Nervous system (NS) and endocrine system together ensure that all the parts of the body work in a controlled and coordinated manner. NS includes brain, spinal cord, sense organs and nerves.

Endocrine glands secrete hormones directly into the blood. Pituitary, thyroid and pancreas are some important endocrine glands that influence our growth and development.

Nervous system is made of nerve cells or neurons. Brain is responsible for thoughts, imagination, motor movements, balance and controls all functions of body. Neurons have the capacity to respond to a stimulus and conduct it to another neuron or effector organ. Dendrites receive an impulse, set off a chemical reaction that creates an electrical impulse. This electrical impulse travels down the cell body, the axon and reaches the end bulbs.

Neurotransmitter stored in the end bulb is released in the synaptic cleft. The chemical crosses the synapse and initiate a similar electrical impulse in the next neuron. Finally, the impulse is delivered from neuron to other cells or effector organ such as muscles or gland to elicit the desired action.

Reflex action is a spontaneous, autonomic and mechanical response to a stimulus controlled by the spinal cord and without the involvement of the brain. It can be of two types: Inborn reflex and Conditioned reflex.

Endocrine Glands

Our body has a number of endocrine glands which produce chemical secretions called hormones. These hormones are carried by blood to the target organs situated elsewhere in the body to stimulate a specific action.

Pituitary gland regulates growth of the child from puberty to reproductive maturity. It also secretes growth hormone and gonad stimulating hormones.

Under secretion of thyroid causes cretinism and goitre. Insulin and glucagon are the two hormones secreted by pancreas. These regulate glucose metabolism in the body.