Neural Control And Coordination Class 11 Notes Biology Chapter 21 - CBSE

Chapter : 21

What Are Neural Control And Coordination ?

Neural System

  • Coordination is the process through which two or more organs interact and complement the functions of one another.
  • Neural system provides an organized network of point to point connection for quick coordination. The endocrine system provides chemical integration through hormones.

Parts Of The Nervous System

Central Nervous System (CNS) (Comprising of the brain and the spinal cord)

  • Cerebrum
  • Medulla Oblongata
  • Cerebellum

Peripheral Nervous System (PNS) (Composed of the cranial and the spinal nerves)

  • Cranial nerves (12 pairs)
  • Spinal nerves (31 pairs)

Autonomic Nervous System (ANS) (made up of chain of parallel sympathetic cords)

  • Sympathetic
  • Parasympathetic


It is the structural and functional unit of the nervous system. Each neuron consists a cell body with cytoplasm, nucleus, nucleolus, mitochondria, Nissl’s granules, golgi structure and thin processes or dendrites originating from dendrons (a relatively long extension) or axon (originates from the cell body).

Types of Neuron

  • Sensory Carry impulse from sensory organs to CNS
  • Motor Carry impulse from CNS to effector organs
  • Interneuron or Synapse connects different neurons

Transmission Of Impulses (Chemical Method)

A nerve impulse is transmitted from one neuron to another through junctions called synapses.

Nerve impulse reaches the Axon Terminal

Ca2+ ions diffuse into synaptic knob

Ca2+ Ions stimulates synaptic vesicies

Synaptic vesicles move to postsynaptic membrane and rupture and pass neurotransmitter to synaptic cleft

Neurotransmitter combine with post synaptic membrane receptors

It cause to open ion channels in the post synaptic membrane

Nerve impulse pass along the second nerve