Tiêu đề Neural Control and Coordination -Ex-1 Solution fie.docx.pdf ✅

1 NEURAL CONTROL AND COORDINATION EXERCISE – 1: Basic Objective Questions Introduction to Coordination and Neural System 1. The process by which two or more organs interact and complement the functions of one another is called (a) Homeostasis (b) Coordination (c) Accommodation (d) Adaptation Ans. (b) Sol. Co-ordination is the term used for the process by which two or more organs interact and complement the functions of one another. It is due to this co-ordination that the body is able to perform complex vital processes which requires involvement of more than two organs. 2. Intercellular communication in multicellular organism occurs through (a) Nervous system only (b) Digestive system only (c) Respiratory system only (d) Both nervous and endocrine system Ans. (d) Sol. The intercellular communication in higher animals occur through two means which are - by help of endocrine system and by the help of the nervous system. Hormones produced by the endocrine glands are carried to the target organs by blood. Whereas in nervous system, neurons help in transmission of impulse. 3. In which animal nerve cell is present but brain is absent? (a) Sponge (b) Earthworm (c) Cockroach (d) Hydra Ans. (d) Sol. Organisms belonging to Phylum Cnidaria generally have nerve cells and sensory cells but lack brain. Hence, Hydra has nerve cells but lacks brain. The organisms of Phylum Porifera or the sponges lack any kind of nervous system at all. Whereas earthworm and cockroaches have a ventral nerve cord along with ganglia. Human Neural System 4. CNS is mostly made of (a) association neurons (b) motor and sensory neurons (c) motor and association neurons (d) sensory and association neurons Ans. (a) Sol. Association neurons are also known as interneurons or relay neurons. Their main function is to carry impulses from a motor neuron to the brain. They constitute the majority portion of the central nervous system. 5. All the nerves of the body associated with the CNS (brain and spinal cord), comprised in (a) Peripheral neural system (b) Somatic neural system (c) Autonomic neural system (d) Sympathetic neural system Ans. (a) Sol. There are two parts of the nervous system. First, central nervous system which consists of brain and spinal cord and the peripheral nervous system which comprises of all the nerves associated with the CNS. 6. The function of visceral organs is controlled by (NCERT Exemplar) (a) Sympathetic and somatic neural system (b) Sympathetic and parasympathetic neural system (c) Central and somatic neural system (d) None of above Ans. (b) Sol. Sympathetic and parasympathetic neural systems are part of autonomic neural system. This system control and coordinates the function of visceral organs. 7. _____ nerve fibers transmit impulse from tissues/organs to the CNS and ____ nerve fibers
2 NEURAL CONTROL AND COORDINATION transmit regulatory impulses from the CNS to the concerned peripheral tissues/organs. (a) a-afferent, b-efferent (b) a-efferent, b-afferent (c) a-sympathetic, b-parasympathetic (d) a-parasympathetic, b-sympathetic Ans. (a) Sol. The complete statement should be - The afferent nerve fibres transmit impulse from tissues/organs to the CNS and the efferent nerve fibres transmit regulatory impulses from the CNS to the concerned peripheral tissues/organs. Neuron: The Structural and Functional Unit of Nervous System 8. Nissl’s granules are not found in (a) Cell body (b) Axon (c) Dendrites (d) Both b and c Ans. (b) Sol. Nissl's granules are made up of rough endoplasmic reticulum and some free ribosomes, both of which play an important role in protein synthesis. They are present in the dendrites and cell body but are absent in axonal part of a nerve fibre. 9. Schwann cells are found in (a) Myelinated nerve fibres (b) Unmyelinated nerve fibres (c) Both a and b (d) None of the above Ans. (c) Sol. Schwann cells are found in both myelinated and non-myelinated nerve fibers. They form myelin sheath around myelinated nerve fibers and in non-myelinated nerve fibers axons are encased in cytoplasm of Schwann cells without myelin sheath formation. 10. If cytons are clustered into groups in the CNS, they are termed __a___ and in PNS, they are called __b__ (a) a-ganglia, b-nuclei (b) a-nuclei, b-ganglia (c) a-glia, b-fasciculi (d) a-fasciculi, b-glia Ans. (b) Sol. The cell bodies of neurons are called cytons. Groups of cytons in the CNS are called nuclei whereas the groups of cytons in the PNS are called ganglia. The nuclei serve various specific functions in the CNS. The different cytons present in the nuclei work in a coordinated manner to serve some important collective function. Nuclei can also give origin to cranial nerves and to the tracts of the spinal cord. Ganglia are also divided into either sensory or autonomic ganglia, depending upon their function. 11. In an axon, nerve impulse travels (a) Away from cyton (b) Towards cyton (c) Both away and towards cyton (d) Not known Ans. (a) Sol. In an axon, nerve impulse travels away from the cyton. Unidirectional transmission of a nerve impulse through nerve fibre is due to the fact that neurotransmitters are released by the axon endings and not by dendrites. 12. The electrical potential difference across the resting plasma membrane is called as the (a) Resting potential (b) Action potential (c) Nerve impulse (d) Both b and c Ans. (a) Sol. In resting state, the potential difference across a membrane is called as it's resting membrane potential. It is generally negative due to the presence of negatively charged proteins inside the membrane and difference in concentration of sodium and potassium in and out of the membrane. Hence in resting state the membrane of a nerve fibre is said to be polarized. 13. A polarized neuron is the one that is (a) Conducting stimulus (b) At resting potential (c) Having action potential (d) None of the above Ans. (b) Sol. Polarized neurons are those which are at the resting membrane potential of about -70 mV. They have the ability to depolarize and then conduct stimuli.
3 NEURAL CONTROL AND COORDINATION 14. The potential difference across the membrane of nerve fibre when it does not show any physiological activity is called resting potential. It is about (a) - 60 mV (b) - 70 mV (c) + 60 mV (d) + 90 mV Ans. (b) Sol. The resting membrane potential is regulated by the intracellular concentrations of ions which respect to the extra cellular concentrations of ions. As the inside of the cell is more electronegative, the resting membrane potential is about -70 mV. 15. Resting membrane potential is maintained by (NCERT Exemplar) (a) Hormones (b) Neurotransmitters (c) Ion pumps (d) None of above Ans. (c) Sol. The concentration gradients across the resting membrane are maintained by the active transport of ions by sodium-potassium pump which transports 3 Na + outward for 2 K + into the cell. 16. In resting condition, the concentration gradient is maintained by (a) Sodium-potassium pump (b) Active transport of ions (c) Utilization of ATP energy (d) All of the above Ans. (d) Sol. In resting condition, the concentration gradient is maintained by sodium-potassium pump, active transport of ions and utilization of ATP energy. 17. Potential difference across the resting membrane is negatively charged. This is due to differential distribution of following ions (Exemplar) (a) Na + and K + ions (b) CO 3+ and Cl - (c) Ca 2+ and Mg 2+ (d) Ca 2+ and Cl - Ans. (a) Sol. The potential difference across the resting membrane is negatively charged due to differential distribution of Na + and K + ions. Sodium ions are present outside the membrane and potassium ions are present inside the membrane. Hence, the (a) option is correct. 18. At resting stage nerve cell has (a) Low K + outside and high Na + inside (b) High K + inside and high Na + outside (c) High K + inside and low Na + outside (d) High K + outside and low Na + inside Ans. (b) Sol. At resting stage, the neuron has high intracellular potassium and the extracellular fluid has high sodium ion concentration. 19. Nerve impulse travels as (a) Mechanical impulse (b) Chemical impulse (c) Electrical impulse (d) Magnetic impulse Ans. (c) Sol. Nerve impulses are electrical impulses because during their progression, sodium channels open leading to entry of sodium inside the neuron. This changes the intracellular potential and this process is propagated forwards. 20. During nerve impulse conduction, current flows (a) From site A to site B on the inner surface (b) From site B to site A on the outer surface (c) Anticlockwise manner (d) All of the above Ans. (d) Sol. As we know impulse conduction occurs as a result of local current circuit. Since current flows from positive to negative, the direction of movement on either side if the membrane is also from positive to negative. Hence, according to the given figure, current flows
4 NEURAL CONTROL AND COORDINATION from A to B on the inner surface and from B to A on the outer surface. This appears to be in anticlockwise direction. So, all the statements are correct. 21. Synapses are of (a) Two types-pre synaptic and post synaptic (b) Two types-electrical and chemical (c) Three types-electric, chemical and mechanical (d) Two types-chemical and mechanical Ans. (b) Sol. There are generally two types of synapses called electrical synapses and chemical synapses. In electrical synapses, the pre and post synaptic membranes are close to each other so that current directly flows from one neuron to the other. Whereas in chemical synapses there is a gap between pre and post synaptic membranes called the synaptic cleft. Chemical transmitters move across this cleft to transmit impulse from one neuron to the next. 22. Energy transformation during nerve conduction is (a) Chemical or radiant (b) Chemical to mechanical (c) Chemical to electrical (d) Chemical to osmotic Ans. (c) Sol. During nerve conduction, energy transformation is chemical to electrical. Biochemical molecules called neurotransmitters help propagate the impulse from one neuron to another. The movement of chemical ions across the neuronal membrane manifests as electrical potential causing depolarization of further neurons by release of neurotransmitters. 23. Chemicals which are released at the synaptic junction are (Exemplar) (a) Hormones (b) Neurotransmitters (c) Cerebrospinal fluid (d) Lymph Ans. (b) Sol. A typical synapse consists of bulbous expansion of a nerve terminal called a synaptic-knob lying close to the membrane of dendrite. The cytoplasm of the synaptic knob contains mitochondria, smooth endoplasmic reticulum, microfilaments and numerous synaptic vesicles. Each vesicles contains neurotransmitters (chemical substances) responsible for the transmission of nerve impulse across the synapse. 24. Which does not act as neurotransmitter? (a) Acetylcholine (b) Epinephrine (c) Cortisone/Tyrosine (d) Norepinephrine Ans. (c) Sol. Cortisone is a corticosteroid whereas tyrosine is an amino acid. Hence these are not neurotransmitters. 25. The neurotransmitter produced at the synapse and neuromuscular junction is: (a) ATP (b) GTP (c) Acetylcholine (d) Phosphokinase Ans. (c) Sol. The neurotransmitter produced at the synapse and neuromuscular junction is acetylcholine. 26. The binding of the neurotransmitter with the receptors opens ion channels allowing the entry of ions which can generate a new potential in the (a) Pre-synaptic membrane (b) Post-synaptic membrane (c) Synaptic cleft (d) Synaptic vesicles Ans. (b) Sol. The binding of the neurotransmitter with the receptors on the post synaptic membrane opens ion channels allowing the entry of ions which can generate a new potential in the post synaptic membrane. 27. The new potential developed in the post-synaptic neuron is (a) Excitatory (b) Inhibitory (c) Either excitatory or inhibitory (d) Neither excitatory nor inhibitory