When we touch a hot plate unknowingly, then this heat is sensed by a receptor P present in our fingers. The receptor triggers an impulse in neuron Q which transmits the message to an organ R which is a part of the central nervous system. Here the impulse is passed on to a neuron S which in turn passes it to a yet another neuron T. The neuron T passes the impulse to a tissue U in our arm. The tissue U then contracts and pulls our hand away from the hot plate.

Name the effector in this whole process.

The gland X which is located just below the brain in the human head secretes a chemical substance Y which controls the development of bones and muscles in the body of a person. Secretion of too little of substance Y as well as the secretion of too much of substance Y by the gland X leads to abnormal development of the body of a person.

Name the gland X. (Pituitary gland/ Pineal gland/ parathyroid gland)

The gland X which is located just below the brain in the human head secretes a chemical substance Y which controls the development of bones and muscles in the body of a person. Secretion of too little of substance Y as well as the secretion of too much of substance Y by the gland X leads to abnormal development of the body of a person.

What is the chemical substance Y?

The gland X which is located just below the brain in the human head secretes a chemical substance Y which controls the development of bones and muscles in the body of a person. Secretion of too little of substance Y as well as the secretion of too much of substance Y by the gland X leads to abnormal development of the body of a person.

What happens if too little of substance Y is secreted?

The gland X which is located just below the brain in the human head secretes a chemical substance Y which controls the development of bones and muscles in the body of a person. Secretion of too little of substance Y as well as the secretion of too much of substance Y by the gland X leads to abnormal development of the body of a person.

Name the system of glands in the human body of which gland X (pituitary gland) is a part.

A and B are the two systems of control and coordination in the human body. The messages in system A are transmitted in the form of chemical substances C which travels comparatively slowly through the bloodstream. The substances C are made in tissues D present in the head and trunk of the human body. The messages in system B are transmitted very quickly in the form of electrical impulses through fibres E. The effect of messages transmitted by system B usually lasts for a much shorter time as compared to those transmitted by system A.

Name the system A. What does system A consist of?

A and B are the two systems of control and coordination in the human body. The messages in system A are transmitted in the form of chemical substances C which travels comparatively slowly through the bloodstream. The substances C are made in tissues D present in the head and trunk of the human body. The messages in system B are transmitted very quickly in the form of electrical impulses through fibres E. The effect of messages transmitted by system B usually lasts for a much shorter time as compared to those transmitted by system A.

Name the chemical substance C.