19 Questions
What are some severe eye problems that can occur due to thyroid issues?
paralysis of extraocular muscles, involvement of optic nerve leading to vision loss, corneal ulcerations
What is a symptom of thyroid storm?
Very high fever
_________ is an enlarged thyroid gland.
Goiter
Goiter always indicates abnormal thyroid function.
False
Match the type of diabetes with its description:
Type I diabetes = Pancreatic atrophy & specific loss of beta cells Type II diabetes = Insulin resistance as a hallmark of the disorder
How are hormones classified according to structure?
Amines and amino acids, peptides and glycoproteins, steroids, fatty acid derivatives
Hormones operate within a feedback system.
True
What happens when blood glucose levels start to decrease?
insulin secretion is inhibited & glucagon stimulates release of glucose from liver
Hormones are released into the circulation by __________ glands.
endocrine
Match the following anterior pituitary hormones with their regulating hypothalamic releasing hormone:
Growth Hormone (GH) = Growth-releasing hormone Thyrotropin (TSH) = Thyrotropin-releasing hormone (TRH) ACTH = Corticotrophin-releasing hormone (CRH)
How are hormones classified based on their structure?
Steroids
What is the main role of vasopressin (antidiuretic hormone) in the body?
Helping control plasma osmolality & making the collecting tubules of the kidney more permeable to water
Thyroid hormones affect only the cardiovascular system, respiratory system, skeletal system, and central nervous system.
False
In hyperthyroidism, the individual may present with nervousness, irritability, weight loss, tachycardia, and ______ intolerance.
heat
What is a common cause of goiter in developing nations?
Iodine deficiency
What is the extreme and life-threatening form of thyrotoxicosis?
Thyroid storm
Which cells in the endocrine pancreas produce insulin?
Beta cells
Type 2 diabetes is more common than Type 1 diabetes.
True
Type 1 diabetes is accompanied by autoantibodies against pancreatic beta cells and their steady destruction occurs well in advance of diagnosis. 80-90% of function of the insulin secreting beta cells must be lost before you start seeing ____________.
hyperglycemia
Study Notes
Hormones
- Hormones are chemical messengers that exert their action on specific targets
- Classified into four types based on structure:
- Amines and amino acids (epinephrine, norepinephrine, thyroid hormones, dopamine)
- Peptides and glycoproteins (growth hormone, thyrotropin, insulin)
- Steroids (sex hormones, estrogens, testosterones)
- Fatty acid derivatives (arachidonic acid, leukotrienes, prostaglandins)
- General characteristics:
- Specific rates and rhythms of secretion
- Affect only cells with appropriate receptors
- Liver metabolizes hormones, inactivating them and making them water-soluble for excretion by the kidneys
- Operate within a feedback system
Negative Feedback System
- Most hormonal control in the body operates through negative feedback
- Similar to a thermostat on a heating system
- When monitored value decreases below set point, feedback mechanism causes value to increase
- Example: blood glucose levels
- Increase in glucose stimulates increase in insulin, enhancing glucose removal from blood and decreasing glucose levels
- Decrease in glucose levels inhibits insulin secretion and stimulates glucagon, releasing glucose from the liver and increasing glucose levels
Hormone Release and Action
- Hormones are released into circulation by endocrine glands
- Water-soluble hormones (insulin, pituitary, and hypothalamic hormones) circulate freely and have a short half-life
- Lipid-soluble hormones (cortisol, thyroid hormones, androgens) circulate bound to proteins and have a longer half-life
- Hormones bind to specific receptors on target cells, which are affected by the hormone
Hypothalamic-Pituitary Axis
- Hypothalamus integrates autonomic nervous system and endocrine gland activity
- Pituitary gland responds to input from the brain (via hypothalamus) and body (via peripheral endocrine glands)
- Hypothalamic-pituitary axis (neuroendocrine axis) regulates hormone secretion
- Hypothalamus secretes releasing hormones that stimulate or inhibit pituitary hormone secretion
Posterior Pituitary Hormones
- Two major posterior pituitary hormones:
- Vasopressin (antidiuretic hormone) helps regulate plasma osmolality
- Oxytocin stimulates uterine contractions and lactation
Anterior Pituitary Hormones
- Each anterior pituitary hormone has a corresponding hypothalamic releasing hormone
- Examples:
- Growth hormone (GH) regulates growth and cell reproduction
- Thyrotropin (TSH) stimulates thyroid hormone synthesis and secretion
- Adrenocorticotropic hormone (ACTH) stimulates adrenal cortex hormone secretion
Alterations of Hormonal Regulation
- Dysfunctional hormone regulation can lead to hypofunction or hyperfunction
- Causes of dysfunction:
- Feedback loop problems
- Decreased production or conversion of hormones
- Inactivation by antibodies before reaching target cells
- Excessive production from non-endocrine tissues
Thyroid Gland and Hormones
- Thyroid gland synthesizes and secretes thyroid hormones (T4 and T3)
- T4 is converted to T3 in body tissues, which has the greatest metabolic effects
- Thyroid hormones regulate growth, maturation, and metabolism
- Thyroid dysfunction is one of the most common endocrine disorders
Thyroid Dysfunction
- Hyperthyroidism: excess thyroid hormone production
- Causes: Graves' disease, thyroid nodules, thyroiditis
- Symptoms: nervousness, irritability, weight loss, tachycardia, heat intolerance
- Treatment: reducing thyroid hormone production or blocking effects on the sympathetic nervous system
- Hypothyroidism: deficient thyroid hormone production
- Causes: Hashimoto's thyroiditis, radiation therapy, surgical removal of thyroid gland
- Symptoms: fatigue, constipation, weight gain, cold intolerance, dry skin
- Treatment: thyroid hormone replacement therapy
Diabetes Mellitus
- Chronic hyperglycemia and disturbances of carbohydrate, fat, and protein metabolism
- Types:
- Type I: autoimmune destruction of beta cells, accounts for 10% of diabetes cases
- Type II: insulin resistance and impaired insulin secretion### Type 1 Diabetes
- Occurs secondary to other diseases such as pancreatitis or a more fulminant disease
- Genetic susceptibility plays a role, but the exact nature of it is not clearly known
- Individuals with a genetic tendency to develop the disease experience an environmental trigger that initiates the autoimmune process
- Environmental factors that contribute to the development of type 1 diabetes include viral infections (CMV, mumps, Epstein-Barr) and cow milk intake in some individuals
- It is a slowly progressive T cell-mediated disease with immune-mediated destruction of beta cells
- Autoantibodies against pancreatic beta cells are present in most individuals at the time of diagnosis
- 80-90% of function of the insulin-secreting beta cells must be lost before hyperglycemia occurs
- Clinical manifestations include glycosuria, polydipsia, polyuria, muscle wasting, and weight loss
- In the absence of insulin, protein and fat metabolism occur, resulting in muscle wasting and weight loss
- Ketoacidosis can occur due to the release of fatty acids from triglyceride stores in adipose tissue
Type 2 Diabetes
- Much more common than type 1 diabetes, and is the most common form of diabetes in the United States
- Insulin resistance is the hallmark of the disorder, characterized by decreased binding of insulin to receptors, decreased number of receptors, and decreased sensitivity of receptors to insulin
- Patients have varying amounts of residual insulin secretion that prevents severe hyperglycemia or ketoacidosis
- Onset occurs at least 7 years before its diagnosis, and 50% of cases in the US are undiagnosed
- Pediatric consideration: type 2 diabetes is becoming more prevalent in children, likely related to the increasing prevalence of obesity in childhood
Metabolic Syndrome
- A term that signifies a collection of certain signs and symptoms that increase the risk of developing type 2 diabetes and/or heart disease
- Individuals with metabolic syndrome have an increased risk of developing these conditions unless they make lifestyle management changes
- The signs and symptoms that lead to the diagnosis of metabolic syndrome include abdominal obesity, triglyceride level greater than 150 mg/dL, and low HDL levels
Hormones
- Hormones are chemical messengers that exert their action on specific targets
- Classified into four types based on structure:
- Amines and amino acids (epinephrine, norepinephrine, thyroid hormones, dopamine)
- Peptides and glycoproteins (growth hormone, thyrotropin, insulin)
- Steroids (sex hormones, estrogens, testosterones)
- Fatty acid derivatives (arachidonic acid, leukotrienes, prostaglandins)
- General characteristics:
- Specific rates and rhythms of secretion
- Affect only cells with appropriate receptors
- Liver metabolizes hormones, inactivating them and making them water-soluble for excretion by the kidneys
- Operate within a feedback system
Negative Feedback System
- Most hormonal control in the body operates through negative feedback
- Similar to a thermostat on a heating system
- When monitored value decreases below set point, feedback mechanism causes value to increase
- Example: blood glucose levels
- Increase in glucose stimulates increase in insulin, enhancing glucose removal from blood and decreasing glucose levels
- Decrease in glucose levels inhibits insulin secretion and stimulates glucagon, releasing glucose from the liver and increasing glucose levels
Hormone Release and Action
- Hormones are released into circulation by endocrine glands
- Water-soluble hormones (insulin, pituitary, and hypothalamic hormones) circulate freely and have a short half-life
- Lipid-soluble hormones (cortisol, thyroid hormones, androgens) circulate bound to proteins and have a longer half-life
- Hormones bind to specific receptors on target cells, which are affected by the hormone
Hypothalamic-Pituitary Axis
- Hypothalamus integrates autonomic nervous system and endocrine gland activity
- Pituitary gland responds to input from the brain (via hypothalamus) and body (via peripheral endocrine glands)
- Hypothalamic-pituitary axis (neuroendocrine axis) regulates hormone secretion
- Hypothalamus secretes releasing hormones that stimulate or inhibit pituitary hormone secretion
Posterior Pituitary Hormones
- Two major posterior pituitary hormones:
- Vasopressin (antidiuretic hormone) helps regulate plasma osmolality
- Oxytocin stimulates uterine contractions and lactation
Anterior Pituitary Hormones
- Each anterior pituitary hormone has a corresponding hypothalamic releasing hormone
- Examples:
- Growth hormone (GH) regulates growth and cell reproduction
- Thyrotropin (TSH) stimulates thyroid hormone synthesis and secretion
- Adrenocorticotropic hormone (ACTH) stimulates adrenal cortex hormone secretion
Alterations of Hormonal Regulation
- Dysfunctional hormone regulation can lead to hypofunction or hyperfunction
- Causes of dysfunction:
- Feedback loop problems
- Decreased production or conversion of hormones
- Inactivation by antibodies before reaching target cells
- Excessive production from non-endocrine tissues
Thyroid Gland and Hormones
- Thyroid gland synthesizes and secretes thyroid hormones (T4 and T3)
- T4 is converted to T3 in body tissues, which has the greatest metabolic effects
- Thyroid hormones regulate growth, maturation, and metabolism
- Thyroid dysfunction is one of the most common endocrine disorders
Thyroid Dysfunction
- Hyperthyroidism: excess thyroid hormone production
- Causes: Graves' disease, thyroid nodules, thyroiditis
- Symptoms: nervousness, irritability, weight loss, tachycardia, heat intolerance
- Treatment: reducing thyroid hormone production or blocking effects on the sympathetic nervous system
- Hypothyroidism: deficient thyroid hormone production
- Causes: Hashimoto's thyroiditis, radiation therapy, surgical removal of thyroid gland
- Symptoms: fatigue, constipation, weight gain, cold intolerance, dry skin
- Treatment: thyroid hormone replacement therapy
Diabetes Mellitus
- Chronic hyperglycemia and disturbances of carbohydrate, fat, and protein metabolism
- Types:
- Type I: autoimmune destruction of beta cells, accounts for 10% of diabetes cases
- Type II: insulin resistance and impaired insulin secretion### Type 1 Diabetes
- Occurs secondary to other diseases such as pancreatitis or a more fulminant disease
- Genetic susceptibility plays a role, but the exact nature of it is not clearly known
- Individuals with a genetic tendency to develop the disease experience an environmental trigger that initiates the autoimmune process
- Environmental factors that contribute to the development of type 1 diabetes include viral infections (CMV, mumps, Epstein-Barr) and cow milk intake in some individuals
- It is a slowly progressive T cell-mediated disease with immune-mediated destruction of beta cells
- Autoantibodies against pancreatic beta cells are present in most individuals at the time of diagnosis
- 80-90% of function of the insulin-secreting beta cells must be lost before hyperglycemia occurs
- Clinical manifestations include glycosuria, polydipsia, polyuria, muscle wasting, and weight loss
- In the absence of insulin, protein and fat metabolism occur, resulting in muscle wasting and weight loss
- Ketoacidosis can occur due to the release of fatty acids from triglyceride stores in adipose tissue
Type 2 Diabetes
- Much more common than type 1 diabetes, and is the most common form of diabetes in the United States
- Insulin resistance is the hallmark of the disorder, characterized by decreased binding of insulin to receptors, decreased number of receptors, and decreased sensitivity of receptors to insulin
- Patients have varying amounts of residual insulin secretion that prevents severe hyperglycemia or ketoacidosis
- Onset occurs at least 7 years before its diagnosis, and 50% of cases in the US are undiagnosed
- Pediatric consideration: type 2 diabetes is becoming more prevalent in children, likely related to the increasing prevalence of obesity in childhood
Metabolic Syndrome
- A term that signifies a collection of certain signs and symptoms that increase the risk of developing type 2 diabetes and/or heart disease
- Individuals with metabolic syndrome have an increased risk of developing these conditions unless they make lifestyle management changes
- The signs and symptoms that lead to the diagnosis of metabolic syndrome include abdominal obesity, triglyceride level greater than 150 mg/dL, and low HDL levels
Learn about the classification of hormones based on their structure, including amines and amino acids, peptides, glycoproteins, and steroids. Understand the different types of hormones and their functions.
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