1) The document discusses neural conduction across neurons and synapses. It defines key terms like neuron, dendrite, axon, synapse, and reflex arc. 2) It explains how stimuli are received by sensory neurons and transmitted across the neuron. At the synapse, electric impulses trigger the release of chemicals that transmit the impulse to the next neuron. 3) Reflex actions are defined as very fast actions mediated by reflex arcs, the pathway traveled by impulses during reflexes. Examples like withdrawing from heat are given.

1. Life Science
Class-X
Topic- Neural conduction across neuron and Synapse
By- Asish Khatua
Integrated B.Sc. B.Ed. (Medical)
Lovely Professional University

2. Let’s Recall-
• Artificial Kidney
• Organ donation
• Excretion in plants

3. Identify

5. Situations-
1) Swati was very happy to eat sweets but she freaked out by eating chilli.
2) Himsikha was very much excited to see a fairy tale movie but she was trembling
out of fear by watching a ghost movie.
3) Suman was curious to know where the nice smell of flowers was coming but he
ran from a place where pungent smell was coming.

6. Continue…
4) Hormot was enjoying listening to sweet and soft music but he closed his ear to
hear loud sound coming from construction area.
5) Akanksha seemed comfortable with room heater on a winter evening but she
freaked out all of a sudden when cooler was turned on.

7. Do you think there is a separate system in
humans for detecting stimuli?

9. Synapse
Sense
organ
(Skin)
Dendrite
Cyton
Axon
Muscle
Sensory
Neuron
Dendrite
Cyton
Axon
Motor
Neuron

10. Pathway of stimulus (Across Neuron)
• Stimulus are received by nerve cells present in sensory organs.
• Nerves are extensively present.
• Synapse= Axon tip + Dendrites
of one of another
neuron neuron

11. What happens in Leprosy (Kust rog)?

12. Poll
Fill in the blanks
1) Stimulus are received by of neuron.
( Dendrite/ Axon)

13. 2) True/False
Synapse is a junction between axon of one neuron and dendrite of
another neuron.

15. Pathway of stimulus (Synapse)
• Synapse= Gap between axon and dendrite
• Electric impulse triggers release of some chemicals.
• These chemicals cross the gap/ synapse and start the same electrical
impulse in dendrite of the next neuron.

16. • Gap between dendrite
and muscle fibre is called
neuromuscular junction.

17. In older age people respond very slow and late.
Why?

18. POLL
1) Match the column
A B
Junction between axon
and dendrite Electrical impulse
Junction between axon Synapse
and muscle fibre
Neuron Neuro-muscular junction

20. Situations-
1) Mausam was travelling with her friends. All of a sudden an insect
came near her eyes. Without even thinking she closed her eyes.
2) Sameer put his fingers over a hot lamp. Instantly, he took his fingers
away.

21. Observe carefully…

22. Reflex action
• Action which are very fast are called reflex action.
E.g.- Taking away hand when mosquito bites
Applying breaks when animals come etc.
Reflex arc-
• The path travelled by impulse
during reflex action is called reflex arc.

23. Share your initial days of bicycle learning and after you got
perfection. What difference you could feel?

24. POLL
1) Which of the following is true for reflex action?
a) It is the action which are very fast in nature.
b) Path of impulse is called reflex arc.
c) Taking away of hand by touching hot object is an example of reflex action
d) All of these

25. 2) Label the diagram of reflex arc.

26. Recap-
• Today we have discussed about pathway of impulse across neuron,
synapse, neuro-muscular junction and reflex action.
1) Define synapse.
2) Explain pathway of stimulus across neuron.
3) Differentiate between pathway of stimulus across neuron and
synapse.
4) Name different reflex action.

27. Homework-
1) Explain reflex arc with diagram.
2) Draw a well labelled diagram of Neuro muscular junction.
3) How impulse transmission occur across neuron?

28. Activity-
1) Explore how plants respond to these environmental stimuli.
a) Light b) Touch c) Gravity d) Water
2) Visit your neighbours to find out if any one in their family is
suffering or had past history of any kind of neural disorder.

29. THANK YOU