When the body is in circular motion on a merry-go-round the circular canals of the internal ear are also on circular motion. Once the merry-go-round stops, it takes time for fine silica particles in circular canal to come in rest. As they are responsible for maintaining the balance of the body so a sense of giddiness prevails till the time silica particles come into proper position.

Eustachian tube helps in equalizing pressure on both sides of the eardrum.

Cone cells help detect colors. Most people have three kinds of cone cells. People without all three see fewer colors, sometimes called color blindness. Some cones respond more strongly to blue light.

Along with the hypothalamus, it is involved in the regulation of sexual behaviour, expression of emotional reactions, e.g., pleasure, excitement, rage and fear and motivation.

The brain might be compared to a computer as its memory banks. The spinal cord to the conducting cable for the computer's input and output and the nerves to a circuit supplying input information to the cable and transmitting the output to muscles and organs. The most important of these components is the Central Processing Unit (CPU) or microprocessor, which acts as the 'brain' of your computer.

Nervous tissue is composed of neurons, also called nerve cells, and neuroglial cells. Four types of neuroglia found in the CNS are astrocytes, microglial cells, ependymal cells, and oligodendrocytes.

Inner ear

Brain : The brain is the body's main information processing organ. It interacts with the spinal cord, which stimulates the body through spinal nerves, and innervates the cranium through cranial nerves.

Dendrites, cell body, axon, axon terminal and synaptic knob.

Thershold stimulus. It fires the signals in the neuron.

The nose contains mucus-coated receptors which are specialised for receiving the sense of smell and are called olfactory receptors. These are made up of olfactory epithelium which consists of three kinds of cells. The neurons of the olfactory epithelium extend from the outside environment directly into a pair of broad bean-sized organs called olfactory bulb. Olfactory bulbs are extensions of the brains limbic system.

The parasympathetic neural system is part of autonomic neural system. This system has some sort of inhibitory effect. The inhibitory effect minimizes the over functioning of certain functions. Functions, like salivating, digestion, are under control of parasympathetic neural system.

The neural system is composed of specialized cells called neurons. It detects stimuli and transmits neural signals. The neural system of complex animals is composed of two parts, viz. central neural system and peripheral neural system. The brain and nerve cord comprise the central neural system and other nerves comprise the peripheral neural system.

(i) Pavlov's experiment.
(ii) Pavlov's Experiment- The concept for which Pavlov experiment is done is to check the conditioned reflexes. Students conduct this experiment to know this concept of conditioned reflex, to examine the rate of salivations among dogs. Everytime when bell isrung they fed the dog of an expected response (drool) to an unlikely stimulus (the bell).
(iii) Conditioned reflex is acquired after birth, i.e., they are adopted during the course of lifetime.
(iv) Scientific attitude, awareness and sense of responsibility.

Differences between cranial nerve and spinal nerve in human are given below.

When a stimulus is applied to a nerve becomes freely permable to Na⁺ followed by the reversal of the polarity at that site. i.e., the outer surface of the membarance becomes  negatively charged and the inner sides become positively charged. The electrical potential differenec across the plasma membarance is called the action potential, which is in fact terrmed as a nerve impluse. Thus, the  shows that Na⁺ ions play an important role in the conduction of nerve impluse.

(a) Structure of Brain.
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:
(i) Forebrain, (ii) Midbrain, and (iii) Hindbrain.
(b) Structure of Eye.
In the human eye, the anterior portion is called cornea. On the cornea there is a dark spot called iris which acts like an aperture to allow optimum light inside for a better vision. The posterior portion of the eye contains the retina which acts like screen where image is focused. Retina is full of photoreceptor cells. These cells convert the light into nerve signals which are sent to the brain to make a perception of image.
(c) Structure of Ear.
Anatomically, the ear can be divided into three major sections called the outer ear, the middle ear and the Inner ear. Outer Ear. The outer ear consists of the pinna and external auditory meatus (canal). The pinna collects the vibrations in the air which produce sound. Middle Ear. The middle ear contains three ossicles called malleus, incus and stapes which are attached to one another in a chain-like fashion. These ossicles transmit sound waves further inside the ear. Inner Ear. The inner ear consists cochlea which has hair like structures. These hair like structures convert sound waves into nerve signals which are sent to the brain to make a perception of sound.