CBSE Questions for Class 11 Medical Biology Neural Control And Coordination Quiz 2 - MCQExams.com

• The nervous system is found in the kingdom Animalia. 
• Except for Porifera, Echinodermata and few worms, the nervous system is found in almost all animals consisting of a brain, a spinal cord, and some nerves. 
• The nervous system is not found in plants and other organisms like microbes, etc.
• Hormones are also secreted by plants known as phytohormones.
• Respiration and diffusion take place in all living cells.

• Axons of neurons can be either myelinated or non-myelinated. 
• Myelin sheath is made up of proteins and fatty substances. 
• It allows electrical impulses to transmit quickly and efficiently along the nerve cells.

• It produces and secretes aqueous humour essential to regulate the pressure within the eye.

• It contains muscles, that act on the crystalline lens via its zonular fibres, in concert with the elastic lens capsule, to change its shape and thus shift the focus of the eye from far to near.

The cornea is the transparent layer of the eye located within otherwise opaque sclera. It serves to refract the light rays. Iris is the coloured part of the eye that controls the amount of light entering the eye by adjusting the size of the pupil, a hole shaped opening in the middle of the eye. Ciliary body and the attached suspensory ligament change the shape (flattened or round) of the lens through relaxation and contraction of ciliary muscles and thereby the focal length to focus on a distant and near object. Thus, the correct answer is option C.    

• The choroid runs behind the retina and at the front of the eye, forming the ciliary body. As it contains many blood cells, the choroid supplies the eye with nutrients and oxygen apart from removing waste.
• The choroid also has a high concentration of a pigment called melanin in its cells. It is this pigment that prevents internal reflection within the eye preventing us from receiving a blurred image.

• A retinal ganglion cell is a type of neuron located near the inner surface of the retina of the eye. 
• It receives visual information from photoreceptors via two intermediate neuron types: bipolar cells and retina amacrine cells. 

• Rods and cones are used to process light, in a human eye. 
• Cones have iodopsin and are found mainly in the central area of the retina (fovea), while rods containing rhodopsin are found in the peripheral retina. 
• Cones sense colour and need more light than rods to work well. 
• Cones are most helpful in normal or bright light. 
• There are 3 types of cones - red, green, and blue - to help you see different ranges of colour. Together, these cones sense combinations of light waves, that enable our eyes to see millions of colours. 
• Iodopsin is a photosensitive violet pigment that occurs in the cones of the retina and is transformed by light into retinal and opsin protein.