Melanocytes are the cells responsible for-producing the skin pigment, melanin, which gives skin its colour and protects it from the sun's UV rays.

Cranial nerves	Nature of nerve	Function
Olfactory nerve	Sensory	Sense of smell
Optic nerves	Sensory	Sense of sight
Oculomotor nerves	Motor	Movement of the eye
Trochlear nerve	Motor	Rotation of the eye ball
Trigeminal nerve	Sensory and motor (mixed)	Functioning of facial parts

Receptors	Stimulus	Effector organs
Mechanoreceptors	Pressure and vibration	Mechanoreceptors are present in the cochlea of the inner ear and the semicircular canal and utriculus.
Chemoreceptors	Chemicals	Taste buds in the tongue and Nasal epithelium.
Thermoreceptors	Temperature	Skin
Photoreceptors	Light	Rod and cone cells of the retina in the eye.

A- Nucleus with nucleolus'
B- Myelin sheath
C- Dendrites
D- Nucleus
E- Schwann cell
F- Node of Ranvier

1. In a neuron the reversal of membrane potential inside the axolemma to negative occurs due to the efflux of K⁺ ions which is called Repolarization.
2. If repolarization becomes more negative than the resting potential -70 mV to about -90 mV, it is called Hyperpolarization.
3. During this, K⁺ ion gates are more permeable to K⁺ even after reaching the threshold level as it closes slowly; hence called Lazy gates.

1. Aqueous humor supplies nutrients and oxygen to the lens, cornea and some retinal cells.
2. The aqueous humor is produced and drained at the same rate, maintaining a constant intra ocular pressure of about 16 mmHg.
3. Any block in the canal of schlemm increases the intra ocular pressure of aqueous humor and leads to 'Glaucoma' where the optic nerve and the retina are compressed due to pressure.

1. The inner part of the cerebral hemisphere constitutes the limbic system.
2. The limbic system is called 'emotional brain' because it plays a primary role in the regulation of pleasure, pain, anger, fear, sexual feeling, and affection.
3. The hippocampus and amygdala also play a role in memory.

1. The ANS autonomic neural system is auto functioning and self-governed.
2. It is a part of the peripheral neural system that innervates smooth muscles, glands and cardiac muscle. This system controls and coordinates the involuntary activities of various organs.
3. ANS controlling centre is in the hypothalamus.

Choroid plexus is a network of blood capillaries found in the roof of the ventricles and forms cerebro spinal fluid (CSF) from the blood.

(i) Fore brain consists of cerebrum and diencephalon
(ii) Hypothalamus forms the floor of the diencephalon maintains the large for eating.