Endocrine System Overview Quiz

Questions and Answers

What is carried in blood attached to a transport protein and is only active when freed?

Thyroid hormone

What does the Thyroid hormone stimulate?

Glucose metabolism and increases basal metabolic rate and body heat

What is Thyroid hormone an important regulator of?

Growth and development with hGH

What do decreased levels of Thyroid hormone stimulate?

TRH and TSH Signup and view all the answers

What does hypothalamic TRH stimulate and what does that cause?

Stimulates the anterior pituitary to release TSH, which stimulates the thyroid to release thyroid hormones Signup and view all the answers

What are the two thyroid gland pathologies?

Graves disease Signup and view all the answers

What are the symptoms of Hypothyroidism in adults?

Myxedema: lethargic, low metabolism, puffy eyes, mental impairment Signup and view all the answers

What is a consequence of lack of iodine in Hypothyroidism?

Goiter Signup and view all the answers

What are the symptoms of Cretinism in infants?

Short, thick body, mental retardation Signup and view all the answers

What does Graves disease cause?

Elevated metabolic rate, sweating, rapid heartbeat, bulging eyes (Exophthalmos) Signup and view all the answers

What is the body's second homeostatic control system?

Endocrine System Signup and view all the answers

What system uses hormones as a control agent?

Endocrine System Signup and view all the answers

What are chemical messengers released into the blood to regulate specific body functions?

Hormones Signup and view all the answers

Where are hormones secreted from?

Endocrine (ductless) glands and tissues Signup and view all the answers

What is the scientific study of hormones and the endocrine organs?

Endocrinology Signup and view all the answers

What describes the Nervous System?

Characteristics of the Nervous System include rapid action, propagation via nerve fibers, neurotransmitters, and brief responses. Signup and view all the answers

What describes the Endocrine System?

Characteristics of the Endocrine System include slower responses, hormones released into body fluids, and prolonged effects on target cells. Signup and view all the answers

What kind of glands have a rich capillary blood supply and form a discrete structure?

All glands Signup and view all the answers

What type of glands secrete hormones into surrounding tissue fluid by exocytosis?

Endocrine Glands Signup and view all the answers

What type of glands secrete various compounds by exocytosis into a duct system?

Exocrine Glands Signup and view all the answers

What type of glands has both endocrine and exocrine functions?

Mixed glands Signup and view all the answers

What are the six pure endocrine glands?

Pineal, Pituitary, Parathyroid, Thyroid, Thymus, Adrenal Glands (Cortex and Medulla) Signup and view all the answers

Pancreas and gonads are a type of what kind of glands?

Mixed glands Signup and view all the answers

What are seven types of endocrine tissue?

Stomach and intestines, Skin and adipose tissue, Heart, Kidneys, and Placenta Signup and view all the answers

What is an example of neuroendocrine organs?

Hypothalamus/Pituitary Glands Signup and view all the answers

What are the two types of chemical regulators?

Circulating hormones (endocrines) and local hormones Signup and view all the answers

What is a circulating hormone and what does it do?

Circulating hormone molecules linger in the bloodstream and exert their effects for minutes or hours. Signup and view all the answers

What does a local hormone do?

Local hormones are usually short-lived and act on local target cells. Signup and view all the answers

What are two examples of local hormones?

Paracrine and Autocrine Signup and view all the answers

What do paracrine hormones do?

Acts on target cells close to the site of release. Signup and view all the answers

What do autocrine hormones do?

Acts on the same cell which secreted it. Signup and view all the answers

How are circulating hormones inactivated?

Inactivated by enzymes in the target tissues or in the bloodstream, or eliminated by the kidneys. Signup and view all the answers

How would kidney or liver disease cause problems?

From increased hormone levels. Signup and view all the answers

What are the two main chemical classes of circulating hormones?

Amino Acid-based and Steroids Signup and view all the answers

What are three types of amino acid-based hormones?

Amines, Peptides, and Proteins Signup and view all the answers

What are steroids synthesized from?

Cholesterol Signup and view all the answers

What are five ways hormones may alter cell activities and metabolism?

<ol> <li>Changing membrane permeability or membrane potential by opening or closing gated ion channels. 2. Synthesis of proteins, lipids, or carbohydrates within the cell. 3. Enzyme activation or deactivation. 4. Induction or suppression of secretory activities. 5. Stimulation of mitosis.</li> </ol> Signup and view all the answers

Since amino acid-based hormones cannot enter cells, what must happen?

A second messenger must convey the hormone signal inside of the cell. Signup and view all the answers

What are four types of molecules that serve as second messengers?

<ol> <li>Cyclic AMP (cAMP) 2. Cyclic GMP (cGMP) 3. Inositol Triphosphate (IP3) 4. Ca2+ ions</li> </ol> Signup and view all the answers

What are the five steps to cyclic AMP (cAMP) for Hormone A?

<ol> <li>Hormone A binds membrane receptor, activating Gs. 2. Gs stimulates adenylate cyclase. 3. AC forms cAMP from ATP. 4. cAMP activates Protein Kinase A. 5. PKA activates/deactivates other enzymes.</li> </ol> Signup and view all the answers

What are the three steps to cyclic AMP for Hormone B?

<ol> <li>Hormone B binds its receptor, activating Gi. 2. Gi inhibits adenylate cyclase. 3. Antagonistic control.</li> </ol> Signup and view all the answers

Can two second messengers work together?

True Signup and view all the answers

What do second messengers activate/trigger?

Activate enzymes and trigger other intracellular activities. Signup and view all the answers

What are the three types of hormone interactions at a target?

<ol> <li>Permissive 2. Synergism 3. Antagonism</li> </ol> Signup and view all the answers

What is a permissive hormone interaction?

One hormone allows another hormone to cause an effect. Signup and view all the answers

What is a synergism hormone interaction?

The effect of two hormones acting together is greater than either acting alone. Signup and view all the answers

What is an antagonism hormone interaction?

One hormone has an opposite effect to another hormone. Signup and view all the answers

What are the three types of control of hormone release?

<ol> <li>Humoral control/Autocontrol 2. Nervous system control 3. Hormonal control</li> </ol> Signup and view all the answers

What is hormonal control of hormone release and give an example?

Hormones control the release of other hormones; an example is neurohormones from the hypothalamus stimulating the anterior pituitary. Signup and view all the answers

What is humoral control/Autocontrol of hormone release and what are three examples?

Substances in the blood regulate the release of hormones; examples include Ca2+ levels regulating PTH, glucose levels regulating insulin and glucagon, and Na+ and K+ levels regulating aldosterone. Signup and view all the answers

What is nervous system control of hormone release?

Neural input stimulates the release of specific hormones. Signup and view all the answers

What are three examples of nervous system control hormone release?

<ol> <li>Sympathetic ANS stimulation of the adrenal glands. 2. Nerve impulses from the hypothalamus causing oxytocin release. 3. Nerve impulses causing ADH release.</li> </ol> Signup and view all the answers

What are the two functional components of the Pituitary Gland?

Anterior Pituitary and Posterior Pituitary Signup and view all the answers

What does the Anterior Pituitary do, what is it made of, and what's its other name?

It synthesizes hormones, made of primarily glandular tissue, also called Adenohypophysis. Signup and view all the answers

What does the Posterior Pituitary secrete, what is it made of, and what is its other name?

It secretes peptide hormones, made of primarily neurosecretory cells, also called Neurohypophysis. Signup and view all the answers

What is the Pituitary Gland connected to and how?

Connected to the Hypothalamus by the infundibulum superiorly. Signup and view all the answers

What are the two vascular linkages of the pituitary gland?

<ol> <li>Hypothalamus to the anterior pituitary. 2. Two capillary beds - the hypophyseal portal system.</li> </ol> Signup and view all the answers

What are the two nervous linkages of the pituitary gland?

<ol> <li>Hypothalamus to the posterior pituitary. 2. Hypothalamic neuron axons.</li> </ol> Signup and view all the answers

What are the two parts of the pituitary gland that regulate hormone release?

Anterior Pituitary and Posterior Pituitary Signup and view all the answers

How does the Anterior Pituitary regulate hormone release?

By hypothalamic releasing and inhibiting hormones transported via blood in the hypophyseal portal system. Signup and view all the answers

What are the two ways the Posterior Pituitary regulates hormone release?

Neuroendocrine release from neurosecretory cells and hormones produced in hypothalamus released from axons ending bulbs. Signup and view all the answers

How is Growth Hormone (hGH) released?

Stimulated by GHRH from the hypothalamus, regulated by negative feedback. Signup and view all the answers

What are the actions of Growth Hormones?

Targets liver, muscle, bone, cartilage; stimulates growth, mobilizes fats, elevates blood glucose. Signup and view all the answers

What are two pathologies of growth hormone and examples of both?

<ol> <li>Hyposecretion: Pituitary dwarfism; 2. Hypersecretion: Pituitary gigantism in childhood, Acromegaly in adulthood.</li> </ol> Signup and view all the answers

How is Thyroid stimulating hormone (TSH) released?

Release is stimulated by TRH from the hypothalamus and indirectly by pregnancy and body temperature. Signup and view all the answers

How is Thyroid stimulating hormone release inhibited?

Inhibited by negative feedback from thyroid hormones and GHIH. Signup and view all the answers

What are two actions of Thyroid stimulating hormones?

Targets thyroid gland; stimulates thyroid hormone release (T3 and T4). Signup and view all the answers

What are two pathologies of Thyroid stimulating hormones?

<ol> <li>Hyposecretion: hypothyroidism; 2. Hypersecretion: hyperthyroidism.</li> </ol> Signup and view all the answers

How is Adrenocorticotropic Hormone (ACTH) release stimulated?

Stimulated by corticotropin-releasing hormone (CRH) from the hypothalamus. Signup and view all the answers

How is Adrenocorticotropic Hormone release inhibited?

Inhibited by negative feedback from glucocorticoids and chronic use of anti-inflammatory steroids. Signup and view all the answers

What does Adrenocorticotropic hormone target?

The adrenal cortex. Signup and view all the answers

What does Adrenocorticotropic hormone stimulate?

Stimulates the release of glucocorticoids. Signup and view all the answers

What are two pathologies of Adrenocorticotropic hormones?

<ol> <li>Hyposecretion: Addison’s disease; 2. Hypersecretion: Cushing’s disease.</li> </ol> Signup and view all the answers

How is Follicle stimulating hormone release stimulated?

Stimulated by gonadotropic-releasing hormone (GnRH) from the hypothalamus. Signup and view all the answers

How is Follicle stimulating hormone release inhibited?

Inhibited by negative feedback from estrogen and inhibin in females and testosterone and inhibin in males. Signup and view all the answers

What does Follicle stimulating hormone target?

Ovaries and testes. Signup and view all the answers

In which sex is Luteinizing Hormone found and what is it?

Found in both sexes; it is called Interstitial cell stimulating hormone in males. Signup and view all the answers

How is Luteinizing Hormone release stimulated?

Stimulated by gonadotropic-releasing hormone. Signup and view all the answers

How is Luteinizing Hormone release inhibited?

Inhibited by negative feedback from estrogen, progesterone in females, and testosterone in males. Signup and view all the answers

What does Luteinizing Hormone target?

Ovaries and testes. Signup and view all the answers

What does Luteinizing Hormone stimulate?

In females, stimulates ovulation; in males, stimulates production of androgens. Signup and view all the answers

How is prolactin release stimulated?

Stimulated by an unidentified prolactin-releasing hormone (PRH) from the hypothalamus. Signup and view all the answers

How is prolactin release enhanced?

Enhanced by estrogen, birth control pills, and breastfeeding. Signup and view all the answers

How is prolactin release inhibited?

Inhibited by dopamine and lack of neural stimulation. Signup and view all the answers

What does prolactin target?

Breast secretory tissue. Signup and view all the answers

What does prolactin stimulate?

Milk production for lactation. Signup and view all the answers

What are six hormones of the Anterior Lobe?

<ol> <li>Prolactin 2. Luteinizing hormone 3. Adrenocorticotropic hormones 4. Follicle stimulating hormone 5. Growth Hormone 6. Thyroid stimulating hormones</li> </ol> Signup and view all the answers

How is Oxytocin released?

Positive feedback from uterine stimulation and suckling. Signup and view all the answers

What does Oxytocin release stimulate?

Uterine contractions and milk ejection. Signup and view all the answers

What does Oxytocin target?

Smooth muscle of the uterus and the breast. Signup and view all the answers

How is Antidiuretic hormone (ADH or vasopressin) release stimulated?

Stimulated by impulses from hypothalamus in response to increased osmolarity, decreased blood volume, or stress. Signup and view all the answers

How is Antidiuretic hormone release inhibited?

Inhibited by adequate hydration or ethanol ingestion. Signup and view all the answers

What two places does Antidiuretic hormone target?

<ol> <li>Kidneys 2. Vascular smooth muscle.</li> </ol> Signup and view all the answers

Where is the Thyroid gland located?

In the anterior neck, inferior to the larynx. Signup and view all the answers

How many lateral lobes does the Thyroid gland have and what are they connected by?

Two lateral lobes connected by isthmus. Signup and view all the answers

What is the largest pure endocrine gland in the body?

Thyroid gland Signup and view all the answers

Does the Thyroid gland have no blood supply?

False Signup and view all the answers

What kind of follicles does the thyroid gland have, and what do they produce?

Spherical follicles lined with cuboidal follicular cells, site of Thyroid hormones production. Signup and view all the answers

What kind of hormones are produced at the spherical follicles in the Thyroid gland?

Thyroxine (T4) and Triiodothyronine (T3) Signup and view all the answers

What are the two main structures of the Thyroid gland?

Spherical follicles and Parafollicular (C cells) Signup and view all the answers

Where are the Parafollicular cells located, what are they, and what do they produce?

Located between follicles, they are a protein hormone, produce calcitonin. Signup and view all the answers

What does the interior of the spherical follicle contain and what is its purpose?

It contains the thyroid 'colloid', which is the inactive storage form of thyroid hormones. Signup and view all the answers

What are the four hormones found in the Thyroid gland?

<ol> <li>Thyroxine 2. Triiodothyronine 3. Amine hormones 4. Tyrosine</li> </ol> Signup and view all the answers

What do thyroid hormones target?

All tissues except adult brain, spleen, testes, uterus, and thyroid gland. Signup and view all the answers

How are thyroid hormones carried and how are they activated?

Thyroid hormones are carried in the blood bound to proteins, and they become active once they enter target cells. Signup and view all the answers

Study Notes

Endocrine System Overview

The endocrine system serves as the body's secondary homeostatic control system.
Hormones, acting as chemical messengers, are vital for regulating body functions.
Endocrine glands are ductless and secrete hormones directly into the bloodstream.

Differentiation between Endocrine and Nervous System

The nervous system operates rapidly via action potentials and neurotransmitters causing brief responses.
The endocrine system is slower, uses hormones circulated in the blood, and allows for more prolonged effects on target cells.

Types of Glands

Endocrine glands (e.g., pituitary, thyroid) secrete hormones into the bloodstream.
Exocrine glands release substances through ducts (e.g., sweat glands).
Mixed glands have both endocrine and exocrine functions (e.g., pancreas, gonads).

Hormone Categories

Local hormones act close to their release site (e.g., paracrine and autocrine).
Circulating hormones travel via blood, affecting distant target cells.
Major chemical classes include amino acid-based hormones and steroids (synthesized from cholesterol).

Mechanisms of Hormone Action

Amino acid-based hormones use second messengers (like cAMP) to convey their signal inside cells.
Hormones can alter cellular activity by modifying membrane permeability, synthesizing molecules, or stimulating mitosis.

Hormone Interactions

Three types:
- Permissive: One hormone enhances the effect of another.
- Synergism: Combined effects of hormones are greater than individual effects.
- Antagonism: One hormone counteracts the effect of another.

Control of Hormone Release

Controlled by humoral factors (e.g., blood levels of certain ions), neural inputs, or hormonal signals.
Examples include calcium levels regulating PTH and nervous system stimulation of adrenal glands.

Pituitary Gland Functions

Divided into anterior (glandular tissue) and posterior (neurosecretory tissue).
Anterior pituitary releases hormones (e.g., GH, TSH) stimulated by signals from the hypothalamus.
Posterior pituitary releases hormones produced by the hypothalamus (e.g., oxytocin, ADH).

Specific Hormones and Their Functions

Growth Hormone (GH): Stimulates growth and metabolism; regulated by GHRH and inhibited by somatostatin.
Thyroid Stimulating Hormone (TSH): Stimulates thyroid hormone release; regulated by TRH from the hypothalamus.
Adrenocorticotropic Hormone (ACTH): Stimulates the adrenal cortex; regulated by CRH from the hypothalamus.
Follicle Stimulating Hormone (FSH): Stimulates ovarian and testicular function; regulated by GnRH.

Thyroid Gland Characteristics

Located in the anterior neck, has rich blood supply and is the largest pure endocrine gland.
Produces thyroid hormones (T3 and T4) from spherical follicles and calcitonin from parafollicular cells.
Thyroid hormones influence metabolic rate and are vital for growth and development.

Common Hormonal Pathologies

Hypothyroidism: Results in low metabolism, lethargy, and can lead to goiter if due to iodine deficiency.
Hyperthyroidism (e.g., Graves’ disease): Characterized by elevated metabolism, sweating, and bulging eyes.
Growth Hormone disorders can lead to conditions like pituitary dwarfism or acromegaly.

Regulation of Thyroid Hormones

TRH from hypothalamus stimulates TSH release from the anterior pituitary, which in turn stimulates the thyroid.
Negative feedback mechanisms maintain homeostasis of hormone levels.

Additional Notes

Local hormones are short-lived and act on nearby cells; circulating hormones have longer-lasting effects.
Pathologies can stem from imbalances in hormone production or signaling pathways, affecting various physiological functions.

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Description

Test your knowledge on the endocrine system's structure and function with this quiz. Explore how hormones act as chemical messengers, the roles of different glands, and the differences between the endocrine and nervous systems. Challenge yourself to understand various hormone categories and their effects on the body.