Question

1. If the cell membrane relies on the creation and maintenance of an electrical membrane potential, why is applying a strong electrical (such as lightening) a problem?

2. A major component of the extra cellular matrix is collagen, a touch fibrous protein. Explain how collagen is involved in cancer progression.

Answer 1

1. Hyperpolarization is the cause for applying strong electrical and please find the detailed explanation below:

Electrical signals are caused by transient changes in the current flow into and out of the neuron, that drives the electrical potential across the plasma membrane away of its resting condition.

Every neuron has a separation of electrical charge across its cell membrane. The membrane potential results from a separation of positive and negative charges across the cell membrane. The relative excess of positive charges outside and negative charges inside the membrane of a nerve cell at rest is maintained because the lipid bilayer acts as a barrier to the diffusion of ions, and give rise to an electrical potential difference, which ranges from about 60 to 70 mV.

The potential across the membrane when the cell is at rest (i.e. when there is no signaling activity) is known as the resting potential. Since , by convention, the potential outside the cell is arbitrarily defined as zero, and given the relative excess of negative charges inside the membrane; the potential difference across the membrane is expressed as a negative value:

Vr = -60 to -70 mV.

Being Vr, the resting potential.

The charge separation across the membrane, and therefore the resting membrane potential, is disturbed whenever there is a net flux of ions into or out of the cell. A reduction of the charge separation is called depolarization; an increase in charge separation is called hyperpolarization. Transient current flow and therefore rapid changes in potential are made possible by ion channel.

2. The role of collagen in Cancer:

A. Excessive collagen deposition and increased ECM stiffness and remodeling define cell fate and promote tumor progression by reshaping tumor microenvironment (TME). Different cellular entities within TME are able to deposit collagen that enables cancer cells to develop a permissive pro-tumorigenic environment.

B. collagen promotes tumor growth because recurrent tumors have high levels of collagen and breast cancer patients with high levels of collagen in their tumors often have worse outcomes.