Chemical coordination is performed by hormones, which are chemical messengers secreted by endocrine glands.
These hormones coordinate the activities of living organisms and also their growth.
The timing and the amount of hormones released are regulated by the feedback mechanism.

In case of a spinal cord injury, signals for reflex actions and involuntary actions will get disrupted.

Plant hormones are organic substances produced naturally in higher plants. They control growth and other physiological functions of the plants. These are required in very small amounts.

The phenomenon of regulation of flowering and germination of seeds by phot

Adrenaline hormone is secreted from adrenal gland into the blood and carried to different parts of the body. At the time of emergency, danger or stress, it is released in large quantities. As a result, it causes fast beating of heart, resulting in more supply of oxygen to muscles.
The blood supply to the digestive system and skin is reduced due to contraction of muscles around small arteries in these organs. The breathing rate also increases because of the contraction of diaphragm and rib muscles. All these responses together help the animal to deal with the emergency situation.

Auxins promote cell elongation and are present at the shoot tip. When tendril comes in contact with a support, auxin stimulates faster growth of the cells on the opposite sides. Thus, the tendril coils around the support.

The flow of signals through neurons takes place in the form of specialized chemicals; called neurotransmitters. The neurotransmitters. The neurotransmitters can only enter a neuron through dedicated receptor channels. Such receptor channels a5re only present at the dendritic end but not at the axonal end. Hence, the flow of signals in a synapse happens from axonal end of one neuron to dendritic end of another neuron but not in the reverse direction.

The endocrine and neural system both works together for the normal functioning of our body. The synthesis and release of certain hormones is regulated by the neural system. Also, the release of certain hormones influences the activity of nerves.
For example, hypothalamus receives neural signals from brain and releases hormones.
In case of deficiency of iodine, body produces less thyroxine hormone. Hypothalamus releases hormones to stimulate pituitary gland which further stimulates thyroid gland to secrete thyoxine.

Reflex action is a special case of involuntary movement involuntary organs. When a voluntary organ is in the vicinity of a sudden danger, it is immediately pulled away from the danger to save itself. For example; when your hand touches a very hot electric iron, you move away your hand in a jerk. All of this happens in flash and your hand is saved from the imminent injury. This is an example of reflex action.
Reflex Arc: The path through which nerves signals; involved in a reflex action; travel is called the reflex arc. The following flow chart shows the flow of signal in a reflex arc. Receptor \(\rightarrow\) Sensory Neuron\(\rightarrow\) Relayneuron \(\rightarrow\) Motor neuron \(\rightarrow\) Effector (muscle) The receptor is the organ which comes in the danger zone. The sensory neurons pick signals from the receptor and send them to the relay neuron. The relay neuron is present in the spinal cord. The spinal cord sends signals to the effector via the motor neuron. The effector comes in action moves the receptor away from the danger.

The central nervous is composed of the brain and the spinal cord. The peripheral nervous system is composed of cranial nerves, spinal nerves and the autonomous nervous system. Brain gets the maximum protection, as it is found inside the skull. Spinal cord gets protection by the vertebral column. Additionally, the brain and the spinal cord are surrounded by a system of three layers called meninges. The cerebrospinal fluid is filled between these membranes which provide a cushion against mechanical shocks.

The differences between the movement in sensitive plant and our legs are as follows :