Endocrine system

.Glucocorticoids (e.g., Cortisol)

1. Produced By: Adrenal cortex.

2. Functions: Regulate metabolism, immune response, and stress response

Steriod Hormoe

Paravocellular neurosecreting cells

Paravocellular neurosecreting cells = small hypothalamic neurons that release regulating hormones into blood to control the anterior pituitary.

Mineralocorticoids (e.g., Aldosterone)

1. Produced By: Adrenal cortex.

2. Functions: Regulate sodium and potassium balance and blood pressure.

Steriod Hormone

What hormone in a bit the growth hormone

Somatostatin

. what is dopamine inhibits

Prolactin

What is Sheehan syndrome?

Sheehan syndrome is when a woman develops hypopituitarism (low pituitary hormones) because her anterior pituitary gets damaged after severe bleeding during childbirth.

What causes it?

• Postpartum hemorrhage (major blood loss)

• → low blood flow to the pituitary

• → ischemia/infarction of the anterior pituitary

What is used to make T3 and T4 and where is it stored?

Iodine is used to make it and stored in the thyroid gland

What are the types of receptors in ADH?

• Osmoreceptors: “Blood is too salty” → ADH + thirst

• Baroreceptors: “Pressure is too low” → ADH + save water

what is it called a thyroid gland and what happens

This is hypothyroidism and it’s gonna be much harder to lose the fat

What is thyroid peroxide?

This is an enzyme used in the T3/T4 synthesis. It does oxidation which turns I- to iodine two which is its active form. this also couples up MITTDIT to make T3/T4

What is hypothyroidism primary?

When the TSH is high, and T4 is low

What are melanotrophs

A chromophobe that secretes melation secreting hormone

What is hypothyroidism secondary?

When both the TSH and the T4 is low

What is hyperthyroidism?

When the TSH is low and the T4 is high

What happens if there’s an increase in the hormone to the bone kidney and the intestines

overall, this will cause an increase of calcium

In the bone, this will increase osteoblast

And the kidney this will increase absorption so you don’t pee it out

In the intestines, this activates vitamin D and increases absorption in the intestine

The steroid creates what

Sugar, salt and sex

• Aldosterone

• Cortisol

• DHEA

• Testosterone

• Estrogen

So the key idea is:

What is cushioning disease?

• Cushing disease = specifically pituitary ACTH tumor

High acth

Acidophil make up what percent of addendhypopsis

‘ 65%

What is Cushing syndrome?

Too much cortisol in the body (hypercortisolism)

The 3 signs (the “warning”)

1. High blood pressure (hypertension)

2. Slow heart rate (bradycardia)

3. Irregular breathing (abnormal respirations)

Somatotraphs are the first group of acidophils what do they secrete?

Growth hormones

MammotrophsAre the second group of aceta fills? Would they secret ?

Prolactin

Hereditary Elliptocytosis

E = Ellipse / Egg shaped

Hereditary Spherocytosis

Small round-no by concave shape

What is a neurophysin II

Carrier protein to transport antidiuretic to the posterior pituitary gland

A immature antidiuretic hormone is known as and what type of cell bodies is used to make it?

Known as a pro hormone when it’s immature

Supraoptic nucleus

What does vasopressin mean?

This is another name for adh this means blood vessel pressure which can also be known as vasoconstriction

Explain how vasopressin

Hypothalamus -pituitary gland-vasopressin-constriction in the blood vessels and kidney reabsorption

What does the thyroid hormones do?

Increased growth and metabolism: it increases basal metabolic rate and brings up bodily functions(like heart rate body temperature nervous reactivity)

Rage is apart of the neurotransmitter, but also the endocrine system

Rage is apart of the neurotransmitter, but also the endocrine system

Steroid hormones

are lipid-soluble (fat-soluble) hormones made from cholesterol.

They can pass through cell membranes and bind to receptors inside the cell (in the cytoplasm or nucleus) to change gene activity.

Difference between endocrine and nervous

Endocrine

•  chemical signals

•  slower hormones go everywhere

•  adapt slowlys

 Nervous

•  chemical and electrical signals

•  response quickly and stops quickly

•  targets locally

What is the epithalamus?

The epithalamus is a small part of the diencephalon (the same brain region that includes the thalamus and hypothalamus).

Main structures

• Pineal gland (most important one)

• Habenular nuclei (sometimes included)

Main function

⭐ sleep/wake timing control. which releases melatonin.

Pinealocytes

Pinealocytes are the main cells in the pineal gland.
Produce and secrete melatonin, the hormone that helps control your sleep-wake (circadian) rhythm

What is a brain sand(corpora arenacea)?

Crystallized deposits are made of calcium carbonate and calcium phosphate.

• This will increase with age

• This can be found in the pineal gland

What is the pineal body surrounded by and its function

• The pineal gland is covered by pia mater

• The pia mater forms a capsule

• That capsule sends connective tissue partitions inward into the pineal gland

What is a pineal gland consist of in terms of cell types

•  pinealocytes 95% large and Light Round nuclei

•  astrocytes dark elongated nuclei 

What is the most prominent secretory product of the pineal body, and what does it do?

Melatonin; it has anti-gonadotrophic effects that may delay puberty by blocking gonadotropin (LH & FSH) secretion from the anterior pituitary, which reduces ovarian/testicular activity and affects reproductive development.\n

What is the prominent secretory product of the pineal body and what are the bad effects

Melatonin which can "delay" puberty through anti-gonadotrophic effect

• anti-gonadotrophic = reduces or blocks hormones that normally stimulate the ovaries/testes, specifically:

• Think will lock FSH and LH production 

Melatonin effect/graphs?

• Higher in kids

• Lower in those who have autism

• Lower in old people

Serotonin

What it does

• Helps regulate mood

• Neruotransmitetr

• Helps regulate sleep

• Affects appetite

• Helps with digestion

• Can cause vasoconstriction (tightening of blood vessels)

Pineal gland connection

The pineal gland uses serotonin to make melatonin.

It means the pineal gland affects your sleep cycle and seasonal mood changes because of the hormones it releases.

Breakdown:

• Pineal hormones (mainly melatonin) act on the:

  • adenohypophysis = the anterior pituitary gland

  • and also affect sex hormones (LH/FSH → ovaries/testes)

So what does that cause?

Because melatonin changes based on light vs dark, the pineal gland helps control:

✅ Circadian rhythm = your daily sleep-wake cycle
✅ Seasonal phenomena = body changes based on seasons (more darkness in winter)

Example:

• Seasonal Affective Disorder (SAD)
  This is when people feel more depressed in winter because there’s less sunlight → more melatonin changes → affects mood/sleep.

It means the pineal gland affects your sleep cycle and seasonal mood changes because of the hormones it releases.

Breakdown:

• Pineal hormones (mainly melatonin) act on the:

  • adenohypophysis = the anterior pituitary gland

  • and also affect sex hormones (LH/FSH → ovaries/testes)

So what does that cause?

Because melatonin changes based on light vs dark, the pineal gland helps control:

✅ Circadian rhythm = your daily sleep-wake cycle
✅ Seasonal phenomena = body changes based on seasons (more darkness in winter)

Example:

• Seasonal Affective Disorder (SAD)
  This is when people feel more depressed in winter because there’s less sunlight → more melatonin changes → affects mood/sleep.

What is the portal system?

A portal system is just a special set of blood vessels that carries hormones from:

Hypothalamus → Anterior pituitary

It’s like a direct hormone delivery highway.

The hypothalamus releases 7 regulatory hormones (mostly releasing/inhibiting hormones)

And those control the anterior pituitary to release 8 hormones (like TSH, ACTH, GH, etc.)

What is Ghrelin

Ghrelin is a hormone that basically tells your brain:

“I’m hungry — feed me.” ✅ Where it’s made

• Mostly in the stomach (especially when your stomach is empty)

✅ What it does

• Increases appetite

• Makes you feel hungry

• Helps stimulate growth hormone (GH) release too

Easy way to remember

Ghrelin = “Grrr-lin”
Like your stomach growling: “grrrr” 😭

The hypothalamus sends two types of “messages”:

The hypothalamus sends two types of “messages”:

Releasing hormones

➡ tell the anterior pituitary: “RELEASE this hormone”

Inhibiting hormones

➡ tell the anterior pituitary: “STOP releasing this hormone”

These hormones go into blood capillaries at the base of the hypothalamus

hypophyseal portal system.

The hypophyseal portal system is a special set of blood vessels that carries hormones directly from the:

Hypothalamus → Anterior Pituitary

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✅ Why it exists

So the hypothalamus can control the anterior pituitary FAST and without the hormones getting diluted in the rest of the bloodstream.

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✅ What travels in it

The hypothalamus sends:

• releasing hormones

• inhibiting hormones

through this portal system to tell the anterior pituitary what to release.

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⭐ Easy way to remember

Portal system = a direct blood “shortcut” between two organs.

What are Paravocellular Neurosecretory

Parvocellular neurons in the hypothalamus make releasing/inhibiting hormones → put them into blood → blood carries them to the anterior pituitary → anterior pituitary releases hormones that control other glands.

what are basophils

• Anterior pituitary cells

• Stain blue/purple

• Produce the main tropic hormones

• Tropic hormones stimulate other endocrine glands

Acidophils

• Anterior pituitary cells

• Stain pink/red

• Produce GH and PRL

• These hormones are mostly direct-acting (not tropic)

Releasing and Inhibiting hormones

glycoprotein hormones

proteins with sugar attached

(glyco = sugar)

Fat like Tish = FSH, LH, TSH

So they’re grouped based on their structure, not their target.

• These are the actual proteins, not the transportation

Somatomammotropins

Somato- = body growth Mammo- = breast/milk -tropin = hormone

So:

• GH = somato (growth)

• PRL = mammo (milk)

And they’re grouped together because they’re structurally similar hormones.

Corticolipotropins

• Corticolipotropins = a hormone family group (NOT a cell type)

• The hormones in this group are:

  • ACTH

  • MSH (melanocyte-stimulating hormone)

• They are grouped together because they both come from the same precursor protein:

  • POMC (proopiomelanocortin)(parent hormone)

Corticotrophs (or adrenocorticolipotrophs)

secrete adrenocorticotropic hormone (ACTH or corticotropin) and lipotropin (LPH, no known function in humans).

Synthesis products of POMC

ACTH and MSH

Addison’s diseases

• In Addison’s disease:

  • cortisol is low → body makes more ACTH

  • more ACTH = more POMC being used

  • more POMC = more MSH

  • so you get darker skin

• So the chain is:
  Addison’s → ↑ ACTH → ↑ MSH → darker skin

•Glycoprotein hormones subunits

• These hormones are like 2-piece Legos:

  • an alpha piece

  • a beta piece

• The alpha piece is the SAME for all of them.

• The beta piece is DIFFERENT, and that’s what makes it:

  • FSH vs LH vs TSH

• So the beta subunit = the “name tag” that tells your body which hormone it is.

• hCG (pregnancy hormone) is similar because it also has:

  • the same alpha

  • its own beta

Human chorionic gonadotropin (hCG)

• a hormone made during pregnancy (by the placenta).

• It is structurally related to the glycoprotein hormones because it is built the same way:

  • 2 subunits (alpha + beta)

• hCG has the same alpha subunit as:

  • FSH, LH, TSH

• But hCG has a different beta subunit, which makes it its own hormone.

Somatomammotropins: Growth Hormone (GH)

• Secretion pattern of GH (mainly):

  • Released in a pulsatile pattern (not steady)

  • Comes out in bursts about every 2 hours

  • Bursts increase during:

    • exercise

    • sleep

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• Main functions of GH:

  • Increases linear growth (height / bone growth)

  • Increases muscle mass

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• How GH causes growth:

  • GH stimulates the liver and other tissues to produce somatomedins

  • Somatomedins = IGFs (insulin-like growth factors)

  • IGFs are what actually cause a lot of the growth effects

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• Diabetogenic effect (this is important):

  • GH can cause insulin resistance

“diabetogenic” means:

• GH can raise blood sugar

• GH can make you more likely to have diabetes-like effects

• GH increases blood glucose

Chromophobe cells

• Chromophobes are pituitary cells that are pale cells that are inactive OR empty after releasing hormones

• They don’t stain red or purple because they have no visible hormone granules

• Most of the time, chromophobes are just:

  • acidophils or basophils that already released their hormones
    (so they look “washed out”)

• They can also be:

  • resting/dormant cells

  • stem cells

Chromophobe" also refers to a type of renal cell carcinoma (distinct from "clear cell")

30% of patients with Birt-Hogg-Dubé syndrome will also develop chromophobe renal cancer.

Chromophobe" also refers to a type of renal cell carcinoma (distinct from "clear cell")

30% of patients with Birt-Hogg-Dubé syndrome will also develop chromophobe renal cancer.

Types of Chromophobe Cell

Amphophils

• They’re called chromophobe-ish because they don’t stain strongly as red or purple

• But they are still pituitary epithelial cells

• They can still be involved in hormone production

Melanotrophs

• These are cells that make MSH

• They may look pale on regular staining

• But they still secrete hormone

The posterior pituitary consists of 3 parts:

• Pars nervosa (main posterior pituitary part)

• Infundibular stalk (the stalk connecting it)

• Median eminence (part at the base of hypothalamus)

ADH (antidiuretic hormone) = vasopressin

regulate water balance: You get thirstier, which increases the volume which is connected to the kidney, and it makes you pee

Where ADH is made (synthesis site):

• Supraoptic nucleus of the hypothalamus

• (the neuronal cell bodies there synthesize it)

Oxytocin

• Causes uterine smooth muscle contraction (labor)

• Also causes milk letdown (squeezes milk out)

Vasopressin (ADH) effects

• Vasoconstriction

  • tightens blood vessels

  • helps raise blood pressure

• Concentrates urine (MAIN effect)

  • tells kidneys to reabsorb water

  • makes urine more concentrated

• Gluconeogenesis

  • helps the body make new glucose (usually in the liver)

• Platelet aggregation

  • helps platelets clump together for clotting

• Release of Factor VIII + vWF (von Willebrand factor)

  • helps with blood clotting

• Effects on brain

  • ADH also acts in the brain to help with water balance/thirst

• Estrogen increases oxytocin effects

  • Estrogen makes the uterus more sensitive to oxytocin

  • So when oxytocin is released, the uterus contracts stronger

  • Estrogen also helps prepare the breasts for lactation

• “Messages increase oxytocin”

  • This means oxytocin can rise with social bonding (hugging, affection, trust, emotional connection)

  • Oxytocin isn’t only for pregnancy — it’s also a “bonding” hormone

• Prostaglandins (not “prostat gulin”)

  • Prostaglandins can cause cramps, bloating, mood changes, and PMS-like symptoms

  • They stimulate uterine contractions, which is why periods can hurt

• Estrogen increases oxytocin effects

  • Estrogen makes the uterus more sensitive to oxytocin

  • So when oxytocin is released, the uterus contracts stronger

  • Estrogen also helps prepare the breasts for lactation

• “Messages increase oxytocin”

  • This means oxytocin can rise with social bonding (hugging, affection, trust, emotional connection)

  • Oxytocin isn’t only for pregnancy — it’s also a “bonding” hormone

• Prostaglandins (not “prostat gulin”)

  • Prostaglandins can cause cramps, bloating, mood changes, and PMS-like symptoms

  • They stimulate uterine contractions, which is why periods can hurt

• When there is too much growth hormone in kids its called

• in kids (before the growth plates close) is called:

  • Gigantism

• The most common cause is a:

  • pituitary adenoma (a benign tumor in the anterior pituitary)

So

Too much GH in adults

• Too much GH in adults (after growth plates are closed) is called:

  • Acromegaly

• It happens because GH is hypersecreted (released too much), usually from a pituitary adenoma.

• Since adults can’t grow taller anymore, GH causes bones and tissues to enlarge/thicken instead of lengthening.

Cretinism

• This is when a baby has too little thyroid hormone (T3/T4) during development

• Causes: thyroid gland not formed, iodine deficiency, or maternal thyroid issues

• Effects: poor brain development (intellectual disability), stunted growth, big tongue (macroglossia), puffy face, big belly/umbilical hernia

Myxedema (adult hypothyroidism)

• Severe hypothyroidism in adults

• Symptoms: fatigue, weight gain, cold intolerance, slow heart rate, depression, puffy skin (non-pitting edema)

Toxic goiter (hyperthyroidism, often Graves disease)

• Thyroid becomes overactive → high T3 and T4

• Symptoms: weight loss, heat intolerance, anxiety, fast heart rate

• The eye bulging (exophthalmos) happens especially in Graves disease

• The thyroid tissue is usually hyperactive, not just “big follicles”

Thyroid Hormone

• Quick answer: Thyroid hormones (T3 and T4) increase growth and metabolism.

• More detailed: T3/T4

  • stimulate mitochondrial protein synthesis → cells make more energy

  • increase carbohydrate absorption and use → more glucose is used for energy

  • regulate fat metabolism → increase fat breakdown

  • promote cell growth and development (especially brain + bone in kids

Goitrogens

food substances that block iodine use

. The only biological role of iodine is

Formation of

• T4 (thyroxine)

• T3 (triiodothyronine)

Cabbage and tapioca contain

thiocyanate

• blocks iodine uptake into the thyroid

Mustard seeds contain

thiourea

• blocks iodination of thyroglobulin (so thyroid hormones can’t be made well)

• Thyroxine (T4) and Triiodothyronine (T3) are the main thyroid hormones

• They:

  • increase the rate of energy release from carbohydrates (boost metabolism)

  • increase the rate of protein synthesis

  • accelerate growth (especially in kids)

  • stimulate activity in the nervous system (more alert/reactive)

• Their release is controlled by:

  • TSH (from the anterior pituitary)

• Calcitonin is another thyroid hormone (made by C cells / parafollicular cells)

• Calcitonin is another thyroid hormone (made by C cells / parafollicular cells)

• Calcitonin:

  • lowers blood calcium and blood phosphate levels

  • does this by inhibiting release of calcium/phosphate from bones

  • increases deposition of calcium/phosphate into bones (helps build bone