The Adrenal Glands And Their Hormones
The adrenal glands are small structures located on top of the kidneys. Structurally, they consist of an outer layer and an inner layer . The adrenal cortex produces numerous hormones, primarily corticosteroids . The cortex is also the source of small amounts of sex hormones those amounts, however, are insignificant compared with the amounts normally produced by the ovaries and testes. The adrenal medulla generates two substancesadrenaline and noradrenalinethat are released as part of the fight-or-flight response to various stress factors.
The primary glucocorticoid in humans is cortisol , which helps control carbohydrate, protein, and lipid metabolism. For example, cortisol increases glucose levels in the blood by stimulating gluconeogenesis in the liver and promotes the formation of glycogen in the liver. Cortisol also reduces glucose uptake into muscle and adipose tissue, thereby opposing the effects of insulin. Furthermore, in various tissues, cortisol promotes protein and lipid breakdown into products that can be used for gluconeogenesis.
In contrast to the glucocorticoids, pituitary, or hypothalamic, hormones do not regulate aldosterone release. Instead, it is controlled primarily by another hormone system, the reninangiotensin system, which also controls kidney function. In addition, the levels of sodium and potassium in the blood influence aldosterone levels.
How The Hypothalamus Of The Brain Controls The Endocrine System
How the hypothalamus of the brain controls the endocrine system? The hypothalamus is the link between the endocrine and nervous systems. The hypothalamus produces releasing and inhibiting hormones, which stop and start the production of other hormones throughout the body.
What part of the brain controls the endocrine system? The pituitary gland is sometimes called the master gland of the endocrine system because it controls the functions of many of the other endocrine glands. The pituitary gland is no larger than a pea, and is located at the base of the brain.
How does the brain work with the endocrine system? The endocrine system works in large part by acting on neurons in the brain, which controls the pituitary gland. The pituitary gland secretes factors into the blood that act on the endocrine glands to either increase or decrease hormone production.
What is the function of the hypothalamus in the brain? The hypothalamus is involved in different daily activities like eating or drinking, in the control of the bodys temperature and energy maintenance, and in the process of memorizing and in stress control. It also modulates the endocrine system through its connections with the pituitary gland.
The Parathyroid Glands And Their Hormones
The parathyroid glands are four pea-sized bodies located behind the thyroid gland that produce PTH. This hormone increases calcium levels in the blood, helping to maintain bone quality and an adequate supply of calcium, which is needed for numerous functions throughout the body . Specifically, PTH causes reabsorption of calcium from and excretion of phosphate in the urine. PTH also promotes the release of stored calcium from the bones as well as bone resorption, both of which increase calcium levels in the blood. Finally, PTH stimulates the absorption of calcium from the food in the gastrointestinal tract. Consistent with PTHs central role in calcium metabolism, the release of this hormone is not controlled by pituitary hormones but by the calcium levels in the blood. Thus, low calcium levels stimulate PTH release, whereas high calcium levels suppress it.
Many of the functions of PTH require or are facilitated by a substance called 1,25-dihydroxycholecalciferol, a derivative of vitamin D. In addition, numerous other hormones are involved in regulating the bodys calcium levels and bone metabolism, including estrogens, glucocorticoids, and growth hormone.
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Chronic Activation Of This Survival Mechanism Impairs Health
A stressful situation whether something environmental, such as a looming work deadline, or psychological, such as persistent worry about losing a job can trigger a cascade of stress hormones that produce well-orchestrated physiological changes. A stressful incident can make the heart pound and breathing quicken. Muscles tense and beads of sweat appear.
This combination of reactions to stress is also known as the “fight-or-flight” response because it evolved as a survival mechanism, enabling people and other mammals to react quickly to life-threatening situations. The carefully orchestrated yet near-instantaneous sequence of hormonal changes and physiological responses helps someone to fight the threat off or flee to safety. Unfortunately, the body can also overreact to stressors that are not life-threatening, such as traffic jams, work pressure, and family difficulties.
Anatomy Of The Endocrine System
The endocrine system is a complex network of glands and organs. It uses hormones to control and coordinate your body’s metabolism, energy level, reproduction, growth and development, and response to injury, stress, and mood. The following are integral parts of the endocrine system:
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The Peripheral Nervous System
The peripheral system is composed of nerves that extend outside of the central nervous system. The nerves and nerve networks that make up the PNS are actually bundles of axons from neuron cells. The nerve bundles can be relatively small or large enough to be easily seen by the human eye.
The PNS is further divided into two different systems: the somatic nervous system and the autonomic nervous system.
What Part Of The Brain Controls Fear
From a biological standpoint, fear is a very important emotion. It helps you respond appropriately to threatening situations that could harm you.
This response is generated by stimulation of the amygdala, followed by the hypothalamus. This is why some people with brain damage affecting their amygdala dont always respond appropriately to dangerous scenarios.
When the amygdala stimulates the hypothalamus, it initiates the fight-or-flight response. The hypothalamus sends signals to the adrenal glands to produce hormones, such as adrenaline and cortisol.
As these hormones enter the bloodstream, you might notice some physical changes, such as an increase in:
- heart rate
- blood sugar
In addition to initiating the fight-or-flight response, the amygdala also plays a role in fear learning. This refers to the process by which you develop an association between certain situations and feelings of fear.
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Does The Hypothalamus Control Anger
Anger starts with the amygdala stimulating the hypothalamus, much like in the fear response. People with damage to this area often have trouble controlling their emotions, especially anger and aggression. Parts of the prefrontal cortex of the brain may also contribute to the regulation of an anger response.
How Can Chemicals Affect The Endocrine System
Scientific research on human epidemiology, laboratory animals, and fish and wildlife suggests that environmental contaminants can disrupt the endocrine system leading to adverse-health consequences. It is important to gain a better understanding of what concentrations of chemicals found in the environment may cause an adverse effect. Various types of scientific studies are necessary to resolve many of the scientific questions and uncertainty surrounding the endocrine disruptor issue. Many such studies are currently underway by government agencies, industry, and academia.
Learn more with EDSP about concerns and examples of endocrine disruption.
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What Could Go Wrong With My Pituitary Gland
The pituitary gland is an important gland in the body and the hormones it produces carry out varied tasks and regulate the function of many other organs. This means that the symptoms experienced when the pituitary gland stops working correctly can be different, depending on which hormone is affected.
Conditions that affect the pituitary gland directly can be divided into three main categories:
A cell type may divide and then form a small benign lump, known as a tumour, and the patient may then suffer from the effects of too much of the hormone the cell produces. If the tumour grows very large, even though still benign, it may squash the surrounding cells and stop them working , or push upwards and interfere with vision a visual field defect. Very occasionally, the tumour may expand sideways and cause double vision as it affects the nerves that control eye movements. It should be emphasised that even when these tumours are large, they very rarely spread to other parts of the body.
What Gland Is Called The Master Gland And Why
pituitary glandglandglandspituitary glandTo help keep your endocrine system healthy:
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What Is Endocrine System
Hormones are chemicals that affect a lot of the bodily functions ranging from hunger, reproduction and growth to much more complicated functions like human emotions and behaviour. These hormones are produced in our body through nine primary glands and these glands, along with other organs that provide auxiliary functions make up the endocrine system.
Let us have a detailed look at the endocrine system notes and explore the major endocrine glands in the human body.
Unlike exocrine glands, endocrine glands secrete their respective substances directly into the bloodstream rather than through a duct. These endocrine glands belong to the bodys control system and they produce hormones which help to regulate the functions of cells and tissues. Some glands are specific to either male or female
What Hormones Does My Hypothalamus Produce
There are two sets of nerve cells in the hypothalamus that produce hormones. One set sends the hormones they produce down through the pituitary stalk to the posterior lobe of the pituitary gland where these hormones are released directly into the bloodstream. These hormones are anti-diuretic hormone and oxytocin. Anti-diuretic hormone causes water reabsorption at the kidneys and oxytocin stimulates contraction of the uterus in childbirth and is important in breastfeeding.
The other set of nerve cells produces stimulating and inhibiting hormones that reach the anterior lobe of the pituitary gland via a network of blood vessels that run down through the pituitary stalk. These regulate the production of hormones that control the gonads, thyroid gland’ data-content=’1456′ > thyroid gland and adrenal cortex, as well as the production of growth hormone, which regulates growth, and prolactin, which is essential for milk production. The hormones produced in the hypothalamus are corticotrophin-releasing hormone, dopamine, growth hormone-releasing hormone, somatostatin, gonadotrophin-releasing hormone and thyrotrophin-releasing hormone.
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How Does The Brain Work
The brain sends and receives chemical and electrical signals throughout the body. Different signals control different processes, and your brain interprets each. Some make you feel tired, for example, while others make you feel pain.
Some messages are kept within the brain, while others are relayed through the spine and across the bodys vast network of nerves to distant extremities. To do this, the central nervous system relies on billions of neurons .
Making Chemical Connections: Neurotransmitters
The chemical exchange between neurons occurs at synapses, the small spaces separating the dendrites and axon endings .
Figure 2.10 The synapse
The first nerve cell releases chemical neurotransmitters that can bind with receptors in the second neuron. The exchange can result in excitation or inhibition, depending upon the type of receptor activated. Figure 2.11 lists the major neurotransmitters along with their roles in the body.
Figure 2.11 The major neurotransmitters
Psychoactive drugs can affect mood, thought, and behavior. Most achieve these effects by impacting upon neurotransmitters and synaptic connections. In Chapter 11 , we will consider the use of psychoactive drugs in the treatment of depression and schizophrenia.
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What Does My Pituitary Gland Do
The pituitary gland is called the ‘master gland’ as the hormones it produces control so many different processes in the body. It senses the body’s needs and sends signals to different organs and glands throughout the body to regulate their function and maintain an appropriate environment. It secretes a variety of hormones into the bloodstream which act as messengers to transmit information from the pituitary gland to distant cells, regulating their activity. For example, the pituitary gland produces prolactin, which acts on the breasts to induce milk production. The pituitary gland also secretes hormones that act on the adrenal glands, thyroid gland’ data-content=’1456′ > thyroid gland, ovaries and testes, which in turn produce other hormones. Through secretion of its hormones, the pituitary gland controls metabolism, growth, sexual maturation, reproduction, blood pressure and many other vital physical functions and processes.
What Is The Endocrine System
Your endocrine system is made up of several organs called glands. These glands, located all over your body, create and secrete hormones.
Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it.
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Which Endocrine Gland Regulates Night Cycles
Pineal Gland Essentials Of the endocrine organs, the function of the pineal gland was the last discovered. Located deep in the center of the brain, the pineal gland was once known as the third eye. The pineal gland produces melatonin, which helps maintain circadian rhythm and regulate reproductive hormones.
How Can I Keep My Endocrine System Healthy
Your endocrine system needs the same things the rest of your body needs to stay healthy. You should exercise, eat right and see your healthcare provider regularly.
If you have a family history of diabetes, thyroid disorders or PCOS, talk to your provider. Managing these conditions can help you avoid a hormone imbalance that can lead to health problems.
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The Thyroid And Parathyroids
The thyroid, located in the front part of the lower neck, is shaped like a bow tie or butterfly and produces the thyroid hormones thyroxine and triiodothyronine. These hormones control the rate at which cells burn fuels from food to produce energy. As the level of thyroid hormones increases in the bloodstream, so does the speed at which chemical reactions occur in the body.
Thyroid hormones also play a key role in bone growth and the development of the brain and nervous system in children. The production and release of thyroid hormones is controlled by thyrotropin, which is secreted by the pituitary gland.
Attached to the thyroid are four tiny glands that function together called the parathyroids. They release parathyroid hormone, which regulates the level of calcium in the blood with the help of calcitonin, which is produced in the thyroid.
Ventricles And Cerebrospinal Fluid
Deep in the brain are four open areas with passageways between them. They also open into the central spinal canal and the area beneath arachnoid layer of the meninges.
The ventricles manufacture cerebrospinal fluid, or CSF, a watery fluid that circulates in and around the ventricles and the spinal cord, and between the meninges. CSF surrounds and cushions the spinal cord and brain, washes out waste and impurities, and delivers nutrients.
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Endocrine System Vs Nervous System Function
The endocrine system works alongside of the nervous system to form the control systems of the body. The nervous system provides a very fast and narrowly targeted system to turn on specific glands and muscles throughout the body. The endocrine system, on the other hand, is much slower acting, but has very widespread, long lasting, and powerful effects. Hormones are distributed by glands through the bloodstream to the entire body, affecting any cell with a receptor for a particular hormone. Most hormones affect cells in several organs or throughout the entire body, leading to many diverse and powerful responses.
Potential Problems With The Hypothalamus
Just like any other part of the body, there are potential diseases and injuries that could particularly affect the hypothalamus. The difficulty with hypothalamic injuries and diseases is that, because the hypothalamic is so far-reaching in its roles in the central nervous system, limbic system, and endocrine system, it can pose a tremendous challenge to diagnose and treat issues that may arise in connection to this organ.
One of the most well-known problems affecting the hypothalamus is hypothalamic disease .
Hypothalamic disease is most commonly caused by physical trauma to the head and can span over a number of disorders or hypothalamus-related malfunctions. Symptoms can manifest as sleeping disorders, problems with appetite, growth abnormalities, and more.
Other causes include surgery, radiation, and tumors. There are even genetic links to hypothalamic diseases like Kallman and Prader-Will syndromes, for example. Diabetes insipidus and hypopituitarism are other known disorders related to the malfunctioning of the hypothalamus.
When symptoms are too difficult to decipher or multiple symptoms occur at once, the issue may be referred to as a hypothalamic-pituitary disorder. This is because the hypothalamus and pituitary gland work so closely together. But dont worry! Its not all a guessing game. There are tests to monitor hormone levels that narrow down the possibilities as to what may be the source of the disorder or disease.
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Where Is My Hypothalamus
Computer artwork of a person’s head showing the left side of the brain with the hypothalamus highlighted.
The hypothalamus is located on the undersurface of the brain. It lies just below the thalamus and above the pituitary gland, to which it is attached by a stalk. It is an extremely complex part of the brain containing many regions with highly specialised functions. In humans, the hypothalamus is approximately the size of a pea and accounts for less than 1% of the weight of the brain.
What Youll Learn To Do: Describe The Role Of The Nervous System And Endocrine Systems
In this section, youll learn about the basics of the central nervous system, which consists of the brain and spinal cord, as well as the peripheral nervous system. The peripheral nervous system is comprised of the somatic and autonomic nervous systems. The somaticnervous system transmits sensory and motor signals to and from the central nervous system. The autonomicnervous system controls the function of our organs and glands, and can be divided into the sympathetic and parasympathetic divisions. Sympathetic activation prepares us for fight or flight, while parasympathetic activation is associated with normal functioning under relaxed conditions. The endocrinesystem consists of a series of glands that produce chemical substances known as hormones, which produce widespread effects on the body. Got all that? Well review each of these systems in the coming pages.
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