Adrenal Glands Overview

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Questions and Answers

What condition results from a deficiency in thyroid hormone secretion during childhood?

Hyperactivity

Stunted growth and mental retardation (correct)

Obesity

Increased energy levels

What is the primary hormone secreted by the alpha cells of the pancreatic islets?

Somatostatin

Insulin

Adrenaline

Glucagon (correct)

Which statement about hyperthyroidism is accurate?

It is primarily caused by a deficiency of iodine.

It leads to symptoms such as nervousness and irregular heart rate. (correct)

It causes an increase in body weight.

Graves' disease is not a form of hyperthyroidism.

Which of the following best describes Type 1 diabetes?

Pancreas fails to produce sufficient insulin due to autoimmune response. Signup and view all the answers

What role does parathyroid hormone (PTH) serve in the body?

Regulates blood calcium levels by mobilizing calcium from bones. Signup and view all the answers

What is the primary function of the adrenal medulla?

Secretes epinephrine and norepinephrine Signup and view all the answers

Which zone of the adrenal cortex is responsible for secreting aldosterone?

Zona glomerulosa Signup and view all the answers

Cushing's syndrome is characterized by excessive production of which hormone?

Cortisol Signup and view all the answers

What primarily controls the secretion of cortisol and cortisone from the adrenal cortex?

Hypothalamic-pituitary axis via ACTH Signup and view all the answers

Addison's disease results from insufficient levels of which hormones?

Cortisol and aldosterone Signup and view all the answers

Which hormone is primarily released by the zona reticularis of the adrenal cortex?

Androgens Signup and view all the answers

What role do opioid peptides like enkephalin play in relation to adrenal hormones?

Regulate metabolism and blood pressure Signup and view all the answers

Which of these hormones are secreted by the adrenal cortex?

Cortisol and aldosterone Signup and view all the answers

What is a key characteristic of the hormones produced by endocrine glands?

They can influence nearly every living cell in the body. Signup and view all the answers

Which of the following hormones is classified as a steroid hormone?

Cortisol Signup and view all the answers

What is the primary function of hypothalamic releasing hormones?

To initiate the production of various hormones from the pituitary gland. Signup and view all the answers

How do emotions impact hormone secretion in the body?

Emotions can lead to increased or decreased hormone release. Signup and view all the answers

Which gland serves as a key player in the hypothalamic-pituitary axis?

Pituitary gland Signup and view all the answers

What distinguishes non-steroid hormones from steroid hormones?

Non-steroid hormones are structurally related to proteins. Signup and view all the answers

Which of the following is NOT a source of hormone secretion?

Exocrine glands Signup and view all the answers

Which of the following effects describes how hormones generally function within the body?

They have a longer-lasting effect compared to nervous signals. Signup and view all the answers

Study Notes

Adrenal Glands

Adrenal glands are located at the superior poles of the kidneys.
Each adrenal gland is composed of two parts: adrenal medulla (20%) and adrenal cortex (80%).

Adrenal Cortex

Secretes corticosteroids:
- Glucocorticoids: Cortisol, corticosterone
- Mineralocorticoids: Aldosterone
Zona Glomerulosa: Outermost layer of the adrenal cortex.
- Secretes Aldosterone.
- Controlled by the renin-angiotensin system and plasma potassium levels.
Zona Faciculata: Middle layer of the adrenal cortex.
- Secretes cortisol, corticosterone and small amounts of adrenal androgens and estrogens.
- Controlled by the hypothalamic-pituitary axis via ACTH.
Zona Reticularis: Innermost layer of the adrenal cortex.
- secretes adrenal androgens (dehydroepiandrosterone and androstenedione), small amounts of estrogens and glucocorticoids.
- Controlled by ACTH and cortical androgen-stimulating hormone.

Adrenal Medulla

Secretes non-steroid hormones:
- Epinephrine (adrenaline)
- Norepinephrine (noradrenaline)
- Dopamine
Also secretes opioid peptides (encephalin) and adrenomedullin.
Plays a role in metabolism, blood pressure, and heart activity.
Most circulating norepinephrine comes from noradrenergic nerve endings.
About half of circulating dopamine comes from sympathetic ganglia.

Disorders of the Adrenal Gland

Addison's disease: Deficiency in cortisol and aldosterone.
- Leads to low blood glucose levels and low blood sodium levels.
- Symptoms: fatigue, weakness, abdominal pain, weight loss, and bronzed skin.
Cushing's syndrome: Excess cortisol.
- Symptoms: excessive glucose production from glycogen and protein, retention of salt and water.

Parathyroid Hormone (PTH)

Controls blood calcium levels
Effects:
- Removes calcium and phosphate from bone
- Increases calcium absorption in the digestive tract
- Causes kidneys to retain calcium and excrete phosphate.

Pancreas

Endocrine gland: secretes hormones into the blood.
Exocrine gland: secretes enzymes, fluids, and ions into the digestive tract.
Islets of Langerhans: Clusters of endocrine cells scattered throughout the pancreas.
Alpha cells: Secrete glucagon, which raises blood sugar levels.
Beta cells: Secrete insulin, which lowers blood sugar levels.
Delta cells: Secrete somatostatin.

Disorders of the Pancreas - Diabetes

Type 1 diabetes: Failure of the pancreas to produce enough insulin.
- Insulin-dependent diabetes.
- Autoimmune disorder where the immune system attacks insulin-producing cells.
Type 2 diabetes: Cells fail to respond adequately to insulin, even when it is present.
- Non-insulin-dependent diabetes.
- May have a genetic component, but lifestyle factors are major determinants.

Endocrine System

Collection of specialized cells, tissues, and glands.
Produces and secretes circulating chemical messenger molecules (hormones).

Hormones

Secreted by endocrine glands.
Endocrine glands are ductless organs that secrete their products into interstitial fluid, lymph, and blood.
Exocrine glands: secrete products into ducts.

Characteristics of the Endocrine System

Hormones reach nearly every living cell.
Each hormone acts only on certain cells.
Endocrine control is slower than nervous system control.
The endocrine and nervous systems interact.

Classification of Hormones

Steroid hormones: Structurally related to cholesterol, lipid-soluble.
Non-steroid hormones: Structurally related to proteins, lipid-insoluble.

Learning Objectives

Discuss the general functions of the endocrine system.
Classify hormones by their chemical makeup.
Describe the endocrine functions of the hypothalamus and pituitary.
Discuss the hormone functions of the pancreas and adrenal glands.
Describe the hormone functions of the thyroid and parathyroid glands.
Discuss the hormones produced by reproductive organs.
Describe other hormone sources and other chemical messengers.
Discuss various disorders of the endocrine system.

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Description

Test your knowledge about the adrenal glands, their location, and their structure. Explore the functions of the adrenal cortex and medulla and learn about the hormones they secrete, including glucocorticoids and mineralocorticoids. This quiz covers the layers of the adrenal cortex and their hormonal regulation.