{"id":20586,"date":"2018-07-30T01:30:33","date_gmt":"2018-07-29T20:00:33","guid":{"rendered":"https:\/\/www.cbselabs.com\/?p=20586"},"modified":"2021-09-18T15:22:37","modified_gmt":"2021-09-18T09:52:37","slug":"ncert-solutions-for-class-11-biology-neural-control-and-coordination","status":"publish","type":"post","link":"https:\/\/www.cbselabs.com\/ncert-solutions-for-class-11-biology-neural-control-and-coordination\/","title":{"rendered":"NCERT Solutions For Class 11 Biology Neural Control and Coordination"},"content":{"rendered":"

NCERT Solutions For Class 11 Biology Neural Control and Coordination<\/span><\/h2>\n

Topics and Subtopics in\u00a0NCERT Solutions for Class 11 Biology Chapter 21 Neural Control and Coordination<\/strong>:<\/strong><\/p>\n\n\n\n\n\n\n\n\n\n\n\n
Section Name<\/strong><\/td>\nTopic Name<\/strong><\/td>\n<\/tr>\n
21<\/td>\nNeural Control and Coordination<\/td>\n<\/tr>\n
21.1<\/td>\nNeural System<\/td>\n<\/tr>\n
21.2<\/td>\nHuman Neural System<\/td>\n<\/tr>\n
21.3<\/td>\nNeuron as Structural and Functional Unit of Neural System<\/td>\n<\/tr>\n
21.4<\/td>\nCentral Neural System<\/td>\n<\/tr>\n
21.5<\/td>\nReflex Action and Reflex Arc<\/td>\n<\/tr>\n
21.6<\/td>\nSensory Reception and Processing<\/td>\n<\/tr>\n
21.7<\/td>\nSummary<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

NCERT Solutions <\/a>Class 11 Biology<\/a>Biology Sample Papers<\/a><\/p>\n

NCERT TEXTBOOK QUESTIONS FROM SOLVED<\/strong><\/span><\/h3>\n

1. Briefly describe the structure of the following:<\/strong><\/span>
\n (a) Brain (b) Eye (c) Ear<\/strong><\/span>
\nSolution:\u00a0<\/strong><\/span>(a) Brain:<\/strong> The brain acts as control and command system of the body. It is protected by skull and is covered by three meninges. It is divisible into three main regions: forebrain, midbrain and hindbrain.
\n(i) Forebrain – It consists of three regions:
\n(a) Olfactory lobes: These are a pair of very small, solid club-shaped bodies which are widely separated from each
\nother. They are fully covered by cerebral hemispheres.
\n(b) Cerebrum – It is the largest and most complex of all the parts of human brain. A deep cleft divides the cerebrum into right and left cerebral hemispheres, connected by myelinated fibres, the corpus callosum.
\n(c) Diencephalon – It encloses a slit-like cavity, the third ventricle. The thin roof of this cavity is known as the epithalamus, the thick right and left sides as the thalami, and floor as the hypothalamus.
\n(ii) Midbrain – It is located between thalamus\/ hypothalamus of forebrain and pons of hindbrain. Its upper surface has two pairs of rounded protrusious called corpora quadrigemina and two bundles of fibres called crura cerebri.
\n(iii) Hindbrain – It consists of:
\n(a) Cerebellum – The second largest part of the human brain is the cerebellum. It consists of two lateral cerebellar hemispheres and central worm-shaped part, the vermis. The cerebellum has its grey matter on the outside, comprising three layers of cells and fibres. It also has Golgi cells, basket cells and granule cells.
\n(b) Pons varolii – An oval mass, called the pons varolii, lies above the medulla oblongata. It consists mainly of nerve fibres which interconnect different regions of the brain.
\n(c) Medulla oblongata – It extends from the pons varolii above and is continuous with the spinal cord below. The mid brain, pons varolii and medulla oblongata are collectively called brain stem.<\/p>\n

(b) Eye:<\/strong> Eye is a hollow spherical structure composed of three coats:
\n– Outer fibrous coat
\n– Middle vascular coat
\n– Inner nervous coat
\n(i) Fibrous coat: It is thick and protects the eyeball. It has two distinct regions – sclera and cornea. Sclera covers most of the eye ball. The sclera or white of the eye contains many collagen fibres. Cornea is a transparent portion that forms the anterior one – sixth of the eyeball. The cornea is avascular (i.e., lacks blood supply).
\n(ii)Vascular coat: It comprises of 3 regions : choroid, iris, ciliary body.
\n(a) Choroid : It lies adjacent to sclera and contains numerous blood vessels and pigmented cells.
\n(b) Iris: The iris is a circular muscular diaphragm containing the pigment giving eye its colour. It extends from the ciliary\u00a0body across the eyeball in front of the lens. It 2. has an opening in the centre called the pupil.
\nIt contains two types of smooth muscles, circular muscles (sphincters) and radial muscles (dilators), of ectodermal origin.
\n(c) Ciliary body: Behind the peripheral margin of the iris, the vascular coat is thickened to form the ciliary body. It is composed of the ciliary muscles and the ciliary processes.
\n(iii) Nervous coat: It consists of retina which is neural and sensory layer of an eye ball.\u00a0It consists of three layers; ganglion cells, bipolar cells and photoreceptor cells (rods and cones).
\nLens: It is a transparent, biconvex, elastic structure that bends light waves as they pass through its surface. It is composed of epithelial cells that have large amounts of clear cytoplasm in the form of fibres.
\nChambers of eyeball: The lens, suspensory ligament and ciliary body divide the eye into an anterior aqueous chamber and a posterior vitreous chamber which are filled with aqueous humour and vitreous humour respectively.<\/p>\n

(c) Ear:<\/strong> There are three portions in an ear:
\n(i) External ear: It further has 2 regions: pinna and external auditory canal or meatus.
\n(a) Pinna: The pinna is a projecting elastic cartilage covered with skin. Its most prominent outer ridge is called the helix. The lobule is the soft pliable part at its lower end composed of fibrous and adipose tissue richly supplied with blood capillaries. It is sensitive as well as effective in collecting sound waves.
\n(b) External auditory canal: It is an S-shaped tube leading inward from the pinna. It is a tubular passage supported by cartilage in its exterior part and by bone in its interior part.
\n(ii) Middle ear: It consists of 3 small bones called ear ossicles – malleus, incus and stapes, which are attached to one another and increase efficiency of transmission of sound waves to inner ear.
\n(iii) Internal ear: It consists of bony and<\/p>\n

2. Compare the following:<\/strong><\/span>
\n (a) Central neural system (CNS) and Peripheral neural system (PNS).<\/strong><\/span>
\n (b) Resting potential and action potential.<\/strong><\/span>
\n (c) Choroid and retina.<\/strong><\/span>
\nSolution:\u00a0<\/strong>(a) CNS: It lies along the mid-dorsal axis of the body. It is a hollow, dorsally placed structure and comprises of brain and spinal cord. It is a centre of information processing and control.
\nPNS: Nerves arising from the central nervous system constitute the peripheral nervous system. It carries information to and from the CNS. It includes spinal nerves and cranial nerves.
\n(b) Resting potential: Outside the plasma membrane of a nerve fibre is the extracellular fluid which is positively charged with respect to the cell contents inside the plasma membrane. A resting nerve fibre shows a potential difference between inside and outside of this plasma membrane. This difference in the electrical charges across the plasma membrane is called the ‘resting potential’.\u00a0A membrane with resting potential across it, is said to be electrically polarized.\u00a0Action potential : Action potential is another name of nerve impulse. The contents inside a cell at the excited state becomes positively charged with respect to extracellular fluid outside it. This change in polarity across the plasma membrane is known as an action potential. The membrane with reversed polarity across it is said to be depolarized.
\n(c) Choroid: Choroid lies adjacent to the sclera and contains numerous blood vessels that supply nutrients and oxygen to the other tissues especially of retina. It contains abundant pigment cells and is dark brown in colour.
\nRetina: It is the neural and sensory layer of the eye ball. It is a very delicate coat and lines the whole of the vascular coat. Its external surface is in contact with the choroid and its internal surface with vitreous humour. It contains ganglion cells, bipolar cells and photoreceptor cells. membranous labyrinth. Membranous labyrinth consists of three semicircular ducts, utricle, saccule and cochlea.<\/p>\n

More Resources for CBSE Class 11<\/strong><\/p>\n