question_answer 9)

Differentiate between (a) Myelinated and non-myelinated axons (b) Dendrites and axons (c) Rods and cones (d) Thalamus and hypothalamus (e) Cerebrum and cerebellum  

Answer:

  (a)           Differences between Myelinated and Non-myelinated Axons                

S.N.	Myelinated Axon	Non-myelinated Axon
1.       2.	The myelinated nerve fibres are enveloped with Schwann cells, which form a myelin sheath around the axon. Myelinated nerve fibres.are found in spinal and cranial nerves,	Unmyelinated nerve fibre are enclosed by a Schwann cell that does not form a myelin sheath around the axon. There are commonly found in autonomous and the somatic nervous systems.

  (b)      Differences between Dendrites and Axons  

S.N.	Dendrite	Axon
1.           2.	These are short fibres which branch repeatedly and project out of the cell body also contain Nissl's granules,       These fibres transmit impulses towards the cell body.	The axon is a long branched , fibre, Which terminates as a bulb-like structure called synaptic knob. It possess synaptic vesicles containing chemicals   : called neurotransmitters. The axons transmit nerve impulses away from the oetl body to a synapse.

  (c) Differences between Rods and Cones  

S.N.	Rod	Cone
1.   2.	The twilight vision is the function of rods. . The rods contain a purplish-red protein called the rhodopsin or visual purple, which contains a derivative of Vitamin-A.	The daylight vision and colour vision are functions of cones. In the human eye, there are three types of cones which possess their own characteristic photopigments that respond to . red, green and blue lights.

    (d) Differences between Thalamus and Hypothalamus  

S.N.	Thalamus	Hypothalaus
1.   2.   3.	The cerebrum wraps around a structure called thalamus. All types of sensory input passes synapses in the thalamus. It controls emotional and memory functions,	It lies at the base of the thalamus.   It contains neurosecretory cells that secrete hypothalamus hormones. It regulates, sexual behaviour expresion of emotional reactions and motivation.

  (e) Differences between Cerebrum and Cerebellum          

S.N.	Cerebrum	Cerebellum
1.   2.   3.	It is the most developed part in brain, A deep cleft divides cerebrum into two cerebral hemispheres. . Its functions are intelligence, learning, memory, speech, etc.	It is the second developed part of brain also called as little cerebrum Externally the whole surface contains gyri and sulci. It contains centres for coordination and error checking during motor and cognition.