Biology

Nervous System and Neurons

1,164 Questions

The nervous system and neurons section covers the structural and functional aspects of the human nervous system. Topics include nerve fibers, the myelin sheath, and sympathetic nervous system functions. This material is crucial for general science preparation in various competitive exams.

Neuron structureMyelin sheath productionSympathetic nervous systemCranial and spinal nervesParasympathetic functions

Nervous System and Neurons Questions

Multiple choice zoology neural control and coordination structure and function of spinal cord the spinal cord spinal cord

Ventral root of spinal nerve has 

  1. Sensory fibres

  2. Motor fibres

  3. Both of the above

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The ventral root (motor root) of each spinal nerve consists of axons from motor neurons, whose cell bodies are found within the grey matter of the spinal cord. A ventral root and a dorsal root unite to form a spinal nerve, which passes outward from the vertebral canal through an intervertebral foramen.

Multiple choice zoology neural control and coordination structure and function of spinal cord the spinal cord spinal cord

The dorsal root of spinal cord contains

  1. Somatic motor fibres

  2. Visceral motor fibres

  3. Somatic sensory fibres

  4. Visceral sensory fibres
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A posterior root ganglion (spinal ganglion) (also known as a dorsal root ganglion), is a cluster of nerve cell bodies (a ganglion) in a posterior root of a spinal nerve. The axons of posterior root ganglion neurons are known as afferents. The posterior root ganglia lie along the vertebral column by the spine. The nerve endings of posterior root ganglion neurons have a variety of sensory receptors that are activated by mechanical, thermal, chemical, and noxious stimuli.

Thus, dorsal root ganglia contain cell bodies of sensory neurons. Axons of these sensory neurons travel into the spinal cord via the dorsal roots.
Thus, the correct answer is option C.

Multiple choice zoology neural control and coordination structure and function of spinal cord the spinal cord spinal cord

Axons of preganglionic neurons in the human sympathetic nervous system emerge from which of the following regions of the spinal cord?

  1. Cranial and sacral

  2. Thoracic and lumbar

  3. Cranial and thoracic

  4. Lumbar and sacral
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sympathetic nervous system is also known as the thoracolumbar outflow because its preganglionic neurons originate in the thoracic and lumbar segments of the spinal cord.

Multiple choice zoology neural control and coordination structure and function of spinal cord the spinal cord spinal cord

Cell bodies of neurons bringing afferent information into the spinal cord are located in

  1. dorsal root ganglia

  2. ventral root ganglia

  3. gray matter of the spinal cord

  4. white matter of the spinal cord
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Afferent (sensory) neurons carry information toward the spinal cord. Their cell bodies are located in the dorsal root ganglia, which are clusters of neurons outside the spinal cord.

Multiple choice zoology neural control and coordination structure and function of spinal cord the spinal cord spinal cord

If dorsal root of spinal cord is broken down then its effect is 

  1. No effect on impulse

  2. Impulse is transmitted fast

  3. Impulse is transmitted but slowly

  4. No impulse is transmitted from receptor
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The dorsal root or the posterior root is the main bundle of nerve fibers that branch off from the spinal cord to enter other areas of the body. This combines with the ventral root to form the spinal nerve. and becomes the afferent sensory root and is responsible for carrying and transmitting the sensory information from the body to the brain for processing the signals by the brain. If the dorsal root is broken, then the transfer of information will not be possible. Thus, the correct answer is option D.

Multiple choice zoology life processes in living organism structure and function of spinal cord the spinal cord spinal cord

Last end of spinal cord is called

  1. Cauda equina

  2. Conus medullaris

  3. Funiculus

  4. Fasciculi
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The spinal cord begins at the occipital bone and extends down to space between the first and second lumbar vertebrae. The terminal portion of the spinal cord is called the conus medularis. It is tapperd and located near the lumbar vertebrae.

Multiple choice zoology neural control and coordination structure and function of spinal cord the spinal cord spinal cord

Unipolar neurons can be traced in

  1. Spinal cord

  2. Motor nerves

  3. Retina

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A unipolar neuron is a type of neuron in which only one protoplasmic process (neurite) extends from the cell body. A pseudounipolar neuron is a kind of sensory neuron in the peripheral nervous system. This neuron contains an axon, that has split into two branches; one branch runs to the periphery and the other to the spinal cord.

Multiple choice zoology neural control and coordination structure and function of spinal cord the spinal cord spinal cord

The sensory ganglion concerned with spinal reflex is located in

  1. Dorsal root of spinal nerve

  2. Ventral root of spinal nerve

  3. Both A and B.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A dorsal root ganglion (or spinal ganglion) (also known as a posterior root ganglion), is a cluster of nerve cell bodies (a ganglion) in a posterior root of a spinal nerve.
The cell bodies of peripheral neurons are often found grouped into clusters called ganglia. On the basis of the type of nerve cell bodies found in ganglia, they may be classified as either sensory or motor. Sensory ganglia are oval swellings located on the dorsal roots of spinal nerves and on the roots of certain cranial nerves.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Organ of Golgi is the sensing structure formed at the junction of

  1. Two nerves

  2. Two bones

  3. Nerve and muscle

  4. Muscle and tendon
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Organ of Golgi. also known as Golgi tendon organ is a kind of proprioreceptor that sense stimulus within the body. It receives information from the tendons and sense tension in muscles. These kind of receptors get activated when the muscles stretch or contract due to any activity. These receptor are made up of collagen strands and formed at the junction of muscle and tendon.
So, the correct answer is 'Muscle and tendon'.
Multiple choice biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

Recently, a new device is innovated which allows brain to bypass spinal cord and can directly send signal to limbs and thus can allow movement of paralysed limbs. What kind of signals the device must be generating which controls these muscles?

  1. Thermal signals

  2. Electric signals

  3. Optical signals

  4. Chemical signals
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A new device referred as neurobridge, have been discovered that can by pass the signals from brain to the limbs with the help of electric signals. For the very first time, such device have been developed which helps to reconnect the brain directly to the muscles allowing voluntary and funcutional control of a paralyzed limb. 

Multiple choice biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

A nerve impulse leaves a neuron through the

  1. Dendrites

  2. Cyton

  3. Axon

  4. Nucleus
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For nerve impulses to be generated and carried, nerve cells should be in contact with each other. The nerve impulse is transmitted in the following sequence:  Axon end- synapse- dendrites- dendron- cyton- axon body- axon end. A nerve impulse travels in a form of electrical charge from axon end to the synapse. Here, the electrical impulse is converted to the chemical impulse in the synaptic cleft. Further this nerve impulse flows from synaptic cleft to dendritic tips, converting the chemical impulse to electrical impulse. Thus, the flow of impulse always flows from one axonal end of a neuron to another dendronal head of a neuron. So, the correct answer is option C.

Multiple choice biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

Which of the following statement about a transmission of a nerve impulse is correct?

  1. Nerve impulse travels from dendritic end towards axonal end.

  2. A neuron transmits electrical impulses not only to another neuron but also to muscle and gland cells.

  3. The chemicals released from the axonal end of one neuron cross the synapse and generate a similar electrical impulse in a dendrite of another neuron.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

For nerve impulses to be generated and carried, nerve cells should be in contact with each other. The nerve impulse is transmitted in the following sequence: 
Axon end- synapse- dendrites- dendron- cyton- axon body- axon end. A nerve impulse travels in a form of electrical charge from axon end to the synapse. Here, the electrical impulse is converted to the chemical impulse in the synaptic cleft. Further this nerve impulse flows from synaptic cleft to dendritic tips, converting the chemical impulse to electrical impulse. Thus, the flow of impulse always flows from one axonal end of a neuron to another dendronal head of a neuron. So, the correct answer is option D.

Multiple choice biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

Transmission of a nerve impulse across _____very similar to impulse conduction along axon.

  1. Ranvier's node

  2. Chemical synapse

  3. Electrical synapse

  4. Myelin sheath
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Electrical synapses allow action potentials to pass directly from one neuron to the next through gap junctions without the delay of neurotransmitter release, making the transmission very similar to continuous impulse conduction along a single axon.

Multiple choice biology control and co-ordination in plants and animals voluntary and involuntary movements impulse and its transmission coordination in human beings- nervous control

Conduction of nerve impulse is 

  1. Faster in non-myelinated fibres

  2. Faster in myelinated fibres

  3. No difference in the rate of conduction in myelinated and non -myelinated fibres.

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Conduction of nerve impulse is faster in myelinated fibres as myelin is an insulating layer or sheath, that forms around nerves, including those in the brain and spinal cord which protect and insulates the axons thus enhance the transmission of electrical impulses.

So, the correct answer is option B.