Plant and Animal Tissues Test - 9

Epidermis is the outer part of skin, which is keratinised and composed of stratified squamous epithelium layers. In the structure of epidermis on the basis of shape of cells and cytoplasm, there are five stratum -
(1) Stratum Malpighii
(2) Stratum spinosum
(3) Stratum granulosum
(4) Stratum lucidum
(5) Stratum corneum
An innermost stratum of epidermis consisting of one layer of cells is called as stratum Malpighii. It is also called as stratum basale. Cells are cubical or columnar in shape. In this stratum two types of cells are present.

Melanocytes - They are called pigmented dendritic cell. These cells are formed by modification of cell which lies at the junction of epidermis and dermis. 

Keratinocytes - They get their nutrition from underlying connective tissue of dermis and divide to form another stratum of the epidermis.

Neurilemma is the outermost covering of Schwann cells that surrounds the axon of the neuron. It is also known as neurolemma.

Thus, the correct answer is 'Covering formed by Schwann cells.'

Myelin sheath is discontinuous because of the presence of nodes of Ranvier. Nodes of Ranvier, the periodic gap in the insulating sheath (myelin) on the axon of certain neurons that serves to facilitate the rapid conduction of nerve impulses. However, nodes of Ranvier interrupt the insulation at intervals, and this discontinuity enables impulses to jump from node to node in a process known as saltatory conduction. Whereas neurolemma is the outermost nucleated cytoplasmic layer of Schwann cells (also called neurolemmocytes) that surrounds the axon of the neuron. 

So, the correct answer is option B.

Neurons are the cells present in thenervous system. Nerve impulses begin at the sensory receptor and are carried tothe CNS through the sensory neuron. The nerve impulse is transmitted throughthe axon of one neuron to the dendrite of the other neuron. Telodendronspresent at the opposite axonic end release neurotransmitters that reach thedendrite of the other neuron through the gaps called synapse. Hence the neuronstransmit information about pain to the brain. Thus the correct answer isoption A.

The structural difference between a neuron and other kinds of cell include the perikaryon and dendrites.

The cell body of a neuron, known as perikaryon, has a large and round nucleus. Nissl granules are present in its cytoplasm forming the characteristic feature.

While dendrites are branched thread like structure arising from cyton which functions to receive impulses from sensory system and transfer it in form of electrical impulses to other neurons via the Axon.

So, the correct option is 'Perikaryon and Dendrites'.

Nissl granules are a large granular body found in neurons. It consists of rough endoplasmic reticulum and clusters of free ribosomes and is a site of protein synthesis. It was named after Franz Nissl, a German psychiatrist, who invented the Nissl staining method.
Thus, the correct answer is option (D), 'Ribosomes'.

Schwann cells that constitute the myelin sheath are lipid-rich cells that create a biological insulation over axon and do not allow the free flow of electrical impulses through it. The myelin sheath is discontinuous and the gap called nodes of Ranvier. This gap has no insulation and thus allows the electrical impulses to pass through and allow saltatory conduction. So electrical impulses jump from one covered area to another.

So the correct answer is 'Gap in the myelin sheath allow for saltatory conduction, where electrical impulses jump from one covered area to another'.

A Nissl body is a large granular body found in neurons. These granules are rough endoplasmic reticulum (RER) with rosettes of free ribosomes and are the site of protein synthesis. These are present in cyton of the nerve cell.

So, the correct answer is option B.

Grey matter is a a major component of the central nervous system, consisting of neuronal cell bodies, neuropil, glial cells, synapses, and capillaries.

So, the correct option is (b) 'populated by cell bodies of neurons'.

The glia cells around the neurons of the peripheral nervous system are called Schwann cells, while the glia cells of the central nervous system are of three different types: Astrocytes, Star shaped cells forming blood brain barrier for the transportation of nutrients into the brain (CNS).

The axon can be defined as a long cytoplasmic process of the cell body of the neuron, which transmits the impulse from the cell body to other neurons. The axon is covered by a lipid-rich membrane called myelin sheath. The myelin sheath is formed by Schwann cells and each Schwann cell covers a part of the axon. The region, where axon is not covered by myelin sheath is the junction of the adjacent myelinated segments called node of Ranvier.
Thus, the correct answer is the option (B), 'Node of Ranvier'.

The nervous system is made up of neurons, specialized cells that can receive and transmit chemical or electrical signals and glia, cells that provide support functions for the neurons by playing an information processing role that is complementary to neurons. 

A neuron can be compared to an electrical wire. It transmits a signal from one place to another. 

Glia can be compared to the workers at the electric company who make sure wires go to the right places, maintain the wires, and take down wires that are broken.
Alveoli and bronchioles are the part of the respiratory system; nephron is a part of the excretory system.

An axon also known as a nerve fibre is a long, slender projection of a nerve cell, or neuron that typically conducts electrical impulses away from the neuron's cell body. The function of the axon is to transmit information to different neurons, muscles and glands. The space between two neuron is known as synapse. The nerve impulse is transmitted towards the synaptic terminal from the dendron.

Golgi I or Golgi type I neuron is a neuron, which has a long axon that begins in the grey matter of the central nervous system and may extend from there.
Golgi II neurons have short axons or no axons at all.
Golgi III and IV do not exist.
Thus, the correct answer is option A.

Each mammalian neuron consists of a cell body, dendrites, and an axon. The cell body contains the nucleus and cytoplasm. The axon extends from the cell body and often gives rise to many smaller branches before ending at nerve terminals. Dendrites extend from the neuron cell body and receive messages from other neurons. 

The dendrites are covered with synapses formed by the ends of axons from other neurons. 

Neurilemma is the outermost nucleated cytoplasmic layer of Schwann cells that surrounds the axon of the neuron. 

The sarcolemma also called the myolemma is the cell membrane of a striated muscle fiber cell. It is not present in the nerve cells.