Nervous System Physiology

The vertebral column (spinal column) protects the spinal cord, not the brain directly. The brain is protected by the skull (cranium), meninges, and cerebrospinal fluid. The vertebral column is part of the axial skeleton that encases and shields the spinal cord from injury.

The cerebellum plays a crucial role in maintaining balance, posture, and coordination of voluntary movements. It receives sensory input and fine-tunes motor commands to ensure smooth, coordinated motion. The pons regulates sleep and breathing, the hypothalamus controls homeostasis, and cerebrospinal fluid provides cushioning, but posture maintenance is primarily cerebellar.

The hindbrain consists of three main parts: pons, cerebellum, and medulla oblongata. Option D correctly identifies two of these subparts. Cerebrum is part of the forebrain, while olfactory lobes are also located in the forebrain region, making options A, B, and C incorrect.

The cerebrum is the largest part of the brain and is responsible for higher cognitive functions including intelligence, reasoning, memory, and language. The hypothalamus regulates hormones and homeostasis, the cerebellum coordinates movement and balance, and the pons connects different brain regions but none of these govern intelligence.

The forebrain is the main thinking part of the brain and includes the cerebrum, which is responsible for higher cognitive functions. The midbrain, pons, and medulla are part of the brainstem and primarily handle reflexes, basic life functions, and signal relay - not thinking or reasoning.

The cerebrum has a highly folded and convoluted surface called the cerebral cortex, which increases surface area for more neurons and complex processing. The hypothalamus, cerebellum (which also has folds but less prominent), and pons do not have the same degree of convoluted surface as the cerebrum.

Cerebrospinal fluid (CSF) surrounds the brain and spinal cord, providing cushioning and protection against mechanical shocks. Vitreous and aqueous humour are fluids in the eye, while lysozyme is an enzyme found in tears and saliva - none protect the brain.

This option is correct. Pilocytic astrocytoma arises in the cerebellum, near the posterior part of the brain and includes the cerebral hemispheres and the spinal cord.

The cardio-accelerator which accelerates the heartbeat is connected to the heart through sympathetic nerve fibres.

The cardiac centre lies in the medulla of the brain and is formed of cardioinhibitor and cardioacclerator.

The mesencephalon or midbrain is a part of the brain stem. It is associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature control. A tubular passage, iter is the passage from the third ventricle of the brain to the infundibulum.

The respiratory centre is located in the medulla oblongata. It consists of both inspiratory and expiratory centres.

Chemoreceptors are located outside CNS and are responsive to changes in blood O₂, CO₂ and hydrogen ion concentration.

The main area involved in muscle memory is the cerebellum.