(Part 2) Include the steps involved in transmitting the impulse “microscopically” through an individual neuron, from one neuron to another, and then from the neuron to the muscle fiber.


(Part 3) Include in this the steps involved in the actual muscle fiber contraction – a.k.a. the Sliding filament theory.

(Part 4) Specify the movements, muscles, bones, and joints involved in stepping up on the step. Explain any and all movements individually across each joint involved specifying the actions involved (i.e. flexion, extension, etc.), the muscles causing such actions, the bones being pulled on by said muscles, the types of joints involved, and how these movements collectively relate to the overall scenario/movements in this application.

(Part 5) Next, specify the movements, muscles, bones, and joints involved in reaching up above your head to the object on the shelf. Again, explain any and all movements individually across each joint involved specifying the actions involved (i.e. flexion, extension, etc.), the muscles causing such actions, the bones being pulled on by said muscles, the types of joints involved, and how these movements collectively relate to the overall scenario/movements in this application..

We do not do your work for you. Once you have attempted to answer your questions, we will be happy to give you feedback on your work. Although it might require more time and effort, you will learn more if you do your own work. Isn't that why you go to school?

However, I will start you out with part 3.

Since this is not my area of expertise, I searched Google under the key words "neuron impulse" to get these possible sources:

http://www.google.com/search?client=safari&rls=en&q=neuron+impulse&ie=UTF-8&oe=UTF-8

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.

(Part 2) Transmittal of the impulse through individual neurons:

1. Resting Potential: The neuron is at rest with a negative charge inside and positive charge outside. This is maintained by the sodium-potassium pump.

2. Stimulus: A signal or stimulus is received from another neuron, which causes a change in the charge distribution across the neuron's membrane.

3. Depolarization: When the stimulus reaches the neuron, sodium channels open in the membrane, allowing sodium ions to rush into the neuron. This depolarizes the membrane, causing a shift in charge from negative to positive.

4. Action Potential: If the depolarization exceeds a certain threshold, an action potential is generated. This is a sudden spike in electrical activity that travels down the neuron.

5. Propagation: The action potential travels along the axon of the neuron due to the opening and closing of ion channels. This process is called propagation.

6. Synaptic Transmission: When the action potential reaches the end of the axon, called the presynaptic terminal, it triggers the release of neurotransmitters into the synapse (the tiny gap between neurons).

7. Receptor Binding: The released neurotransmitters bind to receptors on the dendrites or cell body of the next neuron, initiating a new electrical signal in the recipient neuron.

8. Transmission to the Muscle Fiber: If the signal reaches a motor neuron, it eventually reaches the neuromuscular junction, where the neuron and muscle fiber meet.

(Part 3) Muscle fiber contraction - Sliding filament theory:

1. Activation: The action potential causes the release of calcium ions from the sarcoplasmic reticulum into the muscle cell.

2. Cross-Bridge Formation: Calcium binds to troponin, which causes a shift in troponin-tropomyosin complex, exposing binding sites on actin.

3. Cross-Bridge Cycling: Myosin heads attach to the binding sites on actin, forming cross-bridges. ATP is used to power the myosin heads to bend and pull the actin filaments toward the center of the sarcomere.

4. Sliding Filament: The myosin heads continue to bind and release, pulling the actin filaments closer together. This shortens the sarcomere and results in muscle fiber contraction.

(Part 4) Movements involved in stepping up on the step:

1. Flexion: The hip joint undergoes flexion as the thigh moves toward the abdomen, allowing you to lift your leg and place it on the step.

2. Extension: The knee joint extends as the leg straightens to lift your body weight onto the step.

3. Plantarflexion: The ankle joint performs plantarflexion as the foot pushes off the ground to lift the body.

Muscles involved:

1. Hip Flexors: Muscles like the iliopsoas and rectus femoris help flex the hip joint.

2. Quadriceps: The quadriceps muscles, specifically the rectus femoris, extend the knee joint.

3. Gastrocnemius and Soleus: These calf muscles perform plantarflexion at the ankle joint.

Bones involved:

The femur, tibia, and fibula are the primary bones involved in the movements described.

Joints involved:

The hip joint, knee joint, and ankle joint all play a role in the stepping up motion.

(Part 5) Movements involved in reaching up above your head:

1. Shoulder Flexion: The shoulder joint undergoes flexion as the arm is raised above the head.

2. Elbow Extension: The elbow joint extends as the arm straightens to reach the object on the shelf.

3. Wrist Extension: The wrist joint extends to allow the hand to fully grasp the object.

Muscles involved:

1. Deltoid: The deltoid muscle assists in shoulder flexion.

2. Triceps Brachii: The triceps brachii extends the elbow joint.

3. Extensor Carpi Radialis: This muscle extends the wrist joint.

Bones involved:

The humerus, radius, and ulna are the primary bones involved in the movements described.

Joints involved:

The shoulder joint, elbow joint, and wrist joint are all involved in reaching up above your head.