Comprehensive Physiology and Chemistry: Tonicity, Reflexes, Vision, and Cell Transport

Given a 1.491 g/dL solution of KCl (MW = 74.55), predict what would happen to a RBC when placed into it. Calculate the M, mM, mOsm to help answer the question. Also indicate the tonicity. These equations might help...

molarity (M) = 1.491 g / 74.55 x 10 dL of water / 1 liter of water = 0.2;

So, M = 0.2 moles/liter

Given a 1.491 g/dL solution of KCl (MW = 74.55) millimolarity (mM) = (number of moles / liter of solution) X 1000 mM / mole

millimolarity (mM) = (0.2 moles / liter of solution) X 1000 mM / mole = 200 mM / liter;

So, mM = 200 millimoles / lite

Given a 1.491 g/dL solution of KCl (MW = 74.55) milliosmolarity (mOsm) = mM x the number of dissociable particles

milliosmolarity (mOsm) = 200 mM x 2 dissociable particles = 400 mOsm;

So, milliosmolarity = 400 mOsm

Given a 1.491 g/dL solution of KCl (MW = 74.55), predict what would happen to a RBC when placed into it. Calculate the M, mM, mOsm to help answer the question. Also indicate the tonicity. These equations might help...

- molarity (M) = grams of substance / molecular weight x 10 dL of water / 1 liter of water = 0.2 M

- millimolarity (mM) = (number of moles / liter of solution) X 1000 mM / mole = 200 mM

- milliosmolarity (mOsm) = mM x the number of dissociable particles = 400 mOsm

Once we know the solution is 400 mOsm, we can then figure out what happens to the RBC.

PICTURE: 280 red blood cell pointing towards 400 solution

Since the solution is 400 mOsm and the RBC is 280 mOsm:

water will be pulled out of the cell and it will shrink =

thus it is hypertonic.

When clasping the hands and pulling them apart, what happens to the size of the knee-jerk reflex and why does that occur? #1

(Jendrassik) results in cortical irradiation (more brain wave activity).

When clasping the hands and pulling them apart, what happens to the size of the knee-jerk reflex and why does that occur? #2

brain has increased activity, this disinhibits the Renshaw cells in the spinal cord.

When clasping the hands and pulling them apart, what happens to the size of the knee-jerk reflex and why does that occur? #3

- Enables more excitatory signals to be relayed to the motor neurons and thereby increasing the size of the reflex response

Who has higher visual acuity? Ryan measured his vision as 20/20 and Marabelle measured her vision as 20/15. Both were measured on the Snellen Eye Chart

Marabelle has higher acuity;

she sees at 20 feet what a normal person sees at 15 feet,

so she stands further back

Who has higher visual acuity? Ryan measured his vision as 20/20 and Marabelle measured her vision as 20/15. Both were measured on the Snellen Eye Chart #2

Ryan's vision is still good but not as good as Marabelle;

he sees at 20 feet, what an average person sees at 20 feet

What does someone need to do to the parasympathetic nervous system to increase heart rate? At what heart rates would this be most effective?

They need to withdraw (i.e. decrease output);

This would be most effective at heart rates below 120 BPM and especially predominant below 100 BPM

We changed frequency in order to see an increased response in the frog muscle. What is this called?

temporal summation

Which type of receptor would have the highest density - warm, cold, or touch receptors?

Touch receptors;

typically feel the sensation of touch almost everywhere as we need discrete localization of touch.

When Juanita clasps her hands and pulls them apart (the Jendrassik), what should happen to her EEG and brain wave activity?

The EEG should show bigger amplitude indicating more brain wave activity

Is the knee-jerk reflex considered to be monosynaptic, bisynaptic or polysynaptic?

monosynaptic:

It is mediated directly at the spinal cord and the integration passes through a single synapse

When Valerie looked at the chart with the "spokey wheel" she noticed her left eye saw them all without any differences, but with her right eye, she noticed the spokes in the 3-9 plane stood out. Does she have astigmatism?

Yes, only in the right eye as her left eye did not notice any differences in the astigmatism chart;

Left eye - no differences = normal vision

Right eye - 3-9 plane = astigmatism

The plantar reflex did not result in a Babinski sign. Is this a normal response?

Yes;

since the Babinski sign indicates an abnormal reflex and it was not present

Which body part would have the smallest receptive field size - back of hand, back of neck or fingertip?

The fingertip will have the smallest receptive field size;

it has the lowest two point discrimination threshold compared to the other areas of the body listed.

Mano was very nervous about the upcoming exam and his heart rate went from 100 BPM to 120 BPM when he received it from his professor. What part(s) of the ANS were responsible for the change and how did they accomplish that?

Both the sympathetic and parasympathetic affect the heart rate in this range.

Since heart rate increased, the sympathetic activity increased, while the parasympathetic activity decreased.

Given the molecular weights of the following substances are all the same, order the theoretical hemolysis times for the substances based on their relative polarities. Chiposa = slightly polar Trafolla = very nonpolar Mufract = slightly nonpolar

1. Trafolla = very nonpolar (fastest)

2. Mufract = slightly nonpolar

3. Chiposa = slightly polar (slowest)

We slowly increased the stimulation voltage to the frog nerve in order to quantify the response. From the following data, identify the threshold and maximal voltages.

Stimulus Voltage: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6

Response Voltage: 0.000, 0.0009, 0.0021, 0.0038, 0.0042, 0.0042

Attribute: Subthreshold, threshold, submaximal, submaximal, maximal, supramaximal

Threshold voltage = 0.2

Maximal voltage = 0.5

The previous slide demonstrated the compound action potential response. Is it graded or all-or none? Why does it show that type of behavior? #1

The compound action potential is the sum of the active units in the entire nerve.

Each individual axon (i.e. active unit) is all or none:

together they make up the compound action potential.

The previous slide demonstrated the compound action potential response. Is it graded or all-or none? Why does it show that type of behavior? #2 EXPLANATION

If there are more units active (i.e. recruited) =

compound action potential will be bigger due to the bigger total stimulus.

Thus the compound action potential is graded as its size depends on the size of the stimulus.

Sugar solutions were put into bags of dialysis tubing and then placed into various solutions within a beaker. Predict which one will gain the most weight over time.

Bag: A, B, C, D, E, F

% in sugar: 0, 10, 20, 20, 30, 40

% sugar in beaker: 0, 40, 10, 40, 0, 20

E will gain the most weight over time as it has the biggest concentration difference where water will move into the bag.

Phyllo measured his near point of accommodation at 25 cm. He is 52 years old. What is his visual age and assess his vision.

Age: 10, 20, 30, 40, 50, 60, 70

Near point (cm): 9, 10, 13, 18, 53, 83, 100

His visual age is about 43 years old, while his chronological age is 52 years old. His eyes are better than you would expect for his age

When we performed temporal summation on the muscle, we saw three distinct responses depending on the frequency of stimulation. Identify the characteristics and mechanisms of each response:

#1 TREPPE

Treppe (2-6 Hz):

The response steps up each time and goes back down to baseline.

When we performed temporal summation on the muscle, we saw three distinct responses depending on the frequency of stimulation. Identify the characteristics and mechanisms of each response:

#2 TREPPE

Due to the increased accumulation of calcium since there is not adequate time to resequester it because of the high frequency of stimulation.

When we performed temporal summation on the muscle, we saw three distinct responses depending on the frequency of stimulation:

Identify the characteristics and mechanisms of each response. #1 WAVE SUMMATION

Wave summation (6-10 Hz):

- The response steps up each time but does not back down to baseline

When we performed temporal summation on the muscle, we saw three distinct responses depending on the frequency of stimulation:

Identify the characteristics and mechanisms of each response. #2 : EXPLANATION: WAVE SUMMATION

- Due to the increased accumulation of calcium and increased prestretch of the series elastic elements in the muscle;

- it does not need as much energy to stretch out as it is already partially stretched;

- it does not go back down to baseline.

Consequently, there is more energy for contraction

When we performed temporal summation on the muscle, we saw three distinct responses depending on the frequency of stimulation. Identify the characteristics and mechanisms of each response. #1 TETANUS

Tetanus (10-18 Hz):

- reaches a maximum and does not begin to go back to baseline - it is just a flat line.

When we performed temporal summation on the muscle, we saw three distinct responses depending on the frequency of stimulation. Identify the characteristics and mechanisms of each response. #2 : EXPLANATION TETANUS

due to the increased accumulation of calcium and increased prestretch of the series elastic elements in the muscle just like in eave summation.

- high frequencies, we begin to recruit previously inactive tonic muscle (it needs a high frequency of stimulation to function)

With the EMG, we saw an increased response in the nondominant arm at maximum compared to the dominant arm. What is this called and why does it likely occur?

summation;

- The nondominant response tends to be larger = it has more electrical activity as it is a less familiar pathway

- Your brain is attempting to increase the response through a variety of mechanisms temporally and spatially

Jasmine took isoproterenol - it is a sympathetic agonist. What should happen to her heart rate and EDA?

Since isoproterenol = sympathetic agonist =

stimulates the sympathetic system.

Means that both heart rate and EDA should also increase.

What substance would be most permeable in the xylene layer - water, potassium permanganate or oil?

xylene = nonpolar

a nonpolar substance would be the most soluble =

oil

Subthreshold

No response

Threshold

Smallest voltage that elicits a response

Submaximal

threshold ➞ maximal

(graded: increase stimulation ➞ increase response)

Maximal

voltage above which no increase in response occurs

(smallest voltage to give max response)

Supramaximal

above maximal

(increase in voltage, no increase in response (all same as maximal)

Emulsification

enables mixing

Solution

has dissolved particles

Suspension

has particles that are not dissolved

What are the 3 phases in a twitch

Latent period,

Contraction phase,

Relaxation phase

Twitch

No summation;

Complete

(return to baseline);

increase bc of Ca2+

Treppe (staricase)

Summation;

complete (return to baseline);

Cause of summation: Ca2+

Wave

Summation

Summation;

ncomplete

(no return to baseline);

Cause of summation:

- [Ca2+]

- Pre-streching of series

- elastic elements (SEE)

Tetanus

Summation;

None;

causes of summation:

- ⬆ [Ca2+]

- Pre-streching of series

elastic elements (SEE)

- Tonic muscle recruitment