The peripheral nervous system is made up of the nerve fibres which are spread from the spinal cord, then to all parts of the body. This includes the neck, arms, torso, legs, skeletal muscles and internal organs.

The brain sends messages through the spinal cord and nerves of the peripheral nervous system to control the movement of the muscles and the function of internal organs.

Neurons communicate with each other utilizing axons and dendrites. When a neuron gets a message from another neuron, it sends an electrical indication down the length of its axon. At the end of the axon, the electrical signals is changed over into a chemical indicator, and the axon discharges chemical massages called neurotransmitters.

The brain is made up of numerous systems of communicating neurons. In this way, distinctive parts of the brain can “talk” to each other as well as work together to send messages to the rest of the body.

The hormones circulate throughout the body, each type of hormone is targeted toward certain organs and tissues. The endocrine system gets some help from organs such as  the kidney, liver, heart and gonads, which have secondary endocrine functions. The kidney, for example, secretes hormones such as erythropoietin and renin.  

The thyroid also secretes a range of hormones that affect the whole body. "Thyroid hormones impact vital body functions, including heart rate, skin maintenance, growth, temperature regulation, fertility and digestion," mentioned the lecture.