Ace the Endocrine System

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ENDOCRINE SYSTEM — SUPER SIMPLE EXPLANATION

⭐ 1.

Parathyroid Glands

Think of four tiny bosses sitting on the back of your thyroid.

Their job: keep calcium levels in your blood just right.

They release a hormone called PTH which:

  • Takes calcium out of bones to raise blood levels

  • Tells kidneys to keep more calcium

  • Helps intestines absorb more calcium

If a doctor removes your thyroid and accidentally takes these too → calcium drops → tingling, cramps, spasms.

⭐ 2. Endocrine vs Exocrine

Endocrine = no ducts

Hormones go straight into blood like “messages floating in a river.”

Exocrine = has ducts

Stuff goes through a tube to the outside or into a space.

Example:

  • Sweat gland → duct → sweat to skin

  • Thyroid → no duct → hormones into blood

⭐ 3. Pancreas: Alpha, Beta, Delta

Imagine the pancreas as a kitchen with 3 chefs:

  • Alpha Chef makes Glucagon → raises blood sugar

  • Beta Chef makes Insulin → lowers blood sugar

  • Delta Chef makes Somatostatin → “Hey quiet down!” → slows both insulin & glucagon

⭐ 4. Adrenal Cortex (GFR = Good Food Rules)

Three layers, from outside to inside:

  1. Glomerulosa → makes Aldosterone

    • Controls salt & water → raises BP

  3. Fasciculata → makes Cortisol

    • Controls sugar, stress

  5. Reticularis → makes sex hormones

    • Body hair, sex drive

Salt → Sugar → Sex.

⭐ 5. Non-steroid hormones

These hormones can’t go inside the cell, so they knock on the door and send a message.

Example: insulin, ADH

  • Work fast

  • Don’t last long

⭐ 6. Steroid hormones

These hormones walk straight into the cell because they’re made of fat (lipid).

They go to the nucleus and can change DNA instructions.

  • Slow to start

  • Long lasting

  • Example: cortisol, estrogen, testosterone

⭐ 7. Posterior Pituitary (storage unit)

It does NOT make hormones.

It only stores and releases:

  • ADH → keeps water in the body

  • Oxytocin → labor contractions + milk “let down”

⭐ 8. Hypothyroidism (thyroid too slow)

Body is in “slow mode.”

  • Weight gain

  • Cold

  • Tired

  • Constipated

  • Slow HR

⭐ 9. Hyperthyroidism (thyroid too fast)

Body is in “fast mode.”

  • Weight loss

  • Hot

  • Fast HR

  • Diarrhea

  • Anxiety

⭐ 10. Cushing’s Syndrome (too much cortisol)

Picture someone on strong steroids:

  • Moon face

  • Buffalo hump

  • Big belly, skinny arms

  • Purple stretch marks

  • High sugar

  • Easy infections

⭐ 11. Graves’ Disease

Autoimmune → body makes fake TSH signals telling thyroid to work too much.

  • Bulging eyes

  • Goiter

  • Hyperthyroid symptoms

⭐ 12. Goiter

Just means big thyroid, no matter the cause.

⭐ 13. Cortisol Effects (Glucocorticoids)

  • Raises sugar

  • Weakens immune system

  • Raises BP

  • Long-term → thin skin, osteoporosis

⭐ 14. T3 vs T4

  • T3 has 3 iodine atoms

  • T4 has 4

  • Both increase metabolism

  • T4 turns into T3 in the body

⭐ 15. Thyroid Gland Main Jobs

  • Controls metabolism

  • Helps growth

  • Controls body temp

⭐ 16. Adrenal Medulla

Inner part → “fight or flight.”

Makes:

  • Epinephrine

  • Norepinephrine

Raises HR, BP, blood sugar → gives energy to run or fight.

⭐ 17. Diabetes Type 1 vs Type 2

Type 1

  • No insulin

  • Must take insulin

  • Younger people

Type 2

  • Body doesn’t use insulin right

  • Older/overweight

  • Can use pills or insulin

⭐ 18. Hyper vs Hypocalcemia

High calcium → slow muscles

Low calcium → twitchy muscles

Low Ca = tingling, cramps, spasms.

⭐ 19. Pineal Gland

Makes melatonin → helps you sleep.

⭐ 20. Parathyroid & Thyroidectomy

If parathyroids get removed by accident → low calcium → cramps, tingling.

⭐ 21. Pituitary (Master Gland)

Anterior makes “FLAT PG”:

  • FSH

  • LH

  • ACTH

  • TSH

  • Prolactin

  • Growth Hormone

Posterior stores ADH + Oxytocin

⭐ 22. Thymus

Helps grow T-cells (immune system).

Big in kids, smaller in adults.

⭐ 23. GH Problems

Too much =

  • kids → gigantism

  • adults → acromegaly (big hands/feet/jaw)

Too little = dwarfism

⭐ 24. ADH

Holds water.

Too little → pee a lot (Diabetes Insipidus)

Too much → hold too much water (SIADH)

⭐ 25. Pancreas & Liver

Pancreas = hormones that control sugar

Liver = stores sugar as glycogen, releases sugar when needed

⭐ 26. TSH

Tells thyroid to release T3/T4.

⭐ 27. Prolactin

Makes milk.

⭐ 28. ACTH

Tells adrenal cortex to make cortisol.

⭐ 29. LH

Women → ovulation

Men → testosterone

⭐ 30. FSH

Women → helps eggs grow

Men → helps sperm grow

⭐ 31. Oxytocin

Labor contractions + milk ejection.