Test: Neural Control & Coordination - 1 - NEET MCQ

The hypothalamus performs many functions which are important for the survival and enjoyment of life:

• It serves as a link between 'mind' and body and between nervous and endocrine system.
• The hypothalamus is responsible for hormone production. The hormone produced by this area govern body temperature thirst hunger, sleep, circulation rhythm, mood sex drive etc. This area of the brain also controls the functioning of the pituitary gland.
• Thus, if any injury localised to the hypothalamus it will disrupt the complete regulation of body temperature and other activities.

Line in NCERT: "The hypothalamus contains a number of centres which control body temperature, urge for eating and drinking."

In our body, the neural and the endocrine system jointly coordinate and integrate all the activities of the organs so that they function in a synchronised fashion.

Line in NCERT: "The neural system and the endocrine system jointly coordinate and integrate all the activities of the organs so that they function in a synchronised fashion."

Coordination is the process through which two or more organs interact and complement the functions of one another. For example, the functions of muscles, lungs, heart, blood vessels, kidney, and other organs are coordinated while performing physical exercises.

Line in NCERT: "Coordination is the process through which two or more organs interact and complement the functions of one another."

• The hypothalamus is an important link between the nervous system and the endocrine system, which controls the body's hormones. 
• It helps to maintain homeostasis by regulating various physiological processes, including hunger, thirst, body temperature, and blood pressure, through the release of hormones such as cortisol, adrenaline, and insulin. 
• The hypothalamus also controls the release of hormones from the pituitary gland, which in turn regulates other endocrine glands and their secretions.

Line in NCERT: "The hypothalamus contains a number of centres which control body temperature, urge for eating and drinking."

The myelinated nerve fibres are enveloped with Schwann cells, which form a myelin sheath around the axon. The gaps between the two adjacent myelin sheaths are called Nodes of Ranvier.

Line in NCERT: "The myelinated nerve fibres are enveloped with Schwann cells, which form a myelin sheath around the axon."

The electrical potential difference across the resting plasma membrane is called as the resting potential.

Line in NCERT: "The electrical potential difference across the resting plasma membrane is called as the resting potential."

• Brain stem is the support system of brain and is the collective name for medulla, pons, midbrain. Brain stem also connect the brain with spinal cord.
• The medulla oblongata controls vital functions such as breathing, heart rate, and blood pressure. 
  The pons is involved in the control of movement, sleep, and sensory analysis. 
  The midbrain plays a role in the regulation of motor movements, visual and auditory processing, and the sleep/wake cycle.

Line in NCERT: "Three major regions make up the brain stem; mid brain, pons and medulla oblongata."

The electrical potential difference across the resting plasma membrane is called as the resting potential.The rise in the stimulus-induced permeability to Na+ is extremely shortlived. It is quickly followed by a rise in permeability to K+. Within a fraction of a second, K+ diffuses outside the membrane and restores the resting potential of the membrane at the site of excitation and the fibre becomes once more responsive to further stimulation.

Line in NCERT: "The rise in the stimulus-induced permeability to Na* is extremely short-lived. It is quickly followed by a rise in permeability to K*. Within a fraction of a second, K+ diffuses outside the membrane and restores the resting potential of the membrane at the site of excitation and the fibre becomes once more responsive to further stimulation."

Myelinated nerve fibres are found in spinal and cranial nerves. Unmyelinated nerve fibres are enclosed by a Schwann cell that does not form a myelin sheath around the axon and is commonly found in autonomous and the somatic neural system.

Line in NCERT: "Myelinated nerve fibres are found in spinal and cranial nerves."

Electrical synapses are very rare in our system. At electrical synapses, the membranes of pre and post synaptic neurons are in very close proximity. Impulse transmission across an electrical synapse is always faster than chemical synapse.

Line in NCERT: "Electrical synapses are rare in our system."

Dendrites  are short fibres which branch repeatedly and protrude out of the cell body. One of the fibres arising from the cell body is very long with a branched distal end and it is called Axon. 

Line in NCERT: "Short fibres which branch repeatedly and project out of the cell body are called dendrites."

Each branch of an axon terminates into a synaptic knob. The axon is a long fibre which is branched at the end. Each branch terminates as a bulb-like structure called a synaptic knob. These knobs consist of some synaptic vesicles which contain some neurotransmitters like acetylcholine.

Line in NCERT: "Each branch terminates as a bulb-like structure called synaptic knob which possess synaptic vesicles containing chemicals called neurotransmitters."

The released neurotransmitters bind to their specific receptors which are present on the post-synaptic membrane. The new potential developed may be either excitatory or inhibitory.

Line in NCERT: "The released neurotransmitters bind to their specific receptors, present on the post-synaptic membrane."

Depolarization of the axonal membrane happens due to an increase in Na⁺ permeability, which allows Na⁺ ions to rapidly enter the axoplasm, making Statement A correct. Statement B is also correct, as the diffusion of K⁺ out of the membrane restores the resting potential. Statement C is incorrect because the sodium-potassium pump moves 3 Na⁺ out for every 2 K⁺ in, not the other way around. Hence, the correct statements are A and B.Topic in NCERT: Generation and Conduction of Nerve Impulse

Line in NCERT: "The rise in the stimulus-induced permeability to Na* is extremely short-lived. It is quickly followed by a rise in permeability to K*. Within a fraction of a second, K+ diffuses outside the membrane and restores the resting potential of the membrane at the site of excitation and the fibre becomes once more responsive to further stimulation."

- Assertion Evaluation: The assertion is true because the brain indeed acts as the central command center for both voluntary movements (like walking) and involuntary actions (such as heartbeats and digestion).

- Reason Evaluation: The reason is also true as the skull and meninges (dura mater, arachnoid, and pia mater) do provide essential protection to the brain from physical trauma.

- Explanation Relation: The reason supports the assertion by explaining how the brain's protection allows it to function effectively as the control center. Thus, the reason is the correct explanation of the assertion.

Line in NCERT: "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 behaviour." "The human brain is well protected by the skull."