

























Draw an I – V curve. (8 marks)
Calculate the reversal potential. (2 marks)
Calculate the conductance of this ion channel. (6 marks)
Q2. A human red blood cell has a membrane surface area of about 81µm2 and a membrane thickness of about 110 Aº. If the concentration of urea in the extracellular fluid is 1.6mM, and its intracellular concentration is 0.8mM, calculate the flux of urea in µmoles/sec across the red blood cell membrane. Assume that the diffusion coefficient of urea is 1 x 10-8 cm2/sec. (10 marks)
Q3. During the course of a neurosurgical procedure a drug is applied to the surface of the brain in order to inhibit the activity of a group of neurons that lie 3mm below the surface. Approximately how long will it take the drug to diffuse from the surface to those neurons?  Assume the diffusion coefficient of the drug in brain tissue is         3 x 10-4 cm2/sec. (6 marks)
Q4. Calculate the membrane potential (Vm) of a cell, given the following resistances and equilibrium potentials. Need to show all calculations. (12 marks)
EK = – 94mV, RK = 0.5 x 106 Ω, ENa = 66mV, RNa = 0.5 x 106 Ω
Q5. If EK = -92 mV and VM = -72 mV what will be the direction and magnitude of the ECDF? (4 marks)
Q6. If ENa = 66 mV and VM = -52 mV what will be the direction and magnitude of the ECDF? (4 marks)
Q7. Draw an I-V plot for two different non-voltage dependent ionic currents IA and IB under the following conditions:
·       When the conductance (g) is the same (2pS) for both ions A and B, but equilibrium potentials (-70mV for A, -50mV for B respectively) are different. Label the axes. (5 marks)
·       When the equilibrium potentials for both are the same            (-40mV) but they have different conductance’s (2pS for A, 4pS for B respectively). Label the axes. (5 marks)
Q8. A cell has a membrane potential of – 68 mV with the concentration of an ion [X+] inside (135mM) and concentration outside (8mM). What will be the direction and magnitude of the ECDF? (8 marks)
Q9. Consider a situation where K+ ion has an intracellular fluid (ICF) concentration of 320 mM and an extracellular fluid (ECF) concentration of 35 mM.  What will be the direction and magnitude of the ECDF acting on K+ at Vm = – 82 mV? (8 marks)
Q10. If ICF (K+) ion concentration is 165 mM, what ECF (K+) concentration is required for the condition of no net passive flux of K+ across the membrane at Vm = – 66 mV ? (6 marks)
Q11. What is the Donnan Effect? Two solutions are separated by a membrane permeable to sodium and chloride ions. The concentrations on side 1 are  sodium = 100 mM and proteins = 100mM and the concentrations on side 2 are sodium = 100 mM and      chloride = 100 mM.  At steady state approximate the concentrations of the different species and describe the different forces contributing to this steady state. (10 marks)
Q12. The concentration of carbon at 1 mm into the surface of the titanium slab is 0.25 kg/m3 and at 3 mm the concentration is 0.68 kg/m3. The temperature of the carburizing environment is 925 degrees Celsius, and the rate at which carbon is entering this 2 mm thick region is 1.27 x 10-9 kg/(m2s). What is the diffusion coefficient for this particular treatment? (6 marks)

Do you need a similar assignment done for you from scratch? We have qualified writers to help you. We assure you an A+ quality paper that is free from plagiarism. Order now for an Amazing Discount! Use Discount Code “Newclient” for a 15% Discount!NB: We do not resell papers. Upon ordering, we do an original paper exclusively for you.

The post physiological systems 1 appeared first on Essay Writers.

"Do you need a similar assignment done for you from scratch? We have qualified writers to help you with a guaranteed plagiarism-free A+ quality paper. Discount Code: SUPER50!"

order custom paper


Submit Paper Details
Issue instructions for your paper in the order form. Include a discount code if you have one. Your account will be created automatically.

Make Your Payment

Your payment is processed by a secure system. We accept PayPal, MasterCard, Visa, Amex, and Discover.

The Writing Process
Communicate with your writer, clarify all the questions with our support team, upload all the necessary files for the writer to use.

Download Completed Paper

Check your paper if it meets your requirements, the editable version. If any changes are needed, send the order for revision.

Important Legal Notice

Using this service is LEGAL and IS NOT prohibited by any university/college policies. You are allowed to use our model academic papers in one of the following ways:

  • To gain additional knowledge about the topic;
  • To refer to the paper as a source of ideas and reasoning, given that appropriate references are provided;
  • To paraphrase the ideas contained in the paper (refer to your school’s policy on plagiarism and academic honesty);
  • To use it for direct citing, given that appropriate references are provided.
Need help with your assignment?

We help students with well-written, original essays before the deadlines.
With more than 50,000 orders completed successfully for students around the world, count on us for your academic needs.

We have a team of professional writers, with vast background knowledge, who follow your specific order details and requirements to complete any writing task you need.

The papers written by our professionals can be used as examples, reference sources, or starting points for more research.


Improve your grades
  • Free bibliography page
  • Free outline
  • 915+ certified ENL and ESL writers to choose from
  • Original, fully referenced and formatted writing
  • On-time delivery, or you get a refund
  • Writer is fully qualified in your area of study
  • Writer has your degree level or higher
  • Communicate with your essay writer, a true academic expert, directly
  • Unlimited revision requests within 14 days
  • Plagiarism report to make sure the work is 100% plagiarism free
  • 24/7 instant support by phone, live chat, email, and messaging

© 2021 provides writing and research services for limited use only. All the materials from our website should be used with proper references and in accordance with Terms & Conditions.