Ion Permeabilities and Membrane Potential Analysis - Prof. William J. Higgins, Exams of Animal Anatomy and Physiology

Download Ion Permeabilities and Membrane Potential Analysis - Prof. William J. Higgins and more Exams Animal Anatomy and Physiology in PDF only on Docsity! #1. Consider the following [ion] and permeabilities taken from Reid the Agouti: Ion [Ion]Out [Ion]In Relative mM mM Permeability Na+ 116 8 0.15 K+ 5 118 1.00 Cl- 124 11 0.25 Ca++ 10 0.00008 0.00001 a. The membrane potential = ___________________ b. The maximum height of an action potential = ___________________ c. The value of the after-AP hyperpolarization = ___________________ d. List two changes in ion conductances that would result in an ipsp on the dendrites of this nerve: ________________________ and _______________________ e. List two changes in [ion]Out that would lead to membrane depolarization: ________________________ and _______________________ f. In THIS neuron, which direction does Cl- diffuse. EXPLAIN the reason for your answer! _________________________________________________________________________ _________________________________________________________________________ #2. For each of the following responses, supply the branch of the efferent peripheral nervous system responsible for evoking the response, the causative neurotransmitter released onto the effector organ, and the specific receptor type(s): Response N.S. Branch Neurotransmitter(s) Receptor(s) *Increased Airway diameter __________ _________________ _____________ *Increased Intestinal activity __________ _________________ _____________ *Decreased Skeletal muscle __________ _________________ _____________ Blood flow *Decreased Pupil diameter __________ _________________ _____________ *Increased Sweat gland activity __________ _________________ _____________ *Increased Skeletal muscle tension__________ _________________ _____________ *Increased Salivary gland secretion_________ _________________ _____________ #3. Consider the following measurements taken from a nerve cell 'donated' by your lab partner who is obviously an alien being. While he/she recovers from their mishap, you will cover for them by completing the requested calculations. After all, it's the least you could do after...... Ion [IN]mM [OUT]mM E in mV Relative Permeability Px= 10 mM 10 mM ________ 0.0001 Mz+ 7.9 130 ________ 0.003 Nr+ 103 13 ________ 0.999 Lg- 0.22 ________ -123 0.0001 a. First, fill in the blanks above for the equilibrium potentials and the missing concentration. b. Give an approximation of the membrane potential with the correct sign: ___________________mV c. Now give us the EXACT value for Vm:: ___________________mV d. WHY is the value in your answer part C different from the value you gave in part B? _____________________________________________________________________________ e. For the neuron above, list two changes in ion PERMEABILITY that would result in a post-synaptic ipsp: 1. 2. f. List two changes in [Ion]OUT that would result in a hyperpolarization: 1. 2. g. If this nerve were a post-ganglionic sympathetic fiber, list at least four characteristics or features of it that are unique or specific for or characteristic of a post-ganglionic sympathetic fiber: o. Increases in the conductance of which ion would cause an ipsp? ________________________ p. In this neuron, an increase in the G of Cl- would cause an epsp or ipsp? ________________________ #6. Please explain the effects of the following changes on a somatic neuron and its effector organ. Explain how each change causes each effect. a. Decreased [Ca ++ ] out: A B C D E [Na+] = 7 mM [K+] = 114 mM [Cl-] = 13 mM [Ca++]= 0.001mM Plasma: [Na+] = 105 mM [K+] = 5 mM [Cl-] = 123 mM [Ca++]= 5mM b. Decreased [K + ] out c: Decreased axon diameter: #7. Consider the following measurements taken on a small mammal: Include all units and signs where appropriate!!!!!! Ion [Ion]In [Ion]Out Relative permeability D+ 127 mM 6 mM 1.2 E+ 8 mM 112 mM 0.18 G- 8 mM 112 mM 0.26 H++ 0.001 mM 7 mM 0.0000001 a. What is the membrane potential? a._________________________ b. What is the Equilibrium Potential for H++ ? b._________________________ c. If Vm were set to = -80 mV, then in which direction would G- diffuse? _____________ d. For each of the following, answer with D(epolarization), H(yperpolarization), or No : Increased P of H++ __________ Decreased [H++]out ___________ Increased [D+]out __________ Increased [G-]out ____________ Increased G of E+ __________ Decreased G of D+ ____________