ipl-logo

Cardiac Muscle Physiology Lab Report

1134 Words5 Pages

Group 3: Linzy Dioguardi, Drew Christerson, Kaitlyn Vander Putten, Teryn Wheeler, Callie Womack Shahang Derakhshan Human Physiology Lab 21 September 2017 Lab 4: Cardiac Muscle Physiology 1. There are many electrical changes and movement of ions during membrane polarization in a cardiac action potential. The following is an overview of the five main phases of an action potential: Phase 4 is the resting phase in which is the beginning and ending phase. It takes place at -90mv due to a constant outward leak of potassium. Sodium and calcium channels are closed at resting phase. Phase 0 is the depolarization phase and is similar to that of depolarization in a neuron action potential. Sodium channels begin to open and an increase of sodium moves …show more content…

L-type calcium channels stay open with a small constant current while the potassium channels remain closed. The countercurrents are electrically balanced during this phase. Phase 3 is the repolarization phase where the membrane potential falls to negative values. Potassium channels that began to open during the 1st and 2nd phases allow a significant amount of potassium out of the cell. The calcium channels then close, reducing the influx of calcium into the cell. Repolarization occurs until resting potential is reached, entering back into phase 4. 2. Cardiac muscle cells are very unique in comparison to skeletal muscle cells. There are two different types of cardiac muscle cells that make up the heart. The predominant of these cells is the contractile cells, which make up roughly 99% of the heart itself. These muscles are responsible for the mechanical process of filling and emptying the heart. The second and debatably most important type of cardiac muscle cells are the auto rhythmic cells. These cells make up the conductile network that allow the heart to function independently of the nervous system. These cells are responsible for generating the action potential that initiates a contraction within the heart muscles and allow us to have a …show more content…

Potassium is a fundamental protein the body needs for continuing a steady, rhythmic heartbeat. Too much or too little potassium can lead to a heart attack, or even death, due to how significant it is to the body. The potassium-sodium ion pumps maintain the concentration gradient by regulating the concentration of each ion inside and outside of the cell. Cells, nerves, muscles and the heart all rely on the potassium-sodium concentration gradient to function accurately. Normally, potassium is higher in concentration on the outside of the cell; whereas sodium is higher in concentration on the inside of the cell. Potassium chloride is one of the main components during lethal injections because of its ability to quickly and easily stop the heart. When a large amount of potassium enters the bloodstream, it rushes inside the cells and rapidly reverses the concentration gradient. When the concentration gradient is reversed, the resting electrical potential of the heart dramatically drops and cells are unable to repolarize. Depolarized cells will cause sodium channels to become inactive and cells will not be able to fire action potentials. When cells are unable to fire, the heart is unable to contract and will stop beating while in

Show More
Related
1789 Words | 8 Pages

Electrical signals begin at the SA node, bringing about atria contraction, and after that proceed onward to AV node, postponing electrical impulses to permit blood from the atrium to fill the ventricles. Signals move from the AV node to the heap of His and after that to the Prukinje fibers, which then permit the ventricles to contract. A heartbeat includes a contraction stage systole and an unwinding stage diastole. These contractions of the heart are animated by electrical impulses which begin from the nodes that are available in the heart; sino-atrial (SA node) and the atrioventricular (AV node). These nodes are bunches of nerve of

Read More
490 Words | 2 Pages

It also helps regulate the volume of the our blood and maintaining muscle/nerve function. Chloride- Calcium maintains the balance and pressure of many fluid compartments of the body. It also helps maintain proper acidity in the blood. Potassium- Potassium regulates the heartbeat and muscle function.

Read More
572 Words | 3 Pages

The neuron is known to be polarized at this voltage. Most of the sodium ions (Na+) are located outside the cell while potassium ions (K+) and anions are inside the cell. The inside of the cell has a negative charge at rest compared to the fluid outside the cell; anions are negatively charged molecules that cannot leave through ion channels because they're too big, so they always remain inside the cell. There is no ion movement during the resting

Read More
679 Words | 3 Pages

This experiment was performed in order to test if Potassium reversal potential is a good predictor of membrane potential. We predicted that even though there are many ions in and around a cell, reversal potassium of Potassium will give a good estimate of the membrane potential. In order to test our hypothesis, we measured the membrane potential across crayfish muscle fibers that were submerged in different saline solutions containing varied potassium concentrations. We also calculated the reversal potential of Potassium for those concentrations using Nernst equation. After running a t-test between the recorded membrane potential and calculated Nernst values, we found out that they were significantly different.

Read More
207 Words | 1 Pages

This gene is in charge of making special proteins that control the movement of skeletal muscle. SCN4A is used to create channels that allow sodium ions to flow into the different cells. (Genetics) HYPP occurs when the channels become weakened which makes the muscles more susceptible to involuntary contraction. This leads to potassium

Read More
192 Words | 1 Pages

1. Chloride ions will diffuse into the cell, as it is moving from an area of high concentration, to an area of low concentration. Chloride ions will diffuse into the cell because the equilibrium potential of chloride ions is more negative than the membrane potential, therefore when chloride ions diffuse into the cell the equilibrium potential of chloride ions and the membrane potential will become more balance. If, by the process of active transport, chloride ions moved out of the cell this would create a bigger gap between the equilibrium potential of chloride ions and the membrane potential. 2.

Read More
440 Words | 2 Pages

Single channel conductance () and reversal potential (Vr) were respectively of 100 pS and of 0 mV for outward currents and of 30 pS and of 0 mV for outward currents. Furthermore, the channel activity (NPo) was voltage-dependent, with high open probability at negative potentials and a a voltage-dependent inactivation at positive potentials (Figure XC). These channel properties are in good agreement with previously published data (Nilius…). A second set of experiment was devoted to chacterize the channel biophysical properties in the absence of divalent ions in the pipette, with the purpose to attenuate calcium-dependent inactivation (Citazione), a prerequisite for long duration experiments. Figure XD shows a record of 30 s long of the patch currents from an oxaliplatin treated neuron in the presence of 1 M of icilin at Vm= 40 mV (upper trace) in which at least three channels were active.

Read More
329 Words | 2 Pages

Energy was used to set up the ion gradient and that is why there are more sodium ions outside the membrane than the inside. The sodium ions are transported forcefully outside the cell membrane and the potassium ions are transported forcefully inside the cell membrane. The energy that is used for this is in the form of ATP which is broken down into ADP + P2. This is known as a sodium potassium pump. This process is called an active transport which means that it uses energy by breaking down a molecule of ATP.

Read More
1566 Words | 7 Pages

The negatively charged protein molecules (A-) inside the neuron cannot cross the membrane. In integration to these selective ion channels, there is a pump that utilizes energy to move three sodium ions out of the neuron for every two potassium ions it inserts. Conclusively, when all these forces balance out, and the difference in the voltage between the inside and outside of the neuron is quantified, have the resting membrane potential. The resting membrane potential of a neuron is about -70 mV (mV=millivolt) - this designates that the inside of the neuron is 70 mV

Read More
2152 Words | 9 Pages

Background: Explain on the cellular level how dropping warm Ringers solution on the frog’s heart would affect the cells of the SA node. Dropping warm Ringers solution on the frog’s heart would increase the heart rate because the calcium channels open faster. Explain on the cellular level how dropping warm Ringers solution on the frog’s heart would affect the cells of the contractile muscle of the ventricles. Dropping warm Ringers solution on the frog’s heart would increase the heart rate because the actin binds to the myosin more quickly due to the calcium channels opening faster leading to faster contraction of the heart.

Read More
895 Words | 4 Pages

This means there is no movement of ions in or out of the cell membrane and a resting potential is attained. At this point, there are more sodium ions outside the cell membrane and more potassium ions inside the

Read More
1812 Words | 8 Pages

In this way, the overall magnitude and direction of the heart's electrical depolarization

Read More
414 Words | 2 Pages

After the ACh has found its way to the receptors and is bound to them, the muscle fibers become stimulated. The stimulated muscle fibers result in an impulse being generated. This impulse travels down the membrane until it reaches the Sarcoplasmic Reticulum. The Sarcoplasmic Reticulum is responsible for regulating the Ca2+ ion concentration.

Read More
1117 Words | 5 Pages

However, if the stimulus is sufficient, the potential will rise from -70 mV to -55 mV and the process will continue. Once the threshold for action potential has been reached it will fire into a full signal. This is known as the all or nothing process. • Once the threshold has been reached, more Na+ gates open and Na+ ions rush into the neuron, raising the voltage of the membrane rapidly. This transition is known as “voltage-gated” and occurs very quickly.

Read More
3391 Words | 14 Pages

The impulses are passed on to the cochlear branch of the vestibulocochlear (VIII) nerve and then to the medulla. Within the medulla, most impulses cross to the opposite side and then travel to the midbrain, to the thalamus, and finally to the auditory area of the temporal lobe of the cerebral cortex. In the “resting” position of stereocilia the transduction channels are partially open, leading to a small release of transmitter. This, in turn, generates a spontaneous activity in the auditory nerve and the ascending auditory pathways, even in the absence of sound.

Read More

More about Cardiac Muscle Physiology Lab Report

Open Document