Understand why brain is the ‘command and control system’

This is in continuation to the last article focusing on neural system and mechanisms of neural coordination in a human body. Today, we will discuss the Central Neural System with focus on brain. Transmission of impulses • When an impulse (action potential) arrives at the axon terminal, it stimulates the movement of the synaptic vesicles […]

This is in continuation to the last article focusing on neural system and mechanisms of neural coordination in a human body. Today, we will discuss the Central Neural System with focus on brain.

Transmission of impulses

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• When an impulse (action potential) arrives at the axon terminal, it stimulates the movement of the synaptic vesicles towards the membrane where they fuse with the plasma membrane and release their neurotransmitters in the synaptic cleft.
• The released neurotransmitters bind to their specific receptors, present on the post-synaptic membrane.
• This binding opens ion channels allowing the entry of ions which can generate a new potential in the post-synaptic neuron.
• The new potential developed may be either excitatory or inhibitory.

Central Neural System

The brain

• The brain is the central information processing organ of our body, and acts as the ‘command and control system’.
• It controls the voluntary movements, balance of the body, functioning of vital involuntary organs (e.g., lungs, heart, kidneys, etc.), thermoregulation, hunger and thirst, circadian (24-hour) rhythms of our body, activities of several endocrine glands and human behaviours.
• It is also the site for processing of vision, hearing, speech, memory, intelligence, emotions and thoughts.
• The human brain is well protected by the skull.
• Inside the skull, the brain is covered by cranial meninges consisting of an outer layer called dura mater, a very thin middle layer called arachnoid and an inner layer (which is in contact with the brain tissue) called pia mater.
• The brain can be divided into three major parts: (i) forebrain, (ii) midbrain, and (iii) hindbrain.

Forebrain

• The forebrain consists of cerebrum, thalamus and hypothalamus.
• Cerebrum forms the major part of the human brain.
• A deep cleft divides the cerebrum longitudinally into two halves, which are termed as the left and right cerebral hemispheres.
• The hemispheres are connected by a tract of nerve fibres called corpus callosum.
• The layer of cells which covers the cerebral hemisphere is called cerebral cortex and is thrown into prominent folds.
• The cerebral cortex is referred to as the grey matter due to its greyish appearance.
• The neuron cell bodies are concentrated here giving the colour.

To be continued…