Endocrinology: Pituitary Gland Overview

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Questions and Answers

What is the role of Antidiuretic Hormone (ADH) in the body?

Regulates calcium levels in the blood

Controls heart rate and blood pressure

Stimulates glycogenolysis in the liver

Increases water reabsorption in the kidneys (correct)

What triggers the release of ADH from the pituitary gland?

Activation of the adrenal cortex

Increased blood plasma concentration (correct)

Stimulation of the thyroid gland

Decreased blood plasma concentration

What is a direct consequence of not producing enough ADH?

Excessive urine production (correct)

Increased blood sugar levels

Insufficient insulin levels

Hyperactivity of the thyroid

Which hormone is responsible for regulating other endocrine glands?

Thyroid Stimulating Hormone (TSH) Signup and view all the answers

In the negative feedback mechanism, what does the third hormone do?

Inhibits the release of the first two hormones Signup and view all the answers

Where is Antidiuretic Hormone (ADH) primarily produced?

Hypothalamus Signup and view all the answers

How does ADH affect the kidneys?

Enhances water reabsorption Signup and view all the answers

Which of the following is NOT a function of hormones in regulating homeostasis?

Facilitating neurotransmission Signup and view all the answers

What is a common treatment for Diabetes Insipidus?

Administration of ADH Signup and view all the answers

What sequence best describes the mechanism of tropic hormones?

Hypothalamus releases hormone → Tropic hormone stimulates target gland → Target gland releases hormone Signup and view all the answers

What is the primary function of the posterior pituitary?

Stores and releases hormones Signup and view all the answers

Which hormone is NOT synthesized by the anterior pituitary?

Antidiuretic hormone (ADH) Signup and view all the answers

What condition is primarily caused by insufficient levels of human growth hormone (hGH)?

Pituitary dwarfism Signup and view all the answers

How does human growth hormone (hGH) affect the liver?

Promotes the production of growth factors Signup and view all the answers

What is the result of hypersecretion of hGH during childhood?

Gigantism Signup and view all the answers

What is a common consequence of acromegaly due to excess hGH in adults?

Widening of bones and soft tissue Signup and view all the answers

Which of the following best describes the hormonal action of human growth hormone?

It stimulates metabolic breakdown and fatty acid release. Signup and view all the answers

What distinguishes the anterior pituitary from the posterior pituitary?

It synthesizes its own hormones. Signup and view all the answers

What technology allowed for the creation of synthetic hGH?

Insertion of genetic code into bacteria Signup and view all the answers

Which condition results when the growth plates are fused but hGH is still hypersecreted?

Acromegaly Signup and view all the answers

Study Notes

Regulating the Regulators

The pituitary gland, a small 1cm diameter gland, is attached to and controlled by the hypothalamus.
It releases hormones essential for growth, reproduction, metabolism and development. It is often called the "master gland".
The pituitary gland is made of two distinct lobes: anterior and posterior.

Posterior Pituitary

A part of the nervous system.
It does not produce hormones.
It stores and releases hormones ADH (antidiuretic hormone) and oxytocin (both produced in the hypothalamus).

Anterior Pituitary

Synthesizes hormones including human growth hormone (hGH), prolactin (PRL), thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), follicle stimulating hormone (FSH), and luteinizing hormone (LH).
A portal system called the hypophyseal portal system carries hormones from the hypothalamus to the anterior pituitary.

Human Growth Hormone (hGH)

Regulates growth, development, and metabolism.
Stimulates the liver to produce growth factors.
hGH and growth factors increase protein synthesis, cell growth and division, and metabolic breakdown and release of fats.

Pituitary Dwarfism

Caused by insufficient hGH.
Small adult stature but typical body proportions.

Gigantism

Caused by hypersecretion of hGH in childhood.
Growth plates continue to expand, resulting in excessive growth.

Acromegaly

Hypersecretion of hGH in adulthood, often caused by a tumor.
hGH can no longer increase height (growth plates are fused), but causes bones and soft tissue to widen.
Other health issues may arise as a result.

Synthetic hGH

In 1985, synthetic hGH was produced by inserting the genetic code into rapidly reproducing bacteria and injecting it into children deficient in hGH.
Previously, hGH was obtained from cadavers.

Negative Feedback Mechanism

When certain blood hormone concentrations reach a set point or target cells have responded sufficiently, the endocrine gland that released that hormone is inhibited.
This is crucial for maintaining homeostasis.
Thyroid hormone is a good example of a system that uses this method.

Antidiuretic Hormone (ADH)

ADH regulates water reabsorption in the kidneys.
When blood plasma concentration increases, the hypothalamus sends a signal to the pituitary gland, triggering the release of ADH.
ADH targets the nephrons of the kidneys, making the tubules more permeable to water.

Diabetes Insipidus

Inability to produce ADH.
Results in large volumes of urine, leading to ion loss.
treatable by administering ADH.

Tropic Hormones

Produced in the anterior pituitary.
Target other endocrine glands to release other hormones. This is a multi-step mechanism with the first tropic hormone controlling release of a second and often that hormone controlling the release of a third hormone to carry out the desired bodily function (e.g., growth).

Mechanism of Tropic Hormones

The hypothalamus releases a hormone to the anterior pituitary.
The anterior pituitary releases a tropic hormone into the bloodstream.
The tropic hormone stimulates the target gland to release a third hormone.
The final hormone travels to the target tissue, where it causes a response.

Homework

Page 442, numbers 10-12.

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Description

This quiz provides an in-depth look at the functions and roles of the pituitary gland, often referred to as the 'master gland' of the body. Explore the distinctions between the anterior and posterior lobes, their hormone production, and their critical influence on growth and metabolism.