(a) (i) Define a reflex arc. Why have reflex arcs evolved in animals ? Trace the sequence of events which…
(a) (i) Define a reflex arc. Why have reflex arcs evolved in animals ? Trace the sequence of events which occur, when you suddenly touch a hot object.
(ii) Name the part of nervous system which helps in communication between the central nervous system and other parts of the body. What are the two components of this system ?
Solution
(a)
(i) The pathway in which impulses travel during the reflex action is called a reflex arc.
Because the thinking part of the brain is not fast enough/for quick response to avoid injury.
Reflex arc: Hot Plate(Stimulus) → Receptors(like skin) → Sensory Neurons → Spinal Cord → Motor Neurons → Effectors(like muscles) → Response
(ii) Peripheral Nervous System
Components: Cranial Nerves; Spinal Nerves