Test: CNS, Meninges, Midbrain & Hindbrain - NEET MCQ

The part of the brain that connects the two hemispheres of the brain is called the corpus callosum. It contains a bundle of neuronal fibers found in humans and other higher order mammals that allow the two hemispheres to talk to one another.

Meninges are the membranes that cover and protect the brain and spinal cord. There are three layers of menings: dura mater (closest to the bone), arachnoid (loosely around the brain), pia mater (closely attached to the brain and spinal cord surface).

The cerebellum controls the timing and pattern of the muscle activation during movement. The main function of the cerebellum receives information from the sensory system, the spinal cord, and other parts of the brain and then regulates motor movements. The cerebellum coordinates voluntary movements such as posture, balance, coordination, and speech, resulting in smooth and balanced muscular activity.

So, the correct option is 'coordination of muscular movement'.

• The outer layer of the cranial meninges is known as the dura mater.
• The middle layer is called the arachnoid membrane, and the innermost layer is known as the pia mater.
• The corpus callosum is a part of the forebrain.

Pia mater is the delicate innermost layer of the meninges. It is a thin fibrous tissue that is impermeable to the fluid that surrounds the cerebrospinal fluid and provides protection to the other layers of the meninges. It acts like a cushion of the brain. It allows blood vessels to pass through and nourish the brain. Hence option A is correct.

The box enclosing and protecting the brain is called as the cranium. The cranium is the part of the skull, that encloses the brain. It is sometimes called as the braincase.

• The brain is divided into three parts- the forebrain, the midbrain and the hindbrain.
• The forebrain, which is the largest of all three, consists of the cerebrum, the thalamus and the hypothalamus.

• The cell bodies or neurons or nerve cells are present in a high concentration in the grey matter of the brain and spinal cord.
• The axons of neurons are present in a high concentration in the white matter.

The corpora quadrigemina in mammals are four solid lobes on the dorsal side of the cerebral aqueduct, where the superior posterior pair are called as the superior colliculi and the inferior posterior pair is called the inferior colliculi. The four solid lobes help to decussate several fibres of the optic nerve. The optic lobes or corpora bigemina of fishes, batrachians and birds are structurally homologous with the corpora quadrigemina of mammals.

The pia mater of the brain is the innermost of the three membranes, that cover it. It is the vascular membrane of the brain. It carries the minute branches of the two internal carotids and the two vertebral arteries. It also returns the blood to the heart. The dura mater is the most external membrane of the brain. It forms the internal periosteum of the skull. The dura mater is a dense, tough, inelastic fibrous membrane. The epidermis contains no blood vessels, and cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the dermis. So, the correct answer is option B.

• The hypothalamus is a part of the forebrain. It lies at the base of the thalamus.
• The hypothalamus controls body temperature and hunger.
• It has neurosecretory cells which secrete hormones.

Hindbrain has 3 parts - (1) pons, (2) cerebellum, (3) medulla oblongata. Diencephalon is a small and posterior part of forebrain. It is covered by cerebrum. It consists of thalamus, hypothalamus, epithalamus and metathalamus.

Hence, the correct answer is Option B.

The corpus callosum is a bundle of nerve fibres found in the mammalian brain. It connects the left and right hemispheres of the brain and is responsible for most of the communication between the two. It is composed of white matter, that is, myelinated nerve cells, or axons, whose primary function is to connect grey areas together with neural impulses. The corpus callosum is the largest white matter structure in the brain, found in its interior. Grey matter occupies the periphery. Hence, if the corpus callosum is removed in the mammalian brain, then the communication between cerebral hemispheres will be lost.

The midbrain is located between the hypothalamus of the forebrain and the pons of the hindbrain. The midbrain is also known as the mesencephalon and controls several motor movements.

• The midbrain is present between the hypothalamus of the forebrain and the pons of the hindbrain.
• The corpora quadrigemina is a four lobed structure which is present in the dorsal part of the midbrain.