Endocrine System

What dual roles does the pancreas serve?

It functions as both an exocrine (digestive enzyme secretion) and endocrine (hormone secretion like glucose) organ.

What does bile do?

Emulsifies fat

What hormones does the pancreas dump into the stomach for digestion?

Amylase, lipase, protease

Describe the normal physiology of the pancreas

Insulin lowers blood glucose.

Glucagon raises blood glucose.

What happens if protease (protein breakdown) enzymes activate inside the pancreas?

The pancreas self-digests, a major cause of acute pancreatitis. Usually, proteases should not be activated until they reach the duodenum.

How can pancreatic disease affect the common bile duct?

Disease in the pancreatic head may obstruct the common bile duct.

Why can pancreatic malignancies grow for years without symptoms?

The pancreas is anatomically isolated, allowing tumors to grow silently.

Describe acinar cell injury

Acinar cell injury is the damage to pancreatic acinar cells, which are the primary cells of the exocrine pancreas.

What can obstruct the pancreatic ducts?

Callstones, thick mucus, tumors, or duct spasms.

If there are very high levels of lipase and protease in the blood, what does this indicate?

Pancreatitis.

Why must acute pancreatitis be diagnosed quickly?

To prevent acute hemorrhagic pancreatitis, which can cause shock, renal failure, ARDS, and sepsis.

What systemic complications may occur?

Hypocalcemia (low calcium levels), jaundice (pancreatitis blocking bile duct), and diabetes (low insulin).

What are the major causes of acute pancreatitis?

Gallstones and alcoholism.

Is acute pancreatitis reversible?

Yes, but repeated attacks can lead to chronic pancreatitis.

What are common symptoms of chronic pancreatitis?

Recurrent upper abdominal pain radiating to the back, weight loss, and diabetes.

Major risk factor for chronic pancreatitis?

Alcoholism.

What is the mortality rate of chronic pancreatitis?

~50% after 5 years.

What genetic disorder may lead to chronic pancreatitis?

Cystic Fibrosis.

What type of cancer arises in the exocrine pancreas?

Adenocarcinoma of the pancreatic ducts.

Risk factors for pancreatic cancer?

Obesity and smoking.

Why is pancreatic cancer prognosis poor?

Cancer is insidious (unaware they have it); symptoms appear too late. This cancer is very deadly.

Typical first symptoms of pancreatic cancer?

Upper abdominal or back pain; jaundice from bile duct obstruction.

What are the major roles of endocrine hormones?

- Reproductive + CNS differentiation

- Childhood growth

- Reproductive coordination

- Homeostasis maintenance

- Corrective/adaptive responses to stress

What does the endocrine pancreas produce?

Insulin, essential for glucose metabolism and living.

What causes diabetes mellitus?

Lack of insulin production (type 1) or insulin resistance (type 2). Chronic hyperglycemia.

Diagnostic criteria for diabetes?

Fasting blood glucose >126 mg/dL

Random blood glucose >200 mg/dL

What is a normal A1C?

4-5% is normal. Over 6.5% means that 65% of your RBC have sugar stuck to them.

Is type one or type two diabetes more prevalent?

Type 2; this is an epidemic following the path of obesity in the US.

What causes Type 1 diabetes?

Autoimmune destruction of β-cells.

What is diabetic ketoacidosis?

A life-threatening metabolic state: rapid breathing, confusion, coma. Responsible for the inevitable death that occurred before insulin therapy was developed.

Symptoms of Type 1 diabetes?

Frequent urination, thirst, increased appetite are signs that your body is perceiving this as very low energy levels.

How long can insulin resistance exist before diabetes?

Can delay the development of diabetes by >10 years

How does the body compensate initially for Type 2 diabetes?

Hyperinsulinemia for years releases more insulin than the body needs, but eventually the insulin levels will be insufficient for the body's needs. Eventually diabetes will develop when β-cells can no longer keep up with insulin demand.

What are impaired fasting glucose levels seen in prediabetics?

>100 mg/dL

Major causes of insulin resistance (T2D)?

Visceral obesity and inactivity.

What is gestational diabetes?

Abnormal blood glucose maintenance during pregnancy

Conditions/drugs that can cause diabetes?

Corticosteroids (alter glucose metabolisim), growth hormone, Cushing's disease (too much cortisol.

Is Type 2 diabetes reversible?

Yes, with lifestyle changes.

What are the short-term complications of diabetes?

Ketoacidosis

What are some of the long-term complications of diabetes?

Glycosylation and hyperglycemia

What is glycosylation?

Glucose or sugar binds to cells

How do you minimize diabetic complications?

Minimize hyperglycemia.

What cells do pancreatic endocrine neoplasms originate from?

Islet cells (e.g., insulinomas).

Describe pancreatic endocrine neoplasms.

These tumors are much rarer and deadly than exocrine adenocarcinomas. They are typically benign, but they can secrete excessive amounts of insulin and cause hypoglycemia.

How is endocrine homeostasis maintained?

Negative feedback from target organ hormones.

What does the hypothalamus-pituitary-adrenal axis produce?

ACTH (Adrenocorticotropic hormone), corticosteroids (like cortisol), cortisol, and aldosterone.

What is the role of oxytocin?

Breast duct contraction and milk ejection. This can also produce uterine contractions.

What is the role of ADH?

Renal water retention.

What is the role of prolactin?

Breast milk formation.

What is the role of GH?

Bone and soft tissue growth

What is the role of ACTH?

Causes the adrenal cortex to produce corticosteroids, which will increase glucose metabolism, salt, and water metabolism.

Effects of cortisol?

Muscle breakdown → amino acids for glucose

Inhibits peripheral glucose use

Suppresses immunity and inflammation

What is the role of TSH?

Releases thyroid hormones for metabolism.

What is the role of FSH and LH?

Stimulating the testes and ovaries to produce sex hormones

Many endocrine clands are controlled by the ___________ and ___________ gland.

Hypothalamus and pituitary.

What can the overstimulation of target organs by the pituitary hormone lead to?

Enlargement of the target organs and overproduction of their hormones.

What accounts for most of the manifestations of endocrine disease?

Overproduction of endocrine hormones. This may be caused by hyperplasia or neoplasia of endocrine glands. Underproduction of hormones is usually caused by a disease of the target organ rather than failure of hormone stimulation.

How can pituitary tumors alter adjacent structures?

By pressing on them or overproducing hormones.

What is the "mass effect" of pituitary adenomas?

Compression of nearby structures (e.g., optic nerve).

What is the "stalk effect" of pituitary adenomas?

Blocking hypothalamic inhibition → ↑ prolactin (breast milk production).

Prolactinoma symptoms in females?

Milk production, amenorrhea (absence of a period), infertility, decreased sex drive.

Prolactinoma symptoms in males?

Impotence, low sex drive.

What is hyperpituitaryisim?

The pituitary is producing excessive hormones.

What is hypopituitarism?

Not enough pituitary activity. Consequences are not extreme, but people can experience fatigue, low sex drive, and impotence.

Excess GH as a child?

Giganintisim.

Excess GH as a adult?

Acromegaly.

What disorder does a ACTH adenoma cause?

Cushing syndrome due to cortisol overproduction by the adrenal cortex.

What is Sheehan syndrome?

Happens in women who give birth and have low blood from excessive bleeding or hemorrhage. This causes ishemia of the pituitary gland. Postpartum pituitary infarction.

Posterior pituitary disorders (rare)?

Diabetes insipidus (lack of ADH).

What characterizes Graves disease?

Hyperthyroidism (fast metabolism), goiter (enlarged thyroid gland), and exophthalmos (bug eyes from fat pushing them outwards). AI disease, Thyroid-stimulating immunoglobulin (TSI) ( mimics TSH).

Causes of hypothyroidism?

Thyroiditis (thyroid gland inflammation) or iodine deficiency. Can also be caused by myxedema (thick fluid accumulation in tissues (esp. skin). System slowing of metabolisim.

What is a nontoxic goiter?

Thyroid enlargement. Most are "nontoxic" goiters of Graves disease.

What is thyroiditis?

Inflamed thyroid gland with a nontoxic goiter. Mostly in women due to AI diseases.

Too little thyroid gland activity causes the metabolism to...

Slow down

Too much thyroid gland activity causes the metabolism to...

Speed up.

What percentage of thyroid tumors are benign?

99%, Adenomas with little consequence.

Major risk factor for thyroid carcinoma?

Ionizing radiation.

Prognosis of thyroid cancer?

Very good — 90% 5-year survival even with lymph node spread.

What hormone is elevated in hyperparathyroidism?

Parathormone (PTH). This causes the body to break down bone for calcium and can cause osteoporosis.

What lab finding is typical in hyperparathyroidism?

Hypercalcemia.

Causes of primary and secondary hyperparathyroidism?

Primary: due to hyperplasia or adenomas.

Secondary: due to renal failure, which cannot excrete too much calcium, so the calcium gets too low.

What causes Cushing syndrome?

Excessive cortisol production which is a stress hormone. Too much cortisol can cause T2D and tissue breakdown to get energy. This suppresses the immune system.

What does aldosterone do?

Promotes sodium and water retention, and potassium excretion.

Effects of hyperaldosteronism?

Volume expansion, hypertension, hypokalemia (low potassium).

Primary vs secondary hyperaldosteronism?

Primary: adrenal adenoma

Secondary: renal hypoperfusion → ↑ renin

What is Congenital Adrenal Hyperplasia (CAH)?

A condition caused by lack of cortisol feedback, leading the pituitary to overproduce ACTH.

What does excess ACTH cause in CAH?

Overproduction of adrenal androgens → Adrenogenital Syndrome.

Adrenogenital Syndrome

Leads to a build-up of androgenic hormones in the detus and a deficiency of cortisol and aldosterone. Masculinization in women, men unaffected.

How does CAH affect females?

Causes ambiguous genitalia due to excess androgen exposure in utero.

What are consequences of aldosterone deficiency in CAH?

• Low plasma sodium

• Hyperkalemia• Dehydration

• Low blood pressure

• Can be fatal if undiagnosed

Why is aldosterone deficiency dangerous?

It disrupts fluid and electrolyte balance, risking cardiovascular collapse.

Why is cortisol essential for life?

It supports metabolism, vascular stability, and stress responses.

What causes acute adrenocortical insufficiency?

• Sudden withdrawal of corticosteroids

• Hemorrhagic infarction of adrenal glands

• Sudden worsening of chronic adrenal insufficiency

What is Addison's Disease?

Chronic, progressive adrenal cortex destruction causing cortisol and often aldosterone deficiency.

What is an adrenal crisis?

A life-threatening acute cortisol deficiency causing hypotension, shock, and possible death.

Is adrenal medulla underactivity clinically significant?

No—typically of little consequence.

What is a pheochromocytoma?

Overactive adrenal medulla causing severe HTN.

What is Multiple Endocrine Neoplasia (MEN) syndrome?

Multiple endocrine tumors, including adrenal medulla involvement.

What is a neuroblastoma?

A malignant or sometimes spontaneously regressing tumor of adrenal medulla in young children.