Question
Write down the following activities in the correct order for a simple reflex arc:
  1. Impulse travels in the motor fibre.
  2. Impulse travels in the sensory fibre.
  3. Effector organ stimulated.
  4. Impulse crosses the synapse.

Answer

The pathway taken by nerve impulses in a reflex action is called a reflex arc. It is an automatic response to a stimulus. When a stimulus is given to a receptor, the receptors produce an impulse in the sensory fibre. The sensory fibre carries this message in the form of an electrical stimulus across the synapse. From the synapse, the impulse travels in the motor fibre and stimulates the effector organ to produce the desired response. The correct order for a simple reflex arc is:
(b) → (d) → (a) → (c).

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Three $2\Omega$ resistors, A, B and C, are connected as shown in Figure. Each of them dissipates energy and can withstand a maximum power of 18W without melting. Find the maximum current that can flow through the three resistors?
What is meant by ‘reflection of light’? Define the following terms used in the study of reflection of light by drawing a labelled ray-diagram :
  1. Incident ray.
  2. Point of incidence.
  3. Normal.
  4. Reflected ray.
  5. Angle of incidence.
  6. Angle of reflection.
Write one or two words for each of the following statements/ definitions:
  • Each level of food chain where transfer of energy takes place.
  • The physical factors like temperature, rainfall, light, soil, air and water of an ecosystem.
  • Organisms which depend on the producers for food either directly or indirectly.
  • The physical and biological world where we live in.
  • Selfcontained unit of living things and their non-living environment needing only sunlight for its functioning.
Write the names and symbols of two most reactive metals belonging to group I of the periodic table. Explain by drawing electronic structure how either one of the two metals reacts with a halogen. With which name is the bond formed between these elements known and what is the class of the compound so formed known? State any four physical properties of such compounds.
Why do we need to manage our natural resources?
Give two differences between food chain and food web.
Draw the diagram of alimentary canal of man and label the following parts.Mouth, Oesophagus, Stomach, Intestine.
When we touch a hot plate unknowingly, then this heat is sensed by a receptor P present in our fingers. The receptor triggers and impulse in neuron Q which transmits the message to an organ R which is a part of the central nervous system. Here the impulse is passed on to a neuron S which in turn passes it to a yet another neuron T. The neuron T passes the impulse to a tissue U in our arm. The tissue U then contracts and pulls our hand away from the hot plate.
  1. What is the name of (i) receptor P (ii) neuron Q, and (iii) organ R?
  2. What is (i) neuron S, and (ii) neuron T?
  3. Name the tissue U.
  4. What name is given to the phenomenon in which hand is pulled away quickly from the hot plate?
  5. Name the effector in this whole process.
A 5V battery is connected to two $20 Ω$ resistors which are joined together in series.
  1. Draw a circuit diagram to represent this. Add an arrow to indicate the direction of conventional current flow in the circuit.
  2. What is the effective resistance of the two resistors?
  3. Calculate the current that flows from the battery.
  4. What is the p.d. across each resistor?
Consider the following chemical reactions which take place in different organisms/ tissues under various conditions:
  1. Glucose → Respiration → Respiration Ethanol + Carbon-dioxide + Energy.
  2. Glucose → Respiration → Respiration Carbon-dioxide + Water + Energy.
  3. Glucose → Respiration → Respiration Lactic acid + Energy.
  1. Name one organism which respires according to equation (i) above.
  2. Name one organism which respires according to equation (ii) above.
  3. When and where does respiration represented by equation (iii) above take place?
  4. Which equation/ equations represent aerobic respiration?
  5. Which equation/ equations represent anaerobic respiration?
  6. Which of the above reactions produces the maximum amount of energy?