Test: Human Neural System (NCERT) - NEET MCQ

The visceral nervous system is responsible for transporting impulses between the central nervous system and the internal organs, or viscera. This system manages involuntary bodily functions such as digestion and heart rate, which are critical for maintaining homeostasis. Interestingly, it is often divided into two main components: the sympathetic and parasympathetic nervous systems, which have opposing effects on organ function to help regulate bodily responses to stress and relaxation.

The central nervous system (CNS) is primarily responsible for processing information and regulating bodily functions. It encompasses the brain and spinal cord, serving as the main control center for all activities in the body. The CNS interprets sensory information received from the peripheral nervous system (PNS) and coordinates responses. An interesting fact is that the brain alone contains approximately 86 billion neurons, which play a crucial role in cognitive functions, movement, and sensory perception.

Sympathetic neural system is also called the thoracolumbar division of autonomic neural system because nerves exit the spinal cord from first thoracic (T₁) to second lumbar (L₂) levels. Similarly, parasympathetic division is known as craniosacral division of autonomic neural system.

The somatic neural system is the part of the nervous system that carries sensory and motor information to and from the central nervous system (CNS) to the skeletal muscles, enabling voluntary control of movements. This system is crucial for activities such as walking, writing, and any other actions that require conscious effort. An interesting fact is that the somatic nervous system can rapidly respond to stimuli, allowing for quick reflex actions, often without the need for conscious thought.

The sensory nerves carrying impulses from the receptors to CNS are called afferent nerve fibres.

Each segment of myelin sheath is formed by one schwann cell. Myelin sheath is present in the melinated nerve fibres. It is made up of a substance of lipids, proteins and water called myelin and serves as an insulating layer, preventing loss of energy of the nerve impulse during its passage along the fibre.

Somatic nerves innervate the skeletal muscles. Therefore, these nerves control the movements of the body by acting on the skeleta muscles.

During stress condition, stimulation of the sympathetic nerves to adrenal medulla causes large quantities of adrenaline to be released into the blood circulation and then this hormone is carried to the specific tissues of the body where it produces its effect e.g., increase in heart beat.

Sympathetic neural system accelerates heart beat and inhibits secretion of digestive juices and saliva.