Biology
Given alongside is a partial diagrammatic representation of a certain phenomenon pertaining to the nervous system.
(i) Name the parts numbered 1-7
(ii) Name the phenomenon that the diagram depicts and define it.
(iii) Give the technical term for the point of contact between two nerve cells.
(iv) Name the parts not shown in the diagram that should be included to complete the pathway of the phenomenon.
Answer
(i) The parts numbered 1-7 are:
1 → White matter
2 → Spinal cord
3 → Dorsal root
4 → Association Neuron
5 → Ventral root
6 → Gray matter
7 → Central canal
(ii) The diagram depicts spinal reflex action.
It is defined as an automatic/quick/immediate, involuntary action in the body brought about by a stimulus.
(iii) Synapse
(iv) Receptor, sensory neuron, motor neuron, spinal nerve, effector muscles
Related Questions
Fill in the blanks by choosing the correct alternative given for each.
(i) Brain and spinal cord are the parts of …………… nervous system. (central/peripheral/autonomous)
(ii) …………… is the largest part of the brain. (Cerebellum/cerebrum/medulla oblongata)
(iii) White matter consists mainly of …………… . (axons/dendrites/cytons)
(iv) The part of the brain concerned with body balance is …………… .(cerebrum, cerebellum, medulla oblongata)
Given below are a few common reflexes in humans. Classify them as a simple or conditioned reflex.
(i) Knee-jerk.
(ii) Watering of mouth on seeing a favourite dish.
(iii) Tying of shoe laces while talking.
(iv) Closing of eyelids if a strong beam of light is flashed across.
The basic structural and functional unit of brain is:
- Cyton
- Nephron
- Axon
- Neuron
Which of the following structures is absent in nerve cells ?
- Nucleus
- Cytoplasm
- Centrosome
- Neurilemma