Patho: EXAM 1 & 2 (Endocrine) Study Guide

Patho exam 1

What hormones does the thyroid produce, and what do they do?

The thyroid produces T3 (triiodothyronine) and T4 (thyroxine). They regulate metabolism, promote growth, and support brain/nervous system development.

How is thyroid hormone secretion controlled?

The hypothalamus releases TRH → this stimulates the pituitary to release TSH → which stimulates the thyroid to release T3/T4.

What is negative feedback in the thyroid system?

When T3/T4 levels are high, they tell the hypothalamus and pituitary to stop releasing TRH and TSH. This prevents the thyroid from overproducing hormones.

What causes Graves’ disease?

It’s an autoimmune disorder where antibodies stimulate the TSH receptor, making the thyroid release too much T3/T4.

Why does hyperthyroidism increase metabolism and sympathetic activity?

Extra T3/T4 speeds up how fast cells use energy and also makes tissues more sensitive to adrenaline, which increases heart rate, tremors, and heat production.

What are the common signs and symptoms of hyperthyroidism (Graves’)?

🧠 Quick mini-mnemonic:

“Hot, Skinny, and Fast”
→ Hot (heat intolerance)
→ Skinny (weight loss)
→ Fast (HR, metabolism, tremors)

Weight loss, heat intolerance, tachycardia, tremors, and exophthalmos (bulging eyes from immune swelling behind the eyes).

What is thyrotoxic crisis aka thyroid storm, and what triggers it? s/s?

A life-threatening complication of hyperthyroidism, often triggered by stress, surgery, or infection. s/s: hyperthermia, tachycardia, heart failure, delirum/agitation

Why is thyroid storm dangerous?

Because a sudden surge of thyroid hormone causes hypermetabolic crisis: hyperthermia (very high fever), severe tachycardia, arrhythmias, delirium, nausea/vomiting/diarrhea → can lead to death if untreated.

What are the main causes of hypothyroidism?

Iodine deficiency, Hashimoto’s thyroiditis (autoimmune destruction of the thyroid), thyroidectomy (surgery), or pituitary failure (low TSH).

What happens to metabolism in hypothyroidism?

It slows down because of low thyroid hormone.

What are the common signs and symptoms of hypothyroidism?

Fatigue, cold intolerance, weight gain, bradycardia (slow HR), constipation, dry skin, and myxedema (puffy face and edema).

What is Cushing’s syndrome?

Cushing’s syndrome happens when the body has too much cortisol for a long time. Cortisol is a stress hormone made by the adrenal cortex (outer layer of the adrenal gland).

What does cortisol normally do in the body?

Cortisol helps the body handle stress, increase blood sugar, regulate metabolism, and reduce inflammation so the body can respond to “fight or flight” situations.

What happens when cortisol levels stay high for too long?

Chronically high cortisol causes tissue breakdown, muscle wasting, bone loss, poor wound healing, immune suppression, and fat redistribution (moon face, buffalo hump, truncal/central obesity). It also raises blood sugar, leading to hyperglycemia and diabetes risk.

What are the 3 main causes of Cushing’s syndrome?

1️⃣ Adrenal cause (primary): Adrenal gland tumor or hyperplasia makes too much cortisol. 2️⃣ Pituitary cause (secondary / Cushing’s disease): Pituitary releases too much ACTH, overstimulating the adrenals. 3️⃣ Iatrogenic cause (most common): Long-term steroid medication use (like prednisone or dexamethasone) mimics cortisol → body stops making its own → adrenal gland shrinks.

Why is it dangerous to suddenly stop taking steroid medications?

Long-term steroid use suppresses the HPA axis (hypothalamus-pituitary-adrenal). If stopped abruptly, the adrenal gland can’t produce cortisol, causing acute adrenal insufficiency (adrenal crisis). Always taper steroids slowly so the adrenal gland “wakes up.”

What happens inside the body during Cushing’s syndrome?

Too much cortisol triggers a domino effect of metabolic and tissue changes throughout the body.

How does cortisol affect glucose metabolism in Cushing’s syndrome?

Cortisol increases gluconeogenesis in the liver, causing high blood sugar and sometimes steroid-induced diabetes.

How does cortisol affect protein metabolism in Cushing’s syndrome?

Cortisol breaks down protein to use for energy, leading to muscle wasting, thin arms and legs, and slow wound healing.

How does cortisol affect fat distribution in Cushing’s syndrome?

Fat redistributes unevenly — moving to the face, upper back, and abdomen — causing “moon face,” “buffalo hump,” and truncal obesity.

How does cortisol affect the skin and connective tissue?

Cortisol reduces collagen production, causing thin, fragile skin, purple stretch marks (striae), and easy bruising.

How does cortisol affect bones and calcium balance?

Cortisol increases bone breakdown and decreases calcium absorption, leading to osteoporosis and higher fracture risk.

How does cortisol affect the immune system?

Cortisol suppresses immune responses, making the body more prone to infections and slowing down healing.

How does cortisol affect mood and brain chemistry?

Cortisol crosses the blood-brain barrier and alters neurotransmitters, causing irritability, anxiety, depression, or even psychosis.

Why does Cushing’s syndrome increase androgen (sex hormone) levels?

High ACTH stimulates all adrenal cortex zones, leading to increased androgens like DHEA and testosterone → hirsutism, acne, and irregular periods in women.

can cushing’s disease cause hypo or hypertension

can cause hypertension because (Even though cortisol’s main job is as a glucocorticoid, it can also bind to mineralocorticoid receptors (the ones aldosterone normally binds to).) and retain sodium and water retension

What are the Islets of Langerhans?

The islets of Langerhans are tiny clusters of hormone-producing cells inside the pancreas that act like a blood sugar thermostat, constantly checking if glucose is too high or too low.

What are the three main cell types in the Islets of Langerhans and their functions?

Alpha cells → release glucagon (raises blood sugar); Beta cells → release insulin (lowers blood sugar); Delta cells → release somatostatin (slows digestion and balances insulin/glucagon).

What hormone do alpha cells release and what is its function?

Alpha cells release glucagon, which raises blood sugar by stimulating the liver to break down glycogen and make new glucose.

What hormone do beta cells release and what is its function?

Beta cells release insulin, which lowers blood sugar by moving glucose into cells and storing extra glucose as glycogen.

What hormone do delta cells release and what is its function?

Delta cells release somatostatin, which slows digestion and helps balance the effects of insulin and glucagon.

What triggers insulin release?

High blood glucose levels, such as after eating.

What does insulin do in the body?

Insulin acts like a key that unlocks cells so glucose can enter for energy; it stores extra glucose as glycogen, prevents fat breakdown, and promotes protein synthesis.

What is the overall goal of insulin?

To lower blood glucose and maintain a normal range of about 70–110 mg/dL.

In simple terms, what does insulin do?

“Let’s use or store the sugar we already have.”

What triggers glucagon release?

Low blood glucose levels, such as during fasting or sleeping.

What does glucagon do in the body?

Glucagon signals the liver to break down glycogen into glucose (glycogenolysis) and make new glucose from fats and proteins (gluconeogenesis).

What is the overall goal of glucagon?

To raise blood glucose and prevent hypoglycemia.

In simple terms, what does glucagon do?

“We’re out of sugar! Let’s make more!”

How do insulin and glucagon work together?

They act as balancing hormones—insulin lowers blood sugar after eating, while glucagon raises it during fasting to keep glucose stable.

What happens in the body after eating (fed state)?

Blood glucose rises, the pancreas releases insulin, glucose moves into cells, fat storage increases, and blood glucose returns to normal.

What happens in the body during fasting (hungry state)?

Blood glucose drops, the pancreas releases glucagon, glucose is released from the liver, fat is broken down for energy, and blood glucose returns to normal.

What is homeostasis in relation to insulin and glucagon?

The push–pull relationship between insulin and glucagon that keeps blood sugar stable 24/7.

What happens when insulin is missing or ineffective?

Glucose cannot enter cells, leading to high blood sugar (hyperglycemia) while cells starve for energy—as seen in diabetes mellitus.

In simple terms, what is the main job of insulin?

“INsulin puts sugar IN cells.”

In simple terms, what is the main job of glucagon?

“GlucaGON gets the glucose GONE from the liver into blood.”

What is diabetes mellitus?

A chronic metabolic disorder where there is not enough insulin or the body does not respond to it, causing high blood sugar (hyperglycemia) and energy-starved cells.

What happens to glucose in diabetes mellitus?

Glucose builds up in the blood because it cannot enter the cells for energy.

What causes Type 1 Diabetes Mellitus?

Autoimmune destruction of pancreatic beta cells → no insulin production.

Who typically develops Type 1 Diabetes?

Usually children or young adults, but it can occur at any age.

What is the main pathophysiology of Type 1 Diabetes?

Without insulin, glucose cannot enter cells → body breaks down fat and protein → ketone buildup → risk for diabetic ketoacidosis (DKA).

What are classic signs and symptoms of Type 1 Diabetes?

3 P’s (polyuria, polydipsia, polyphagia), weight loss, fatigue, fruity breath, and Kussmaul respirations.

What is the treatment for Type 1 Diabetes?

Lifelong insulin therapy, blood-sugar monitoring, meal planning, and exercise.

What causes Type 2 Diabetes Mellitus?

Insulin resistance—cells don’t respond properly to insulin; pancreas may later produce less insulin.

Who typically develops Type 2 Diabetes?

Adults, but now common in teens with obesity and sedentary lifestyles.

What is the main pathophysiology of Type 2 Diabetes?

Insulin is present but ineffective → glucose stays in blood → pancreas overworks → beta-cell fatigue and decreased insulin output.

What are common signs and symptoms of Type 2 Diabetes?

Fatigue, blurred vision, recurrent infections, slow wound healing, mild 3 P’s, and dark skin folds (acanthosis nigricans).

What is the treatment for Type 2 Diabetes?

Lifestyle changes (diet, exercise, weight loss), oral hypoglycemics, and insulin if needed.

How does the onset differ between Type 1 and Type 2 Diabetes?

Type 1 = sudden onset; Type 2 = gradual onset.

How does insulin production differ between Type 1 and Type 2 Diabetes?

Type 1 = no insulin; Type 2 = decreased or resistant insulin response.

What is the main metabolic problem in Type 1 Diabetes?

No insulin production at all.

What is the main metabolic problem in Type 2 Diabetes?

Cells don’t respond to insulin (producing insulin resistance).

What body type is typical for Type 1 vs Type 2 Diabetes?

Type 1 = thin or underweight; Type 2 = overweight or obese.

Which acute complication is linked with Type 1 Diabetes?

Diabetic Ketoacidosis (DKA).

Which acute complication is linked with Type 2 Diabetes?

Hyperosmolar Hyperglycemic Non-Ketotic Syndrome (HHNKS / HHS).

What is a simple way to remember Type 1 vs Type 2?

Type 1 = “no insulin = no key.” Type 2 = “insulin there, but lock is rusty.”

What are long-term complications of uncontrolled diabetes?

Nerve damage (neuropathy), eye disease (retinopathy), kidney failure (nephropathy), poor wound healing, and heart disease.