Human Neural System Questions in English

(A) The autonomic nervous system $(ANS)$ is a part of the peripheral nervous system that transmits impulses from the $CNS$ to involuntary organs and smooth muscles of the body.
It does not act on skeletal muscles,as skeletal muscles are controlled by the somatic nervous system.
It is classified into the sympathetic and parasympathetic nervous systems.
Therefore,the statement that it acts on skeletal muscles is incorrect.

(C) On the basis of the nature of nerve fibres,nerves are classified into three types:
$(i)$ Sensory (Afferent) Nerves: These contain only sensory nerve fibres,which carry impulses from sense organs to the central nervous system.
$(ii)$ Motor (Efferent) Nerves: These contain only motor nerve fibres,which carry impulses from the central nervous system to the effector organs (muscles or glands).
$(iii)$ Mixed Nerves: These contain both sensory and motor nerve fibres,allowing them to perform both functions.

(C) The human neural system is divided into two parts: the Central Neural System $(CNS)$ and the Peripheral Neural System $(PNS)$.
$CNS$ includes the brain and the spinal cord,which act as the site of information processing and control.
$PNS$ consists of all the nerves associated with the $CNS$ (cranial nerves and spinal nerves).
Therefore,the human neural system comprises both $CNS$ and $PNS$.

(C) The autonomic nervous system $(ANS)$ is a part of the peripheral nervous system that controls and coordinates the involuntary activities of various internal organs,such as the heart,smooth muscles,and glands.
This system is divided into two main parts:
$1$. Sympathetic nervous system
$2$. Parasympathetic nervous system

(D) The $Autonomic$ $neural$ $system$ is a division of the peripheral nervous system that transmits impulses from the $CNS$ to the involuntary organs and smooth muscles of the body.
It regulates involuntary physiological processes such as heart rate, digestion, and respiratory rate.

(D) The system responsible for providing an organized network of point-to-point connections for quick coordination is called the neural system.
This system is composed of highly specialized cells called neurons,which detect stimuli throughout the body and transmit them to the brain for processing.

(D) The Central Nervous System $(CNS)$ comprises the brain and the spinal cord and is the site of information processing and control.
The Peripheral Nervous System $(PNS)$ comprises all the nerves of the body associated with the $CNS$ (brain and spinal cord).
Since all the given statements ($A$,$B$,and $C$) are scientifically correct according to the human neural system,the correct answer is $D$.

(A) The sympathetic nervous system is a division of the autonomic nervous system that prepares the body for 'fight-or-flight' responses.
It innervates the arrector pili muscles,which are small muscles attached to hair follicles.
When the sympathetic nervous system is activated,these muscles contract,causing the hairs to stand upright,a phenomenon known as 'piloerection' or erection of hairs.

(B) The human neural system is divided into two parts: the Central Neural System $(CNS)$ and the Peripheral Neural System $(PNS)$.
The $PNS$ is further divided into the somatic neural system and the autonomic neural system.
The somatic neural system relays impulses from the $CNS$ to skeletal muscles,which are under voluntary control.
The autonomic neural system transmits impulses from the $CNS$ to the involuntary organs and smooth muscles of the body.

(C) The human neural system is divided into two parts: the Central Neural System $(CNS)$ and the Peripheral Neural System $(PNS)$.
The Peripheral Neural System $(PNS)$ is further divided into the Somatic Neural System and the Autonomic Neural System.
The Autonomic Neural System is responsible for transmitting impulses from the $CNS$ to the involuntary organs and smooth muscles of the body.
Therefore,the autonomic neural system is a division of the peripheral neural system.

(D) Neural crest cells are a specialized population of cells that detach from the dorsal edges of the neural tube during neurulation. As the neural tube closes,these cells migrate away and differentiate into various structures,including the peripheral nervous system,specifically the autonomic ganglia,sensory ganglia,and adrenal medulla. Therefore,the correct sequence is that they break off from the neural tube and form structures like autonomic ganglia.

(B) The digestive system is regulated by the autonomic nervous system $(ANS)$, which consists of two divisions: the sympathetic and parasympathetic nervous systems.
The parasympathetic nervous system is responsible for the 'rest and digest' response.
It stimulates digestive activities, such as increasing the secretion of digestive enzymes, promoting peristalsis, and increasing blood flow to the gastrointestinal tract to facilitate nutrient absorption.
In contrast, the sympathetic nervous system is associated with the 'fight or flight' response, which inhibits digestive processes to redirect energy to other vital organs.

(B) The correct matching is as follows:
$1$. Hydra: It possesses a simple nervous system consisting of a network of neurons known as a nerve net $(P-I)$.
$2$. Insect: Their nervous system is more complex, consisting of a brain, ganglia, and a network of nerve tissues $(Q-II)$.
$3$. Human: Humans have a highly developed central nervous system comprising the brain and spinal cord $(R-III)$.
Therefore, the correct sequence is $(P-I), (Q-II), (R-III)$.

(A) The human neural system is divided into two parts: the Central Neural System $(CNS)$ and the Peripheral Neural System $(PNS)$.
The $PNS$ comprises all the nerves of the body associated with the $CNS$.
The nerve fibers of the $PNS$ are of two types: afferent fibers and efferent fibers.
The efferent nerve fibers may be further classified into the Somatic Neural System $(SNS)$ and the Visceral Neural System $(VNS)$ (or Autonomic Neural System).
Therefore,the $VNS$ is a part of the Peripheral Neural System $(PNS)$.

(C) The peripheral nervous system $(PNS)$ consists of two types of nerve fibers:
$1$. Afferent nerve fibers: These fibers transmit impulses from tissues/organs to the central nervous system $(CNS)$.
$2$. Efferent nerve fibers: These fibers transmit regulatory impulses from the $CNS$ to the concerned peripheral tissues/organs.
Therefore,$P$ represents Afferent nerve fibers and $Q$ represents Efferent nerve fibers.

(C) The human neural system is divided into two parts: the Central Neural System $(CNS)$ and the Peripheral Neural System $(PNS)$.
$CNS$ includes the brain and the spinal cord.
$PNS$ comprises all the nerves of the body associated with the $CNS$.
The $PNS$ is further divided into two divisions: the Somatic Neural System and the Autonomic Neural System $(ANS)$.
Therefore,the $ANS$ is a part of the $PNS$,not the $CNS$.
Option $C$ is incorrect because the $ANS$ is not a part of the $CNS$.

(B) The peripheral nervous system is divided into two divisions: the somatic neural system and the autonomic neural system.
$1$. The $Somatic$ $Neural$ $System$ relays impulses from the $CNS$ to skeletal muscles.
$2$. The $Autonomic$ $Neural$ $System$ transmits impulses from the $CNS$ to the involuntary organs and smooth muscles of the body.
Therefore,$P$ represents the Somatic Neural System and $Q$ represents the Autonomic Neural System.

(A) The neural system is classified based on the presence or absence of a myelin sheath around the axons.
$1$. Myelinated nerve fibers are found in spinal and cranial nerves ($I$ and $IV$).
$2$. Unmyelinated nerve fibers are commonly found in the autonomic and the somatic neural systems ($II$ and $III$).
Therefore,$P$ (unmyelinated) corresponds to $II$ and $III$,and $Q$ (myelinated) corresponds to $I$ and $IV$.

(C) $Endoneurium$: It is the delicate connective tissue layer that surrounds individual nerve fibers (axons).
$Perineurium$: It is the connective tissue layer that surrounds a bundle of nerve fibers,known as a nerve fascicle.
$Epineurium$: It is the outermost layer of dense connective tissue that encloses the entire nerve,which consists of multiple bundles (fascicles) of nerve fibers.
Therefore,the covering of a bundle of nerves (a nerve trunk) is the $epineurium$.