Endocrine Module 9 Flashcards

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Questions and Answers

Define endocrine, paracrine, and autocrine.

Endocrine: Hormones are released into circulation to act on a distant target organ (i.e. TSH, ADH); Paracrine: Hormones act locally on cells close to where they are released (i.e. estrogen and testosterone); Autocrine: Hormones produce a biologic action on the cell that released them (i.e. insulin).

What are the different structural types of hormones?

Amines and amino acids; 2. Peptides and proteins; 3. Steroids, which are made from cholesterol.

What is the function of the hypothalamus?

The hypothalamus serves as a link between the nervous and endocrine systems. It regulates homeostasis, body temperature, hunger, behavior, emotion, and pain.

What is the role of the pituitary gland?

The pituitary gland is known as the 'master gland,' since it stimulates target organs to secrete their hormones. Signup and view all the answers

Explain the concept of negative feedback and give an example.

Negative feedback is how the body maintains homeostasis by monitoring hormone levels to keep them within normal range. Example: The action of ADH, which dilutes blood. Signup and view all the answers

Explain the concept of positive feedback and give an example.

Positive feedback enhances or increases the amount of hormone released. Example: Oxytocin causes uterine contractions, leading to more oxytocin release. Signup and view all the answers

Explain the ways in which hormones can be over-secreted.

Increased secretion can result from: 1. Pathology in the target gland; 2. Over-stimulation by the pituitary or hypothalamus; 3. Hormone-producing tumors; 4. Hyperactive genetic mutations. Signup and view all the answers

How does decreased hormone secretion occur?

Decreased secretion can stem from: 1. Disorders of the target gland; 2. Insufficient stimulating hormones from the pituitary; 3. Defective hormones; 4. Unresponsive hormone receptors. Signup and view all the answers

Adrenal insufficiency can be caused by what ways?

<ol> <li>Primary adrenal insufficiency (Addison's disease); 2. Decreased ACTH stimulation from the pituitary; 3. Decreased CRH from the hypothalamus.</li> </ol> Signup and view all the answers

With Addison's disease, what hormones and lab values will be altered?

Insufficient cortisol and aldosterone, elevated ACTH levels, low sodium, increased potassium, and hypotension. Signup and view all the answers

What can cause Cushing syndrome?

<ol> <li>Iatrogenic from long-term steroid treatment; 2. Over-secretion by adrenal glands; 3. Tumors secreting ACTH.</li> </ol> Signup and view all the answers

What are the signs and symptoms of Cushing syndrome?

Signs include buffalo hump, abdominal obesity, round face, muscle weakness, easy bruising, and more. Signup and view all the answers

What lab values will be altered in primary and secondary hyperthyroidism?

In primary hyperthyroidism, TSH will be low; in secondary, TSH will be high; T4 and T3 will be elevated in both cases. Signup and view all the answers

What are signs and symptoms of hypothyroidism?

Signs include weight gain, fatigue, weakness, bradycardia, cold intolerance, and possible goiter. Signup and view all the answers

What are the roles of insulin and glucagon?

Insulin moves glucose into cells to reduce blood sugar levels; glucagon releases glucose into the blood when levels are low. Signup and view all the answers

Define glycogenesis, glycolysis, gluconeogenesis, and glycogenolysis.

Glycogenesis: storage of glucose as glycogen; Glycolysis: breakdown of glucose for energy; Gluconeogenesis: formation of glucose; Glycogenolysis: breakdown of glycogen. Signup and view all the answers

What is insulin resistance?

Insulin resistance occurs when insulin does not effectively stimulate glucose uptake into cells. Signup and view all the answers

What is metabolic syndrome?

Metabolic syndrome is a condition characterized by elevated blood sugar, high cholesterol, hypertension, and obesity. Signup and view all the answers

What are polydipsia, polyphagia, and polyuria?

Polydipsia: increased thirst; Polyphagia: increased appetite; Polyuria: increased urination. Signup and view all the answers

What are the primary microvascular complications of diabetes?

Retinopathy, nephropathy, and neuropathy. Signup and view all the answers

What are the primary macrovascular complications of diabetes?

Peripheral vascular disease, coronary artery disease, heart attack, and stroke. Signup and view all the answers

Study Notes

Endocrine System Terminology

Endocrine: Hormones released into circulation to distant target organs (e.g., TSH, ADH).
Paracrine: Hormones act locally on nearby cells (e.g., estrogen, testosterone).
Autocrine: Hormones affect the cell that released them (e.g., insulin).

Hormone Structural Types

Amines and Amino Acids: Simple hormone structure derived from amino acids.
Peptides and Proteins: Chains of amino acids forming larger hormone molecules.
Steroids: Hormones derived from cholesterol.

Hypothalamus Functions

Bridges nervous and endocrine systems.
Controls functions of other endocrine glands via the pituitary gland.
Regulates homeostasis, body temperature, hunger, and pain.
Produces releasing hormones that stimulate pituitary hormone release.

Pituitary Gland Role

Known as the "master gland" due to its role in stimulating other endocrine glands to release hormones.

Negative Feedback Mechanism

Maintains homeostasis by monitoring and adjusting hormone levels.
Prevents over-secretion of hormones.
Example: ADH release decreases when blood becomes dilute, stopping further secretion.

Positive Feedback Mechanism

Enhances hormone release in response to stimuli.
Example: Oxytocin increases uterine contractions, leading to more oxytocin release.

Hormone Over-Secretion Causes

Pathological over-secretion by target glands.
Excessive stimulation from the pituitary or hypothalamus.
Hormones produced by neoplasms (tumors) in other sites.
Genetic mutations affecting hormone receptors.

Hormone Under-Secretion Causes

Disorders of the target gland, either congenital or acquired.
Insufficient stimulating hormone from the pituitary.
Inadequate releasing hormone from the hypothalamus.
Defective hormones or unresponsive target organ receptors.

Adrenal Insufficiency Causes

Primary adrenal insufficiency, such as Addison's disease due to adrenal dysfunction.
Secondary adrenal insufficiency, from decreased ACTH stimulation.
Tertiary adrenal insufficiency, from decreased CRH from the hypothalamus.

Addison's Disease Impact

Insufficient secretion of cortisol and aldosterone results in high ACTH levels.
Low aldosterone leads to low sodium and high potassium levels, causing hypotension.

Cushing Syndrome Causes

Latrogenic causes from long-term steroid treatment.
Over-secretion by adrenal glands due to adenomas or carcinomas.
ACTH-secreting pituitary tumors (Cushing's disease) or ectopic ACTH tumors.

Cushing Syndrome Symptoms

Physical features: buffalo hump, abdominal obesity, round face (moon facies).
Physiological symptoms: muscle weakness, easy bruising, thin skin, osteoporosis.
Other symptoms include hirsutism, immunosuppression, and psychological changes.

Hyperthyroidism Lab Values

Primary Hyperthyroidism: Low TSH (thyroid overactivity).
Secondary Hyperthyroidism: High TSH (pituitary overactivity).
Elevated T4 and T3 in both types.

Hypothyroidism Symptoms

Symptoms include weight gain, fatigue, weakness, bradycardia, and cold intolerance.
Constipation, joint pain, anemia, and possible goiter may occur.

Insulin and Glucagon Functions

Insulin: Facilitates glucose uptake into cells to lower blood sugar levels.
Glucagon: Stimulates glucose release into the bloodstream when levels drop.

Metabolic Processes

Glycogenesis: Insulin-promoted storage of glucose as glycogen.
Glycolysis: Breakdown of glucose for energy.
Gluconeogenesis: Formation of glucose from non-carbohydrate sources.
Glycogenolysis: Breakdown of glycogen to release glucose.

Insulin Resistance

Condition where insulin fails to stimulate adequate glucose uptake.
Often associated with obesity and reduced insulin receptor numbers.

Metabolic Syndrome Overview

A collection of conditions increasing risks for heart disease, stroke, and type 2 diabetes.
Key features: elevated blood sugar, high cholesterol, hypertension, obesity.

Diabetes Symptoms

Polydipsia: Increased thirst.
Polyphagia: Increased appetite.
Polyuria: Increased urination.

Diabetes Complications

Microvascular: Retinopathy, nephropathy, neuropathy.
Macrovascular: Peripheral vascular disease, coronary artery disease, heart attacks, and strokes.

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Description

Test your knowledge on the different types of hormonal actions and their definitions in this Module 9 quiz. Understand the distinctions between endocrine, paracrine, and autocrine signaling as well as the structural types of hormones. Great for students studying human biology or endocrinology.