31 Years NEET Previous Year Questions: Neural Control & Coordination - NEET MCQ

• Statement I describes the corpus callosum, a structure in the brain. The corpus callosum is a large bundle of nerve fibers that connects the two cerebral hemispheres, allowing for communication between them. This statement is correct.
• Statement II mentions the brain stem and lists its components as the medulla oblongata, pons, and cerebrum. The error here is in including the cerebrum as part of the brain stem. In actuality, the brain stem consists of the medulla oblongata, the pons, and the midbrain, not the cerebrum. The cerebrum is part of the forebrain and is responsible for higher cognitive functions such as thinking, perceiving, planning, and understanding language. Therefore, Statement II is incorrect.

Topic in NCERT: HindBrain
Line in NCERT: "The hemispheres are connected by a tract of nerve fibres called corpus callosum. Three major regions make up the brain stem; mid brain, pons and medulla oblongata."

To match List I with List II correctly, we start by identifying the function of each brain region described in List I and match these descriptions to the corresponding functions stated in List II:

• Pons: The pons is part of the brainstem located between the midbrain and the medulla oblongata. It principally acts as a bridge connecting various parts of the brain, and it is also involved in controlling essential functions like sleep and respiration.
• Hypothalamus: The hypothalamus is a small portion at the base of the brain that plays a crucial role in hormone release and regulation of essential bodily functions, including temperature control, thirst, hunger, sleep, mood, and sexual behavior. It contains several neurosecretory cells that produce hormones.
• Medulla: The medulla oblongata, also part of the brainstem, primarily controls autonomic functions such as breathing, heart rate, and digestion (including gastric secretions).
• Cerebellum: The cerebellum is located at the back of the brain and is responsible for controlling motor skills, balance, coordination, and posture. It helps refine the movements dictated by the motor cortex.

Now, let's match these descriptions to those listed in List II:
A. Pons should match with "Connects different regions of the brain." - this corresponds to III.
B. Hypothalamus should match with "Neurosecretory cells." - this corresponds to IV.
C. Medulla should match with "Controls respiration and gastric secretions." - this corresponds to II.
D. Cerebellum should match with "Provides additional space for Neurons, regulates posture and balance." - this corresponds to I.

When we look at the given options:
Option A: A-II, B-III, C-I, D-IV (wrong)
Option B: A-III, B-IV, C-II, D-I (correct)
Option C: A-I, B-III, C-II, D-IV (wrong)
Option D: A-II, B-I, C-III, D-IV (wrong)

The correct answer is Option B: A-III, B-IV, C-II, D-I.

• The limbic system, which includes structures such as the amygdala and hippocampus, plays a significant role in regulating emotions, including fear, pleasure, and anger. The hypothalamus, another component of the limbic system, is involved in various functions, including the regulation of sexual behavior and responses to pleasure and excitement. Therefore, option D is correct.
• Option (A), (B) and (C) are not correct because corpora quadrigemina is a part of the midbrain and consists of four round swellings. Corpus callosum is a tract of nerve fibres that connects right and left cerebral hemispheres. Thalamus is a major coordinating centre in the forebrain for sensory and motor signalling. Midbrain, pons and medulla oblongata together form the brain stem.

Topic in NCERT: Limbic System

Line in NCERT: "the limbic system which is concerned with olfaction, autonomic responses, regulation of sexual behaviour, expression of emotional reactions, and motivation."

Option (c) is the correct answer as impulse transmission across an electrical synapse is always faster than that across a chemical synapse.

• Chemical synapses use chemicals for transmission which are known as neurotransmitters.
• The membranes of presynaptic and postsynaptic neurons are in close proximity in an electrical synapse.
• In an electrical synapse, the transmission of the impulse occurs in the form of an electrical current from one neuron to the next neuron.

Topic in NCERT: Transmission of Impulses

Line in NCERT: "Impulse transmission across an electrical synapse is always faster than that across a chemical synapse."

Option (a) is the correct answer because
(a) Multipolar neurons are present in cerebral cortex.
(b) Bipolar neurons are found in the retina of the eye.
(c) Myelinated nerve fibres are found in spinal and cranial nerves
(d) Unmyelinated nerve fibres are commonly found in autonomous and somatic neural systems.

Hypothalamus is thermoregulatory centre. Hence it is called “thermostat” of the body. It keeps body temperature at roughly 37°C by means of a complex thermostat system.

Topic in NCERT: Hypothalamus and its Functions

Line in NCERT: "The hypothalamus contains a number of centres which control body temperature."

• Medulla oblongata possess important centres for : Respiration, Cardiovascular reflexes, Gastric secretions.
• Corpus callosum : It is a tract of nerve fibres by which the hemispheres are connected with each other.
• Hypothalamus : It is centre for body temperature, urge for eating(hunger) and drinking (thirst).
• The limbic system (emotional motor system) is responsible for the experience and expression of emotion but not movement. It is located in the core of the brain and includes the amygdala, hippocampus and hypothalamus.

Pre-synaptic membrane is involved in the release of neurotransmitter in the chemical synapse. The receptors sites for neurotransmitters are present on postsynaptic membrane of neuron.

Topic in NCERT: Transmission of Impulses

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

Cerebellum maintains the balance and body posture. It is not concerned with logical part.

The hypothalamus is a highly complex structure in the brain that regulates many important brain chemicals. The hypothalamus is responsible for hormone production. The hormones produced by this area govern body temperature, thirst, hunger, sleep, circadian rhythm, moods, sex drive, and the release of other hormones in the body. This area of the brain controls the pituitary gland and other glands in the body.

Topic in NCERT: Hypothalamus and its Functions

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

Cerebrum is the first and most developed part of fore brain. It makes 2/3 part of total brain. Pons is a small spherical projection, which is situated below the midbrain and upper side of the medulla oblongata. It acts as a relay centre among different parts of brain. B and D are thalamus and spinal cord respectively.
Topic in NCERT: CENTRAL NEURAL SYSTEM
Line in NCERT: "The human brain can be divided into three major parts: (i) forebrain, (ii) midbrain, and (iii) hindbrain."

Cerebrum controls reading, thinking, learning, speech, emotions and planned muscle movements like walking. So, it is a seat of intelligence.
The cerebellum coordinates voluntary movements such as posture, balance, coordination, and speech, resulting in smooth and balanced muscular activity.
Hypothalamus secretes hormones which control the secretions of pituitary gland.
Midbrain or mesencephalon is associated with motor control, vision, hearing, temperature regulation, alertness.
Topic in NCERT: CENTRAL NEURAL SYSTEM
Line in NCERT: "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."

A-Receptor, C-Synaptic vesicles B  is synaptic cleft. A synapse is  formed by the membranes of a synaptic neuron and post synaptic neuron, which may or may not separated by a gap called synaptic cleft. It is filled by fluid called neurotransmitter which are involved in transmission of impulse at these synapses.

Topic in NCERT: Neurotransmitters

Line in NCERT: "The axon terminals contain vesicles filled with these neurotransmitters."

The most abundant intracellular cation is K⁺.

Topic in NCERT: Generation and Conduction of Nerve Impulse

Line in NCERT: "K* and negatively charged proteins and low concentration of Na*."

When a neurone is in resting state i.e., not conducting any impulse, the axonal membrane is comparatively more permeable to K+ ion and nearly impermeable to Na+ ions.

Topic in NCERT: Generation and Conduction of Nerve Impulse

Line in NCERT: "When a neuron is not conducting any impulse, i.e., resting, the axonal membrane is comparatively more permeable to potassium ions (K*) and nearly impermeable to sodium ions (Na+)."

Hypothalamus contains important nerve centres that controls the body temperature, thirst, hunger and eating, water balance and sexual function.

Topic in NCERT: Hypothalamus and its Functions

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

Hypothalamus part of human brain is concerned with the regulation of body temperature. The hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions. The hypothalamus is small cone-shaped structure, projects downward, ending in the pituitary.

Topic in NCERT: Hypothalamus and its Functions

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

During the propagation of nerve impulse when a stimulus of adequate strength is applied to a polarised membrane, the permeability of the membrane to Na⁺ is greatly increased at the point of stimulation. As a result the sodium ion channels permit the influx of Na⁺ by diffusion. Since, there are more Na⁺ ions entering than leaving, the electrical potential of the membrane changes from - 70 mV towards zero. At 0 mV the membrane is said to be depolarised. While the resting potential is determined largely by K⁺ ions, the action potential is determined largely by Na⁺ ions. Action potential is another name of nerve impulse. The stimulated negatively charged point on the outside of the membrane sends out an electrical current to the positive point adjacent to it. This local current causes the adjacent inner part of the membrane to reverse its potential from -70 mV to-+30 mV.

Topic in NCERT: Transmission of Impulses

Line in NCERT: "The rise in the stimulus-induced permeability to Na* is extremely short-lived."

Once the events of depolarization have occurred, a nerve impulse or spike is initiated. Action potential is another name of nerve impulse. It lasts about 1 msec (millisecond). The stimulalted, negatively charged point on the outside of the membrane sends out an electrical current to the positive point (still polarized adjacent to it). This local current causes the adjacent inner part of the membrane to reverse its potential from –70 mV to +30 mV. The reversal repeats itself over and over until the nerve impulse is conducted through the length of the neuron

Topic in NCERT: Transmission of Impulses

Line in NCERT: "The outer surface of the membrane becomes negatively charged and the inner side becomes positively charged."

In a resting state of the neural membrane, Na⁺ concentration is  higher on the outer side and K⁺ concentration   is more within the cell. This concentration gradient is maintained by voltage gated channels. Hence if diffusion is allowed Na⁺ would enter the cell and K⁺ would leave. 

Topic in NCERT: Transmission of Impulses

Line in NCERT: "The rise in the stimulus-induced permeability to Na* is extremely short-lived."

A primitive type of nervous system, without brain is found in the form of intra epidermal nerve net. However, there is no brain in Hydra to coordinate the response.

Topic in NCERT: NEURAL SYSTEM

Line in NCERT: "The neural organisation is very simple in lower invertebrates. For example, in Hydra it is composed of a network of neurons."

Neurons are the chief functional units of the nervous system. An ordinary neuron has a soma or cyton and a long thread called axon which is enclosed in a multilayered myelin sheath,  made by Schwann  cells. The myelin  sheath is interrupted at the spaces between schwann cells to form gaps. These gaps are called Nodes of Ranvier.
These nodes and the myelin sheath create condition that speed up the nerve impulses.

Topic in NCERT: NEURON AS STRUCTURAL AND FUNCTIONAL UNIT OF NEURAL SYSTEM

Line in NCERT: "The gaps between two adjacent myelin sheaths are called nodes of Ranvier."