MLT 234: Hormones

These flashcards cover key terms and concepts related to endocrine regulation, hormone functions, and associated medical conditions as highlighted in the lecture notes.

Steroid Hormones

Hormones that have receptors on the interior of the cell and can pass through the cell membrane without help.  They are produced by cholestrol, have a long half-life, some are bound to proteins, some that are unbound that are physiologically active

Protein Hormones

Hormones that have receptors on the outer surface of the cell and require a second messenger to enter the cell. They are stored until needed, are water-soluble and have a short half-life

Negative Feedback Loop

A process where the end product reduces the action that initiated its production, often maintaining homeostasis.

Positive Feedback Loop

A process that reinforces actions and continues to produce more of the target hormone until a specific condition is met.

Tropic Hormones

Hormones that stimulate other glands to release hormones. Normally released from the Pituitary gland. (Hypothalamus-Pituitary-Target Organ)

Direct Hormones

Hormones that directly affect target organs or cells. Released from Hypothalamus to target organs

What is the final hormone product in Zone G, which is responsible for salt regulation?

Aldosterone

What is the final hormone product in Zone F, which is responsible for sugar regulation?

Cortisol

DHEA and DHEAS

Weak androgens that are precursors to testosterone and estrogen.

Dexamethasone Suppression Test

A test used to diagnose conditions like Cushing's by assessing cortisol levels.

Cushing's Syndrome

A condition characterized by excessive cortisol production.

Addison's Disease

A disorder where there is insufficient production of adrenal hormones, often with low DHEAS.

FSH (Follicle Stimulating Hormone)

A hormone that rises before ovulation and peaks around the 14th day of the menstrual cycle.

Luteinizing Hormone (LH)

A hormone that surges at ovulation and helps regulate the menstrual cycle.

Amenorrhea

The absence of menstruation.

Oligomenorrhea

Infrequent or irregular menstrual cycles typically longer than 35 days.

Hypergonadotropic Hypogonadism

A condition characterized by elevated gonadotropins but low sex hormones.

Hypogonadotropic Hypogonadism

A condition where the production of gonadotropins is inadequate, resulting in low sex hormones.

Euthyroid Sick

A condition where the thyroid function appears normal despite symptoms of hypothyroidism.

Primary, Secondary, and Tertiary Disorders

Primary relates to the target organ; secondary to the pituitary; tertiary to the hypothalamus.

Endocrine

Secretion from a ductless gland into the systemic circulation.

Hormones

Complex chemical substance produced in one part of the body that affects a target organ in another part of the body

Functions of the Endocrine System

1. Regulate metabolism

2. Regulate homeostasis

3. Regulate growth

4. Regulate Reproduction

Amlenes

Hormones that are synthesized by amino acids

What two systems is the Hypothalamus connected to?

The nervous system and the endocrine system.

What tests do we use to measure hormone levels?

Stimulation Tests - for hormone deficiency

Suppression Tests - for hormones produced in excess

Why do we need sensitive tests for hormones?

To help detect low hormone levels and they are labeled immunoassays (which are very sensitive tests)

In lab tests, what is the relationship between proteins and hormone levels?

They are inversely proportional. High amount of proteins equals low hormone levels. Low amount of protein equals high hormone levels.

What hormones is a great indicator of Pituitary Dysfunction?

Prolactin

What happens if Prolactin was released or produced in excess?

Inhibits the production and release of FSH and LH which suppresses Ovulation

What hormones are released from the Anterior Pituitary gland?

1. TSH 2. LH 3. FSH 4. GH 5. ACTH

What hormones are released from the Posterior Pituitary gland?

1. ADH (or Vassopressin) 2. Oxytocin

What hormones are released from the Hypothalamus?

1. GHRH (Growth Hormone Releasing Hormone) 2. GnRH (Gonadotropin Releasing Hormone) 3. TRH (Thyrotopin Releasing Hormone) 4. CRH (Corticotropin Releasing Hormone) 5. Dopamine 6. Somatostatin

What hormones are Direct Hormones?

Growth Hormones and Prolactin

What hormones are Tropic hormones?

1. LH 2. FSH 3. TSH 4. ACTH

What are the 3 zones in the outer adrenal cortex? What substance/hormones are they each regulating?

1. Zone G- Salt 2. Zone F- Sugar 3. Zone R- Sex (two different ones depending on the gender Male or Female)

What kind of hormones does the Cortex layer produce?

Steroid hormones

What is the final hormone product in Zone R, which is responsible for sex regulation?

DHEA and DHEAS

How is the G Zone regulated?

Through renin and angiotensin controlling vasoconstriction, and vasodilation

What is the function of the G Zone?

Acts on kidney to retain sodium and excrete potassium and increases blood volume and blood pressure

What is Hyperaldosteronism?  What disorders are associated with it?

A condition characterized by high levels of Na+ and low levels of K+, primary and seconday Aldesterone Disorders. Primary Hyperaldosteronism is a disorder that is involves the issue with the Adrenal gland. Secondary Hyperaldosteronism is a disorder that involves the issue outside of the Adrenal glan such as Malignant Hypertension and Disorder in the R-A-A system

What is Hypercortisolsim? What disorders are associated with it?

A condition characterized by excessive cortisol levels in the body and lack of diurnal cortisol variation. Primary Hypercortisolism is associated with Adrenal tumors. Secondary Hypercortisolim is associated with and is a good marker for diagnosing Cushing’s Disease.

What two disorders are associated with Addison’s Disease?

Hypoaldosteronism and Hypercortisolim

How can one test for the Cortisol levels at different times of the day?

Dexamethasone Suppression Test for high ACTH levels. Cortisol Stimulation Test for low ACTH levels.