Tag: nervous system in animals

Dendrites are the small extension of nerve cells that receive signals from sensory receptors or other neurons. The nerve impulse is not conducted by them. The long extension of the cell body of the nerve cell is called as axon that serves to conduct the nerve impulse away from the cell body. The increased diameter of axon results in reduced resistance to local current flow which in turn causes the action potential at its one site to activate the adjacent site. Soma is the metabolic center of the nerve cell where the metabolic contents are manufactured. It is not involved in nerve impulse conduction. Thus, the correct answer is option B.

Schwann/Schwarm cells of peripheral nervous system form the myelin sheath around the myelinated fibers. Gaps between two Schwann cells form nodes of Ranvier which are the unmyelinated areas. Dendrites are the small extension of nerve cells that receive signals from sensory receptors or other neurons and brings them towards the cell body. The synaptic knob is the small button like structure present at the end of the axonal branch at the synapse and serves to store the neurotransmitters which are released in the synaptic cleft. The correct answer is A.

Dendrites are the small extension of nerve cells that receives signals from sensory receptors or other neurons through axon and brings them towards the cell body. Thus, the correct answer is option A.

Neurotransmitters are endogenous chemicals that enable the process of neurotransmission. They transmit signals across a chemical synapse from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell. 

• The different cells in the body can regenerate in order to replace the damaged or the worn-out cells. 
• The neurons are one of the brain cells. The cells divide during the embryonal stage. After the birth of a child, the cells lose their capacity to divide. 
• These cells have the least capacity of regeneration. 
• Thus, the correct answer is option C. 

The axon can be defined as the long cytoplasmic process of the cell body, which transmits the impulse from the cell body to other neurons. The axon of the neuron 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.
Thus, the correct answer is the option D.

The dendrites of the neuron are called as 'afferent processes' because they transmit impulses to the neuron cell body.
Thus, the correct answer is the option (B), 'Dendrite'.

Cells of the nervous system are called nerve cells or neurons. Neurons have specialized cell parts, called dendrites and axons. A thin sheath covers the axon of the nerve cell. This sheath is called as neurilemma. The sarcolemma also called the myolemma, is the cell membrane of a striated muscle fiber cell. It is not present in the nerve cell. 

Unlike unmyelinated axons in periphary nerves which an embedded in neurilemma of Schwann cells, those of central nerves lie free in neuropil(nertwork of glial cells and nerve cell components).

Nissl granules are specialized structures found in the cell body (cyton) and dendrites of neurons, but they are notably absent from the axon and the axon hillock.