In the peripheral nervous system, acetylcholine activates muscles, and is a major neurotransmitter in the autonomic nervous system. Neurons in every region of the brain use GABA to fine-tune neurotransmission Answer : (d)

12 Cranial nerves found in man Frogs have ten pairs of cranial nerves. Answer : (a)

Within the orbit, the eye is suspended by six extraocular muscles (four rectus muscles and two oblique muscles), suspensory ligaments, and surrounding orbital fat. Answer : (a)

Saltatory conduction is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials. The main purpose of myelin is to increase the speed at which electrical impulses propagate along the myelinated fiber.myelinated fibers, propagate by saltatory conduction. Saltatory transmission occurs at the Node of Ranvier Answer : (b)

Motor neurons causes action in muscle cells The interface between a motor neuron and muscle fiber is a specialized synapse called the neuromuscular junction. Upon adequate stimulation, the motor neuron releases a flood of Acetylcholine that bind to postsynaptic receptors and triggers a response in the muscle fiber which leads to muscle movement. Answer : (d)

Action potential of a nerve cell is + 20 mv. Answer : (c)

A motor neuron carries the message from the central nervous system to the effector. Answer : (b)

Broca's area is connected to another brain region known as Wernicke's area. Wernicke's area is associated with processing and understanding language. Memory is required for word and grammar and experience. Articulation is due to voluntary muscles present in larynx and the pharyngeal, oral, and nasal cavities, tongue, the upper lip, the lower lip Answer : (d)

Parasympathetic nerve endings release Acetylcholine Answer : (c)

Answer : (a)

Broca's area is a region in the frontal lobe of the dominant hemisphere (usually the left) of the hominid brainwith functions linked to speech production Answer : (d)

The olfactory lobe, or olfactory bulb, is the structure within the brain that receives neural input from the nasal cavity, thus processing the sense of smell. Answer : (b)

The temporal lobes are involved in several functions of the body including: Auditory Perception, Memory, Speech,Language Comprehension, Emotional Responses Visual Perception, Facial Recognition Answer : (c)

Answer : (d)

The aqueous humour is a transparent, watery fluid similar to plasma, but containing low protein concentrations. Hyaluronic acid is present in aqueous humor. Hyaluronic acid, also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. Answer : (c)

TThe total volume of CSF in the adult ranges from 140 to 270 ml Answer : (b)

Relaxation of the ciliary muscle causes the zonular fibers to become taut, flattening the lens, increasing the focal distance and object distant object can be seen clearly. Reverse happens when we see nearby object Answer : (a)

Fovea centrailsis a small depression in the retina of the eye where clarity of vision is highest. where retinal cones are particularly concentrated. Answer : (c)

The ventral roots are composed, predominantly, of efferent somatic motor fibers. Answer : (c)

Muller’s fibers are living optical fibers in the vertebrate retinawhich serve as support cells for the neurons of the retina Answer : (d)

Cranial Nerve	Name	Function
I	The Olfactory Nerve	Sense of Smell
II	The Optic Nerve	Vision
III	The Oculomotor Nerve	Raise eyelids, move eyes, regulate the size of pupils, focus of lenses.
IV	The Trochlear Nerve	Eye movements, proprioception
V	The Trigeminal Nerve	Sensations of the head and face, chewing movements, and muscle sense.
VI	The Abducent Nerve	Produce movements of the eyes
VII	The Facial Nerve	Facial expressions, secretion of saliva, taste.
VIII	The Vestibulocochlear Nerve	Balance or equilibrium sense. Hearing.
IX	The Glossopharyngeal Nerve	Taste and other sensations of tongue, swallowing, secretion of saliva, aid in reflex control of blood pressure and respiration.
X	The Vagus Nervehistorically cited as the pneumogastric nerve	Transmit impulses to muscles associated with speech, swallowing, the heart, smooth muscles of visceral organs in the thorax, and abdomen.
XI	Accessory nerve	Turning movements of the head, movements of the shoulder and viscera, voice production.
XII	Hypoglossal	Tongue movements

Answer : (a)

The dorsal root ganglia contain the cell bodies of sensory neurons Answer : (c)

The middle ear contains three tiny bones, called the ossicles. These three bones form a connection from the eardrum to the inner ear. As sound waves hit the eardrum, the eardrum moves back and forth causing the ossicles to move. As a result, the sound wave is changed to a mechanical vibration. Answer : (b)

Body coordination is maintained by Nervous system and Endocrine system Answer : (b)

Medullated nerve fiber - a nerve fiber encased in a sheath of myelin Answer : (d)

The phrenic nerve is a nerve that originates in the neck (C3-C5) and passes down between the lung and heart to reach the diaphragm. Answer : (b)

depolarization is a change within a cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell. the sodium ions rush back into the cell, they add positive charge to the cell interior, and change the membrane potential from negative to positive. Answer : (c)

Color blindness occurs when one or more types of cones are either totally absent, or has a limited spectral sensitivity. Answer : (a)

A reflex arc is the nerve pathway which makes such a fast, automatic response possible. without the delay of routing signals through the brain. Answer : (d)

The Oculomotor NerveRaise eyelids, move eyes, regulate the size of pupils, focus of lenses. Olfactory and optic nerve have sensory nerve. While Vagus have both motor and sensory nerve.It is the longest nerve of the autonomic nervous system in the human body. Answer : (c)

Cerebellum part of brain controlling balance and coordination Answer : (d)

Conditioned reflexes is a learned response performed by a trained animal to a signal that was previously associated with an event of consequence for that animal. Conditioned reflex (CR) was first used by the Russian physiologist I. P. Pavlov Answer : (b)

During starvation the body does everything possible to preserve the brain. After 2 or 3 days of fasting, the liver begins to synthesize ketone bodies from precursors obtained from fatty acid breakdown. The brain uses these ketone bodies as fuel, thus cutting its requirement for glucose. After several days of fasting, all cells in the body begin to break down protein. This releases amino acids into the bloodstream, which can be converted into glucose by the liver Since much of our muscle mass is protein, this phenomenon is responsible for the wasting away of muscle mass seen in starvation. Answer : (c)

Iris control the amount of light entering the eye through the pupil. Answer : (a)

The occipital lobe is the visual processing area of the brain. It is associated with visuospatial processing, distance and depth perception, color determination, object and face recognition, and memory formation. Answer : (b)

Pia mater often referred to as simply the pia, is the delicate innermost layer of the meninges, the membranes surrounding the brain and spinal cord. Answer : (c)

No taste sensation is evoked when distilled water is put on human tongue because man does not possess taste buds for tasting water. The taste buds present on the tongue send nerve impulses to the brain which actually preceives the taste sensation. Some mammals such as rhesus monkeys, pigs, cats and dogs possess some taste buds which send nerve impulses to the brain when distilled water is applied on them. It seems, therefore, that water may stimulate these taste buds to evoke taste sensation in these animals. Answer : (a)

Iodopsinclass of light-sensitive pigments found in the retinal cones of the vertebrate eye. Rhodopsinpigment-containing sensory protein that converts light into an electrical signal. Answer : (d)

Calcium (Ca2+) is a vital element in the process of neurotransmitter release; when Ca2+ channels are blocked, neurotransmitter release is inhibited. Answer : (c)

alcohol affects the cerebellum, muscle movements become uncoordinated. Answer : (b)

Answer : (d)

After the peak of action potential, called spike potential, the permeability ofthe membrane to Na+ decreases, while it becomes more permeable for K+ whichrapidly diffuses out from the cytoplasm to extracellular fluid due toelectrochemical gradient. Soon, this part of membrane regains its originalpolarity and becomes electropositive on outside and electronegative on inside.This is known as repolarization and the nerve fibre is called repolarized nerve Answer : (c)

vasomotor nerve A motor nerve effecting dilation, such as a vasodilator nerve, orcontraction, such as a vasoconstrictor nerve, of the blood vessels. Answer : (a)

Answer : (a)

Answer : (d)

Answer : (c)

resting stage of neuron, sodium ions (Na+) are maintained at high concentrations outside of the cell, thus Na+ will diffuse in to the cell Answer : (c)

As an action potential (nerve impulse) travels down an axon there is a change in polarity across the membrane of the axon. In response to a signal from another neuron, sodium- (Na+) and potassium- (K+) gated ion channels open and close as the membrane reaches its threshold potential. Answer : (d)

The hypoglossal nerve provides motor control of the extrinsic muscles of the tongue. The hypoglossal nerve also supplies movements including clearing the mouth of saliva and other involuntary activities Answer : (a)

Lens is spherical, to increase the refraction of light. This difference compensates for the smaller angle of refraction between the eye's cornea and the watery medium, Answer : (c)