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If the stress is not soon relieved, the body adapts to the stress in the second stage called the stage of resistance    . If a person is starving for example, the body may send signals to the gastrointestinal tract to maximize the absorption of nutrients from food.

If the stress continues for a longer term however, the body responds with symptoms quite different than the fight-or-flight response. During the stage of exhaustion    , individuals may begin to suffer depression, the suppression of their immune response, severe fatigue, or even a fatal heart attack. These symptoms are mediated by the hormones of the adrenal cortex, especially cortisol, released as a result of signals from the HPA axis.

Adrenal hormones also have several non–stress-related functions, including the increase of blood sodium and glucose levels, which will be described in detail below.

Adrenal cortex

The adrenal cortex consists of multiple layers of lipid-storing cells that occur in three structurally distinct regions. Each of these regions produces different hormones.

Visit this link to view an animation describing the location and function of the adrenal glands. Which hormone produced by the adrenal glands is responsible for the mobilization of energy stores?

Hormones of the zona glomerulosa

The most superficial region of the adrenal cortex is the zona glomerulosa, which produces a group of hormones collectively referred to as mineralocorticoids    because of their effect on body minerals, especially sodium and potassium. These hormones are essential for fluid and electrolyte balance.

Aldosterone is the major mineralocorticoid. It is important in the regulation of the concentration of sodium and potassium ions in urine, sweat, and saliva. For example, it is released in response to elevated blood K + , low blood Na + , low blood pressure, or low blood volume. In response, aldosterone increases the excretion of K + and the retention of Na + , which in turn increases blood volume and blood pressure. Its secretion is prompted when CRH from the hypothalamus triggers ACTH release from the anterior pituitary.

Aldosterone is also a key component of the renin-angiotensin-aldosterone system (RAAS) in which specialized cells of the kidneys secrete the enzyme renin in response to low blood volume or low blood pressure. Renin then catalyzes the conversion of the blood protein angiotensinogen, produced by the liver, to the hormone angiotensin I. Angiotensin I is converted in the lungs to angiotensin II by angiotensin-converting enzyme    (ACE). Angiotensin II has three major functions:

  1. Initiating vasoconstriction of the arterioles, decreasing blood flow
  2. Stimulating kidney tubules to reabsorb NaCl and water, increasing blood volume
  3. Signaling the adrenal cortex to secrete aldosterone, the effects of which further contribute to fluid retention, restoring blood pressure and blood volume

For individuals with hypertension, or high blood pressure, drugs are available that block the production of angiotensin II. These drugs, known as ACE inhibitors, block the ACE enzyme from converting angiotensin I to angiotensin II, thus mitigating the latter’s ability to increase blood pressure.

Questions & Answers

who discovered the cell
Mwesigwa Reply
Robert Hooke
Hi am Prince am new here
Asare Reply
Yeah hw uu
muscles of upper limb
pelvic has 2 Bones each Bone has two parts name the parts
Luchindo Reply
what and what
Inomenet bone
describe the structure of an atom
Obulejo Reply
what is mitosis?
atom is made of protons, nuetran and elections, which is very particle cannot be destructive nor be creative,
mitosis increase in size for separation new cell with its component including nucleus and it's content,
what are the abdominal region
I love how people can ask questions and receive answers 👌 great course btw 🙏
Global Reply
yes I wud also like to much because we can know aboth each and every thing in a deciplinary manner
explain endocrine system
JOY Reply
ductless gland, secretes hormone chemical substance which r very essential for the life activities of animals, humanbeings ,
list endocrine system
please I am still waiting for an answer
Hi Joy, The major glands that make up the endocrine system are the: .hypothalamus .pituitary . thyroid .parathyroids .adrenals .pineal body .the ovaries and the testes. Hope that helps
what are endocrine system nd their functions
The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems.
Endocrine system function. The endocrine system is responsible for regulating a range of bodily functions throughout the release of hormones.
Hormones are secreted by the glands of the endocrine system, traveling through the bloodstream to various organs and tissues in the body. The hormones then tell these organs and tissues what to do or how to function.
Some examples of bodily functions that are controlled by the endocrine system include: . metabolism . growth and development . sexual function and reproduction . heart rate . blood pressure . appetite . sleeping and waking cycle .and body temperature.
The glands of the endocrine system and their functions include: . hypothalamus produces multiple hormones that control the pituitary gland. It's also involved in regulating many functions, including sleep-wake cycle, body temperature, and appetite.
.pituitary gland is located below the hypothalamus. The hormones it produces affect growth and reproduction. They can also control the function of other endocrine system.
. pineal gland is found in the middle of your brain. It's important for your sleep-wake cycle.
.Thyroid gland is located in the front part of your neck. It's very important for metabolism.
. parathyroid gland is also located in the front part of your neck, the parathyroid gland is very important for maintaining control of calcium levels in your bones and blood.
aderenalin gland
pituitary gland, thyroid gland, thymus gland, epinephrine gland, prostate gland,
chemicals substance secreted by glands is for vital funtioning and also defencing mechanism of an organal system.
How many bones are in adult body
Godfried Reply
What produce blood in the body
blood cell are made in the bone marrow, the bone marrow is the soft, spongy material in the center if the bones it produce about 95% of the body blood cell
what is compound
Obulejo Reply
compound is the compose of many identical molecules
what are the three layers of the heart
Florence Reply
pericardium myocardium endocardium
epicardium, myocardium, and endocardium
innermost layer is the endocardium. intermediate layer is the epicadium(also known as the visceral pericadium) outermost layer is the myocardium
how do the lymphatic release excess fluid to the blood stream
Chiamaka Reply
what is lymphatic
it's a one way drainage system which drains excess water from the blood vessels to the heart
Pls what is lymphatic
lymphatic is an organs system in vertebrate that is part of the circulatory system and the immune system
importance of studying anataomy
Daud Reply
importance of anatomy
knowing how body structures look their colours shapes and adaptational characteristics
what is serotonin
Serotonin is the key hormone that stabilizes our mood. It enables brain cells and other nervous system cells to communicate with each other.
thank you
no problem :)
wat are the types of Epethelial tissue...?
name one experimental example illustrating osmosis
Simple Science Experiment: Osmosis with Potato Slices
dialysis of urin for the detoxification of blood from urial contents. is the good example for osmosis,
what is Anatomy
Wisdom Reply
anatomy is a study of structure of the body and their physical relationship between is constituents part
any with the diagram of the cross section of the heart
what IS epididymis
Dalouta Reply
définition of epididymis
what are the relative directional terms of the human body
epididymis is a long, coiled tube that rests on the backside of each testicle. It carries and stores sperm cells that are created in the testes. It's also the job of the epididymis to bring the sperm to maturity — the sperm that emerge from the testes are immature and incapable of fertilization.

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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