Advertisements
Advertisements
Question
How are the messages carried across a synapse? Explain with the help of a labelled diagram.
Advertisements
Solution
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.
APPEARS IN
RELATED QUESTIONS
What are the two parts of the vertebrate nervous system?
What is the long fibre of a neuron known as?
What are the main organs of the human nervous system? Draw a labelled diagram to show the main organs of the human nervous system.
The human body contains a large number of cells A which are very long and branched, and look like electric wires. The longest branch of this cell is B whereas there are many small branches C. Any two A cells do not join to one another completely in the human body. There is a microscopic gap D between every pair of adjacent A cells through which electric impulses can pass by the release of a chemical substance.
(a) What are cells A?
(b) What is the name of (i) branch B, and (ii) branches C?
(c) What is the microscopic gap D known as?
(d) What is the function of cells like A in the human body?
(e) The cells A are of three types. name the three types.
Fill in the blank:
Sense organs have special cells called ____________ for picking up information and transmitting it to the nerves.
Give the functions of retina, pupil, and optic nerve.
Fill in the blank:
Basic structural unit of the nervous system is the ..................
State whether the following statement is true (T) or false (F):
Each neuron consists of three parts called cell body, cyton, and axon.
Describe the two parts of the nervous system.
Choose the correct answer.
Number of cranial nerves _____________
Mention, if the following statement is True or False
The nerve impulse in the eye develops due to the chemical changes brought about in the sensitive cells (rods and cones) by the light energy of the image.
Multiple choice question.
___________ is in direct contact of brain in human.
How many pairs of cervical spinal nerves are present in humans?
What are masses of grey matter located in white matter in the cerebral hemisphere?
Which is the ninth cranial nerve in humans?
Which nerve controls the movement of shoulder muscle and neck?
“Nervous and hormonal systems together perform the function of control and coordination in human beings.” Justify the statement.
Visceral nervous system comprises of ______.
Complete the following table:
| No. | Name of Nerve | Type of Nerve | Function |
| 1. | Optic | ||
| 2. | Facial | ||
| 3. | Hypoglossal | ||
| 4. | Trigeminal | ||
| 5. | Auditory | ||
| 6. | Glossopharyngeal |
Mohan is fond of playing basketball. His concentration is on shooting the ball into the opponent's basket as given in the picture.
- Which part of the brain helps Mohan to concentrate in putting the ball into the basket?
- Name the sense organ that helps to gauge the distance between the ball and the basket.
- Name the part of the brain that co-ordinates all the voluntary muscles of his body.
