Tag: zoology

Questions Related to zoology

Otolith (otoconia) are CaCO$ _3$ particles found in the

zoology option a: neurobiology and behaviour structure and function of ear perception of stimuli neural control and coordination

  1. Perilymph

  2. Endolymph

  3. Bones

  4. Vitreous humour

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Correct Option: B
Explanation:

An otolith, also called statoconium or otoconium, is a structure in the saccule or utricle of the inner ear, specifically in the vestibular labyrinth of vertebrates. They are sensitive to gravity and linear acceleration. In mammals, otoliths are small particles, composed of a combination of a gelatinous matrix and calcium carbonate in the endolymph of the saccule and utricle. The inertia of these small particles causes them to stimulate hair cells, when the head moves. 

Eye and ear are the examples of 

zoology option a: neurobiology and behaviour structure and function of ear perception of stimuli neural control and coordination

  1. Telereceptors

  2. Gustatory receptors

  3. Exteroreceptors

  4. Interoreceptors

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Correct Option: A
Explanation:

A sensory receptor such as a visual receptor or an auditory receptor, that can be stimulated by distant stimuli and that mediates a far sense is called as telereceptor. 

Ear dust is not situated in endolymph of

zoology option a: neurobiology and behaviour structure and function of ear perception of stimuli neural control and coordination

  1. Utriculus

  2. Ampulla

  3. Sacculus

  4. Endolymphatic sac

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Correct Option: B
Explanation:

While semicircular canals respond to angular acceleration in specific directions, hair cells in the utricle and saccule respond to linear accelerations. The utricle and saccule are sac-like structures, that contain a patch of sensory hair cells called as the macula. The hair cells in the macula, which are similar to those in the cristae, are embedded in the otolith (ear stone) membrane, a gelatinous structure, that contains a large number of hexagonal prisms of calcium carbonate called as otoconia (ear dust). 

Since the density of the otoconia is greater than the surrounding endolymph, the otolith membrane will be displaced by the force of gravity or other linear accelerations. In humans, the enlarged ends of each of three semicircular bony canals in the inner ear are known as osseous ampullae. Tiny hairs in this ampullae help to keep the brain informed of how the head is oriented, helping the person's sense of balance. 
Therefore, the correct answer is option B.

Which part of the human ear converts pressure variations into electrical signals?

zoology option a: neurobiology and behaviour structure and function of ear perception of stimuli neural control and coordination

  1. Eustachian tube

  2. Auditory nerve

  3. Ear drum

  4. Cochlea

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Correct Option: D
Explanation:

When the pressure variations strike the ear, they find their way through the external auditory canal to the tympanic membrane, setting it into vibration. The signal is thus converted to mechanical vibrations in solid matter. These vibrations of the tympanic membrane are transmitted to the ossicles, which in turn transmit them to the cochlea. Here, the signal undergoes a second change of nature, being converted into pressure variations within the liquid. These are then transformed again by specialised hair cells, which convert the liquid waves into nervous signals. Inside the cochlea, the tectorial membrane moves along with the pressure variations of the cochlear fluid. This membrane is in contact with the cilia on the top of the hair cells. There are two kinds of hair cells. The outer hair cells are the actual receptors. When the tectorial membrane moves, so does the hair on the outer cells. This movement is then encoded into electrical signals and goes to the brain through the cochlear nerve.

How many coils are present in cochlear duct of rabbit?

zoology option a: neurobiology and behaviour structure and function of ear perception of stimuli neural control and coordination

  1. $\displaystyle 2 \frac{1}{2}$

  2. $\displaystyle 2 \frac{3}{4}$

  3. $\displaystyle 1 \frac{1}{2}$

  4. $\displaystyle 1 \frac{1}{4}$

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Correct Option: A
Explanation:

The cochlea is the auditory portion of the inner ear. It is a spiral-shaped cavity in the bony labyrinth, in rabbit making 2.5 turns around its axis, the modiolus. A core component of the cochlea is the organ of Corti, the sensory organ of hearing.

So, the correct answer is option A.

Which of the following cells do not form layer and remain structurally separate?
zoology nervous system neural tissue structure of neuron nervous tissues

  1. Epithelial cells

  2. Muscle cells

  3. Nerve cells

  4. Gland cells

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Correct Option: C
Explanation:
Nerve cells or neurons are the cells specialised to conduct an electrochemical current. Nerve tissue is made up of these cells. Only nerve cells do not form layers and remain structurally separate.
So the correct option is, 'Nerve cells'.

Neurilemma is outer covering of _______________.

zoology tissue level of organisation neural tissue structure of neuron nervous tissues

  1. Blood capillaries

  2. Muscle fibre

  3. Intestine

  4. Nerve fibre

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Correct Option: D

Plasmalemma of axon is called ______________.

zoology tissue level of organisation neural tissue structure of neuron nervous tissues

  1. Axolemma

  2. Neurilemma

  3. Sarcolemma

  4. None of these

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Correct Option: A

Neuro-fibrils are present in ___________.

zoology tissue level of organisation neural tissue structure of neuron nervous tissues

  1. Cyton

  2. Muscles

  3. Bones

  4. Connective tissue

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Correct Option: A

Function of nerves tissue is?

zoology tissue level of organisation neural tissue structure of neuron nervous tissues

  1. Excitability

  2. Sensitivity

  3. Elasticity

  4. Contraction

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Correct Option: A
Explanation:

  • Nervous tissues are the class of specialized tissues majorly found in the central and peripheral nervous system. 
  • These tissues are made up of neurons and their supporting cells called neuroglia. 
  • These tissues are responsible for the control and coordination throughout the body. 
  • The nervous tissues or neurons are excitable cells that work on the basis of action potentials.

So, the correct answer is 'Excitability'.