Colour blindness results in absence or malfunctioning of one or more of the three types of cone cells responsible for colour vision.

The Autonomic Nervous System or ANS or visceral nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness and controls visceral functions. It affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition (urination) and sexual arousal.

Ketonuria is a medical condition in which ketone bodies are present in the urine. It is seen in conditions in which the body produces excess ketones as an alternative source of energy. It is seen during starvation or more commonly in type I Diabetes mellitus.

In frogs (amphibians), the skin plays a vital role in gas exchange. When the frog is out of the water, mucus glands in the skin keep the frog moist, which helps absorb dissolved oxygen from the air. A frog may also breath much like a human, by taking air through their nostrils and down into their lungs.

The pancreatic islets or islets of Langerhans are the regions of the pancreas that contain its endocrine, ie, hormone producing cells. It was discovered by Paul Langerhans. They consist of 1 to 2% of the pancreas volume and receive 10- 15% of its blood flow. These are irregularly shaped patches of endocrine tissue located within the pancreas of most vertebrates.

In the grey matter of spinal cord, ten laminae are present.  The grey matter is sub- divided on the basis of neuronal cells with similar function.

The most common type of goitre is endemic goitre, caused by iodine deficiency. Iodine is an essential nutrient that is required for the production of thyroid hormone. When iodine intake is low, thyroid hormone production is low, and in response the pituitary gland secretes greater quantities of the hormone thyrotropin or thyroid stimulating hormone (TSH). This excess thyrotropin stimulates not only thyroid hormone production but also thyroid growth.

Edinger-Westphal nucleus is also known as the accessory oculomotor nucleus. It is the accessory parasympathetic cranial nerve nucleus of the oculomotor nerve (cranial nerve III), supplying the constructing muscles of the iris.

Adrenalin is a natural stimulant made in the adrenal gland of the kidney. Its biological name is epinephrine. It is carried in the blood stream and affects the autonomous nervous system. It control the functions such as, the heart rate, dilation of the pupil, secretion of sweat and saliva, altering body's metabolism etc.

The production of language is linked to the Broca's area. It controls mator functions involved with speech production. People who have damage this area of the brain can understood words but struggle to put them together in speech.