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Adrenal Glands

Adrenal Glands

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This lesson will identify the location of the adrenal glands as well as the functions of hormones produced by the adrenal glands.

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Tutorial

What's Covered

Welcome to this lesson on the adrenal glands. Today you will be looking at the structure and function of the adrenal glands, and the role they play in the endocrine system. Specifically, you will learn about:

  1. Adrenal Glands Overview
  2. Adrenal Glands Structure
  3. Adrenal Cortex
  4. Adrenal Medulla

1. Adrenal Glands Overview

The adrenal glands are located just above the kidneys. You have two kidneys, and therefore, two adrenal glands. Adrenal glands produce hormones that help regulate various things, such as glucose levels of the blood, blood pressure, and blood circulation.


2. Adrenal Gland Structure

Refer to the image below as you work through this next section.

The image above is a cross section of an adrenal gland. The adrenal cortex is the outer part of the adrenal gland and the adrenal medulla is the inner part. It's important to understand this structure of adrenal glands, because each of these parts of adrenal glands possess different functions.


3. Adrenal Cortex

The adrenal cortex secretes glucocorticoids and mineralocorticoids. These are two classes of hormones that are secreted by the adrenal cortex. Glucocorticoids help to increase blood glucose levels and also play a role in decreasing inflammation of tissues. Hypoglycemia is a condition in which a person has chronic low blood sugar and sometimes happens because too little cortisol is produced.

Cortisol also plays a role in inflammation; Cortizone is an over the counter drug that you can buy at any drugstore sort of acts like cortisol. Cortisol also stimulates the liver to synthesize glucose, which is a process called gluconeogenesis. Overall, cortisol plays a role in inflammation and in controlling glucose levels of the blood

Example An example of a glucocorticoid is cortisol. Cortisol is an example of a glucocorticoids. Cortisol is the main glucocorticoid of the body, and it helps to increase glucose levels if glucose levels drop too low.

Terms to Know

    • Adrenal Cortex
    • The outer covering of the adrenal gland that secretes hormones that regulate body mineral levels, metabolism and aid in the production of sex hormones.
    • Glucocorticoids
    • Hormones that affect glucose metabolism of the body, the most abundant one being cortisol a.k.a. the stress hormone.
    • Gluconeogenesis
    • The process of converting amino acids and lipids into glucose, this process takes place in the liver.
    • Hypoglycemia
    • The clinical term for low blood sugar.

Mineralocorticoids are the other class that are produced by the adrenal cortex. Mineralocorticoids help to adjust the concentration of mineral salts, like potassium or sodium, in your extra cellular fluids.

Example An example of a mineralocorticoid is aldosterone, which acts on the nephrons of the kidneys. Aldosterone stimulates sodium reabsorption and therefore, water reabsorption. Aldosterone secretion is triggered by a decrease in blood pressure or blood volume, or a decrease in sodium levels of the blood.

Term to Know

    • Mineralcorticoids
    • Hormones that maintain mineral homeostasis; aldosterone is a hormone that stimulates the kidneys to retain sodium.

4. Adrenal Medulla

The adrenal medulla is the inner part of the adrenal gland. The adrenal medulla produces and secretes epinephrine and norepinephrine. Normally epinephrine and norepinephrine act as neurotransmitters elsewhere in the body, however when they're released by the adrenal medulla they help to regulate blood circulation.

Epinephrine and norepinephrine help to increase heart rate. They also help to dilate and constrict arterials along with dilating bronchioles. This allows oxygen to flow to cells that demand more energy when the body is stressed or excited. They're often called stress hormones, because they play a big role when the body is stressed or excited, in the flight or fight response.

Terms to Know

    • Adrenal Medulla
    • The adrenal medulla releases hormones called catecholamines (adrenaline) that elevate our metabolism in response to stress. The adrenal medulla is controlled by the sympathetic nervous system (SNS).
    • Epinephrine
    • Classified as a catecholamine (adrenaline) and is secreted from the adrenal medulla; epinephrine is found in higher amounts in the blood than its counterpart norepinephrine.
    • Norepinephrine
    • Classified as a catecholamine (adrenaline) and is secreted from the adrenal medulla; norepinephrine is found in lower amounts in the blood than its counterpart epinephrine.

Summary

This lesson has been an overview on the structure, function, and role of the adrenal glands in the endocrine system. Specifically, you learned about functions of the adrenal cortex and the adrenal medulla.

Keep up the learning and have a great day!

Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND

TERMS TO KNOW
  • Adrenal Cortex

    The outer covering of the adrenal gland that secretes hormones that regulate body mineral levels, metabolism and aid in the production of sex hormones.

  • Glucocorticoids

    Hormones that affect glucose metabolism of the body, the most abundant one being cortisol a.k.a. the stress hormone.

  • Gluconeogenesis

    The process of converting amino acids and lipids into glucose, this process takes place in the liver.

  • Hypoglycemia

    The clinical term for low blood sugar.

  • Mineralcorticoids

    Hormones that maintain mineral homeostasis; aldosterone is a hormone that stimulates the kidneys to retain sodium.

  • Adrenal Medulla

    The adrenal medulla releases hormones called catecholamines (adrenaline) that elevate our metabolism in response to stress. The adrenal medulla is controlled by the sympathetic nervous system (SNS).

  • Epinephrine

    Classified as a catecholamine (adrenaline) and is secreted from the adrenal medulla; epinephrine is found in higher amounts in the blood than its counterpart norepinephrine.

  • Norepinephrine

    Classified as a catecholamine (adrenaline) and is secreted from the adrenal medulla; norepinephrine is found in lower amounts in the blood than its counterpart epinephrine.