extracellular space around it due to the passive channels. Once the sensory receptors have detected a stimulus, the graded potentials open up sodium chemical gates which cause sodium to enter the cell but, for an action potential to occur the graded potential must reach a certain threshold (-55mv). Once the graded potential reaches its threshold it can now turn into an action potential, the voltage-gated sodium channels open up, and the inside of the cell becomes highly positive due to all of…
temporal relationship between 〖Na〗^+ conductance (g_Na) and K^+ conductance (g_(K )), and the relative changes in the V_m during an action potential. 〖 g〗_Na increased as the V_m moved towards 0 mV causing depolarization of the membrane and started to decrease immediately after the peak of the action potential. Whereas, g_(K ) increased immediately following the action potential peak during the repolarization of the plasma membrane where the V_m moved away from 0 mV and became negative (Figure…
hillock and initial segment where action potentials begin (an area called the “trigger zone”). Sometimes axons have side branches called collaterals, which usually branch off at a 90 ° angle and allow a neuron to communicate with many cells at once. Each axon branch ends in a thin extension series called telodendria, which ends at the synaptic terminals. Me Oh…
Myelin is imperative for the functioning of adequate conduction velocity speed in axons. Myelin is made of water, lipids and proteins and appears white in color. This combination of lipids and proteins form a whitish protective cover or sheath over the axon of numerous nerve fibers. This sheath covering the axon speeds up the impulses that are being conducted, which is important in the transmission of impulses in our body. Without myelin speeding up conduction, the impulses would decelerate.…
the process repeats. Once the electrical potential of Neuron A (presynaptic neuron) reaches -60mV the sodium and potassium channels in the neuron open at the beginning of the axon. The influx of positive sodium ions into the cell makes the inside of the cell more positive and leaves the outside of the cell more negative. The cell is at rest at -70mV and as it gets more positive, it reaches threshold (gets more excited). This change in electrical potential also excites neighboring sodium and…
The interactions with the taste receptor cells will produce an action potential that will induce an action potential in taste sensory neurons. A neuron has 3 main parts: the dendrite, the cell body, and the axon. Information will be able to move faster in bigger and myelinated axons. In sensory neurons, the action potential is trigger at the dendrite. Each neuron has a cell membrane that encloses each neuron. The cell membrane is semi-permeable…
generating action potentials spontaneously and coordinating contractions during the cardiac cycle. All the cardiac muscle fibers in each region of the heart are electrically linked together. The intercalated disks are connections that electrically join the muscle fibers of the heart into a single unit that can conduct electrical impulses through the entire wall of the heart chamber without stopping. Four structures are embedded in the wall of the heart and responsible for generating the action…
startled and move away performing a sequence of steps called an c-start used as an escape mechanism, the name was give due to their characteristic shape. The intricacies of the c-start are important to figure out why such an escape reflex comes to action; the escape reflex is studied on the Goldfish (carassius auratis) by Mirjany…
The authors created the Accelerated Sensor of Action Potentials 1 (ASAP 1) using a green fluorescent protein source on the extracellular side of the plasma membrane to highlight the membrane potential changes as demonstrated by the fluctuation in the fluorescent brightness. Neuronal action potentials generated are monitored up to 200 Hz in frequency using this device. The general purpose of this experiment was to further understand information processing in the brain and how brain activity is…
This study analyzed the differences and the relationships of the isolated sciatic nerve in regards to the compound action potential and the neuromuscular junction stimulations of the Rana pipens gastrocnemius. A total of five exercises were used to identify the effects on the stimulation of the sciatic nerve and the gastrocnemius. A dissection for both labs were performed to isolate the nerve and to isolate the gastrocnemius. Both experiments used LabChart to perform various stimulations on the…