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

Choroid plexus is found in the superior part of the inferior horn of the lateral ventricles. It is continuous with the inferior of the body of the lateral ventricles. It passes through the interventricular foramen and is present at the top of the third ventricle. There is also choroid plexus in the fourth ventricle, in the bottom half of the cerebellum.

The dura mater is the most superior of the meningeal layers. This tissue separates the cranial cavity into compartments and protects the brain from displacement. The arachnoid mater is the middle layer of the meninges. They transfer cerebrospinal fluid from the ventricles back into the bloodstream. The pia mater is the innermost layer of the meninges. Unlike the other layers, this tissue adheres closely to the brain, running down into the sulci and fissures of the cortex. It fuses with the ependyma, the membranous lining of the ventricles to form structures, called as the choroid plexus, which produce cerebrospinal fluid.

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.

The meninges are the layers that are closely present around the brain. The dura mater is an outermost tough and fibrous layer. It closely lines the cranium. It is followed by the arachnoid mater that forms the middle meninx. The piamater is the innermost meninx which adheres closely to the surface of the brain. It is highly vascular due to the rich supply of the blood vessels. So, it provides oxygen and nutrients to the cells of the brain. 

Hence, the correct answer is 'Duramater'

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.

The arbor vitae (Latin for "tree of life") is the cerebellar white matter, so called for its branched, tree-like appearance. In some ways it more resembles a fern and is present in both cerebellar hemispheres. It brings sensory and motor information to and from the cerebellum.

Based on the surface appearance, three lobes can be distinguished within the cerebellum: the anterior lobe (above the primary fissure), the posterior lobe (below the primary fissure), and the flocculonodular lobe (below the posterior fissure).

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 cranium or the skull is the outermost covering that protects the brain.
• The dura mater is the outermost layer of the meninges.
• The pia mater, which is the innermost layer, is in contact with the brain tissue.

• 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.

Surrounding the adult brain are layers of mesodermally-derived connective tissue, called as meninges. Whereas cyclostomes and fishes only have a single envelope called as the primitive meninx, amphibians have two layers, consisting of an outer dura mater, which is extremely dense and protective, and a pia-arachnoid or secondary meninx, which is more delicate and vascular. They do not have a separate arachnoid layer.

The pons is a part of the brain stem, located above the medulla oblongata and below the midbrain. The primary function of the pons is to stimulate and control the intensity of breathing. Therefore, the correct answer is option D.

• 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 hypothalamus is located below the thalamus, just above the brainstem. It forms the ventral part of the diencephalon.

The epithalamus comprises the thalamus, hypothalamus and also the pituitary gland. It is located at the dorsal aspect of the diencephalon. It also includes the habenula, pineal gland and also the stria medullaris. The thalamus and hypothalamus have been previously described. The pineal gland contains no true neurons, only glial cells. Through a complicated process involving the hormone melatonin, it participates in the regulation of the body’s circadian (24-hour) rhythms. The stria medullaris connects fibers from the habenular nuclei with the limbic system. The specific function of the habenular nuclei in human beings is unclear. 
So, the correct answer is 'Roof of the diencephalon'.

The central nervous system is made up of two types of tissue: the grey matter and the white matter. The grey matter is mainly composed of neuronal cell bodies and unmyelinated axons. In the grey matter, these axons are mainly unmyelinated, meaning they are not covered by a whitish-colored, fatty protein called myelin.

The vagus nerve is the pneumogastric nerve. It is the tenth cranial nerve and interfaces with the parasympathetic (it is relating to the part of the autonomic nervous system which balances the action of the sympathetic nerves) control of the heart, lungs and digestive tract.

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 hypothalamus, the amygdala and the hippocampus are structures of the forebrain.
• They are a part of the limbic system and control emotional reactions.
• The pons is not involved in such activities.

Pons varolii or pons is the part of the hindbrain and situated between midbrain and medulla oblongata, regulates pneumotaxic centre, has inner gray and outer white matter. As a part of the brainstem, the pons helps in the transferring of nervous system messages between various parts of the brain and the spinal cord. The primary function of pons varolii is to regulate breathing, sleeping etc.

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.