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The correct answer is (C) Three

To ELABORATE: The inner LAYER of the EYE is retina and it contains three LAYERS of neural cells which are:

i. Ganglion cells

ii. Bipolar cells

iii. Photoreceptor cells.

Correct choice is (b) False

Explanation: The afferent neurons receive the signals from a sensory organ and TRANSMITS the IMPULSE via a dorsal nerve ROOT into the CNS and at the LEVEL of the spinal cord.

Right option is (a) Hippocampus

The best explanation: The hindbrain comprises of the PONS, the MEDULLA oblongata and the cerebellum. The hippocampus is present in the forebrain and is a PART of the LIMBIC system, which controls emotional REACTIONS.

Correct answer is (c) There is a slow influx of sodium ions

Explanation: When a stimulus is applied to a POLARIZED axonal membrane, the polarity of the membrane is reversed. It becomes PERMEABLE to sodium ions and LEADS to its RAPID influx. Outer SURFACE of the membrane becomes negatively charged.

The correct ANSWER is (a) Action potential

The explanation is: A nerve impulse is also KNOWN as an action potential. It changes the RESTING MEMBRANE potential as it reverses the POLARITY of the axonal membrane. It becomes permeable to sodium ions and leads to its rapid influx.

The correct answer is (c) Between HYPOTHALAMUS and pons

Easy explanation: 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.

Right choice is (a) Synaptic knobs

The explanation: An AXON is a part of the nerve cell or the neuron. Each axon is a long FIBER that projects from the cell BODY. The TERMINAL end of the axon branches out and each end TERMINATES with a synaptic knob.

Right answer is (a) True

Easiest explanation: Visceral NERVOUS SYSTEM is the part of the peripheral nervous system that comprises the whole complex of nerves, fibres, ganglia, and plexuses by which impulses TRAVEL from the CNS to the VISCERA and vice-versa.

The correct answer is (d) SECRETE the stimuli

For explanation: The neurons are not responsible for secreting the stimuli. Instead, their main FUNCTIONS include-detecting, RECEIVING and transmitting stimuli over LARGE distances in our BODY.

Correct option is (b) Lignin

The explanation: A neuron is a MICROSCOPIC structure COMPOSED of three major parts, namely, call body, dendrites, and axon. The cell body CONTAINS cytoplasm with typical cell organelles and certain granular BODIES CALLED Nissl’s granules.

Right ANSWER is (d) Afferent nerve fibers

Best explanation: The organ of corti contains HAIR CELLS present in rows, which act as auditory receptors.The hair cells are present on the internal SIDE of the organ of corti and are in close contact with the afferent nerve fibers.

Correct CHOICE is (c) Oval WINDOW

The EXPLANATION: The scala vestibuli is a part of the cochlea ALONG with the scala tympani and the scala media. The scala vestibuli ends at the oval window at the base of the cochlea, while the scala tympani TERMINATES at the round window.

The correct choice is (b) False

To elaborate: The ORGAN of CORTI is a structure present on the basilar MEMBRANE of the COCHLEA in the labyrinth of the inner ear. The organ of corti contains hair cells present in rows, which act as AUDITORY receptors.

Right choice is (b) Endolymph

Explanation: The LABYRINTH is a STRUCTURE PRESENT in the INNER ear. It consists of TWO parts-the bony and the membranous labyrinths. The membranous labyrinth contains a fluid which is known as endolymph.

The correct option is (a) Mast cells

To EXPLAIN I WOULD say: The retina is the innermost LAYER SURROUNDING the eye. It contains three types of neural cells-the ganglion cells, the BIPOLAR cells and the photoreceptor cells. The light entering the eye falls on the retina.

Right answer is (a) True

For explanation I would say: The brain can be divided into three major parts:

i. Forebrain

ii. Midbrain

iii. Hindbrain

The HUMAN brain is well protected by the skull. Inside the skull, the brain is covered by CRANIAL meninges.

Right ANSWER is (c) Choroid layer

Best explanation: The choroid layer is thin over the POSTERIOR two-thirds of the EYEBALL, but it becomes thick in the ANTERIOR part to form the ciliary body. The ciliary body itself continues forward to form a pigmented and OPAQUE structure called the iris.

Right OPTION is (b) In Spinal cord and cranial NERVES

Explanation: Myelinated NERVE fibres are FOUND in spinal and cranial nerves. Unmyelinated nerve fibres are enclosed by a Schwann cell that does not form a myelin sheath around the axon and is commonly found in autonomous and the somatic NEURAL system.

Right choice is (d) Dendrite

To explain: SHORT and repeatedly branched fibres are called DENDRITES. These branches project out of the cell body of the neuron. These branches also contain Nissl’s granules in their cytoplasm.

Right choice is (a) WHITE

To explain: Each type of cone CELL is responsive to different colors of light and various degrees of COMBINATIONS give SENSATIONS of different colors. when all CONES are stimulated equally, a sensation white light is perceived.

Correct choice is (a) True

The explanation is: There are three TYPES of NEURONS or nerve cells. These types are multipolar neurons, unipolar neurons and BIPOLAR neurons. Unipolar neurons LACK dendrites. They have a cell body with only one axon.

Right option is (a) Choroid

The explanation: The eyeball is surrounded by THREE protective LAYERS. The middle LAYER is known as the choroid, which is rich in BLOOD vessels and has a bluish appearance. The CILIARY body is a part of the choroid.

Right CHOICE is (a) 3

To explain: NEURONS or nerve cells are CLASSIFIED into three TYPES based on the number of axon and dendrites. The three types of neurons are namely, multipolar neurons, unipolar neurons and BIPOLAR neurons.

Correct ANSWER is (b) Synaptic vesicles

To explain: Neurotransmitters are the chemicals which help in the TRANSMISSION of impulses from NEURON to neuron and from to neuron the target TISSUE or cell. They are stored in the synaptic vesicles.

The correct CHOICE is (a) Scala NATURAE

For explanation: The cochlea, which is a SPIRAL BONY structure of the labyrinth present in the inner ear, contains the scala vestibuli, the scala tympani and scala media. Scala naturae is not a PART of the cochlea.

Right answer is (a) Cochlea

To explain: The EAR is divided into THREE parts- the OUTER ear, the middle ear and the inner ear. The OVAL window is a PORTION of the cochlea, which is located in the inner ear. It is attached to the stapes of the middle ear.

Right option is (b) False

The explanation is: The SPACE between the cornea and the LENS is KNOWN as the aqueous CHAMBER. It CONTAINS a fluid known as aqueous humor. The space between the lens and the retina is known as the vitreous chamber.

Correct OPTION is (c) Dense connective tissue

The best I can EXPLAIN: The eyeball is surrounded by three LAYERS. The sclera is the outermost opaque and fibrous layer that surrounds the eye. It is MADE up of dense connective tissue and provides protection and form.

Correct answer is (d) Stimulus and response

The explanation is: The EFFERENT neurons carry the signals from the CENTRAL nervous SYSTEM to the effector organs. The stimulus and response thus form a REFLEX arc, for EXAMPLE; the knee jerk reflex.

The correct choice is (d) Glomerulus

Easiest explanation: The NEURON is the structural and FUNCTIONAL unit of the nervous SYSTEM. The neuron or the NERVE cell has three main parts-the cell body, the axon and the dendrites. Glomerulus is a part of nephron.

The correct option is (b) Involuntary action in RESPONSE to a peripheral nervous STIMULATION

To explain: A REFLEX action is an involuntary action taken by our BODY in response to peripheral nerve stimulation. This process does not require the conscious effort of our brain and it takes place instantly to SAVE us from bearing any harm.

Correct ANSWER is (B) 3

Best EXPLANATION: At resting membrane potential, to maintain the ionic gradient, 3 sodium IONS are transported out of the axonal membrane for EVERY 2 potassium ions moving into the cell, by the Na-K pump.

Right OPTION is (a) Cell to cell connection only

The best I can explain: The NEURAL system provides an ORGANIZED network of point to point connections for quick coordination. These FUNCTIONS of the organs or the organ systems must be coordinated in our body to MAINTAIN homeostasis.

The CORRECT choice is (c) Macula

Explanation: The OTOLITH is a part of the vestibular apparatus, which is a complex structure present in the INNER ear. It is LOCATED above the cochlea. The sensory part of the otolith (saccule and UTRICLE) is the macula.

Correct choice is (c) Ciliary body

The best I can explain: The MIDDLE LAYER of the eye is known as the choroid layer. The choroid id thicker in the anterior PORTION of the eye and forms the ciliary body. The ciliary body continues FORWARD to form the iris.

The correct choice is (c) It lies beside the thalamus

For explanation: 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.

The correct answer is (b) Peripheral nervous system

To EXPLAIN I would say: PNS stands for the Peripheral nervous system. The PNS COMPRISES of all the nerves of the BODY ASSOCIATED with the central nervous system-brain and the spinal CORD.

The correct OPTION is (B) Eustachian tube

The BEST I can explain: The middle ear cavity is connected with the pharynx through the Eustachian tube. It lies in the inner ear. The function of the Eustachian tube is to equalize AIR pressure on either side of the ear drum.

The CORRECT OPTION is (c) FOVEA

For explanation: Cone cells are densely PACKED in the fovea, which is the CENTRAL pit of the macula lutea. The macula lutea is a yellow-pigmented region present near the center of the retina, which is the innermost layer of the eye.

Right choice is (B) False

Easy explanation: Scotopic VISION or twilight vision is a function of rod CELLS, while photopic vision or colored vision is a function of CONE cells. The rod cells and cone cells are the photopigments present in the RETINA.

Correct choice is (d) Neurotransmitters

To elaborate: Neurotransmitters are chemical COMPOUNDS that help in the transmission of NERVE impulses or action potentials. NISSL’s granules, Schwan cells and SYNAPTIC knobs do not PARTICIPATE in this process.

The correct choice is (c) Ligaments

For explanation I would say: The LENS PRESENT in the eye is a transparent CRYSTALLINE STRUCTURE through which light passes before it falls on the RETINA. The lens is held in place by the ligaments which are attached to the ciliary body.

Right CHOICE is (d) Retina of EYE

For explanation I would say: Bipolar neurons are found in the retina of the eye. They possess ONE axon and one DENDRITE. The cerebral cortex and autonomic ganglia have MULTIPOLAR neurons. Unipolar neurons are found in embryo.

Right choice is (B) 3

The best explanation: The ear is divided into three parts-the outer ear, the middle ear and the INNER ear. The middle ear CONSISTS of three bones known as the ear OSSICLES. The bones are known as malleus, INCUS and stapes.

The CORRECT answer is (c) Choroid

Explanation: The eyeball is surrounded by three membranes-the outermost sclera, the MIDDLE choroid and the innermost retina. The choroid LAYER is rich in blood vessels and hence gives a BLUISH appearance.