CRIMEAN FEDERAL UNIVERSITY

[CALCIUM AND NERVE IMPULSES]

BY- RUSHI DAVE

INTRODUCTION

• Calcium, a positively charged molecule, is useful many places within the human body.

• The role of calcium inside the nervous system extends from the initiation of a nerve signal to the action taking place.

• Calcium signals an impulse to a muscle cell and continues to be useful until the contraction is complete.

Calcium, a positively charged molecule, is useful many places

within the human body.

The role of calcium inside the nervous system extends from the

initiation of a nerve signal to the action taking place.

Calcium signals an impulse to a muscle cell and continues to be useful until the contraction is complete.

NERVE IMPULSE CONDUCTION

• A nerve impulse begins conduction as electrical impulses, initiated by the brain, travel down through nervous system cells.

• The electricity causes a change in polarity by opening channels to move positive sodium or potassium ions in or out.

• Positive molecules are stored in membranes guarded by gated channels.

• This means they must be stimulated in order to release the positive ions which help to conduct the nerve impulse.

NERVE IMPULSE AND CALCIUM

• It is well-known that calcium is another positive molecule useful for the conduction of a nerve impulse to a muscle fiber.

• However, Clay Armstrong, a neurobiologist, believes that calcium may play a larger role.

• Armstrong suspects that calcium is in charge of the gated channels that release potassium and sodium to facilitate a nerve impulse.

Armstrong's theory proposes that calcium ions are like

a door to these gated channels.

Calcium must move to release the ions and calcium

must return before the impulse will stop and

homeostasis is returned.

CALCIUM AND MUSCLE CONTRACTIONS

• When a nerve impulse reaches a muscle cell, movement of the muscle requires calcium as well.

• Your muscle cells store calcium and upon nerve impulse, the cell is flooded with calcium.

• In order for a skeletal muscle to move, two myofilaments, actin and myosin, inside a muscle fiber must bind to one another to create a pulling action which shortens the muscle.

However, a molecule known as tropomyosin

blocks the binding site and must be moved to

create a contraction.

Calcium binds to troponin which is attached to

tropomyosin.

Upon binding with calcium, troponin moves

tropomyosin, exposing the binding site and creating movement.

How Can Low Calcium Levels Affect the Release of Neurotransmitters?

• Neurotransmitters -- signalling molecules produced in your nervous system -- allow for communication between nerve cells, facilitating brain functioning, nerve signalling to muscle tissue and a number of other neurological processes.

• Calcium from your diet plays an important role in neurotransmitter signalling, with low calcium potentially inhibiting neurotransmitter release.

PROCESS OF NEUROTRANSMITTER RELEASE AND COMMUNICATION

• The release of neurotransmitters is a tightly controlled process, designed to help regulate the signalling between two nerve cells.

• Neurotransmitters are stored within nerve cells, packaged in small compartments called vesicles.

• When a nerve cell becomes activated, these vesicles fuse with the membrane on the surface of the nerve cell and release neurotransmitter into a synapse, a space between two nerve cells.

The chemicals then stimulate the neighboring nerve cell, located on the

opposite side of the synapse, triggering the activation of an electrical

signal within that neuron.

From there, the newly activated nerve can release additional

neurotransmitters to activate other nerve cells, ultimately allowing for communication between large networks of nerves.

ROLE OF CALCIUM

• Your nerves rely on calcium to properly regulate the release of neurotransmitters.

• When a nerve cell becomes activated, it transmits an electrical pulse that moves down the length of the cell toward the synapse.

• This electrical signal triggers the flow of calcium into the nerve cell close to the synapse.

• This influx of calcium promotes the fusion of neurotransmitter vesicles to the cell membrane, triggering neurotransmitter release.

EFFECTS OF LOW CALCIUM

• Without adequate calcium, your nerve cells might not be able to properly trigger the release of neurotransmitters into the synapse.

• As a result, people with severe calcium deficiency might develop nerve defects due to a breakdown in nerve communication.

• For example, long-term calcium deficiency might disrupt nerve signalling to your muscles and heart, increasing your risk of muscle weakness cramping or heart arrhythmia, or it might lead to depression due to altered nerve communication in your brain.

• In addition, calcium deficiency can affect your bone tissue, increasing your risk of osteoporosis.

INTAKE RECOMMENDATION

• You can help support proper neurotransmitter release by consuming adequate calcium each day to prevent a calcium deficiency.

• Men and women age 19 to 70 require 1,000 and 1,200 milligrams of calcium daily, respectively, while all adults over age 71 require 1,200 milligrams daily, according to MedlinePlus.

• Incorporate dark leafy greens, dairy products and tofu in your diet as sources of calcium, or take calcium supplements under the supervision of a doctor to meet your daily recommended calcium intake.

THE END