Questions
What are the gaps through out the length of the myelin sheath called?
- Synaptic clefts
- Axons
- Dendron
- Node of Ranvier
- Synapse
Which of the following prevents the mixing of impulses in the adjacent axons?
- Myelin sheath
- Acetylcholine
- Synaptic cleft
- Nissil granules
- Neurilemma
In neurons, axon is surrounded by a white insulating sheath. What is this sheath called?
- Myelin sheath
- Neurilemma
- Node of Ranvier
- Cyton
- Dendrite
Axon terminals are closely placed near the dendrites of other neurons but are not connected. What are such gaps called?
- Node of Ranvier
- Excited region
- Synaptic clefts
- Dendrite
- Neurilemma
Which of the following statements is not correct?
- Optic nerve arising from the eye and ending in the brain is called mixed nerve.
- A nerve arising from brain and supplying blood to the muscles of the eyeball for rotating the eye is a motor nerve.
- The myelin sheath acts like an insulation.
- A wave of irritability is called an impulse.
- Acetylcholine sets a new impulse in the dendrites of the adjacent neuron.
What is the sheet of fibres connecting the two cerebral hemispheres called?
- Corpus callosum
- Meninges
- Frontal lobe
- Diencephalon
- Synaptonemal cleft
What is 'jumping of the action potential' at the Nodes of Ranvier called?
- Recovery phase
- Active phase
- Saltatory conduction
- Neurotransmission
Which of the following statements is incorrect about nerve impulse?
- In normal condition, the outer side of the nerve fibre carries positive charge.
- The condition when outer side of nerve fibre carries normal (+) charge is called depolarized state.
- Nerve impulse travels at a maximum speed of about 100 metres per second only.
- Repolarization of nerve takes place due to active transport of Na+ ions again to the outside.
- Conduction of nerve impulse is a wave of depolarization followed by repolarisation.
The space between the covering membranes of brain is filled with a watery fluid, which acts like a cushion to protect the brain from shocks. What is this fluid called?
- Cerebral fluid
- Cerebrospinal fluid
- Meningial fluid
- Synovial fluid
- Acetylcoline
Which of the following is an example of conditioned reflex?
- Withdrawal of hand on touching a hot surface
- Sneezing during cold
- Withdrawal of hand on pricking a needle
- Salivation in dog on seeing bread
- Increased heart beat during stress
Suppose the terminal ends of axon are in contact with dendrites of four adjacent neurons, the nerve impulse of the axon will
- travel in one of the neurons because the impulse travels from dendrites of one neuron into the axon of another neuron
- travel only in one neuron, which is in closest contact and with the same intensity
- get distributed in all the four neurons resulting in weak impulse
- travel in all the four neurons
- travel in only two neurons, which are most closely associated
Which of the following is true about association neurons?
- They convey the impulse from receptor to the brain.
- They carry impulse from the main nervous system to an effector.
- They interconnect the sensory and motor neurons.
- They conduct depolarization impulse.
- They convey the impulse from receptor to an effector.
Anesthesia reduces pain by blocking nerve conduction due to
- blockage of neurotransmitter receptors
- blockage of Na+ channels
- blockage of K+ channels
- blockage of blood flow in the target organ
- increasing the blood flow in the target part
What is the pre-excitation potential difference between outside and inside of a nerve called?
- Reaction potential
- Action potential
- Spike potential
- Resting potential
- Jumping potential
During development of action potential in a nerve fibre, why are the positive and negative charges on outer and inner sides of axon membranes reversed?
- Due to movement of K+ ions out of the axon.
- As more K+ ions enter the axon than Na+ ions leave the same.
- As more Na+ ions enter the axon than K+ ions leave the same.
- Due to all Na+ ions entering the axon.
- Due to high concentration of Cl- ions.
Which of the following chemicals sets a new impulse in the dendrites of the adjacent neuron?
- Epinephrine
- Acetylcholine
- Nor-epinephrine
- Neurilemma
- Adrenaline
In mammalian eye, the power of accommodation is controlled by changing the shape of the lens. Which of the following governs it?
- Cornea
- Pupil
- Iris
- Ciliary body
- Lens
Canal of Schleman is present at the junction of
- sensory and non-sensory retina
- choroid and ciliary body
- sclera and cornea
- ciliary body and iris
- iris and cornea
When we move from dark to light, we fail to see for some time but soon the visibility becomes normal. What is this condition called?
- Accomodation
- Adaptation
- Photoperiodism
- Mutation
- Polarisation
A frog with crushed brain is pinched on the leg and the leg is drawn away. It is
- automatic motor response
- neurotransmitter induced response
- conditional reflex
- simple reflex
- conditional and neurotransmitter induced the response