Myelinated Axons

Non-myelinated Axons

1. Transmission of nerve impulse is faster.

1. Transmission of nerve impulse is slower.

2. Myelinated axon has a myelin sheath.

2. Myelin sheath is absent.

3. Node of Ranvier is present between adjacent myelin sheaths.

3. Node of Ranvier is absent.

4. Found in the brain, the spinal cord, the cranial and spinal nerves.

4. Found in autonomous and somatic neural systems.

5. Schwann cells are observed inside the myelin sheath.

5. Schwann cells are not observed inside the myelin sheath.

Dendrites

Axons

1. Dendrite is a small projection arising from the neuron. It conducts the nerve impulse toward the cell body.

1. Axon is a single, long projection that conducts the nerve impulse away from cell body to the next neuron.

2. Nissl’s granules are present in dendrites.

2. Nissl’s granules are absent from axons.

3. Dendrites are always non-myelinated.

3. Axons can be myelinated or non-myelinated.

Rods

Cones

1. Rods help in twilight vision.

1. Cones help in colour vision.

2. They have visual purple pigment called rhodopsin.

2. They have visual violet pigment called iodopsin.

3. Rods are the photoreceptor cells of the retina that are sensitive to dim light.

3. Cones are the photoreceptor cells of the retina that are sensitive to bright light.

Thalamus

Hypothalamus

Thalamus is the part of the forebrain that receives nerve impulses of pain, temperature, touch, etc., and conducts them to the cerebral hemisphere.

Hypothalamus is the part of the forebrain that controls involuntary functions such as hunger, thirst, sweating, sleep, fatigue, sexual desire, temperature regulation, etc.

Cerebrum

Cerebellum

Part of the forebrain that controls voluntary functions. It is the place where intelligence, will power, memory, etc.

Part of the hindbrain that controls voluntary functions and controls the equilibrium.