Question 1

Muscle contraction is initiated by a signal sent by the central nervous system through the release of __________.

Accepted Answer

Muscle contraction is initiated by a signal sent by the central nervous system (CNS) via a motor neuron. When the neural signal reaches the neuromuscular junction or motor end plate, it triggers the release of a neurotransmitter called acetylcholine. Acetylcholine binds to receptors on the sarcolemma, generating an action potential that spreads through the muscle fibre and causes the release of calcium ions into the sarcoplasm, thereby initiating muscle contraction. Answer: acetyl choline

Question 2

The specific receptors for neurotransmitters in a synapse are present on :

Accepted Answer

Neurotransmitters are released from the synaptic vesicles of the pre-synaptic neuron into the synaptic cleft. These neurotransmitters bind to specific receptors present on the post-synaptic membrane. This binding opens ion channels, generating a new action potential in the post-synaptic neuron. Answer: Post-synaptic membrane

Question 3

Which of the following is not a part of human central neural system ?

Accepted Answer

The central neural system consists of the brain and the spinal cord. The brain is protected by cranial meninges, which are made up of three layers: the outer dura mater, the middle arachnoid, and the inner pia mater. The pericardium is a double-walled membranous sac that encloses the heart, not the central neural system. Answer: Pericardium

Neural Control and Coordination — Previous Year Questions & Solutions