Electrical chemical at synapses. By nerve cells neurones. By the bloodstream. Muscles or glands. Target cells in particular tissues. Muscle contraction or secretion. Chemical change. Very rapid. Short until nerve impulses stop. Long until hormone is broken down. Pituitary gland. It measures around 43 cm in length. In case of the Peripheral nervous system PNS , the autonomic or involuntary nervous system regulates the processes like the breathing rate, the blood pressure, on the other hand, the somatic or voluntary nervous system connects the brain and the spinal cord with the sensory receptors and muscles in the skin, with the help of the nerves.
Nervous system helps in taking the quick decision, and how to respond to the different things, it controls the emotions also. This all works through the electrical signals that run through out the body from the brain. It is the network of glands that secrete chemicals in response to the stimuli.
Hence hormones are called as the chemical messenger. The endocrine system depends on hormones to evoke the response from the target cells. These hormones are secreted by special glands at near-by or distant from their target cells and then gradually travel through the blood or other intercellular fluid.
As said earlier, this process takes a long time to respond, as hormones are first synthesized, ultimately sent to the target cell, and then it performs its function inside the cell. In simple language, they provide the signal to the cell of the target part, and the action remains for a long period.
All the glands are the part of an endocrine system only, which includes: Hypothalamus, pituitary gland, thyroids and parathyroid glands, pineal gland and the pituitary glands are some of the important parts of the endocrine system, present in the head portion of the body.
The pancreas, kidneys and the adrenal glands are found in the stomach part while the ovaries and the testes are present in the abdominal part of the body. By maintaining the functions of the organs present in the body, these glands help in regulating the homeostasis. For example, the growth hormone secreted by the pituitary gland are responsible the growth of the body, especially during childhood, but along with that heart rate, breathing, cellular metabolism is also maintained simultaneously.
We can say that both the systems are used to give signals to the internal body parts, both types use the source as brain but in different ways, the one nervous system respond quickly to the stimuli, while the another endocrine system send their signals using different pathway and slowly as compared to the nervous system.
Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. They primarily work in sending signals to various parts of the body with the help of hormones and act as the chemical messenger. The rate of response of the nervous system is fast and early to the stimuli, by the action potentials and neurotransmitters, while the endocrine system responds slowly by secreting hormones, travelling through the circulatory system to the target tissue.
Interneurons allow the brain to combine the multiple sources of available information to create a coherent picture of the sensory information being conveyed. The spinal cord is the long, thin, tubular bundle of nerves and supporting cells that extends down from the brain. It is the central throughway of information for the body. Within the spinal cord, ascending tracts of sensory neurons relay sensory information from the sense organs to the brain while descending tracts of motor neurons relay motor commands back to the body.
When a quicker-than-usual response is required, the spinal cord can do its own processing, bypassing the brain altogether.
A reflex is an involuntary and nearly instantaneous movement in response to a stimulus. Reflexes are triggered when sensory information is powerful enough to reach a given threshold and the interneurons in the spinal cord act to send a message back through the motor neurons without relaying the information to the brain see Figure 4.
When you touch a hot stove and immediately pull your hand back, or when you fumble your cell phone and instinctively reach to catch it before it falls, reflexes in your spinal cord order the appropriate responses before your brain even knows what is happening.
If the central nervous system is the command centre of the body, the peripheral nervous system PNS represents the front line. As you can see in Figure 4. The autonomic nervous system ANS is the division of the PNS that governs the internal activities of the human body, including heart rate, breathing, digestion, salivation, perspiration, urination, and sexual arousal. Many of the actions of the ANS, such as heart rate and digestion, are automatic and out of our conscious control, but others, such as breathing and sexual activity, can be controlled and influenced by conscious processes.
The somatic nervous system SNS is the division of the PNS that controls the external aspects of the body , including the skeletal muscles, skin, and sense organs. The somatic nervous system consists primarily of motor nerves responsible for sending brain signals for muscle contraction. The autonomic nervous system itself can be further subdivided into the sympathetic and parasympathetic systems.
The sympathetic division of the ANS is involved in preparing the body for behaviour, particularly in response to stress, by activating the organs and the glands in the endocrine system.
The parasympathetic division of the ANS tends to calm the body by slowing the heart and breathing and by allowing the body to recover from the activities that the sympathetic system causes. The sympathetic and the parasympathetic divisions normally function in opposition to each other, with the sympathetic division acting a bit like the accelerator pedal on a car and the parasympathetic division acting like the brake.
Our everyday activities are controlled by the interaction between the sympathetic and parasympathetic nervous systems. For example, when we get out of bed in the morning, we would experience a sharp drop in blood pressure if it were not for the action of the sympathetic system, which automatically increases blood flow through the body. Similarly, after we eat a big meal, the parasympathetic system automatically sends more blood to the stomach and intestines, allowing us to efficiently digest the food.
And perhaps you have had the experience of not being at all hungry before a stressful event, such as a sports game or an exam when the sympathetic division was primarily in action , but suddenly finding yourself feeling starved afterward, as the parasympathetic takes over. The nervous system is designed to protect us from danger through its interpretation of and reactions to stimuli. But a primary function of the sympathetic and parasympathetic nervous systems is to interact with the endocrine system to elicit chemicals that provide another system for influencing our feelings and behaviours.
A gland in the endocrine system is made up of groups of cells that function to secrete hormones. A hormone is a chemical that moves throughout the body to help regulate emotions and behaviours. When the hormones released by one gland arrive at receptor tissues or other glands, these receiving receptors may trigger the release of other hormones, resulting in a series of complex chemical chain reactions.
The endocrine system works together with the nervous system to influence many aspects of human behaviour, including growth, reproduction, and metabolism. And the endocrine system plays a vital role in emotions. Because the glands in men and women differ, hormones also help explain some of the observed behavioural differences between men and women. The major glands in the endocrine system are shown in Figure 4.
The pituitary secretes hormones that influence our responses to pain as well as hormones that signal the ovaries and testes to make sex hormones. The pituitary gland also controls ovulation and the menstrual cycle in women.
Other glands in the endocrine system include the pancreas , which secretes hormones designed to keep the body supplied with fuel to produce and maintain stores of energy ; the pineal gland , located in the middle of the brain, which secretes melatonin , a hormone that helps regulate the wake-sleep cycle; and the thyroid and parathyroid glands , which are responsible for determining how quickly the body uses energy and hormones, and controlling the amount of calcium in the blood and bones.
The body has two triangular adrenal glands , one atop each kidney. The adrenal glands produce hormones that regulate salt and water balance in the body, and they are involved in metabolism, the immune system, and sexual development and function. The most important function of the adrenal glands is to secrete the hormones epinephrine also known as adrenaline and norepinephrine also known as noradrenaline when we are excited, threatened, or stressed.
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