The Adrenal Gland & Stress Regulation

Adrenal Gland

What Is the Adrenal Gland?

-The adrenal glands are two triangular glands, one placed on top of each kidney.

- They are the glands that produce hormones that primarily relate to stress

The Adrenal Gland Overview

The adrenal cortex is responsible for the outermost part of Gland and is responsible for the production of Mineralocorticoids and Glucocorticoids

The Adrenal Medulla is the inner part of the gland and is Responsible for the production of epinephrine and Norepinephrine

Why is it part of the Endocrine System?

-The Endocrine system is a hormone pruduction system that controls many of the slow moving processes within our body such as cell growth.

-The adrenal gland produces hormones that affect the way the body copes and reacts to different situations. Ie. Releasing Adrenalin to deal with stress

The Two Parts of the Adrenal Gland-The outer region known as the cortex secretes hormones

which have important effects on the way in which energy is stored and food is used, on chemicals in the blood, and on characteristics such as hairiness and body shape.

Hormones Produced-(Cortex)- Hydrocortisone, corticosterone, aldosterone and androgen

-The smaller, inner region known as the Medulla is part of the sympathic nervous system and is the body's first line of defence and response to physical and emotional stresses.

Hormones Produced -(Medulla)- Epinephrine, norepinephrine

Cortex Functions: Key Hormones and what they do

• hydrocortisone hormoneThis hormone, also known as cortisol, controls the body's use of fats, proteins, and carbohydrates.

• corticosteroneThis hormone, together with hydrocortisone hormones, suppresses inflammatory reactions in the body and also affects the immune system.

• aldosterone hormoneThis hormone inhibits the level of sodium excreted into the urine, maintaining blood volume and blood pressure.

• androgenic steroids (androgen hormones)These hormones have minimal effect on the development of male characteristics.

• Overview: The adrenal cortex regulates use of various functions that relate the retention of ions, the use of fats, proteins and carbs and development of certain characteristics

Medulla Functions• epinephrine (Also called adrenaline.)

This hormone increases the heart rate and force of heart contractions, facilitates blood flow to the muscles and brain, causes relaxation of smooth muscles, helps with conversion of glycogen to glucose in the liver, and other activities

• norepinephrine (Also called noradrenaline.)This hormone has little effect on smooth muscle, metabolic processes, and cardiac output, but has strong vasoconstrictive effects, thus increasing blood

pressure.

Overall: Increases blood pressure to deal with stressful situations that the body may encounter

Examples Of Homeostatic Mechanisms Of The Adrenal Gland

• Epinephrane and Norepinephrane- Raise blood sugar and fatty acid levels and also increase heart rate during times of stress

• Glucocorticoids- Natural steroid used as an anti-inflammatory

• Mineralocorticoids- Promote salt reabsorption in the kidneys back to the blood stream

Roles Of GlucocorticoidsIn Homeostasis

  One role of the Glucocorticoids, such as cortisol, is to work in our bodies as an anti-inflammatory.

 They depress the immune system to dull the effects of inflammation when a part of the body is irritated by damage or injury to tissue.

  This prevents or reduces the negative effects of inflammation such as redness, swelling, heat, and pain.

  They also assist in glucose homeostasis by stimulating gluconeogenisis in the liver, which initiates the conversion of fats and proteins into glucose when needed.

 

Overview of the Adrenal Gland and Homeostasis

• The adrenal gland contributes to homeostasis in the following ways:

  Provides excess amounts of energy to the muscles in emergencies to prevent them from tiring

Keeps blood pressure from dropping• Contributes to the maintaining of electrolytes

and water in the blood stream

Roles of Epinephrine and Norepinephrine in Homeostasis

• In emergencies, our adrenal gland is signaled to release epinephrine and norepinephrine (also known as adrenaline).

• These chemicals override our body’s usual control of glucose, and homeostasis for glucose is altered.

• Adrenaline breaks down glycogen into glucose to produce larger amounts of ATP in times of stress to produce the energy we need.

• This leads to increased breathing and heart rate to meet the demands of the ATP production.

• Once the emergency is over, adrenaline is produced by the adrenal gland at a much lower rate, and regular glucose homeostasis is resumed

Stress

-   - In stressful situations epinephrine and norepinephrine are released from the adrenal medulla into the bloodstream.

-Norepinephrine responsible for the “fight or flight” response.

-Epinephrine increases heart rate and cell metabolism – faster energy source.

Adrenal Gland Hormones

-Different hormones produced in both cortex and medulla.

- Hormones secreted directly into the bloodstream.

What are the hormones produced and their effect?

• -         Adrenal cortex: secretes hormones that have an effect on the body’s metabolism, on chemicals in the blood, and on certain body characteristics.

• -         Four different hormones produced in cortex: hydrocortisone, corticosterone, aldosterone, and androgen hormones.

• Takes instructions from the pituitary gland.

Hormones Produced contd

• -  Adrenal medulla: the body's first line of defense and response to physical and emotional stresses.

• -  Two different hormones produced in medulla: epinephrine and norepinephrine regulate “fight or flight” response.

-Takes instructions form the nervous system.

Cushing’s Syndrome

• ~ Cushing’s syndrome occurs when the body’s tissues are exposed to high levels of cortisol for too long. Many people develop Cushing’s syndrome because they take glucocorticoids—steroid hormones that are chemically similar to naturally produced cortisol—such as prednisone for asthma, rheumatoid arthritis, lupus, and other inflammatory diseases. Glucocorticoids are also used to suppress the immune system after transplantation to keep the body from rejecting the new organ or tissue.

• ~develop Cushing’s syndrome because their bodies produce too much cortisol. Normally, the production of cortisol follows a precise chain of events. First, the hypothalamus, a part of the brain about the size of a small sugar cube, sends corticotropin-releasing hormone (CRH) to the pituitary gland. CRH causes the pituitary to secrete adrenocorticotropin hormone (ACTH), which stimulates the adrenal glands. When the adrenals, which are located just above the kidneys, receive the ACTH, they respond by releasing cortisol into the bloodstream

• ~ Symptoms are as following most people with the disorder have upper body obesity, a rounded face, increased fat around the neck, and relatively slender arms and legs. Children tend to be obese with slowed growth rates.

• Other signs appear in the skin, which becomes fragile and thin, bruises easily, and heals poorly. Purple or pink stretch marks may appear on the abdomen, thighs, buttocks, arms, and breasts. The bones are weakened, and routine activities such as bending, lifting, or rising from a chair may lead to backaches and rib or spinal column fractures.

~Other common signs and symptoms include

• 1.severe fatigue • 2.weak muscles • 3.high blood pressure • 4.high blood glucose • 5.increased thirst and urination • 6.irritability, anxiety, or depression • 7.a fatty hump between the shoulders

Addison’s disease • ~ Causes failure to produce adequate levels of cortisol• ~ Symptoms are         Chronic, worsening fatigue         Muscle weakness         Loss of appetite         Weight loss • About 50 percent of the time, one will notice          Nausea          Vomiting • Diarrhea

Other symptoms include         Low blood pressure that falls further when

standing, causing dizziness or fainting          Skin changes in Addison's disease, with areas of

hyperpigmentation, or dark tanning, covering exposed and non-exposed parts of the body; this darkening of the skin is most visible on scars; skin folds; pressure points such as the elbows, knees, knuckles, and toes; lips; and mucous membranes

• ~Leaves a craving for salty foods• ~ Treatments involve replacing or substituting the

hormones that are not being made by the adrenal glands

• Cortisol performs vital tasks in the body including         helping maintain blood pressure and cardiovascular function         reducing the immune system’s inflammatory response         balancing the effects of insulin, which breaks down glucose for energy • regulating the metabolism of proteins, carbohydrates, and fats