Neural Control and Coordination Mock Test – Class 11 Biology

1. Arrange the following events in a complete sensory-to-response pathway.
P. A peripheral stimulus initiates sodium-dependent depolarisation in an afferent neuron.
Q. The afferent action potential reaches a pre-synaptic terminal in the CNS.
R. Neurotransmitter binds receptors and changes the next neuron’s membrane potential.
S. Central processing organises regulatory output.
T. An efferent impulse reaches the appropriate peripheral target.

2. During vigorous exercise, muscular oxygen demand rises and cardiovascular adjustment occurs normally. Peripheral input also reaches the CNS, but breathing fails to increase after selective damage to a medullary respiratory centre. The strongest interpretation is:

3. Four isolated cells are examined.

Which observation most completely supports identification of the cell as a specialised neuron?

4. An action potential reaches a chemical-synapse terminal. Synaptic vesicles move towards the pre-synaptic membrane but cannot merge with it. Which event is blocked most directly, and what follows?

5. A treatment allows normal sodium influx and depolarisation at an axonal site but prevents from diffusing outward afterwards. The most direct consequence is:

6. A selective lesion destroys hypothalamic neurosecretory cells. Regulation of temperature, hunger and thirst remains nearly normal, and an approximately -hour rhythm is still detectable. The most direct expected defect is:

7. A probe passes inward through the cranium and three meninges before entering a folded region rich in neuronal cell bodies. Deeper tissue contains many myelinated fibre tracts. The complete outside-to-inside relation is:

8. Identical axonal regions are depolarised normally in two solutions. Solution P has the usual low extracellular concentration. Solution Q has a greatly increased extracellular concentration, while potassium permeability rises normally after depolarisation. Repolarisation is slower in Q. The strongest explanation is:

9. In a chemical-synapse experiment, transmitter release and receptor binding occur normally. Trial P makes the post-synaptic neuron more likely to become excited, while Trial Q reduces its likelihood of excitation. The recorded potentials are respectively:

10. Hearing and control of the speech muscles remain functional, but a person cannot relate heard information to memory, organise coherent thought or communicate a meaningful verbal response. The lesion most directly affects:

11. Evaluate the following statements about neurons.
I. They are specialised cells of the neural system.
II. They can detect and receive different kinds of stimuli.
III. They participate in transmission of neural information.
IV. Their defining role is to release hormones into blood as endocrine glands.

12. Use the arrangement described below. Structure P belongs to the hindbrain and has an extensively folded surface. The folds provide additional space for accommodating a large number of neurons. Structure P is:

13. Consider the following statements about the limbic system.
I. It includes inner cerebral regions and associated deep structures.
II. The amygdala and hippocampus are included among its deep components.
III. It consists only of the pons and medulla oblongata.
IV. It interacts with the hypothalamus in behavioural regulation.

14. After a widespread central injury, four findings occur: initiation of intended limb movement is impaired; breathing and cardiovascular reflexes are abnormal; temperature and hunger are unstable; and memory-linked association of sensory inputs is reduced. Peripheral nerves still conduct. Which set of affected regions most completely accounts for the findings?

15. A record classifies four structures in the human neural system.

Which records are assigned to the appropriate division?

16. A peripheral receptor and its afferent axon are intact. At axonal Region P, an action potential forms normally, but a barrier prevents internal and external local currents from influencing adjacent Region Q. Direct stimulation of the CNS beyond Q still produces normal chemical synaptic transmission and an appropriate efferent response. The failed process is:

17. Consider the following statements about functional areas of the cerebral cortex.
I. Motor areas participate in control of movements.
II. Sensory areas receive and process sensory information.
III. Association areas support intersensory association, memory and communication.
IV. Association areas are defined as purely motor regions lacking higher integrative roles.

18. An individual detects an odour normally and maintains body temperature, hunger and thirst. The odour, however, no longer evokes the usual emotional significance, motivational response or associated autonomic change. The most likely disturbance involves:

19. Match each description with its most appropriate interpretation. A Column II entry is used once.

20. Assertion: Increased permeability follows the brief increase in permeability at an excited axonal region.
Reason: During repolarisation, diffuses inward and makes the axoplasmic surface more positive.

21. Two neurons have intact terminal vesicles and receive the same proximal stimulus. Neuron P has been demyelinated, while Neuron Q retains myelin but has blocked post-synaptic receptors. In P, proximal stimulation produces a weak terminal response, but direct stimulation of its terminal causes normal transmitter release and a normal response in the next cell. In Q, transmitter release occurs after either stimulation method, but the next cell does not respond normally. The results indicate that:

22. Neural activity is recorded in Hydra, an insect and a vertebrate. Hydra shows spread through a neuronal network, the insect uses a brain with ganglia and neural tissues, and the vertebrate uses a more developed neural system. Which conclusion is justified?

23. A peripheral stimulus reaches the central neural system and is processed normally, but the resulting command cannot reach a skeletal muscle. The interrupted pathway is most specifically:

24. A neuron is shown with a central nucleated region, several short branched processes and one long process ending in terminal branches. The three regions are respectively:

25. A neuronal process is unusually long, lacks the repeated short branching typical of the receiving region and ends near a muscle in several terminal branches. It is identified as an axon mainly because it:

26. During an intended hand movement, visual information reaches the CNS, a skeletal muscle moves, heartbeat adjusts, and the person later remembers the event. Which interpretation assigns the input, two outputs and higher function consistently?

27. In a sagittal arrangement, structure P is surrounded by the cerebrum, while structure Q lies at the base of P. P and Q are respectively:

28. Two myelinated axons have intact terminal vesicles and functional post-synaptic receptors. Fibre P retains its myelin, while Fibre Q is experimentally demyelinated without cutting the axonal membrane. Proximal stimulation reaches Q’s terminal less efficiently, but direct terminal stimulation produces normal transmitter release. The evidence supports:

29. Evaluate the following statements about the functions of the brain.
I. It participates in control of voluntary movement and maintenance of balance.
II. It regulates vital involuntary and homeostatic functions.
III. It contributes to approximately -hour rhythms and influences several endocrine glands.
IV. Its activity is restricted to movement and excludes memory, emotion and thought.

30. The following records compare Schwann-cell association, sheath formation and occurrence.

Which records are internally consistent?

31. A peripheral stimulus reaches the CNS and is processed normally. The CNS then sends output through pathway X to a skeletal muscle and pathway Y to smooth muscle of an involuntary organ. After Y is interrupted, the skeletal response remains normal but the smooth-muscle response is lost. The damaged component is:

32. Arrange the stages in a pathway that begins with peripheral input carried through a brain-associated nerve and ends with a skeletal-muscle response through a spinal-cord-associated nerve.
P. An impulse travels centrally through a cranial afferent fibre.
Q. A central pre-synaptic terminal releases neurotransmitter.
R. CNS processing organises a motor command.
S. The command enters a spinal somatic efferent fibre.
T. The skeletal muscle receives the output.

33. In an experiment, activity produced in one cerebral hemisphere normally appears shortly afterwards in the other. After one internal fibre tract is severed, each hemisphere still responds to local stimulation, but transfer of activity between them is greatly reduced. The severed tract is:

34. A lesion damages the midbrain, pons and medulla oblongata but leaves the cerebellum intact. Which classification most accurately describes the affected anatomical group?

35. Two adjacent axonal regions are labelled P and Q. P is depolarised, with its inner surface positive, while Q is still resting, with its inner surface negative. The local current initially flows:

36. Select the symbolic relation that correctly distinguishes resting potential, action potential and impulse conduction along an axon.

37. Arrange the structures in the normal direction of information flow from a neuronal soma towards either another neuron or a muscle.
P. Bulb-like synaptic knobs containing transmitter-filled vesicles
Q. Usually long axon
R. Cell body
S. Distal axonal branches
T. Synapse or neuromuscular junction

38. A resting neuron is exposed to a treatment that stops sodium-potassium pumping while leaving the membrane initially intact. After sufficient time, the strongest supported prediction is that:

39. During vigorous exercise, the following events are involved in meeting the altered demand:
P. Muscular activity increases.
Q. Oxygen demand of active tissues rises.
R. Breathing, heartbeat and blood flow increase.
S. After exercise stops, the altered activities gradually move towards resting levels.
Select the biologically appropriate order.

40. Examine the following midbrain records.

Which records are consistently interpreted?

41. A resting axon initially has high internal , high external , retained negatively charged proteins and normal ion-selective permeability. A treatment makes the membrane freely permeable to the intracellular proteins but initially leaves sodium and potassium permeability unchanged. The most direct prediction is:

42. Two neural discontinuities are observed. At X, a short exposed region lies between intact myelin segments on one axon, and a new action potential forms there. At Y, membranes belonging to different neurons lie very close together and electrical current passes directly between them. X and Y are respectively:

43. In an experiment, stimulation of the left cerebral hemisphere is followed by activity in the right hemisphere and in several other brain regions. After Lesion X, transfer to the right hemisphere is selectively reduced, but communication among other regions remains. After Lesion Y, communication among several brain regions is reduced, while direct left-right transfer through the intact interhemispheric tract persists. X and Y most directly damage:

44. Consider the following statements about propagation of an action potential along an axon.
I. A depolarised region produces local current towards an adjacent resting region.
II. Local current can reverse the polarity of the adjacent membrane.
III. A new action potential is generated in the newly depolarised region.
IV. Propagation requires every region of the axon to depolarise simultaneously.

45. In a sagittal model, a probe first passes from outside the skull into a cerebral hemisphere and then follows the central axis inferiorly towards the spinal cord. Arrange the structures in the stated route.
P. Cerebral white matter
Q. Pons
R. Pia mater
S. Midbrain
T. Dura mater
U. Medulla oblongata
V. Cerebral grey cortex
W. Arachnoid
X. Cranium
Y. Spinal cord

46. Consider the following statements about chemical synaptic transmission.
I. Neurotransmitter is released from the pre-synaptic terminal.
II. Specific receptors occur on the post-synaptic membrane.
III. Receptor activation can open post-synaptic ion channels.
IV. Every post-synaptic potential must produce excitation.

47. Use the spatial description below. Structure P is a deep forebrain region surrounded by the cerebrum and involved in coordinating major sensory and motor signalling. Structure P is:

48. A junction found in human neural tissue has membranes in very close proximity and permits direct current flow. A researcher rejects its identification as an electrical synapse solely because electrical synapses are rare in humans. The best evaluation is:

49. The records below describe four hindbrain observations.

Which records are internally consistent?

50. An experiment records cerebellar activity while an animal maintains balance. In Trial P, information from the semicircular canals and auditory system reaches the cerebellum normally. In Trial Q, both inputs are interrupted while the motor pathways to the muscles remain intact. Which result is most strongly supported?