In this experiment we will be dealing with two chemicals that intend to inhibit a nerve impulse.
3. Increasing frequency of stimulation to the trigger zone: DOES NOT increase the production of action potentials.
3. Considering your answers to Questions 1 and 2, why did activity in Annie’s motor nerves produce a skeletal muscle response that fatigued during repetitive stimulation?
This was discovered when tests indicated that many patients better results with medications that affect the serotonin as well as the dopamine transmissions in the brain. (6)
Next with a stimulation duration of 50us, the stimulus amplitude should be set to the maximal tolerable stimulus intensity. With stimulus frequency of 2Hz, observe and record the leg movement, increase it by 5Hz but should not exceed 50Hz. With the electrodes connected to the analogy output channel and ground of the DAQ board. With the corresponding LabVIEW program, the frequency and amplitude (voltage) of the stimulation supplied to the leg can be controlled. With this the “sweet spot” of the lowest amplitude and best frequency to cause evoked movement can be found and recorded. Now the stimulation frequency should be set to 10Hz and the duration of stimulation pulse to 5ms or less. The range if leg movement changes can be observed as amplitude changes. Electrical stimulation in increments of 0.01V should be delivered and the minimal voltage required to generate muscle twitch should be recorded. The pulse duration should then be increased by durations of 10ms and the minimum voltage should be recorded this should be repeated for a variety of pulse
The results in Figure 2. show that increasing the stimulus strength (V) from 0 to o.40V will result in an increase of Active Muscle force generated by the gastrocnemius muscle in the Buffo Marinus, confirming the hypothesis. The force generated plateaus when the stimulus is beyond o.40V.
epinephrine and dopamine, will have an average HR higher than the average HR of stimulants when administered separately. For daphnia 2, it can be concluded from the data that 1mM epinephrine administration resulted in average of 256 BPM, an almost 10% increase from base average BPM of 210 BPM. Administration of 1mM dopamine resulted in average BPM of 212 BPM, similar to the base average BPM of 210 BPM. Lastly, the daphnia was subjected to a combined epinephrine and dopamine solution. From the data, it can be concluded that the combined solution caused the average BPM to increase almost 4%, that is average 218 BPM, in comparison to baseline BPM of the second daphnia. From the second daphnia results: epinephrine and dopamine combined solution didn’t have any drastic increase, almost no effect, when compared to stimulants being administered separately. Hence, this hypothesis is also rejected by the data. Previous research by Barrazo has shown that stimulation of dopamine signaling pathways leads to “decreased movement with different time-courses of
3. Describe what would happen to the resting membrane potential if the sodium-potassium transport pump was blocked.
Once stimulated by the chemoreceptor trigger zone, the integrative vomiting centre coordinates the activation of all the nearby neural structures required to produce the multifaceted patterned response that will then lead to the processing and action of vomiting. The integrative vomiting centre coordinates the various inputs to the motor component of the emetic reflex, consisting of both somatic and autonomic systems, as the reflex involves both voluntary and involuntary processes. The abdominal and respiratory musculature, and visceral components involved in mediating changes in gastric motility and gastric tone are controlled by somatic pathways, while the autonomic pathways control sweating, salivation and pallidity of the skin. The activation of autonomic pathways plays a role in the intensity and duration of the nausea that accompanies emesis, as opposed to the actual action of vomiting (myVMC,
A simple spinal reflex is a reflex—involuntary, graded, patterned response to a stimulus—that is produced via a single synapse between sensory axons and motor neurons and confined to the spinal cord. In this experiment, two simple spinal reflexes—the myotactic reflex and the H-reflex—were stimulated. We compared a) the latency period—the amount of time between a stimulus and the effector response— and the amplitude—magnitude of an electrical signal—of each reflex; then, b) the effect of the Jendrassik Maneuver (JM) upon the latency period and amplitude of each respective reflex. For the myotactic response, a mechanical stimulus, a sharp strike of the patellar tendon, was utilized to elicit a signal in stretch receptors; however, to trigger the H-reflex, an electrical impulse was applied. These reflexes originate from an action potential produced by a sensory neuron when a stimulus is applied. Sensory neurons transmit the action potentials to an integrating center—the spinal cord—where a response is determined. Then, this response is taken back to the effector organ via motor neurons. The reflex occurs while the brain is becoming aware of the stimulus. Furthermore, the myotactic reflex is
The Purpose of this exercise is to understand how muscle twitch, contract and react to different activities.
But because they have a longer half-life and can rapidly cross the blood brain barrier, they are the choice of users. (Doweiko, 2014) Amphetamines and stimulants in general excite the CNS through stimulation of norepinephrine (Momaya, Fawal, & Estes, 2015), a neurotransmitter that helps, in conjunction with epinephrine to respond to the ?fight or flight? reaction to stress (Parse, 2015). Stimulants cause the release of norepinephrine from storage in sympathetic nerve endings. It then leads to the increase of arousal, heart rate, respiratory rate, and blood pressure. (Momaya, Fawal, & Estes, 2015) When taken orally, the stimulant is absorbed through the lining of the small intestine. It then reaches the brain through the bloodstream and produces regional effects. That is, it will cause a neurotransmitter activity in one region, while shutting of another region. Stimulants also seem to have an effect to alter the dopamine neurotransmission system. (Doweiko, 2014) The system is instrumental for movement and plays a role in Parkinson?s Disease when shut off. It also involves our pleasure center (rewarding properties), thus which is why we reach a euphoric state with certain stimulants. (Dopamine Neurotransmitter, 2015) (Steinkellner, Freissmuth, Sitte, & Montgomery,
Review Sheet Results 1. Describe how increasing the stimulus frequency affected the force developed by the isolated whole skeletal muscle in this activity. How well did the results compare with your prediction? Your answer: When the stimulus frequency was at the lowest the force was at its lowest level out of all of the experiments. As the stimulus frequency was increased to 130, s/s the force increased slightly but fused tetanus developed at the higher frequency. When the stimulus frequency was increased to the amounts of 146-150 s/s, the force reached a plateau and maximal tetanic tension occurred, where no further increases in force occur from additional stimulus frequency. 2. Indicate what type of force was developed by the isolated skeletal muscle in this activity at the following stimulus frequencies: at 50 stimuli/sec, at 140 stimuli/sec, and above 146 stimuli/sec. Your answer: At 50- Unfused
Attach copies of your experimental recordings showing the response of the ileum to the direct addition of noradrenaline and of acetylcholine to the tissue bath.