change within an individual that results from the chronic exposure Acclimation change within an individual that results from the chronic exposure Changes that individuals display after they have been in new environments for days, weeks, or months Change in how a gene is expressed Change in phenotype not genotype Tends to be reversible Phenotypic plasticity

Heat Acclimatization Change in Gene Expression expanded plasma volume increased sodium chloride retention reduced heart rate Increased cardiac output to skin capillary beds and active muscle. increased sweat rate, earlier onset of sweat production Reversible: will revert to acute http://www.sportsci.org/encyc/heataccl/heataccl.html

b = rise / run b = (log 40 – log 1) / (log 700 – log 10) b = (1.6 – 0) / (2.85 - 1) b = 1.6 / 1.85 b = 0.86

(log 40 – log a) / (log 700 – log 1) = b

Action Potential Stages: Summary The resting potential = 1 Threshold potential A graded potential is initiated = 2 The sodium voltage gated channels are first inactivated. = 5 The sodium voltage gated channels switch from inactivated to active but closed = 7 The potassium voltage channels open = 5 The end of the absolute refractory period = 7-8 The end of the relative refractory period = 8-9

The resting potential Threshold potential A graded potential is initiated The sodium voltage gated channels are first inactivated. The sodium voltage gated channels switch from inactivated to active but closed The potassium voltage channels open The end of the absolute refractory period The end of the relative refractory period

Use the following information to answer the following questions Use the following information to answer the following questions. SHOW ALL WORK 1. [K+] outside = 5 mM [K+] inside = 150 mM PK=20 2. [Na+] outside = 140 mM [ [Na+] inside = 10 mM PNa=1

The Nernst Equation can be used to determine the potential difference for a single ion

What is the potential difference at the cell membrane for Sodium ions? ENa = 58 * log (140/10) = 58 * log (14) = 58 * 1.15 = 66 mV Significance? maximum positive if only Na  

What is the potential difference at the cell membrane for Potassium ions? EK = 58 * log (5/150) = 58 * log 0.0333 = 58 * - = -86 mV Significance? = maximum negative if only K  

2. The Goldmann Equation can be used to determine the resting potential when more than one ion is involved.

What is the resting potential for this cell? 58 * log [(20*5 + 1*140)/(20*150 + 1*10)] = 58 * log [240/3010] = 58 * log [0.08] = = 58 * -1.1 -63.7 mV = resting potential

The diameter of a squid neuron is 200 microns The diameter of a squid neuron is 200 microns. How many seconds does it take to travel about 3 m)? velocity = 30 m/s T = ? T = d / v = 3 m / 30 m/sec = 3/30 sec = 0.1 sec

The above figure from your textbook is a typical illustration of an axon wrapped with Schwann cells with nodes of Ranvier in between. In the above figure, the internodal length is about 40 mm and the internodal thickness (diameter) is about 9 mm. In reality, a mammalian motor neuron with an internodal length of 1.5 mm, would have an thickness (diameter) of about 18 microns.

What is the ratio of internodal length to thickness for the figure? IL / T = 40 mm / 9 mm = 4.4 to 1

What is the ratio of internodal length to thickness for an actual neuron? IL / T = 1.5 mm / 0.018 mm = 83.3 to 1

In the figure, the total length is about 100 mm In the figure, the total length is about 100 mm. What is the correct length of the figure in mm if the illustration was proportionately accurate to the thickness of 9 mm. Vertical exaggeration = 9 mm / 0.018 mm = 500 X distance is > than 2 internodes > 2*1.5 mm 1.5 mm * 2 * 500 = 1500 mm = 1.5 m 1.5 m * 39.375 in / m = 59 in / 12 in / ft = 5 ft