Case Study Questions Class 11 Biology Chapter 21 Neural Control and Coordination
CBSE Class 11 Case Study Questions Biology Neural Control and Coordination. Important Case Study Questions for Class 11 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Neural Control and Coordination.
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CBSE Case Study Questions Class 11 Biology Neural Control and Coordination
CASE 1
The neural system of all animals is composed of highly specialised cells called neurons which can detect, receive and transmit different kinds of stimuli. The neural organisation is very simple in lower invertebrates. For example, in Hydra it is composed of a network of neurons. The neural system is better organised in insects, where a brain is present along with a number of ganglia and neural tissues. The vertebrates have a more developed neural system.
The human neural system is divided into two parts –
- The central neural system (CNS)
- The peripheral neural system (PNS)
The CNS includes the brain and the spinal cord and is the site of information processing and control. The PNS comprises of all the nerves of the body associated with the CNS (brain and spinal cord). The nerve fibres of the PNS are of two types: Afferent fibres and Efferent fibres. The afferent nerve fibres transmit impulses from tissues/organs to the CNS and the efferent fibres transmit regulatory impulses from the CNS to the concerned peripheral tissues/organs.
The PNS is divided into two divisions called somatic neural system and autonomic neural system. The somatic neural system relays impulses from the CNS to skeletal muscles while the autonomic neural system transmits impulses from the CNS to the involuntary organs and smooth muscles of the body. The autonomic neural system is further classified into sympathetic neural system and parasympathetic neural system.
Visceral nervous system is the part of the peripheral nervous system that comprises the whole complex of nerves, fibres, ganglia, and plexuses by which impulses travel from the central nervous system to the viscera and from the viscera to the central nervous system.
1.) The afferent nerve fibres transmit impulses from ____________
a) Tissues to the CNS
b) Organs to the CNS
c) CNS to tissues
d) Both a and b
2.) The efferent nerve fibres transmit impulses from ____________
a) Tissues to the CNS
b) Organs to the CNS
c) CNS to tissues
d) Organ to organ
3.) How many types of nerve fibres do PNS have? Name them.
4.) Give the divisions of peripheral nervous system and their function?
5.) How impulses travel from the central nervous system to the viscera and from the viscera to the central nervous system?
Answer key
1.) d
2) c
3) The nerve fibres of the PNS are of two types:
- Afferent fibres
- Efferent fibres
4) The PNS is divided into two major divisions called somatic neural system and autonomic neural system. The somatic neural system relays impulses from CNS to the skeletal muscles while ANS transmits impulses from CNS to the smooth muscles.
5) Visceral nervous system is the part of the peripheral nervous system that comprises the whole complex of nerves, fibres, ganglia, and plexuses by which impulses travel from the central nervous system to the viscera and from the viscera to the central nervous system.
CASE 2
The brain is the central information processing organ of our body, and acts as the ‘command and control system’. It controls the voluntary movements, balance of the body, functioning of vital involuntary organs, thermoregulation, hunger and thirst, circadian rhythms of our body, activities of several endocrine glands and human behaviour. It is also the site for processing of vision, hearing, speech, memory, intelligence, emotions and thoughts. The human brain is well protected by the skull. Inside the skull, the brain is covered by cranial meninges consisting of an outer layer called dura mater, a very thin middle layer called arachnoid and an inner layer (which is in contact with the brain tissue) called pia mater. The brain can be divided into three major parts: forebrain, midbrain, and hindbrain.
The forebrain consists of cerebrum, thalamus and hypothalamus. Cerebrum forms the major part of the human brain. A deep cleft divides the cerebrum longitudinally into two halves, which are termed as the left and right cerebral hemispheres. The hemispheres are connected by a tract of nerve fibres called corpus callosum. The layer of cells which covers the cerebral hemisphere is called cerebral cortex and is thrown into prominent folds. The cerebral cortex is referred to as the grey matter due to its greyish appearance. The neuron cell bodies are concentrated here giving the colour. The cerebral cortex contains motor areas, sensory areas and large regions that are neither clearly sensory nor motor in function. These regions called as the association areas are responsible for complex functions like intersensory associations, memory and communication. Fibres of the tracts are covered with the myelin sheath, which constitute the inner part of cerebral hemisphere. They give an opaque white appearance to the layer and, hence, is called the white matter. The cerebrum wraps around a structure called thalamus, which is a major coordinating centre for sensory and motor signaling. Another very important part of the brain called hypothalamus lies at the base of the thalamus. The hypothalamus contains a number of centres which control body temperature, urge for eating and drinking. It also contains several groups of neurosecretory cells, which secrete hormones called hypothalamic hormones. The inner parts of cerebral hemispheres and a group of associated deep structures like amygdala, hippocampus, etc., form a complex structure called the limbic lobe or limbic system. Along with the hypothalamus, it is involved in the regulation of sexual behaviour, expression of emotional reactions (e.g., excitement, pleasure, rage and fear), and motivation.
1.) Left cerebral hemispheres and right cerebral hemispheres are connected by a ____________
a) Cerebral cortex
b) Neurosecretory cells
c) Tract of nerve fibres
d) Limbic lobe
2.) Myelin sheath is also known as _____________
a) Cerebral cortex
b) White matter
c) Corpus callosum
d) Limbic lobe
3.) Define hypothalamic hormones.
4.) How two hemisphere are formed from cerebrum?
5.) Explain association areas present at cerebral cortex? Give the functions of association area.
6) Define Dura mater, Arachnoid and Pia mater.
Answer key
1.) c
2) b
3) The hypothalamus contains several groups of neurosecretory cells, which secrete some chemicals called hypothalamic hormones.
4) A deep cleft divides the cerebrum longitudinally into two parts i.e. left and right, which are named as the left and right cerebral hemispheres.
5) Cerebral cortex contains motor areas, sensory areas and large regions that are neither clearly sensory nor motor in function. These regions called as the association areas are responsible for complex functions like intersensory associations, memory and communication.
6) The human brain is well protected by the skull. Inside the skull, the brain is covered by cranial meninges consisting of an outer layer called dura mater, a very thin middle layer called arachnoid and an inner layer which is in contact with the brain tissue called pia mater.
CASE 3
The ears perform two sensory functions, hearing and maintenance of body balance. Anatomically, the ear can be divided into three major sections called the outer ear, the middle ear and the inner ear. The outer ear consists of the pinna and external auditory meatus (canal). The pinna collects the vibrations in the air which produce sound. The external auditory meatus leads inwards and extends up to the tympanic membrane (the ear drum). There are very fine hairs and wax-secreting glands in the skin of the pinna and the meatus. The tympanic membrane is composed of connective tissues covered with skin outside and with mucus membrane inside. The middle ear contains three ossicles called malleus, incus and stapes which are attached to one another in a chain-like fashion. The malleus is attached to the tympanic membrane and the stapes is attached to the oval window of the cochlea. The ear ossicles increase the efficiency of transmission of sound waves to the inner ear. A Eustachian tube connects the middle ear cavity with the pharynx.
The fluid-filled inner ear called labyrinth consists of two parts, the bony and the membranous labyrinths. The bony labyrinth is a series of channels. Inside these channels lies the membranous labyrinth, which is surrounded by a fluid called perilymph. The membranous labyrinth is filled with a fluid called endolymph. The coiled portion of the labyrinth is called cochlea. The membranes constituting cochlea, the reissner’s and basilar, divide the surounding perilymph filled bony labyrinth into an upper scalavestibuli and a lower scala tympani. The space within cochlea called scala media is filled with endolymph. At the base of the cochlea, the scalavestibuli ends at the oval window, while the scala tympani terminates at the round window which opens to the middle ear.The organ of corti is a structure located on the basilar membrane which contains hair cells that act as auditory receptors.
1.) ____________ connects the middle ear cavity with the pharynx.
a) Eustachian tube
b) Tympanic membrane
c) Pinna
d) Malleus
2.) Sound Vibrations collected by pinna, leads inwards and extends up to the ear drum by __________
a) Labyrinth
b) Auditory meatus
c) Tympanic membrane
d) Scala media
3.) What is Scala media?
4.) Name the middle ear
5.) What is labyrinth?
Answer key
1) a
2) b
3.) The space present within the cochlea is called asScala media. It is filled with endolymph.
4.) The middle ear contains three ossicles called malleus, incus and stapes which are attached to one another in a chain-like fashion.
5.) The fluid-filled inner ear called labyrinth consists of two parts,
- The bony labyrinths – The bony labyrinth is a series of channels. Inside these channels lies the membranous labyrinth, which is surrounded by a fluid called perilymph.
- The membranous labyrinths – The membranous labyrinth is filled with a fluid called endolymph. The coiled portion of the labyrinth is called cochlea.
CASE 4
The adult human eye ball is nearly a spherical structure. The wall of the eye ball is composed of three layers. The external layer is composed of a dense connective tissue and is called the sclera. The anterior portion of this layer is called the cornea. The middle layer, choroid, contains many blood vessels and looks bluish in colour. The choroid layer is thin over the posterior two-thirds of the eye ball, but it becomes thick in the anterior part to form the ciliary body. The ciliary body itself continues forward to form a pigmented and opaque structure called the iris which is the visible coloured portion of the eye. In front of the lens, the aperture surrounded by the iris is called the pupil. The diameter of the pupil is regulated by the muscle fibres of iris.
The inner layer is the retina and it contains three layers of neural cells – from inside to outside – ganglion cells, bipolar cells and photoreceptor cells. There are two types of photoreceptor cells, namely, rods and cones. These cells contain the light-sensitive proteins called the photopigments. The daylight (photopic) vision and colour vision are functions of cones and the twilight (scotopic) vision is the function of the rods. The rods contain a purplish-red protein called the rhodopsin or visual purple, which contains a derivative of Vitamin A. In the human eye, there are three types of cones which possess their own characteristic photopigments that respond to red, green and blue lights. The sensations of different colours are produced by various combinations of these cones and their photopigments. When these cones are stimulated equally, a sensation of white light is produced.
The optic nerves leave the eye and the retinal blood vessels enter it at a point medial to and slightly above the posterior pole of the eye ball. Photoreceptor cells are not present in that region and hence it is called the blind spot. The fovea is a thinned-out portion of the retina. It is the point where the visual acuity (resolution) is the greatest.
The space between the cornea and the lens is called the aqueous chamber and contains a thin watery fluid called aqueous humor. The space between the lens and the retina is called the vitreous chamber and is filled with a transparent gel called vitreous humor.
1.) Sclera is made up of _________________
a) Mucoid connective tissue
b) Loose connective tissue
c) Dense connective tissue
d) Pigmented connective tissue
2.) In human Retina,which layers of neural cells is present
a) Ganglion cells
b) Bipolar cells
c) Photoreceptor cells.
d) All of the above
3.) Give the name of photoreceptor cells present in retina and their function
4.) Define fovea
5) Explain aqueous chamber and vitreous chamber?
Answer key
1) c
2) d
3) There are two types of photoreceptor cells, namely, rods and cones. These cells contain the light-sensitive proteins called the photopigments. The daylight (photopic) vision and colour vision are functions of cones and the twilight (scotopic) vision is the function of the rods. The rods contain a purplish-red protein called the rhodopsin or visual purple
4.) Fovea is defined as thinned-out portion of the retina. It is the point where the visual acuity resolutions the greatest.
5) The space between the cornea and the lens is called the aqueous chamber and contains a thin watery fluid called aqueous humor.
The space between the lens and the retina is called the vitreous chamber and is filled with a transparent gel called vitreous humor.
CASE 5
A nerve impulse is transmitted from one neuron to another through junctions called synapses. A synapse is formed by the membranes of a pre-synaptic neuron and a post-synaptic neuron, which may or may not be separated by a gap called synaptic cleft. There are two types of synapses, namely, electrical synapses and chemical synapses. At electrical synapses, the membranes of pre- and post-synaptic neurons are in very close proximity. Electrical current can flow directly from one neuron into the other across these synapses. Transmission of an impulse across electrical synapses is very similar to impulse conduction along a single axon. Impulse transmission across an electrical synapse is always faster than that across a chemical synapse. Electrical synapses are rare in our system.
At a chemical synapse, the membranes of the pre- and post-synaptic neurons are separated by a fluid-filled space called synaptic cleft. Chemicals called neurotransmitters are involved in the transmission of impulses at these synapses. The axon terminals contain vesicles filled with these neurotransmitters. When an impulse (action potential) arrives at the axon terminal, it stimulates the movement of the synaptic vesicles towards the membrane where they fuse with the plasma membrane and release their neurotransmitters in the synaptic cleft. The released neurotransmitters bind to their specific receptors, present on the post-synaptic membrane. This binding opens ion channels allowing the entry of ions which can generate a new potential in the post-synaptic neuron. The new potential developed may be either excitatory or inhibitory.
1.) Impulse transmission across an electrical synapse is always __________ across a chemical synapse.
a) slower than
b) faster than
c) greater than
d) leaser than
2) Identify the incorrect statement
Statement 1 – Impulse transmission across an electrical synapse is always slower.
Statement 2 – A nerve impulse is transmitted from one neuron to another through junctions. Statement 3 – Electrical synapses are common in our system.
Statement 4 – Chemical synaptic neurons are separated by synaptic cleft.
a) Only 1
b) Both 2 & 3
c) Only 3
d) None of the above
3.) Give the name of components by whichsynapses is formed?
4.) Explain how neurotransmitters are released in synaptic cleft?
5) How action potential is responsible for the formation of new potential?
Answer key
1.) b
2.) a
3.) Synapse is formed of the membranes of a pre-synaptic neuron and a post-synaptic neuron, this membrane may or may not be separated by a gap called synaptic cleft.
4.) When an impulse comes at the axon terminal, it stimulates the movement of the synaptic vesicles towards the membrane where they fuse with the plasma membrane and release their neurotransmitters in the synaptic cleft.
5.) When an action potential arises at the axon terminal, it stimulates the movement of the synaptic vesicles towards the membrane and release their neurotransmitters in the synaptic cleft. The released neurotransmitters bind to their specific receptors, present on the post-synaptic membrane. This binding opens ion channels allowing the entry of ions which can generate a new potential in the post-synaptic neuron. The new potential developed may be either excitatory or inhibitory.