Thursday, July 29, 2010

PBL-Group 1

Group members

• Nur Hidayah Binti Shaari (D20071029446)

• Muna Munirah Binti Haji Zakaria (D2007109562)

• Nor Fadhillah Binti Ramli ( D20071029484)

• Mohd Zulhusni Bin Zulkipli (D20071029461)

1. Why ion control the electrical signal in brain.

• Sodium

• Potasium

2. What the mechanisme involve that facilitated how two ion channels collaborate in the control of electrical signals in the brain.

The mechanism that involves is the action of the sodium potassium pump. Sylvia S. Mader(2006) says that sodium potassium pump is a membrane protein that actively transport Na+ out and K+ into the axon. The work of the pump the will maintain the enequal distribution of Na+ and k+ across the membrane. The mechanism goes like this,

- Cells pump extra potassium into their interiors and pump extra sodium out to the surrounding fluid.

- Electrical impulses in neurons are created when these ions are allowed to return to their original locations by passing rapidly through channels in nerve cells' outer membranes.

- Nerve cells possess wire-like extensions, called axons, which initiate these impulses and carry them from one cell to the next.

The electrical signal in the brain is actually been transmitted uses the information send by the nerve impulses occurs as the action potential occurs. The action potential is a rapid change in polarity across and axomembrane, Sylvia S. Mader (2006).

When an action potential occur, the gates of sodium channel open and  depolarization occurs. The when the gates of pottasium channel open. The repolarization occurs.

  •       What happen in CNS?

CNS is actually make up by the brain and the spinal cord. Here the sensory information is received and the motor control is initiated, sylvia S. Mader (2006)

  •  Why CNS only exist in vertebrate?

 As we know, The CNS is made up by brain and spinal cord. CNS is only exist in vetebrate as  both the spinal cord and the brain is surround by vetebrae. Usually the invetebrae are lack of brain. Thus the did not have CNS.

  •     What is the factor that causes epileptic seizures, pain and abnormal muscle movement.

Some people have mutations in potassium channels that decrease this control, causing excessive nerve firing manifested as epileptic seizures and uncontrolled muscle movements called myokymia and ataxia.

Sources: News

  •      How the the electrical impulses in neurons are created.

Nerve impulses are electrical as they run along the nerve. They then become chemical as they travel over the synaptic cleft. When a neuron receives a stimulus of sufficient strength the electrical current moves along the dendrite and axon to the neurotransmitter swellings. The movement of ions causes these electrical impulses.