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प्रश्न
How are the messages carried across a synapse? Explain with the help of a labelled diagram.
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उत्तर
A receptor in a sense organ is in touch with the dendrites of the sensory neuron. When a stimulus acts on the receptor, a chemical reaction is initiated that produces an electrical impulse in the receptor. This impulse travels from the dendrites of the sensory neuron (say A) to its cell body and, then, along its axon. At the end of the axon of the sensory neuron A, the electrical impulse releases chemical substances called neurotransmitters into the synapse which cross the synapse and start a similar electrical impulse in the dendrites of the next neuron (say B). From the dendrites, this electrical impulse is carried to the cell body and, then, to the axon of the second neuron.
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संबंधित प्रश्न
Draw the structure of a neuron.
Nervous system is absent in _____________.
Name two systems which taken together perform the functions of control and coordination in human beings.
Name the following:
Flap like structure of outer ear.
Differentiate between rods and cones.
State whether the following statement is true (T) or false (F):
The largest part of the brain is the cerebrum.
State whether the following statement is true (T) or false (F):
There are 31 pairs of cranial nerves.
Distinguish between the following pair of words:
Nervous system and hormonal system
Nervous and hormonal systems together perform the function of control and coordination in human beings. Justify this statement with the help of an example.
Explain the Term: Reflex action
Give Technical Term:
The find cytoplasmic processes of the cell body of a neuron.
State the Location of:
Pinnae
Complete the following sentence with appropriate Word
The ventral root ganglion of the spinal cord contains cell bodies of the:
Column ‘II’ is a list of items related to ideas in Column ‘I’. Match the term in Column ‘II’ with the suitable idea given in Column ‘I’.
| Column I | Column II | ||
| (i) | Auditory canal | (a) | Channels pressure waves of air into the middle ear. |
| (ii) | Auditory (Eustachian tube) | (b) | Collects pressure waves of air. |
| (iii) | Auditory nerve | (c) | Converts pressure waves of air into vibrations of bone. |
| (iv) | Incus | (d) | Dissipates sound waves. |
| (v) | Malleus | (e) | Equalizes pressure between the middle ear and the atmosphere. |
| (vi) | Oval window | (f) | Provide information about the spatial orientation of the head. |
| (vii) | Pinna | (g) | Transfers vibrations from a bone to a fluid. |
| (viii) | Round window | (h) | Transfers vibrations from a bone to a membrane. |
| (ix) | Semi-circular canal | (i) | Transfers vibrations from a bone to a bone. |
| (x) | Stapes | (j) | Transfers vibrations from a membrane to a bone. |
| (xi) | Tympanic membrane | (k) | Transmits action potential to the auditory cortex. |
______ and ______ increases the surface area of cerebrum.
Which is the ninth cranial nerve in humans?
Subdural space is present between (i)____________ and (ii)____________.
Loss of function in which nerve would result in paralysis of muscles of mastication?
Destruction of the anterior horn cells of the spinal cord would result in loss of ______.
