Explore topic-wise InterviewSolutions in .

(i) Spinal cord 

(ii) (a) Cranium (b) Duramater, Arachnoid membrane, Piamater 

(iii) 31 pairs of Spinal nerves

Correct option is  a. synapse

Correct option is b. Neurons

Correct option is  a. central

Hyposecretion – Thyroxin

(b) towards, away from

The two antagonistic components of ANS are sympathetic and para sympathetic system.

Dura  mater .

Motor or efferent neuron carries impulses from the Central Nervous System to effector organs such as muscle fibre or gland.

The components of Nervous system are brain, spinal cord and brain.

The site for processing of vision, hearing, memory, speech, intelligence, and thought is brain.

Correct Answer is Thalamus

1. Basic structural unit of the nervous system is the neuron.

2. Central nervous system consists of brain and spinal cord.

3. A neuron consists of cell body, dendrite and axon.

4. The neurons carrying impulses from the brain to the muscles are called motor or efferent neurons.

5. Peripheral nervous system consists of nerves.

6. The three main parts of the brain are cerebrum, cerebellum and medulla oblongata (brain stem).

Frontal lobe: It controls motor actions, thinking, memory and reasoning. It has Broca’s area which helps in speech production. 

Parietal lobe: It helps in understanding information regarding skin-like touch, pressure, pain, and temperature. Occipital lobe: It is the visual processing center. It controls the sense of hearing, smell, and taste. It has Wernicke’s area which helps in language understanding. 

Temporal Lobe: Hearing, understanding language, memory for language take place because of the temporal lobe.

Hyposecretion – Insulin, and glycogen

• Hypothalamus controls major bodily needs i.e., primary needs of an individual like hunger, thirst, sex as well as temperature regulation, and sleep. 
• It is also called the pleasure center of our body.

Occipital lobe

Correct Answer is Occipital lobe

Correct Answer is  Amygdala

Correct Answer is Cerebellum

Correct Answer is  Parietal lobe

Correct Answer is  Frontal lobe

Correct Answer is Temporal Lobe

Correct Answer is  Hypothalamus

1. False. The epidermis of the skin is made up of epithelial cells.

2. True.

3. True.

4. False. Cochlea is a part of inner ear.

5. False. Retina is present on the inner surface of the eye.

Sense organs are the parts of body which act as receptors that receive stimuli and send impulse to the brain. They help the body to know about the surroundings.

Cochlea is the odd one out as it is a part of inner ear while the rest three are parts of outer ear.

1. Eyes for sight.

2. Ears for hearing.

3. Nose for smelling.

4. Tongue for taste.

5. Skin for touch, heat, cold and pressure

Reflex action: Reflex actions are automatic responses to stimuli. These actions are not under the control of the animal. They are of definite and mechanical type. Peripheral nervous system and spinal cord both control certain action and the brain is not in action. Some examples of reflex actions are: 

1. Pupil becomes narrow when strong light falls on it. 

2. The aroma of the food makes the mouth watering. 

3. The hand is withdrawn as we touch the hot plate. 

4. Flow of bile from the gall bladder into the duodenum. 

5. A loud thud may lead to opening of the mouth. 

In a reflex action brain is not involved, removing the hand on touching a hot plate is a reflex action. The impulse of heat goes from the hand to the spinal cord and the order is sent back to the muscles of the hand to remove the hand from the hot plate.

A bundle of nerve fibres joined together as a tubular sheath that transmits impulses between brain or spinal cord and other body parts is called a nerve. The nerves constitute the peripheral nervous system. 

Nerves are of two types in humans: 

1. Cranial nerves: They emerge from the brain. There are 12 pairs of cranial nerves. 

2. Spinal nerves: They emerge from the spinal’ cord. There are 31 pairs of spinal nerves.

• The pituitary gland is one of the endocrine glands, i.e., glands that secrete chemical substances into the bloodstream. 
• It is also called as master gland as it helps other glands to produce their secretions and secretes the majority of hormones. 
• It consists of the anterior lobe and posterior lobe
•  Anterior lobe: It secretes somatotropin, growth hormone, and adrenocorticotropic hormone. It helps the growth of the body and aids the adrenal gland. The hormones secreted by this gland are also vital for the nourishment of foetus. 
• Hypo or hypersecretion in the anterior lobe: Hyposecretion leads to dwarfism, wherein a person is very short (twothree feet tall). On the other hand, hypersecretion can lead to gigantism, wherein a person becomes very huge and is eight-nine feet tall. Hypersecretion can also result in acromegaly, wherein a person has the features of a chimpanzee
• Posterior lobe: It secretes oxytocin (which creates a feeling of happiness), pituitrin (which helps smooth muscle functioning of the stomach), thyrotrophic follicle-stimulating luteinizing hormone (which helps in the nourishment of foetus), and endorphins (which help to create neurotransmitters).

• Exocrine glands directly release their secretions into the organ or tissue while endocrine glands secrete chemical substances into the bloodstream. 
• Exocrine glands have separate ducts for their secretion and so, they are also called duct glands, e.g. sweat glands and tear glands. On the other hand, endocrine glands are called ductless glands as they don’t have a separate duct. e.g. pituitary gland and thyroid gland.

One of the important parts of the brain is the limbic system. 

• Hippocampus, amygdala, thalamus, and hypothalamus are parts of the limbic system. 
• Hippocampus is responsible for the storage of long-term memories. 
• Amygdala stores emotional memories of our experiences. 
• Thalamus is called a relay station of the brain. It receives all information from the body and sends it to various parts of the brain. 
• Hypothalamus controls major bodily needs like hunger, thirst, sex as well as temperature regulation, and sleep.

Neurotransmitters are chemical messengers. The important neurotransmitters are:

Acetylcholine: It is a chemical released by motor neurons of the nervous system to activate muscles. 

Dopamine: It is released by the brain. If the level of dopamine is normal, we experience happy, pleasant feelings. It also plays an important role in the motivational process. 

Norepinephrine: It increases the force of skeletal muscles, especially during fight or flight response. 

Serotonin: It plays a role mainly in cognition, reward, learning, and memory. It also controls wakefulness, sleep, hunger, thirst, and liking. 

Glutamate: It helps in learning, memory, and maintaining sugar levels. 

GABA (Gama Amino Butyric Acid): It is the chief inhibitory neurotransmitter i.e. its principal role is to reduce the excitability of neurons throughout the nervous system. If it is less, it leads to convulsions and we cannot control body movements.

Memory : cerebrum : : breathing: medulla oblongata

Balance : cerebellum : : reasoning : cerebrum

Hypothalamus is the link between nervous system and endocrine system as it controls the secretion of hormones from anterior pituitary gland.

• Endocrine glands secrete chemical substances called hormones.
• Hormones are like messengers that are responsible for certain behaviours or the absence of reactions. 
• e.g. Thyroid gland secretes the thyroxin hormone. Its hypersecretion leads to Grave’s disease while hyposecretion results in cretinism or myxedema.

The conditioned reflexes are the result of practice and learning. Playing the harmonium by striking a particular key, on seeing a music note is an example of conditioned reflexes.

Cranium (skull) and three connective tissue membrane meninges – Duramater, Arachnoid membrane and piamater protect the brain.

(i) (A) largest

(ii) (A) four

(iii) (B) Thalamus

(iv) (A) Hypothalamus

(v) (A) beta-amyloid plaque

Hyposecretion – Thyroxin

If we touch a sharp pointed object, we immediately withdraw our hand.

Here the skin is the receptor and it receives the stimulus, that is the pain. This stimulus (pain) in turn triggers an impulse in sensory neuron. The sensory neuron transmits or convey the message to the spinal cord. Spinal cord interprets the stimulus and the impulse is passed on to the relay neuron which in turn transmits it to a motor neuron. Motor neuron carry command from the spinal cord to our arm. Muscle in our arm contracts and we withdraw our hand immediately

A. (iii) 

B. (i) 

C. (iv) 

D. (ii)

Spinal cord has the following functions.

1. It is the centre of reflex actions below the neck.

2. It carries messages from the skin and muscles to the brain.

3. All the stimuli and responses are passed from and to the brain through the spinal cord.

Brain consists of main three parts and lies in the cranial cavity of skull.

1. The cerebrum 

2. The cerebellum 

3. The medulla oblongata 

Cerebrum: It is very large and form two third of the whole brain. The two hemispheres are separated from each other by a deep longitudinal groove, the median fissure. The outer surface is folded with ridges and grooves. The hemispheres are hollow from inside and their walls have outer and inner portions. The outer portion has cell bodies of the neurons and it is called grey matter. 

The wavery edges of the folded layer has large number of neurons to the extent of nine billion. The inner portion of the cerebrum has axons and it is called white matter. 

Functions: 

1. It controls all the voluntary activities. 

2. It is the seat of intelligence, consciousness and will power.

Correct Answer is  Thinking

1. The central nervous system (brain and spinal cord)

2. The peripheral nervous system

3. The autonomic nervous system

Correct Answer is  Tectum

Cerebellum is the odd one out as it is apart of brain while rest three are parts of a neuron,