Define reflex action. With the help of a flow chart show the path of a reflex action such as sneezing.

Q: Define reflex action. With the help of a flow chart show the path of a reflex action such as sneezing.

**Reflex Action:** A reflex action is a sudden, involuntary, and spontaneous response to a stimulus that occurs without conscious thought. It is controlled primarily by the spinal cord or brain stem to provide a rapid protective response. **Path of a Reflex Action (Sneezing):** Sneezing is a reflex triggered by irritants in the nasal cavity. ```diagram {"xrange": [-1.0, 1.0], "yrange": [-20.16, 2.16], "lines": [{"from": [0.0, 0.0], "to": [0.0, -3.0], "label": ""}, {"from": [0.0, -3.0], "to": [0.0, -6.0], "label": ""}, {"from": [0.0, -6.0], "to": [0.0, -9.0], "label": ""}, {"from": [0.0, -9.0], "to": [0.0, -12.0], "label": ""}, {"from": [0.0, -12.0], "to": [0.0, -15.0], "label": ""}, {"from": [0.0, -15.0], "to": [0.0, -18.0], "label": ""}], "points": [{"x": 0.0, "y": 0.0, "label": "Stimulus: Irritant (Dust) in Nose"}, {"x": 0.0, "y": -3.0, "label": "Receptors: Nasal Lining"}, {"x": 0.0, "y": -6.0, "label": "Sensory Neuron"}, {"x": 0.0, "y": -9.0, "label": "Relay Neuron (Brain Stem/Spinal Cord)"}, {"x": 0.0, "y": -12.0, "label": "Motor Neuron"}, {"x": 0.0, "y": -15.0, "label": "Effectors: Diaphragm & Abdominal Muscles"}, {"x": 0.0, "y": -18.0, "label": "Response: Sneeze (Expulsion of Air)"}]} ```

Chemical Reactions and Equations

Control and Coordination

Official Answer

Reflex Action: A reflex action is a sudden, involuntary, and spontaneous response to a stimulus that occurs without conscious thought. It is controlled primarily by the spinal cord or brain stem to provide a rapid protective response.

Path of a Reflex Action (Sneezing):

Sneezing is a reflex triggered by irritants in the nasal cavity.

involuntarystimulusreflex arcsensory neuronmotor neuroneffectorspinal cord

Marking Scheme

1Definition of reflex action (1 mark)
2Correct sequence in flow chart (Sensory -> CNS -> Motor) (1 mark)
3Correct identification of effectors and response for sneezing (1 mark)

Hint

A reflex action must be involuntary and very fast. Follow the signal from the nose to the muscles.

Quick Oral Answer

The main advantage of a reflex action is its speed, which helps protect the body from immediate harm before the brain can even perceive the danger.

Analysis & Explanation

Reflex actions are biological mechanisms that prioritize speed over conscious processing. The 'Reflex Arc' is the neural pathway that controls a reflex. In the case of sneezing, the body reacts to a physical stimulus (irritant) to maintain homeostasis and protect the respiratory tract, which is the site of the gas exchange reactions mentioned in the text.

Common Mistakes

1Including the conscious brain in the primary reflex arc path.
2Confusing sensory and motor neurons (sensory goes 'to' the CNS, motor goes 'away' from it).

Interesting Facts

Sneezing can travel at speeds of up to 100 miles per hour, helping to clear the respiratory system of potential contaminants effectively.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2024?

This question carries 3 marks in the CBSE Class 10 Science 2024 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Chemical Reactions and Equations" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Control and Coordination" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2024 paper?

This is a Short Answer question from Section C in the CBSE Class 10 Science 2024 paper.