Adrenal Glands Overview

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Questions and Answers

Which of the following is NOT a function of melatonin?

Regulation of blood glucose levels (correct)

Influence circadian rhythms

Protect against damage by free radicals

Inhibit reproductive functions

Which cell type in the pancreas produces glucagon, a hormone that increases blood glucose levels?

Alpha cells (correct)

Pancreatic polypeptide cells

Beta cells

Delta cells

What is the primary function of the exocrine pancreas?

Production of melatonin, which affects circadian rhythms

Secretion of digestive enzymes and alkaline fluid (correct)

Production of hormones like insulin and glucagon

Regulation of blood glucose levels

Which of the following statements is TRUE about the relationship between insulin and glucagon?

They have opposing actions on blood glucose levels. (D) Signup and view all the answers

What is the role of the pineal gland in regulating circadian rhythms?

The pineal gland produces melatonin, which regulates circadian rhythms. (B) Signup and view all the answers

Which of the following statements accurately describes the location of the pancreas?

The pancreas is located in the loop between the inferior border of the stomach and the proximal portion of the small intestine. (A) Signup and view all the answers

What is the primary effect of insulin on target cells?

Accelerating glucose uptake and enhancing ATP production. (D) Signup and view all the answers

Which of the following hormones is primarily secreted by the zona reticularis, and stimulates the development of pubic hair before puberty?

Androgens (B) Signup and view all the answers

Which of the following is NOT a characteristic of diabetes mellitus?

Decreased production of melatonin. (A) Signup and view all the answers

How does glucagon contribute to regulating blood glucose levels?

By stimulating the breakdown of glycogen and glucose release. (B) Signup and view all the answers

Which of the following is NOT a direct effect of epinephrine and norepinephrine release from the adrenal medulla?

Increased production of cortisol (C) Signup and view all the answers

What is the primary difference between the exocrine and endocrine functions of the pancreas?

The exocrine pancreas secretes digestive enzymes, while the endocrine pancreas secretes hormones. (D) Signup and view all the answers

Which of the following statements accurately describes the relationship between the adrenal cortex and the adrenal medulla?

The adrenal cortex and adrenal medulla share a common precursor for their hormone production (A) Signup and view all the answers

Which of the following is a primary function of mineralocorticoids, primarily produced in the zona glomerulosa?

Regulation of electrolyte balance, particularly Na+ and K+ (C) Signup and view all the answers

The secretion of glucocorticoids from the zona fasciculata is primarily regulated by:

Negative feedback from hormones like cortisol (D) Signup and view all the answers

What is the physiological consequence of a decrease in blood sodium levels?

Increased release of aldosterone from the zona glomerulosa (C) Signup and view all the answers

How does the release of glucocorticoids from the adrenal cortex impact the immune system?

They suppress the activity of the immune system (A) Signup and view all the answers

Which of the following hormones is primarily responsible for the breakdown of glycogen in the liver during the fight-or-flight response?

Epinephrine (D) Signup and view all the answers

Which of the following statements accurately describes the relative proportions of epinephrine and norepinephrine secreted by the adrenal medulla?

Epinephrine comprises approximately 75-80% and norepinephrine 20-25% of the medullary secretion (A) Signup and view all the answers

Which of the following is NOT a direct effect of glucocorticoids on the body?

Increased sensitivity of salt receptors in taste buds (D) Signup and view all the answers

A patient is experiencing prolonged stress. Which of the following is the dominant hormone during the resistance phase?

Glucocorticoids (A) Signup and view all the answers

What is the primary role of thyroid hormones in growth and development?

Ensuring normal nervous system development. (D) Signup and view all the answers

Which hormonal effect describes how insulin works to facilitate growth?

Permissive effect (C) Signup and view all the answers

Which of the following is NOT a characteristic of the alarm phase of the stress response?

Glucocorticoids are the dominant hormones. (D) Signup and view all the answers

What is the main function of parathyroid hormone (PTH) and calcitriol in relation to growth?

Facilitating the absorption of calcium for bone development. (D) Signup and view all the answers

Which hormone is directly responsible for mobilizing lipid reserves during the resistance phase of the stress response?

Glucocorticoids (C) Signup and view all the answers

Which of the following best describes the relationship between growth hormone and insulin in terms of their effects on growth?

Synergistic (D) Signup and view all the answers

Why is it crucial for thyroid hormones to be present during fetal development?

They support the growth and development of the nervous system. (B) Signup and view all the answers

In the absence of thyroid hormones before puberty, what is the likely consequence on skeletal development?

Delayed bone growth (A) Signup and view all the answers

Which hormone is primarily responsible for maintaining normal blood glucose concentrations in adults?

Insulin (A) Signup and view all the answers

What is the name of the hormone that is produced by the kidneys and helps regulate red blood cell production?

Erythropoietin (D) Signup and view all the answers

Which of the following is NOT a function of the endocrine system?

Stimulation of muscle contraction (C) Signup and view all the answers

What is the primary difference between type 1 and type 2 diabetes mellitus?

Type 1 diabetes is caused by a lack of insulin production, while type 2 diabetes is caused by insulin resistance. (A) Signup and view all the answers

Which of the following hormones is released by the heart in response to increased blood volume?

Natriuretic Peptides (C) Signup and view all the answers

What is the role of the thymus in the immune system?

Maturation of lymphocytes (D) Signup and view all the answers

What is the name of the enzyme that converts angiotensinogen to angiotensin I?

Renin (D) Signup and view all the answers

Which of the following is a consequence of poorly managed diabetes mellitus?

Increased risk of cardiovascular disease (B) Signup and view all the answers

Which of the following hormones is primarily responsible for stimulating the development and maturation of sperm?

Testosterone (B) Signup and view all the answers

What is the name of the structure formed after ovulation that releases estrogens and progesterone?

Corpus luteum (A) Signup and view all the answers

Which of the following organs does NOT have a secondary endocrine function?

Liver (B) Signup and view all the answers

Study Notes

Adrenal Glands

Lie along the superior border of each kidney
Consists of two main parts: cortex and medulla
Superficial Adrenal Cortex
- Stores lipids, notably cholesterol and fatty acids
- Manufactures steroid hormones (corticosteroids)
Inner Adrenal Medulla
- Controlled by the sympathetic division of the autonomic nervous system (ANS)
- Secretes epinephrine and norepinephrine (catecholamines)
Adrenal Cortex Zones
- Zona Glomerulosa (SALT):
  - Outermost region
  - Produces mineralocorticoids, e.g., aldosterone
  - Stimulates sodium retention and potassium excretion
  - Increased sensitivity to salts in taste buds
  - Released in response to blood sodium levels, blood volume, or blood pressure decreasing or potassium increasing.
- Zona Fasciculata (SUGAR):
  - Middle region
  - Produces glucocorticoids, e.g., cortisol, corticosterone, cortisone
  - Regulated by negative feedback loops, inhibiting CRH (hypothalamus), ACTH (anterior pituitary)
  - Effects include accelerating glucose synthesis, glycogen formation (especially in the liver) and anti-inflammatory actions.
- Zona Reticularis (SEX):
  - Innermost region
  - Has a branching network of endocrine cells
  - Produces small amounts of androgens (sex hormones), such as androgens, under stimulation of ACTH
  - Some converted to estrogens

Adrenal Medulla

Contains two types of secretory cells:
- 75-80% produce epinephrine
- 20-25% produce norepinephrine
Activation results in:
- Mobilization of glycogen reserves & acceleration of glucose breakdown in skeletal muscles.
- Breakdown of fats into fatty acids in adipose tissue
- Glycogen breakdown in the liver
- Stimulation of cardiac muscle strength and contraction
Primarily responds to stress

Pineal Gland

Located in the posterior portion of the roof of the third ventricle
Contains pinealocytes which synthesize melatonin
Functions of Melatonin
- Influence circadian rhythms
- Inhibit reproductive functions
- Protect against free radical damage

Pancreas

Both an exocrine and endocrine gland
Located in the loop between the inferior border of the stomach and the proximal portion of the small intestine.
Exocrine Pancreas:
- Makes up roughly 99% of the pancreas
- Consists of clusters of gland cells (pancreatic acini) and their attached ducts which produce enzymes and alkaline fluid for digestive processes.
Endocrine Pancreas:
- Consists of cells clustered into pancreatic islets (islets of Langerhans)
  - Alpha (α) cells produce glucagon
  - Beta (β) cells produce insulin
  - Delta (δ) cells produce a peptide hormone identical to GH–IH
  - Pancreatic polypeptide cells (PP cells) produce pancreatic polypeptide (PP).
Insulin: Stimulates transport of glucose into cells; regulates glycogen breakdown in liver and glucose release
Glucagon: Mobilizes energy reserves; stimulates glycogen breakdown in skeletal muscle and liver cells, stimulates triglycerides breakdown.

Other Endocrine Organs

Many organs have secondary endocrine functions
Intestines: Release hormones coordinating digestive activity
Kidneys: Release calcitriol, erythropoietin, and renin (involved in blood pressure regulation)
Heart: Produce natriuretic peptides (ANP and BNP) acting to oppose angiotensin II
Thymus: Produces thymosin to promote lymphocyte development and maturation, affecting immune system
Testes: interstitial endocrine cells produce androgens, mainly testosterone
Ovaries: Produce estrogens including estradiol; produces progesterone (after ovulation). Nurse cells (Sertoli cells) support sperm differentiation and produce inhibin for feedback regulation.
Adipose tissue: secretes leptin to provide feedback control over appetite, and to aid in maintaining normal levels of GnRH and gonadotropin synthesis.

General Adaptation Syndrome (GAS)

The body's response to chronic stress
Divided into three phases: Alarm, Resistance, Exhaustion
Alarm Phase: Characterized by immediate response to stress, directed by sympathetic nervous system, mobilizing energy reserves (primarily glucose), and preparing for "fight or flight" responses.
Resistance Phase: Occurs if the stress continues, using lipids and amino acids for energy. Conserving glucose for nervous tissue. Glucocorticoids are the dominant hormones in this phase.
Exhaustion Phase: Occurs with chronic stress as homeostasis breaks down. If not relieved, exhaustion can be fatal.

Hormone Interactions

Antagonistic Effects: effect depends on balance between hormones
Synergistic Effects: additive effect of multiple hormones
Permissive Effect: one hormone is required for another to have an effect
Integrative Effects: hormones produce different effects, but complementary results

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Description

Explore the anatomy and functions of the adrenal glands, including their structure, hormone production, and the specific roles of the adrenal cortex and medulla. This quiz will help you understand the significance of adrenal hormones in regulating bodily functions.